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Question 1
Correct
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A 65-year-old man with a history of claudication for several years is evaluated in the clinic. A duplex scan reveals an 85% stenosis of the superficial femoral artery. After two weeks, he returns with a sudden onset of severe leg pain that has been present for an hour. Upon examination, absent pulses are noted in the affected limb, and it is significantly cooler than the opposite limb. What is the most likely cause of this presentation?
Your Answer: Thrombosis
Explanation:When dealing with an already present lesion, the probability of encountering a complication like thrombosis is higher than that of an embolus. To address this, patients should be administered heparin and undergo imaging with duplex scanning. Although an early surgical bypass or intra-arterial thrombolysis may be necessary, performing an embolectomy is generally not recommended as the lesion is not an embolus, rendering the operation ineffective.
Understanding Claudication
Claudication is a medical condition that causes pain in the limbs during physical activity. It is usually caused by arterial insufficiency, which occurs when atheroma develops in the arterial wall and blocks the blood flow to the tissues. The most common symptom of claudication is calf pain that worsens during exercise and improves with rest. However, if the disease is located in more proximal areas, other symptoms such as buttock claudication and impotence may occur.
The condition usually develops progressively, and in severe cases, it can lead to critical limb ischemia, which is characterized by severe pain, diminished sensation, pallor, and absent pulses. Risk factors for claudication include smoking, diabetes, and hyperlipidemia.
To diagnose claudication, doctors may measure ankle-brachial pressure indices, perform duplex scanning, or conduct formal angiography. Treatment options depend on the severity of the condition. Patients with long claudication distances and no ulceration or gangrene may be managed conservatively, while those with rest pain, ulceration, or gangrene will require intervention. All patients should receive an antiplatelet agent and a statin, unless there are compelling contraindications.
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This question is part of the following fields:
- Cardiovascular System
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Question 2
Incorrect
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A 65-year-old man arrives at the emergency department exhibiting confusion, agitation, anterograde and retrograde amnesia, and confabulation. He also has an ataxic gait. His medical history includes chronic alcohol abuse and malnutrition, and he does not regularly take any medications or vitamin supplements. What vitamin deficiency could be causing his symptoms?
Your Answer: A
Correct Answer: B1
Explanation:The Importance of Vitamin B1 (Thiamine) in the Body
Vitamin B1, also known as thiamine, is a water-soluble vitamin that belongs to the B complex group. It plays a crucial role in the body as one of its phosphate derivatives, thiamine pyrophosphate (TPP), acts as a coenzyme in various enzymatic reactions. These reactions include the catabolism of sugars and amino acids, such as pyruvate dehydrogenase complex, alpha-ketoglutarate dehydrogenase complex, and branched-chain amino acid dehydrogenase complex.
Thiamine deficiency can lead to clinical consequences, particularly in highly aerobic tissues like the brain and heart. The brain can develop Wernicke-Korsakoff syndrome, which presents symptoms such as nystagmus, ophthalmoplegia, and ataxia. Meanwhile, the heart can develop wet beriberi, which causes dilated cardiomyopathy. Other conditions associated with thiamine deficiency include dry beriberi, which leads to peripheral neuropathy, and Korsakoff’s syndrome, which causes amnesia and confabulation.
The primary causes of thiamine deficiency are alcohol excess and malnutrition. Alcoholics are routinely recommended to take thiamine supplements to prevent deficiency. Overall, thiamine is an essential vitamin that plays a vital role in the body’s metabolic processes.
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This question is part of the following fields:
- General Principles
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Question 3
Correct
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An 80-year-old man comes to the clinic complaining of hearing loss in one ear that has persisted for the last 3 months. Upon examination, Webers test indicates that the issue is on the opposite side, and a CT scan of his head reveals a thickened calvarium with areas of sclerosis and radiolucency. His blood work shows an elevated alkaline phosphatase, normal serum calcium, and normal PTH levels. What is the most probable underlying diagnosis?
Your Answer: Pagets disease with skull involvement
Explanation:The most probable diagnosis for an old man experiencing bone pain and raised ALP is Paget’s disease, as it often presents with skull vault expansion and sensorineural hearing loss. While multiple myeloma may also cause bone pain, it typically results in multiple areas of radiolucency and raised calcium levels. Although osteopetrosis can cause similar symptoms, it is a rare inherited disorder that usually presents in children or young adults, making it an unlikely diagnosis for an older patient with no prior symptoms.
Understanding Paget’s Disease of the Bone
Paget’s disease of the bone is a condition characterized by increased and uncontrolled bone turnover. It is believed to be caused by excessive osteoclastic resorption followed by increased osteoblastic activity. Although it is a common condition, affecting around 5% of the UK population, only 1 in 20 patients experience symptoms. The most commonly affected areas are the skull, spine/pelvis, and long bones of the lower extremities.
Several factors can predispose an individual to Paget’s disease, including increasing age, male sex, living in northern latitudes, and having a family history of the condition. Symptoms of Paget’s disease include bone pain, particularly in the pelvis, lumbar spine, and femur. In untreated cases, patients may experience bowing of the tibia or bossing of the skull.
To diagnose Paget’s disease, doctors may perform blood tests to check for elevated levels of alkaline phosphatase (ALP), a marker of bone turnover. Other markers of bone turnover, such as procollagen type I N-terminal propeptide (PINP), serum C-telopeptide (CTx), urinary N-telopeptide (NTx), and urinary hydroxyproline, may also be measured. X-rays and bone scintigraphy can help identify areas of active bone lesions.
Treatment for Paget’s disease is typically reserved for patients experiencing bone pain, skull or long bone deformity, fractures, or periarticular Paget’s. Bisphosphonates, such as oral risedronate or IV zoledronate, are commonly used to manage the condition. Calcitonin may also be used in some cases. Complications of Paget’s disease can include deafness, bone sarcoma, fractures, skull thickening, and high-output cardiac failure.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 4
Incorrect
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A 30-year-old G3 P3 woman presents to her GP with complaints of heaviness and dragging sensation suggestive of prolapse after a forceps delivery last year.
Which ligament has been damaged that runs between the cervix and lateral pelvic wall?Your Answer: Ovarian ligament
Correct Answer: Cardinal ligament
Explanation:The cardinal ligament is responsible for connecting the cervix to the lateral pelvic wall. When this ligament, along with the uterosacral ligament, becomes weak, it can lead to uterine prolapse. It is important not to confuse the ovarian ligament, which connects the ovaries and uterus but does not contain blood vessels, with the suspensory ligament that contains the ovary’s neurovascular supply and connects the ovary, uterus, and pelvic wall. The pubocervical ligament, which connects the cervix to the posterior aspect of the pubic bone, can also weaken and cause vaginal prolapse. Finally, the round ligament connects the uterine fundus and the labia majora.
Pelvic Ligaments and their Connections
Pelvic ligaments are structures that connect various organs within the female reproductive system to the pelvic wall. These ligaments play a crucial role in maintaining the position and stability of these organs. There are several types of pelvic ligaments, each with its own unique function and connection.
The broad ligament connects the uterus, fallopian tubes, and ovaries to the pelvic wall, specifically the ovaries. The round ligament connects the uterine fundus to the labia majora, but does not connect to any other structures. The cardinal ligament connects the cervix to the lateral pelvic wall and is responsible for supporting the uterine vessels. The suspensory ligament of the ovaries connects the ovaries to the lateral pelvic wall and supports the ovarian vessels. The ovarian ligament connects the ovaries to the uterus, but does not connect to any other structures. Finally, the uterosacral ligament connects the cervix and posterior vaginal dome to the sacrum, but does not connect to any other structures.
Overall, pelvic ligaments are essential for maintaining the proper position and function of the female reproductive organs. Understanding the connections between these ligaments and the structures they support is crucial for diagnosing and treating any issues that may arise.
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This question is part of the following fields:
- Reproductive System
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Question 5
Correct
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You are developing a research project investigating the pathophysiology of abetalipoproteinemia. You determine that a viable focus would be the rate-limiting enzyme involved in lipogenesis.
Which enzyme will be the target of your investigation?Your Answer: Acetyl CoA carboxylase
Explanation:The enzyme that limits the rate of lipogenesis is acetyl CoA carboxylase.
During lipogenesis, fatty acids are produced from acetyl-CoA. Acetyl CoA carboxylase is the enzyme that controls the rate of this process.
Carbamoyl phosphate synthetase I is the enzyme that limits the rate of the urea cycle.
Glycogen phosphorylase is the enzyme that controls the rate of glycogenolysis.
Isocitrate dehydrogenase is the enzyme that limits the rate of the citric acid cycle.
Rate-Determining Enzymes in Metabolic Processes
Metabolic processes involve a series of chemical reactions that occur in living organisms to maintain life. Enzymes play a crucial role in these processes by catalyzing the reactions. However, not all enzymes have the same impact on the rate of the reaction. Some enzymes are rate-determining, meaning that they control the overall rate of the process. The table above lists the rate-determining enzymes involved in common metabolic processes.
For example, in the TCA cycle, isocitrate dehydrogenase is the rate-determining enzyme. In glycolysis, phosphofructokinase-1 controls the rate of the process. In gluconeogenesis, fructose-1,6-bisphosphatase is the rate-determining enzyme. Similarly, glycogen synthase controls the rate of glycogenesis, while glycogen phosphorylase controls the rate of glycogenolysis.
Other metabolic processes, such as lipogenesis, lipolysis, cholesterol synthesis, and ketogenesis, also have rate-determining enzymes. Acetyl-CoA carboxylase controls the rate of lipogenesis, while carnitine-palmitoyl transferase I controls the rate of lipolysis. HMG-CoA reductase is the rate-determining enzyme in cholesterol synthesis, while HMG-CoA synthase controls the rate of ketogenesis.
The urea cycle, de novo pyrimidine synthesis, and de novo purine synthesis also have rate-determining enzymes. Carbamoyl phosphate synthetase I controls the rate of the urea cycle, while carbamoyl phosphate synthetase II controls the rate of de novo pyrimidine synthesis. Glutamine-PRPP amidotransferase is the rate-determining enzyme in de novo purine synthesis.
Understanding the rate-determining enzymes in metabolic processes is crucial for developing treatments for metabolic disorders and diseases. By targeting these enzymes, researchers can potentially regulate the rate of the process and improve the health outcomes of individuals with these conditions.
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This question is part of the following fields:
- General Principles
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Question 6
Correct
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A researcher is studying Chronic Myeloid Leukaemia (CML). She creates a fluorescent DNA probe that can attach to the BCR-ABL fusion gene to observe the Philadelphia translocation directly.
What is the molecular method employed by the scientist?Your Answer: Fluorescence In Situ Hybridisation (FISH)
Explanation:The technique of fluorescence in situ hybridization involves the use of fluorescent DNA or RNA probes that attach to particular gene locations of interest, allowing for the direct observation of chromosomal abnormalities.
Overview of Molecular Biology Techniques
Molecular biology techniques are essential tools used in the study of biological molecules such as DNA, RNA, and proteins. These techniques are used to detect and analyze these molecules in various biological samples. The most commonly used techniques include Southern blotting, Northern blotting, Western blotting, and enzyme-linked immunosorbent assay (ELISA).
Southern blotting is a technique used to detect DNA, while Northern blotting is used to detect RNA. Western blotting, on the other hand, is used to detect proteins. This technique involves the use of gel electrophoresis to separate native proteins based on their 3-D structure. It is commonly used in the confirmatory HIV test.
ELISA is a biochemical assay used to detect antigens and antibodies. This technique involves attaching a colour-changing enzyme to the antibody or antigen being detected. If the antigen or antibody is present in the sample, the sample changes colour, indicating a positive result. ELISA is commonly used in the initial HIV test.
In summary, molecular biology techniques are essential tools used in the study of biological molecules. These techniques include Southern blotting, Northern blotting, Western blotting, and ELISA. Each technique is used to detect specific molecules in biological samples and is commonly used in various diagnostic tests.
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This question is part of the following fields:
- General Principles
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Question 7
Correct
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An 80-year-old woman complains of altered bowel movements and a sigmoidoscopy reveals an abnormal, ulcerated mass in the sigmoid colon. She undergoes anterior resection. Upon pathological examination, it is found that the tumor has invaded the muscularis propria but not the underlying tissues. Out of 36 lymph nodes, two are positive. What is the Dukes stage of this tumor?
Your Answer: C
Explanation:Staging Colorectal Cancer: Dukes System
Colorectal cancer can be staged using either the TNM classification system or the simpler Dukes system. Both methods are used to determine the appropriate treatment and prognosis for the patient. The Dukes system categorizes the cancer into four stages based on the extent of its spread.
Stage A refers to cancer that is confined to the mucosa or submucosa only, with a 93% 5-year survival rate. Stage B indicates that the cancer has invaded into the muscularis propria but has not spread beyond it, with a 77% 5-year survival rate. Stage C is characterized by the presence of local lymph node metastases, regardless of the depth of invasion, and has a 48% 5-year survival rate. Finally, Stage D indicates the presence of distant metastases, with a 6% 5-year survival rate. However, if the metastases are isolated to the liver, a 25-40% 5-year survival rate is possible.
In summary, the Dukes system provides a simple and effective way to stage colorectal cancer based on the extent of its spread. This information is crucial in determining the appropriate treatment and predicting the patient’s prognosis.
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This question is part of the following fields:
- Clinical Sciences
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Question 8
Correct
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A 82-year-old female experiences a fall and is brought to the emergency department. X-rays reveal a displaced fracture above the greater and lesser trochanter of the proximal femur on the right side. What would be the best surgical approach for this patient?
Your Answer: Hemiarthroplasty
Explanation:When a hip fracture occurs within the joint capsule, there is a higher chance of the femoral head experiencing avascular necrosis. This type of fracture is considered displaced and requires treatment with hemiarthroplasty or total hip replacement, especially for older patients. However, younger patients may opt for hip fixation instead of replacement as prosthetic joints have a limited lifespan.
Hip fractures are a common occurrence, particularly in elderly women with osteoporosis. The femoral head’s blood supply runs up the neck, making avascular necrosis a risk in displaced fractures. Symptoms include pain and a shortened and externally rotated leg. Patients with non-displaced or incomplete neck of femur fractures may still be able to bear weight. Hip fractures are classified based on their location, either intracapsular or extracapsular. The Garden system is a commonly used classification system that categorizes fractures into four types based on stability and displacement. Blood supply disruption is most common in Types III and IV.
Undisplaced intracapsular fractures can be treated with internal fixation or hemiarthroplasty if the patient is unfit. Displaced fractures require replacement arthroplasty, with total hip replacement being preferred over hemiarthroplasty if the patient was able to walk independently outdoors with no more than a stick, is not cognitively impaired, and is medically fit for anesthesia and the procedure. Extracapsular fractures are managed with a dynamic hip screw for stable intertrochanteric fractures and an intramedullary device for reverse oblique, transverse, or subtrochanteric fractures.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 9
Incorrect
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A 43-year-old man is seeking information about the COVID-19 vaccine. He has heard that the vaccine may not provide complete protection and wants to know how effective it is. As his healthcare provider, you provide him with the following data for this specific vaccine:
Vaccinated Not vaccinated Total
COVID-19 occurred 10 90 100
COVID-19 did not occur 90 10 100
Column totals 100 100 200
What is the most appropriate response to this patient's inquiry?Your Answer: 90/100 - 10/100 = 80%
Correct Answer: (10/100 - 90/100) / 90/100 = -90%
Explanation:Understanding Relative Risk in Clinical Trials
Relative risk (RR) is a measure used in clinical trials to compare the risk of an event occurring in the experimental group to the risk in the control group. It is calculated by dividing the experimental event rate (EER) by the control event rate (CER). If the resulting ratio is greater than 1, it means that the event is more likely to occur in the experimental group than in the control group. Conversely, if the ratio is less than 1, the event is less likely to occur in the experimental group.
To calculate the relative risk reduction (RRR) or relative risk increase (RRI), the absolute risk change is divided by the control event rate. This provides a percentage that indicates the magnitude of the difference between the two groups. Understanding relative risk is important in evaluating the effectiveness of interventions and treatments in clinical trials. By comparing the risk of an event in the experimental group to the control group, researchers can determine whether the intervention is beneficial or not.
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This question is part of the following fields:
- General Principles
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Question 10
Incorrect
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A patient in their 60s is diagnosed with first-degree heart block which is shown on their ECG by an elongated PR interval. The PR interval relates to a particular period in the electrical conductance of the heart.
What factors could lead to a decrease in the PR interval?Your Answer: Decreased conduction velocity of the SA node
Correct Answer: Increased conduction velocity across the AV node
Explanation:An increase in sympathetic activation leads to a faster heart rate by enhancing the conduction velocity of the AV node. The PR interval represents the time between the onset of atrial depolarization (P wave) and the onset of ventricular depolarization (beginning of QRS complex). While atrial conduction occurs at a speed of 1m/s, the AV node only conducts at 0.05m/s. Consequently, the AV node is the limiting factor, and a reduction in the PR interval is determined by the conduction velocity across the AV node.
Understanding the Cardiac Action Potential and Conduction Velocity
The cardiac action potential is a series of electrical events that occur in the heart during each heartbeat. It is responsible for the contraction of the heart muscle and the pumping of blood throughout the body. The action potential is divided into five phases, each with a specific mechanism. The first phase is rapid depolarization, which is caused by the influx of sodium ions. The second phase is early repolarization, which is caused by the efflux of potassium ions. The third phase is the plateau phase, which is caused by the slow influx of calcium ions. The fourth phase is final repolarization, which is caused by the efflux of potassium ions. The final phase is the restoration of ionic concentrations, which is achieved by the Na+/K+ ATPase pump.
Conduction velocity is the speed at which the electrical signal travels through the heart. The speed varies depending on the location of the signal. Atrial conduction spreads along ordinary atrial myocardial fibers at a speed of 1 m/sec. AV node conduction is much slower, at 0.05 m/sec. Ventricular conduction is the fastest in the heart, achieved by the large diameter of the Purkinje fibers, which can achieve velocities of 2-4 m/sec. This allows for a rapid and coordinated contraction of the ventricles, which is essential for the proper functioning of the heart. Understanding the cardiac action potential and conduction velocity is crucial for diagnosing and treating heart conditions.
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This question is part of the following fields:
- Cardiovascular System
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Question 11
Incorrect
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What is the incorrect pairing in the following options?
Your Answer: Oesophageal passage through diaphragm and T10
Correct Answer: Termination of dural sac and L4
Explanation:Sorry, your input is not clear. Please provide more information or context for me to understand what you want me to do.
Anatomical Planes and Levels in the Human Body
The human body can be divided into different planes and levels to aid in anatomical study and medical procedures. One such plane is the transpyloric plane, which runs horizontally through the body of L1 and intersects with various organs such as the pylorus of the stomach, left kidney hilum, and duodenojejunal flexure. Another way to identify planes is by using common level landmarks, such as the inferior mesenteric artery at L3 or the formation of the IVC at L5.
In addition to planes and levels, there are also diaphragm apertures located at specific levels in the body. These include the vena cava at T8, the esophagus at T10, and the aortic hiatus at T12. By understanding these planes, levels, and apertures, medical professionals can better navigate the human body during procedures and accurately diagnose and treat various conditions.
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This question is part of the following fields:
- Neurological System
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Question 12
Correct
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A 30-year-old male presents with a recurrent history of chest infections. During the examination, it is observed that there is an absence of palpable vas deferens, but both testes are present in the scrotum. What is the probable underlying disease association?
Your Answer: Cystic fibrosis
Explanation:Understanding Absence of the Vas Deferens
Absence of the vas deferens is a condition that can occur either unilaterally or bilaterally. In 40% of cases, the cause is due to mutations in the CFTR gene, which is associated with cystic fibrosis. However, in some non-CF cases, the absence of the vas deferens is due to unilateral renal agenesis. Despite this condition, assisted conception may still be possible through sperm harvesting.
It is important to understand the underlying causes of absence of the vas deferens, as it can impact fertility and the ability to conceive. While the condition may be associated with cystic fibrosis, it can also occur independently. However, with advancements in assisted reproductive technologies, individuals with this condition may still have options for starting a family. By seeking medical advice and exploring available options, individuals can make informed decisions about their reproductive health.
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This question is part of the following fields:
- Reproductive System
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Question 13
Correct
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A 35-year-old female comes to your clinic complaining of a headache that she characterizes as a 'tight-band' around her head. The pain is present on both sides of her head. She reports no accompanying nausea or vomiting. There are no auras or any radiation of the pain down her neck or onto her eyes.
What is the initial treatment of choice for this condition based on the probable diagnosis?Your Answer: Aspirin
Explanation:First-line treatment for tension headaches includes aspirin, paracetamol, or an NSAID. Sumatriptan is typically prescribed for migraines, while high-flow oxygen is used to treat cluster headaches. Prophylaxis for tension headaches may involve low-dose amitriptyline.
Tension-type headache is a type of primary headache that is characterized by a sensation of pressure or a tight band around the head. Unlike migraine, tension-type headache is typically bilateral and of lower intensity. It is not associated with aura, nausea/vomiting, or physical activity. Stress may be a contributing factor, and it can coexist with migraine. Chronic tension-type headache is defined as occurring on 15 or more days per month.
The National Institute for Health and Care Excellence (NICE) has produced guidelines for managing tension-type headache. For acute treatment, aspirin, paracetamol, or an NSAID are recommended as first-line options. For prophylaxis, NICE suggests up to 10 sessions of acupuncture over 5-8 weeks. Low-dose amitriptyline is commonly used in the UK for prophylaxis, but the 2012 NICE guidelines do not support this approach. The guidelines state that there is not enough evidence to recommend pharmacological prophylactic treatment for tension-type headache, and that pure tension-type headache requiring prophylaxis is rare. Assessment may uncover coexisting migraine symptomatology with a possible diagnosis of chronic migraine.
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This question is part of the following fields:
- Neurological System
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Question 14
Correct
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A young woman visits her doctor and shares the news that she is expecting her first child. She expresses her excitement and wonders if the baby starts breathing while still in the womb. The doctor explains that breathing movements do occur intermittently even in the early weeks of pregnancy.
At what point during the pregnancy are these movements believed to start?Your Answer: Week 10
Explanation:The development of the lungs begins at week 4 of embryonic development with the formation of the respiratory diverticulum. By week 5, the diverticulum divides into left and right buds, with the stem forming the trachea and larynx. As the weeks progress, the branching yields secondary and tertiary bronchial buds, which will form the future bronchopulmonary segments. By week 10, intermittent breathing movements can be observed, although the lungs are not yet developed enough to support life outside of the uterus.
Embryology is the study of the development of an organism from the moment of fertilization to birth. During the first week of embryonic development, the fertilized egg implants itself into the uterine wall. By the second week, the bilaminar disk is formed, consisting of two layers of cells. The primitive streak appears in the third week, marking the beginning of gastrulation and the formation of the notochord.
As the embryo enters its fourth week, limb buds begin to form, and the neural tube closes. The heart also begins to beat during this time. By week 10, the genitals are differentiated, and the embryo exhibits intermittent breathing movements. These early events in embryonic development are crucial for the formation of the body’s major organs and structures. Understanding the timeline of these events can provide insight into the complex process of human development.
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This question is part of the following fields:
- General Principles
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Question 15
Correct
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An 80-year-old woman comes to the emergency department with a painless visual disturbance that started 2 hours ago. She has a medical history of hypertension and dyslipidemia.
During the examination, there is no facial asymmetry, and the patient appears comfortable. The visual field test shows homonymous hemianopia on the right side, and automated perimetry indicates macular sparing. The patient is unable to name familiar objects, such as a pen or a spoon.
Which artery is most likely to have been occluded?Your Answer: Posterior cerebral artery
Explanation:The correct answer is the posterior cerebral artery. When a lesion occurs in the posterior cerebral artery, it can result in contralateral homonymous hemianopia with macular sparing and visual agnosia. This is because the visual cortex is supplied by the posterior cerebral artery, which is responsible for the patient’s symptoms. The macula is usually spared because the posterior pole of the occipital cortex, which processes visual signals from the macula, receives collateral flow from the middle cerebral artery.
On the other hand, lesions in the anterior cerebral artery, which supplies the frontal cortex, can cause contralateral hemiparesis, altered sensorium, and aphasia. Meanwhile, occlusion of the anterior inferior cerebellar artery, which supplies the lateral pons, can lead to sudden onset vertigo, vomiting, ataxia, nystagmus, and dysarthria.
Lastly, the central retinal artery is not the correct answer as occlusion of this artery typically results in amaurosis fugax, which is a painless transient ‘descending curtain’ visual field defect, rather than homonymous hemianopia.
Stroke can affect different parts of the brain depending on which artery is affected. If the anterior cerebral artery is affected, the person may experience weakness and loss of sensation on the opposite side of the body, with the lower extremities being more affected than the upper. If the middle cerebral artery is affected, the person may experience weakness and loss of sensation on the opposite side of the body, with the upper extremities being more affected than the lower. They may also experience vision loss and difficulty with language. If the posterior cerebral artery is affected, the person may experience vision loss and difficulty recognizing objects.
Lacunar strokes are a type of stroke that are strongly associated with hypertension. They typically present with isolated weakness or loss of sensation on one side of the body, or weakness with difficulty coordinating movements. They often occur in the basal ganglia, thalamus, or internal capsule.
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This question is part of the following fields:
- Neurological System
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Question 16
Incorrect
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A 60-year-old man complains of low back pain that has been bothering him for the past three months. He also experiences shortness of breath with minimal exertion. Upon examination, his ESR is found to be elevated at 100 mm/hr. What is the most probable diagnosis for this patient?
Your Answer: Infectious mononucleosis
Correct Answer: Multiple myeloma
Explanation:ESR and its association with diseases
Erythrocyte sedimentation rate (ESR) is a laboratory test that measures the rate at which red blood cells settle in a tube over a period of time. Elevated ESR levels are often associated with inflammatory diseases such as rheumatoid arthritis, systemic lupus erythematosus, and polymyalgia rheumatica. In these conditions, the body’s immune system is activated, leading to inflammation and tissue damage. Malignancies such as myeloma can also cause an increase in ESR levels, particularly in females and with increasing age.
On the other hand, low ESR levels are seen in conditions such as polycythaemia, where there is an excess of red blood cells in the body. It is important to note that ESR is not a specific diagnostic test and must be interpreted in conjunction with other clinical findings. Multiple myeloma, a type of plasma cell neoplasm, is the most common haematological malignancy and can lead to a range of symptoms such as hypercalcaemia, renal failure, anaemia, and bone pain. While it is not curable, advances in treatment have significantly improved the median survival of patients. the association between ESR and various diseases can aid in the diagnosis and management of these conditions.
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This question is part of the following fields:
- Haematology And Oncology
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Question 17
Correct
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A 22-year-old man arrives at the emergency department with a stab wound on the left side of his neck above the clavicle. Upon examination, there is no indication of damage to the pleura or any major blood vessels. However, a winged scapula is observed on the left side of his back, with the scapula protruding from the chest wall and the inferior angle pointing towards the midline. What nerve is responsible for this condition?
Your Answer: Long thoracic nerve
Explanation:The nerve responsible for a winged scapula is the long thoracic nerve, which originates from C5-7 and travels along the thorax to reach the serratus anterior muscle. Damage to this nerve can cause the scapula to lift off the thoracic wall and limit shoulder movement. Other nerves that can cause a winged scapula include the accessory nerve and dorsal scapular nerve. The transverse cervical nerve supplies the neck, the phrenic nerve supplies the diaphragm, the greater auricular nerve supplies the mandible and ear, and the suprascapular nerve supplies the shoulder muscles and joints.
The Long Thoracic Nerve and its Role in Scapular Winging
The long thoracic nerve is derived from the ventral rami of C5, C6, and C7, which are located close to their emergence from intervertebral foramina. It runs downward and passes either anterior or posterior to the middle scalene muscle before reaching the upper tip of the serratus anterior muscle. From there, it descends on the outer surface of this muscle, giving branches into it.
One of the most common symptoms of long thoracic nerve injury is scapular winging, which occurs when the serratus anterior muscle is weakened or paralyzed. This can happen due to a variety of reasons, including trauma, surgery, or nerve damage. In addition to long thoracic nerve injury, scapular winging can also be caused by spinal accessory nerve injury (which denervates the trapezius) or a dorsal scapular nerve injury.
Overall, the long thoracic nerve plays an important role in the function of the serratus anterior muscle and the stability of the scapula. Understanding its anatomy and function can help healthcare professionals diagnose and treat conditions that affect the nerve and its associated muscles.
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This question is part of the following fields:
- Neurological System
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Question 18
Correct
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A 26 year old female presents to the emergency department with hand tingling following a fall. Upon examination, she is diagnosed with a fracture of the medial epicondyle. What nerve lesion is the most probable cause?
Your Answer: Ulnar nerve
Explanation:The lateral epicondyle is in close proximity to the radial nerve.
The ulnar nerve originates from the medial cord of the brachial plexus, specifically from the C8 and T1 nerve roots. It provides motor innervation to various muscles in the hand, including the medial two lumbricals, adductor pollicis, interossei, hypothenar muscles (abductor digiti minimi, flexor digiti minimi), and flexor carpi ulnaris. Sensory innervation is also provided to the medial 1 1/2 fingers on both the palmar and dorsal aspects. The nerve travels through the posteromedial aspect of the upper arm and enters the palm of the hand via Guyon’s canal, which is located superficial to the flexor retinaculum and lateral to the pisiform bone.
The ulnar nerve has several branches that supply different muscles and areas of the hand. The muscular branch provides innervation to the flexor carpi ulnaris and the medial half of the flexor digitorum profundus. The palmar cutaneous branch arises near the middle of the forearm and supplies the skin on the medial part of the palm, while the dorsal cutaneous branch supplies the dorsal surface of the medial part of the hand. The superficial branch provides cutaneous fibers to the anterior surfaces of the medial one and one-half digits, and the deep branch supplies the hypothenar muscles, all the interosseous muscles, the third and fourth lumbricals, the adductor pollicis, and the medial head of the flexor pollicis brevis.
Damage to the ulnar nerve at the wrist can result in a claw hand deformity, where there is hyperextension of the metacarpophalangeal joints and flexion at the distal and proximal interphalangeal joints of the 4th and 5th digits. There may also be wasting and paralysis of intrinsic hand muscles (except for the lateral two lumbricals), hypothenar muscles, and sensory loss to the medial 1 1/2 fingers on both the palmar and dorsal aspects. Damage to the nerve at the elbow can result in similar symptoms, but with the addition of radial deviation of the wrist. It is important to diagnose and treat ulnar nerve damage promptly to prevent long-term complications.
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This question is part of the following fields:
- Neurological System
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Question 19
Incorrect
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A 28-year-old man presents to your clinic with painful swellings in his groin. He reports that he first noticed the swellings 3 days ago and has been experiencing pain, tenesmus, and blood on defecation for the past week. He denies any other symptoms.
You inquire about his sexual history. He reports having had unprotected sex with a new partner 2 weeks ago.
What is the probable cause of his symptoms, considering his clinical presentation and sexual history?Your Answer: Treponema pallidum
Correct Answer: Chlamydia trachomatis
Explanation:Lymphogranuloma venereum (LGV) is caused by Chlamydia trachomatis serovars L1, L2, and L3 and can present with proctitis and swollen lymph nodes in the groin. This sexually transmitted infection can affect various parts of the body, including the rectum, mouth/throat, and genitals, and is typically contracted through unprotected sexual activity.
Hepatitis B can also be transmitted through sexual contact, but its symptoms are often non-specific, such as anorexia, fever, arthralgia, vomiting, and dark urine.
Syphilis, caused by Treponema pallidum, typically presents with a painless ulcer, fatigue, headaches, joint pain, and lymphadenopathy in men, but it is unlikely to cause proctitis.
HIV, a virus that can lead to AIDS if left untreated, is a risk factor for LGV but usually presents with flu-like symptoms and remains asymptomatic for many years.
Understanding Lymphogranuloma Venereum
Lymphogranuloma venereum (LGV) is a sexually transmitted infection caused by Chlamydia trachomatis serovars L1, L2, and L3. This infection is commonly found in men who have sex with men and those who have HIV. While historically it was more prevalent in tropical regions, it is now seen in developed countries as well.
The infection typically progresses through three stages. The first stage involves a small, painless pustule that later forms an ulcer. In the second stage, painful inguinal lymphadenopathy occurs, which may occasionally form fistulating buboes. The third stage involves proctocolitis.
LGV is treated using doxycycline.
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This question is part of the following fields:
- General Principles
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Question 20
Correct
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A man in his early fifties comes to the clinic complaining of vomiting undigested food for the past few weeks. He reports no abdominal pain, changes in bowel habits, fever, or vertigo. He has type 2 diabetes that is not well controlled. What could be the probable reason for his vomiting?
Your Answer: Gastric paresis
Explanation:The correct answer is gastric paresis, which is a type of autonomic neuropathy commonly linked to type 2 diabetes. Its symptoms include vomiting undigested food due to the stomach’s inability to digest it properly.
Gastroenteritis, on the other hand, is characterized by vomiting and diarrhea, along with fever and diffuse abdominal pain. It is caused by an infection.
Peptic ulcers typically cause upper abdominal pain and can lead to haematemesis, which is not present in this patient’s case.
Vestibular neuritis may also cause vomiting, but it is usually accompanied by severe vertigo and nystagmus.
Autonomic Neuropathy: Causes and Features
Autonomic neuropathy is a condition that affects the autonomic nervous system, which controls involuntary bodily functions such as heart rate, blood pressure, and sweating. The features of autonomic neuropathy include impotence, inability to sweat, and postural hypotension, which is a sudden drop in blood pressure upon standing up. Other symptoms include a loss of decrease in heart rate following deep breathing and dilated pupils following adrenaline instillation.
There are several causes of autonomic neuropathy, including diabetes, Guillain-Barre syndrome, multisystem atrophy (MSA), Shy-Drager syndrome, Parkinson’s disease, and infections such as HIV, Chagas’ disease, and neurosyphilis. Certain medications, such as antihypertensives and tricyclics, can also cause autonomic neuropathy. In rare cases, a craniopharyngioma, a type of brain tumor, can lead to autonomic neuropathy.
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This question is part of the following fields:
- Neurological System
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Question 21
Incorrect
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A young adult presents to the emergency department on a Sunday morning after a night out with friends. Upon waking up, they realize they had fallen asleep with their arm draped over the back of a park bench and are now diagnosed with a radial nerve injury. Which muscle is expected to exhibit weakness during examination as a result of this injury?
Your Answer: Dorsal interossei
Correct Answer: Extensor carpi ulnaris
Explanation:The radial nerve supplies all extensor muscles in the upper limb, including the extensor carpi ulnaris. The only exception is the brachioradialis muscle, which is not an extensor. The median nerve is responsible for wrist and finger flexion, as well as thumb opposition, while the ulnar nerve innervates the interossei muscles.
Upper limb anatomy is a common topic in examinations, and it is important to know certain facts about the nerves and muscles involved. The musculocutaneous nerve is responsible for elbow flexion and supination, and typically only injured as part of a brachial plexus injury. The axillary nerve controls shoulder abduction and can be damaged in cases of humeral neck fracture or dislocation, resulting in a flattened deltoid. The radial nerve is responsible for extension in the forearm, wrist, fingers, and thumb, and can be damaged in cases of humeral midshaft fracture, resulting in wrist drop. The median nerve controls the LOAF muscles and can be damaged in cases of carpal tunnel syndrome or elbow injury. The ulnar nerve controls wrist flexion and can be damaged in cases of medial epicondyle fracture, resulting in a claw hand. The long thoracic nerve controls the serratus anterior and can be damaged during sports or as a complication of mastectomy, resulting in a winged scapula. The brachial plexus can also be damaged, resulting in Erb-Duchenne palsy or Klumpke injury, which can cause the arm to hang by the side and be internally rotated or associated with Horner’s syndrome, respectively.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 22
Correct
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A 67-year-old female smoker with a two-month history of worsening shortness of breath presents for evaluation. On examination, she appears comfortable at rest with a regular pulse of 72 bpm, respiratory rate of 16/min, and blood pressure of 128/82 mmHg. Physical findings include reduced expansion on the left lower zone, dullness to percussion over this area, and absent breath sounds over the left lower zone with bronchial breath sounds just above this region. What is the likely clinical diagnosis?
Your Answer: Pleural effusion
Explanation:Pleural Effusion and its Investigation
Pleural effusion is a condition where there is an abnormal accumulation of fluid in the pleural space, which is the space between the lungs and the chest wall. This can be caused by various factors such as post-infection, carcinoma, or emboli. To determine the cause of the pleural effusion, a pleural tap is the most appropriate investigation. The sample obtained from the pleural tap is sent for cytology, protein concentration, and culture.
A normal pleural tap would have clear appearance, pH of 7.60-7.64, protein concentration of less than 2%, white blood cells count of less than 1000/mm³, glucose level similar to that of plasma, LDH level of less than 50% of plasma concentration, amylase level of 30-110 U/L, triglycerides level of less than 2 mmol/l, and cholesterol level of 3.5-6.5 mmol/l.
A transudative tap is associated with conditions such as congestive heart failure, liver cirrhosis, severe hypoalbuminemia, and nephrotic syndrome. On the other hand, an exudative tap is associated with malignancy, infection (such as empyema due to bacterial pneumonia), trauma, pulmonary infarction, and pulmonary embolism.
In summary, pleural effusion can be caused by various factors and a pleural tap is the most appropriate investigation to determine the cause. The results of the pleural tap can help differentiate between transudative and exudative effusions, which can provide important information for diagnosis and treatment.
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This question is part of the following fields:
- Respiratory System
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Question 23
Incorrect
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A 23-year-old male presents to the emergency department with decreased level of consciousness after a night of excessive alcohol intake. He is observed to have increased urine output. There is no history of substance abuse according to his companions.
What is the probable cause of the patient's polyuria?Your Answer: Cranial diabetes insipidus
Correct Answer: antidiuretic hormone inhibition
Explanation:Alcohol bingeing can result in the suppression of ADH in the posterior pituitary gland, leading to polyuria. This occurs because alcohol inhibits ADH, which reduces the insertion of aquaporins in the collecting tubules of the nephron. As a result, water reabsorption is reduced, leading to polyuria. The other options provided are incorrect because they do not accurately describe the mechanism by which alcohol causes polyuria. Central diabetes insipidus is a disorder of ADH production in the brain, while nephrogenic diabetes insipidus is caused by kidney pathology. Osmotic diuresis occurs when solutes such as glucose and urea increase the osmotic pressure in the renal tubules, leading to water retention, but this is not the primary mechanism by which alcohol causes polyuria.
Polyuria, or excessive urination, can be caused by a variety of factors. A recent review in the BMJ categorizes these causes by their frequency of occurrence. The most common causes of polyuria include the use of diuretics, caffeine, and alcohol, as well as diabetes mellitus, lithium, and heart failure. Less common causes include hypercalcaemia and hyperthyroidism, while rare causes include chronic renal failure, primary polydipsia, and hypokalaemia. The least common cause of polyuria is diabetes insipidus, which occurs in less than 1 in 10,000 cases. It is important to note that while these frequencies may not align with exam questions, understanding the potential causes of polyuria can aid in diagnosis and treatment.
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This question is part of the following fields:
- Renal System
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Question 24
Incorrect
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A 36-year-old woman presents to her GP with a history of long-standing fatigue, dyspnea, and chest discomfort that has recently worsened. Despite being physically active, she has been experiencing these symptoms. She is a social drinker and does not smoke. Her family history is unremarkable except for her mother who died of 'chest disease' at the age of 50. During examination, her observations are as follows:
Blood pressure: 135/85mmHg
Pulse: 95 beats/min
Respiration: 25 breaths/min
An ECG shows no abnormalities, and cardiac enzymes are within normal ranges. She is referred for echocardiography, which reveals a right pulmonary artery pressure of 35 mmhg.
What substance is elevated in this patient, underlying the disease process?Your Answer: Prostacyclin
Correct Answer: Endothelin
Explanation:Understanding Endothelin and Its Role in Various Diseases
Endothelin is a potent vasoconstrictor and bronchoconstrictor that is secreted by the vascular endothelium. Initially, it is produced as a prohormone and later converted to ET-1 by the action of endothelin converting enzyme. Endothelin interacts with a G-protein linked to phospholipase C, leading to calcium release. This interaction is thought to be important in the pathogenesis of many diseases, including primary pulmonary hypertension, cardiac failure, hepatorenal syndrome, and Raynaud’s.
Endothelin is known to promote the release of angiotensin II, ADH, hypoxia, and mechanical shearing forces. On the other hand, it inhibits the release of nitric oxide and prostacyclin. Raised levels of endothelin are observed in primary pulmonary hypertension, myocardial infarction, heart failure, acute kidney injury, and asthma.
In recent years, endothelin antagonists have been used to treat primary pulmonary hypertension. Understanding the role of endothelin in various diseases can help in the development of new treatments and therapies.
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This question is part of the following fields:
- Cardiovascular System
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Question 25
Incorrect
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A 20-year-old college student comes to you with complaints of fever, lethargy, and painful swollen submandibular lymph nodes. After diagnosis, you find out that he has infectious mononucleosis. What advice would you give him?
Your Answer: He can resume sexual activity after 7 days
Correct Answer: He should avoid rugby
Explanation:Patients should refrain from engaging in contact sports for a period of 4 weeks due to the risk of splenic rupture. However, swimming is considered a safe activity. It is important to advise patients accordingly.
Understanding Infectious Mononucleosis
Infectious mononucleosis, also known as glandular fever, is a viral infection caused by the Epstein-Barr virus (EBV) in 90% of cases. It is most commonly seen in adolescents and young adults. The classic symptoms of sore throat, pyrexia, and lymphadenopathy are present in around 98% of patients. Other symptoms include malaise, anorexia, headache, palatal petechiae, splenomegaly, hepatitis, lymphocytosis, haemolytic anaemia, and a rash. The symptoms typically resolve after 2-4 weeks.
The diagnosis of infectious mononucleosis is confirmed through a heterophile antibody test (Monospot test) in the second week of the illness. Management is supportive and includes rest, drinking plenty of fluids, avoiding alcohol, and taking simple analgesia for any aches or pains. It is recommended to avoid playing contact sports for 4 weeks after having glandular fever to reduce the risk of splenic rupture.
Interestingly, there is a correlation between EBV and socioeconomic groups. Lower socioeconomic groups have high rates of EBV seropositivity, having frequently acquired EBV in early childhood when the primary infection is often subclinical. However, higher socioeconomic groups show a higher incidence of infectious mononucleosis, as acquiring EBV in adolescence or early adulthood results in symptomatic disease.
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This question is part of the following fields:
- General Principles
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Question 26
Incorrect
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Which one of the following structures does not pass behind the piriformis muscle in the greater sciatic foramen?
Your Answer: Posterior cutaneous nerve of the thigh
Correct Answer: Obturator nerve
Explanation:The greater sciatic foramen does not serve as a pathway for the obturator nerve.
The Greater Sciatic Foramen and its Contents
The greater sciatic foramen is a space in the pelvis that is bounded by various ligaments and bones. It serves as a passageway for several important structures, including nerves and blood vessels. The piriformis muscle is a landmark for identifying these structures as they pass through the sciatic notch. Above the piriformis muscle, the superior gluteal vessels can be found, while below it are the inferior gluteal vessels, the sciatic nerve (which passes through it in only 10% of cases), and the posterior cutaneous nerve of the thigh.
The boundaries of the greater sciatic foramen include the greater sciatic notch of the ilium, the sacrotuberous ligament, the sacrospinous ligament, and the ischial spine. The anterior sacroiliac ligament forms the superior boundary. Structures passing through the greater sciatic foramen include the pudendal nerve, the internal pudendal artery, and the nerve to the obturator internus.
In contrast, the lesser sciatic foramen is a smaller space that contains the tendon of the obturator internus, the pudendal nerve, the internal pudendal artery and vein, and the nerve to the obturator internus. Understanding the contents and boundaries of these foramina is important for clinicians who may need to access or avoid these structures during surgical procedures or other interventions.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 27
Correct
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A 50-year-old woman comes to see you at the clinic with progressive muscle weakness, numbness, and tingling in her left arm. She reports experiencing neck and shoulder pain on the left side as well. She has no significant medical history and is generally healthy. She denies any recent injuries or trauma. Based on your clinical assessment, you suspect that she may have thoracic outlet syndrome.
What additional physical finding is most likely to confirm your suspicion of thoracic outlet syndrome in this patient?Your Answer: Absent radial pulse
Explanation:Compression of the subclavian artery by a cervical rib can result in an absent radial pulse, which is a common symptom of thoracic outlet syndrome. Adson’s test can be used to diagnose this condition, which can be mistaken for cervical radiculopathy. Flapping tremors are typically observed in patients with encephalopathy caused by liver failure or carbon dioxide retention. An irregular pulse may indicate an arrhythmia like atrial fibrillation or heart block. Aortic stenosis, which is characterized by an ejection systolic murmur, often causes older patients to experience loss of consciousness during physical activity. A bounding pulse, on the other hand, is a sign of strong myocardial contractions that may be caused by heart failure, arrhythmias, pregnancy, or thyroid disease.
Cervical ribs are a rare anomaly that affects only 0.2-0.4% of the population. They are often associated with neurological symptoms and are caused by an anomalous fibrous band that originates from the seventh cervical vertebrae and may arc towards the sternum. While most cases are congenital and present around the third decade of life, some cases have been reported to occur following trauma. Bilateral cervical ribs are present in up to 70% of cases. Compression of the subclavian artery can lead to absent radial pulse and a positive Adsons test, which involves lateral flexion of the neck towards the symptomatic side and traction of the symptomatic arm. Treatment is usually only necessary when there is evidence of neurovascular compromise, and the traditional operative method for excision is a transaxillary approach.
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This question is part of the following fields:
- Respiratory System
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Question 28
Incorrect
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A 26-year-old male presents to his general practitioner with polyuria. He complains that it has been affecting his social life, as he often has to go to the bathroom in the middle of social situations. The patient mentions that he notices this mostly when he drinks alcohol with his friends. He is otherwise feeling well. There is no significant past medical history and he is not on any regular medication. Clinical examinations are normal. A urine dipstick test shows no abnormalities. Blood results show no electrolyte abnormalities. The general practitioner explains that his symptoms are likely related to alcohol intake, as alcohol can cause polyuria.
What is the most likely physiological explanation for this patient's polyuria?Your Answer: Antidiuretic hormone resistance
Correct Answer: Suppressed antidiuretic hormone secretion
Explanation:Polyuria in the patient is most likely caused by alcohol bingeing, which can suppress ADH secretion in the posterior pituitary gland. This leads to decreased water reabsorption in the kidneys and subsequent polyuria. Other potential causes such as ADH resistance from chronic lithium ingestion, diabetes insipidus, osmotic diuresis from hyperglycemia, and chronic kidney disease are less likely based on the patient’s symptoms and investigative findings.
Polyuria, or excessive urination, can be caused by a variety of factors. A recent review in the BMJ categorizes these causes by their frequency of occurrence. The most common causes of polyuria include the use of diuretics, caffeine, and alcohol, as well as diabetes mellitus, lithium, and heart failure. Less common causes include hypercalcaemia and hyperthyroidism, while rare causes include chronic renal failure, primary polydipsia, and hypokalaemia. The least common cause of polyuria is diabetes insipidus, which occurs in less than 1 in 10,000 cases. It is important to note that while these frequencies may not align with exam questions, understanding the potential causes of polyuria can aid in diagnosis and treatment.
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This question is part of the following fields:
- Renal System
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Question 29
Incorrect
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A 32-year-old woman is being seen in the Oncology department for evaluation. She has been diagnosed with osteosarcoma of the left femur. Her medical history reveals a previous diagnosis of rhabdomyosarcoma, which was effectively treated when she was eleven years old.
What is the typical biological function of the protein impacted in the patient's underlying genetic disorder?Your Answer: Repair of double-strand DNA breaks
Correct Answer: Holding the cell cycle at the G1/S phase checkpoint to allow detection and repair of DNA damage
Explanation:The TP53 gene, which encodes the protein p53, is crucial in preventing the cell cycle from entering the S phase until DNA has been checked and repaired. This is particularly important in individuals with Li-Fraumeni syndrome (LFS), an inherited susceptibility to cancer that often results in the development of multiple sarcomas from a young age. LFS is caused by a mutation in one allele of the TP53 gene. One of the key functions of p53 is to hold the cell cycle at the G1/S checkpoint, allowing for the detection and repair of any DNA damage before replication occurs.
The identification of double-strand DNA breaks is not a function of p53. This is typically carried out by the MRN protein complex, which acts upstream of DNA repair proteins such as BRCA1 and BRCA2.
Inhibition of apoptosis is also not a primary function of p53. While p53 can promote apoptosis if cell cycle checkpoints are not satisfied, its primary role is in regulating the cell cycle.
Similarly, mismatch repair of single-strand DNA breaks is not a function of p53. This is typically carried out by mismatch repair proteins such as MLH-1 and MSH-2, which may be mutated in the familial cancer syndrome Lynch syndrome.
Understanding p53 and its Role in Cancer
p53 is a gene that helps suppress tumours and is located on chromosome 17p. It is frequently mutated in breast, colon, and lung cancer. The gene is believed to be essential in regulating the cell cycle, preventing cells from entering the S phase until DNA has been checked and repaired. Additionally, p53 may play a crucial role in apoptosis, the process of programmed cell death.
Li-Fraumeni syndrome is a rare genetic disorder that is inherited in an autosomal dominant pattern. It is characterised by the early onset of various cancers, including sarcoma, breast cancer, and leukaemia. The condition is caused by mutations in the p53 gene, which can lead to a loss of its tumour-suppressing function. Understanding the role of p53 in cancer can help researchers develop new treatments and therapies for those affected by the disease.
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This question is part of the following fields:
- General Principles
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Question 30
Incorrect
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You are a foundation year 3 doctor who has been requested to undergo blood testing for the detection of antibodies against the novel coronavirus (COVID-19) as a part of a hospital-wide screening initiative. You inquire with the phlebotomist about the specific antibody being evaluated, and he confirms that it is an IgG antibody test.
What is the primary function of this antibody?Your Answer: Transferred through breast milk to provide neonatal protection from the novel coronavirus
Correct Answer: Enhances phagocytosis of the novel coronavirus
Explanation:The presence of IgG antibodies in COVID-19 patients can be detected within seven to ten days after infection, indicating recent infection. These antibodies play a role in enhancing the phagocytosis of bacteria and viruses. IgA is the primary immunoglobulin found in breast milk and urogenital tract secretions, while IgM is typically the first antibody produced during a viral attack, indicating an active infection or recent recovery. IgE is associated with providing immunity against parasites.
Immunoglobulins, also known as antibodies, are proteins produced by the immune system to help fight off infections and diseases. There are five types of immunoglobulins found in the body, each with their own unique characteristics.
IgG is the most abundant type of immunoglobulin in blood serum and plays a crucial role in enhancing phagocytosis of bacteria and viruses. It also fixes complement and can be passed to the fetal circulation.
IgA is the most commonly produced immunoglobulin in the body and is found in the secretions of digestive, respiratory, and urogenital tracts and systems. It provides localized protection on mucous membranes and is transported across the interior of the cell via transcytosis.
IgM is the first immunoglobulin to be secreted in response to an infection and fixes complement, but does not pass to the fetal circulation. It is also responsible for producing anti-A, B blood antibodies.
IgD’s role in the immune system is largely unknown, but it is involved in the activation of B cells.
IgE is the least abundant type of immunoglobulin in blood serum and is responsible for mediating type 1 hypersensitivity reactions. It provides immunity to parasites such as helminths and binds to Fc receptors found on the surface of mast cells and basophils.
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This question is part of the following fields:
- General Principles
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Question 31
Correct
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A 16-year-old male presents to the emergency department after falling onto outstretched hands. An x-ray confirms a fracture in one of the bones in his forearm. Based on the mechanism of injury, which bone is most likely affected by this fracture?
Your Answer: Distal shaft of the radius
Explanation:The forearm has two weight-bearing bones, the scaphoid at the wrist and the radius within the forearm. If someone falls onto outstretched hands, there is a risk of fracturing both of these bones. The shaft of the radius is particularly vulnerable as it carries the weight and takes the full compression of the fall. The ulna is more likely to fracture from stress applied to the side of the arm rather than down its length. The lunate bone at the wrist is not involved in weight-bearing.
Anatomy of the Radius Bone
The radius bone is one of the two long bones in the forearm that extends from the lateral side of the elbow to the thumb side of the wrist. It has two expanded ends, with the distal end being the larger one. The upper end of the radius bone has articular cartilage that covers the medial to lateral side and articulates with the radial notch of the ulna by the annular ligament. The biceps brachii muscle attaches to the tuberosity of the upper end.
The shaft of the radius bone has several muscle attachments. The upper third of the body has the supinator, flexor digitorum superficialis, and flexor pollicis longus muscles. The middle third of the body has the pronator teres muscle, while the lower quarter of the body has the pronator quadratus muscle and the tendon of supinator longus.
The lower end of the radius bone is quadrilateral in shape. The anterior surface is covered by the capsule of the wrist joint, while the medial surface has the head of the ulna. The lateral surface ends in the styloid process, and the posterior surface has three grooves that contain the tendons of extensor carpi radialis longus and brevis, extensor pollicis longus, and extensor indicis. Understanding the anatomy of the radius bone is crucial in diagnosing and treating injuries and conditions that affect this bone.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 32
Incorrect
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You are administering lidocaine to numb the skin of a young patient before a minor procedure. What is a true statement about this medication?
Your Answer: Can be safely administered with adrenaline in ring blocks
Correct Answer: Can be used to treat ventricular tachycardia
Explanation:Lidocaine: Characteristics and Uses
Lidocaine is a medication that is quickly broken down by the liver, making it unsuitable for oral administration. Its effects last for only 20 minutes, but this can be extended to approximately 90 minutes when combined with the vasoconstrictor adrenaline. However, this combination should not be used in areas where there is a risk of ischaemia.
Lidocaine is a potent antiarrhythmic drug that falls under class I, as it prolongs the action potential. It can be used to treat ventricular tachycardia, although it is not included in the ALS algorithm and should only be administered by a specialist.
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This question is part of the following fields:
- Pharmacology
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Question 33
Correct
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The femoral nerve is accidentally severed by a negligent surgeon during a failed femoro-popliteal bypass surgery. What function will be affected?
Your Answer: Extension of the knee joint
Explanation:The quadriceps muscle, which is responsible for knee joint extension, is supplied by the femoral nerve.
The femoral nerve is a nerve that originates from the spinal roots L2, L3, and L4. It provides innervation to several muscles in the thigh, including the pectineus, sartorius, quadriceps femoris, and vastus lateralis, medialis, and intermedius. Additionally, it branches off into the medial cutaneous nerve of the thigh, saphenous nerve, and intermediate cutaneous nerve of the thigh. The femoral nerve passes through the psoas major muscle and exits the pelvis by going under the inguinal ligament. It then enters the femoral triangle, which is located lateral to the femoral artery and vein.
To remember the femoral nerve’s supply, a helpful mnemonic is don’t MISVQ scan for PE. This stands for the medial cutaneous nerve of the thigh, intermediate cutaneous nerve of the thigh, saphenous nerve, vastus, quadriceps femoris, and sartorius, with the addition of the pectineus muscle. Overall, the femoral nerve plays an important role in the motor and sensory functions of the thigh.
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This question is part of the following fields:
- Neurological System
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Question 34
Correct
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A runner presents to the emergency department with intense leg discomfort. He had neglected to warm up and participated in a 200m sprint race. As he neared the finish line, he felt pain in the back of his thigh. The pain has intensified and is now focused on the outer part of the knee. The runner is incapable of bending his knee. Which structure has sustained damage?
Your Answer: Biceps femoris tendon
Explanation:Sports that involve sudden bending of the knee, such as sprinting, often result in injuries to the biceps femoris, particularly if the athlete has not properly warmed up. The most frequent type of injury is avulsion, which occurs at the point where the long head connects to the ischial tuberosity. Compared to the other hamstrings, the biceps femoris is more prone to injury.
The Biceps Femoris Muscle
The biceps femoris is a muscle located in the posterior upper thigh and is part of the hamstring group of muscles. It consists of two heads: the long head and the short head. The long head originates from the ischial tuberosity and inserts into the fibular head. Its actions include knee flexion, lateral rotation of the tibia, and extension of the hip. It is innervated by the tibial division of the sciatic nerve and supplied by the profunda femoris artery, inferior gluteal artery, and the superior muscular branches of the popliteal artery.
On the other hand, the short head originates from the lateral lip of the linea aspera and the lateral supracondylar ridge of the femur. It also inserts into the fibular head and is responsible for knee flexion and lateral rotation of the tibia. It is innervated by the common peroneal division of the sciatic nerve and supplied by the same arteries as the long head.
Understanding the anatomy and function of the biceps femoris muscle is important in the diagnosis and treatment of injuries and conditions affecting the posterior thigh.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 35
Incorrect
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A 40-year-old woman has just been diagnosed with HIV and is now taking a drug regimen that includes multiple medications. One of these drugs is designed to inhibit the virus from integrating its DNA into cells.
What drug is most likely being taken by this patient?Your Answer: Ritonavir
Correct Answer: Raltegravir
Explanation:Integrating HIV drugs that end with -gravir is significant because they are integrase inhibitors, while enfuvirtide functions as an entry inhibitor.
Antiretroviral therapy (ART) is a treatment for HIV that involves a combination of at least three drugs. This combination typically includes two nucleoside reverse transcriptase inhibitors (NRTI) and either a protease inhibitor (PI) or a non-nucleoside reverse transcriptase inhibitor (NNRTI). ART reduces viral replication and the risk of viral resistance emerging. The 2015 BHIVA guidelines recommend that patients start ART as soon as they are diagnosed with HIV, rather than waiting until a particular CD4 count.
Entry inhibitors, such as maraviroc and enfuvirtide, prevent HIV-1 from entering and infecting immune cells. Nucleoside analogue reverse transcriptase inhibitors (NRTI), such as zidovudine, abacavir, and tenofovir, can cause peripheral neuropathy and other side effects. Non-nucleoside reverse transcriptase inhibitors (NNRTI), such as nevirapine and efavirenz, can cause P450 enzyme interaction and rashes. Protease inhibitors (PI), such as indinavir and ritonavir, can cause diabetes, hyperlipidaemia, and other side effects. Integrase inhibitors, such as raltegravir and dolutegravir, block the action of integrase, a viral enzyme that inserts the viral genome into the DNA of the host cell.
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This question is part of the following fields:
- General Principles
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Question 36
Correct
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An 82-year-old woman visits her doctor with a medical history of myocardial infarction that has resulted in permanent damage to the conduction system of her heart. The damage has affected the part of the conduction system with the highest velocities, causing desynchronisation of the ventricles.
What is the part of the heart that conducts the fastest?Your Answer: Purkinje fibres
Explanation:The Purkinje fibres have the highest conduction velocities in the heart’s electrical conduction system. The process starts with the SA node generating spontaneous action potentials, which are then conducted across both atria through cell to cell conduction at a speed of approximately 1 m/s. The only pathway for the action potential to enter the ventricles is through the AV node, which has a slow conduction speed of 0.05ms to allow for complete atrial contraction and ventricular filling. The action potentials are then conducted through the Bundle of His, which splits into the left and right bundle branches, with a conduction speed of approximately 2m/s. Finally, the action potential reaches the Purkinje fibres, which are specialized conducting cells that allow for a faster conduction speed of 2-4m/s. This fast conduction speed is crucial for a synchronized and efficient contraction of the ventricle, generating pressure during systole.
Understanding the Cardiac Action Potential and Conduction Velocity
The cardiac action potential is a series of electrical events that occur in the heart during each heartbeat. It is responsible for the contraction of the heart muscle and the pumping of blood throughout the body. The action potential is divided into five phases, each with a specific mechanism. The first phase is rapid depolarization, which is caused by the influx of sodium ions. The second phase is early repolarization, which is caused by the efflux of potassium ions. The third phase is the plateau phase, which is caused by the slow influx of calcium ions. The fourth phase is final repolarization, which is caused by the efflux of potassium ions. The final phase is the restoration of ionic concentrations, which is achieved by the Na+/K+ ATPase pump.
Conduction velocity is the speed at which the electrical signal travels through the heart. The speed varies depending on the location of the signal. Atrial conduction spreads along ordinary atrial myocardial fibers at a speed of 1 m/sec. AV node conduction is much slower, at 0.05 m/sec. Ventricular conduction is the fastest in the heart, achieved by the large diameter of the Purkinje fibers, which can achieve velocities of 2-4 m/sec. This allows for a rapid and coordinated contraction of the ventricles, which is essential for the proper functioning of the heart. Understanding the cardiac action potential and conduction velocity is crucial for diagnosing and treating heart conditions.
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This question is part of the following fields:
- Cardiovascular System
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Question 37
Incorrect
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Which upper limb muscle is not supplied by the radial nerve?
Your Answer: Anconeus
Correct Answer: Abductor digiti minimi
Explanation:The mnemonic for the muscles innervated by the radial nerve is BEST, which stands for Brachioradialis, Extensors, Supinator, and Triceps. On the other hand, the ulnar nerve innervates the Abductor Digiti Minimi muscle.
The Radial Nerve: Anatomy, Innervation, and Patterns of Damage
The radial nerve is a continuation of the posterior cord of the brachial plexus, with root values ranging from C5 to T1. It travels through the axilla, posterior to the axillary artery, and enters the arm between the brachial artery and the long head of triceps. From there, it spirals around the posterior surface of the humerus in the groove for the radial nerve before piercing the intermuscular septum and descending in front of the lateral epicondyle. At the lateral epicondyle, it divides into a superficial and deep terminal branch, with the deep branch crossing the supinator to become the posterior interosseous nerve.
The radial nerve innervates several muscles, including triceps, anconeus, brachioradialis, and extensor carpi radialis. The posterior interosseous branch innervates supinator, extensor carpi ulnaris, extensor digitorum, and other muscles. Denervation of these muscles can lead to weakness or paralysis, with effects ranging from minor effects on shoulder stability to loss of elbow extension and weakening of supination of prone hand and elbow flexion in mid prone position.
Damage to the radial nerve can result in wrist drop and sensory loss to a small area between the dorsal aspect of the 1st and 2nd metacarpals. Axillary damage can also cause paralysis of triceps. Understanding the anatomy, innervation, and patterns of damage of the radial nerve is important for diagnosing and treating conditions that affect this nerve.
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This question is part of the following fields:
- Neurological System
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Question 38
Correct
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You are a senior doctor working on the geriatric ward. One afternoon, you are notified that the radiology department has implemented a new imaging technology for detecting bone fractures. This technology has enhanced accuracy, but the precision remains unchanged from the previous method.
What implications does this have for future reports of bone fractures on imaging scans?Your Answer: The results are now more likely to be close to the true value
Explanation:In statistics, reliability refers to the consistency of a measure, while validity measures the accuracy of reported results in relation to the true value. Validity ensures that reported results are more likely to be close to the correct answer, reducing the likelihood of skewed data. However, validity does not affect a test’s level of bias. Reliability, on the other hand, measures the consistency of measurements produced by a test, ensuring that they are all within a small range of each other when measuring the same sample multiple times.
Understanding Reliability and Validity in Statistics
Reliability and validity are two important concepts in statistics that are used to determine the accuracy and consistency of a measure. Reliability refers to the consistency of a measurement, while validity refers to whether a test accurately measures what it is supposed to measure.
It is important to note that reliability and validity are independent of each other. This means that a measurement can be valid but not reliable, or reliable but not valid. For example, if a pulse oximeter consistently records oxygen saturations 5% below the true value, it is considered reliable because the value is consistently 5% below the true value. However, it is not considered valid because the reported saturations are not an accurate reflection of the true values.
In summary, reliability and validity are crucial concepts in statistics that help to ensure accurate and consistent measurements. Understanding the difference between these two concepts is important for researchers and statisticians to ensure that their data is reliable and valid.
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This question is part of the following fields:
- General Principles
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Question 39
Correct
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What specific receptor in the heart does adrenaline need to act on to increase heart rate and cardiac muscle contraction?
Your Answer: Beta-1 receptor
Explanation:Activation of β1 adrenergic receptors results in cardiac muscle contraction. Adrenaline, which is a nonselective agonist of all adrenergic receptors, specifically acts on β1 receptors to cause this effect. In contrast, activation of β2 receptors leads to smooth muscle relaxation and bronchodilation in the airway lining. Alpha-1 receptors, on the other hand, cause vasoconstriction, increased peripheral resistance, increased blood pressure, and mydriasis. Alpha-2 receptors can lead to vasoconstriction of certain blood vessels, suppression of norepinephrine release, and decreased motility of smooth muscle in the gastrointestinal tract, among other effects.
Adrenergic receptors are a type of G protein-coupled receptors that respond to the catecholamines epinephrine and norepinephrine. These receptors are primarily involved in the sympathetic nervous system. There are four types of adrenergic receptors: α1, α2, β1, and β2. Each receptor has a different potency order and primary action. The α1 receptor responds equally to norepinephrine and epinephrine, causing smooth muscle contraction. The α2 receptor has mixed effects and responds equally to both catecholamines. The β1 receptor responds equally to epinephrine and norepinephrine, causing cardiac muscle contraction. The β2 receptor responds much more strongly to epinephrine than norepinephrine, causing smooth muscle relaxation.
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This question is part of the following fields:
- General Principles
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Question 40
Incorrect
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A young man in his early twenties collapses during a game of basketball and is declared dead upon arrival at the hospital. The autopsy shows irregularities in his heart. What is the probable cause of the irregularities?
Your Answer: Dilated cardiomyopathy
Correct Answer: Hypertrophic cardiomyopathy
Explanation:The condition that is most commonly associated with sudden death is hypertrophic cardiomyopathy, making the other options less likely.
Symptoms of acute myocarditis may include chest pain, fever, palpitations, tachycardia, and difficulty breathing.
Dilated cardiomyopathy may cause right ventricular failure, leading to symptoms such as difficulty breathing, pulmonary edema, and atrial fibrillation.
Restrictive cardiomyopathy and constrictive pericarditis have similar presentations, with right heart failure symptoms such as elevated JVP, hepatomegaly, edema, and ascites being predominant.
Hypertrophic obstructive cardiomyopathy (HOCM) is a genetic disorder that affects muscle tissue and is inherited in an autosomal dominant manner. It is caused by mutations in genes that encode contractile proteins, with the most common defects involving the β-myosin heavy chain protein or myosin-binding protein C. HOCM is characterized by left ventricle hypertrophy, which leads to decreased compliance and cardiac output, resulting in predominantly diastolic dysfunction. Biopsy findings show myofibrillar hypertrophy with disorganized myocytes and fibrosis. HOCM is often asymptomatic, but exertional dyspnea, angina, syncope, and sudden death can occur. Jerky pulse, systolic murmurs, and double apex beat are also common features. HOCM is associated with Friedreich’s ataxia and Wolff-Parkinson White. ECG findings include left ventricular hypertrophy, non-specific ST segment and T-wave abnormalities, and deep Q waves. Atrial fibrillation may occasionally be seen.
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This question is part of the following fields:
- Cardiovascular System
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Question 41
Incorrect
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A 60-year-old man is admitted to the hospital with pneumonia. During routine daily blood tests, the following results are obtained:
Hb 105 g/L
WCC 14.2 * 109/l
CRP 98 mg/l
Na+ 136 mmol/l
K+ 6.1 mmol/l
Glucose 12.8 mmol/l
Urea 7.8 mmol/l
eGFR 56 mL/min/1.73m2 (>90 mL/min/1.73m2)
The patient has a medical history of diabetes mellitus, hypertension, and chronic kidney disease. He is currently taking paracetamol, amlodipine, furosemide, and spironolactone.
What is the most appropriate modification to his management?Your Answer: Start metformin
Correct Answer: Stop spironolactone
Explanation:To address the hyperkalaemia in this patient, the most appropriate step would be to stop the potassium-sparing diuretic, spironolactone. Starting metformin or erythropoietin, or increasing furosemide, would not be the most appropriate actions at this time.
Potassium-sparing diuretics are classified into two types: epithelial sodium channel blockers (such as amiloride and triamterene) and aldosterone antagonists (such as spironolactone and eplerenone). However, caution should be exercised when using these drugs in patients taking ACE inhibitors as they can cause hyperkalaemia. Amiloride is a weak diuretic that blocks the epithelial sodium channel in the distal convoluted tubule. It is usually given with thiazides or loop diuretics as an alternative to potassium supplementation since these drugs often cause hypokalaemia. On the other hand, aldosterone antagonists like spironolactone act in the cortical collecting duct and are used to treat conditions such as ascites, heart failure, nephrotic syndrome, and Conn’s syndrome. In patients with cirrhosis, relatively large doses of spironolactone (100 or 200 mg) are often used to manage secondary hyperaldosteronism.
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This question is part of the following fields:
- General Principles
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Question 42
Correct
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From which of the following cell types do giant cells typically arise?
Your Answer: Macrophages
Explanation:Macrophages are still the most frequent cell type that can generate giant cells, despite the possibility of other cell types doing so.
Giant cells are masses that result from the fusion of various types of cells. Typically, these masses are composed of macrophages. It is important to note that giant cells are not the same as granulomas, although the agents that cause them may be similar. In fact, giant cells are often a reaction to foreign materials, such as suture material, and can be seen in histological sections stained with haematoxylin and eosin. Overall, giant cells are a unique phenomenon in cellular biology that can provide insight into the body’s response to foreign substances.
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This question is part of the following fields:
- Haematology And Oncology
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Question 43
Incorrect
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A 4-year-old boy is presented to the emergency department by his father due to an increase in facial and leg swelling. The father reports no significant medical or family history but has noticed his son passing frothy urine for the past 3 days.
During the examination, there is facial and pitting oedema. Laboratory tests confirm hypoalbuminaemia, and a urine dipstick shows proteinuria +++.
What is the probable result on light microscopy of a renal biopsy?Your Answer: Basement membrane thickening, capillary obliteration, mesangial widening
Correct Answer: Normal architecture
Explanation:In minimal change disease, light microscopy typically shows no abnormalities.
Minimal change disease is a condition that typically presents as nephrotic syndrome, with children accounting for 75% of cases and adults accounting for 25%. While most cases are idiopathic, a cause can be found in around 10-20% of cases, such as drugs like NSAIDs and rifampicin, Hodgkin’s lymphoma, thymoma, or infectious mononucleosis. The pathophysiology of the disease involves T-cell and cytokine-mediated damage to the glomerular basement membrane, resulting in polyanion loss and a reduction of electrostatic charge, which increases glomerular permeability to serum albumin.
The features of minimal change disease include nephrotic syndrome, normotension (hypertension is rare), and highly selective proteinuria, where only intermediate-sized proteins like albumin and transferrin leak through the glomerulus. Renal biopsy shows normal glomeruli on light microscopy, while electron microscopy shows fusion of podocytes and effacement of foot processes.
Management of minimal change disease involves oral corticosteroids, which are effective in 80% of cases. For steroid-resistant cases, cyclophosphamide is the next step. The prognosis for the disease is generally good, although relapse is common. Roughly one-third of patients have just one episode, one-third have infrequent relapses, and one-third have frequent relapses that stop before adulthood.
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This question is part of the following fields:
- Renal System
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Question 44
Correct
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A previously healthy woman of 23 years-old presented with acute epigastric pain. On investigations, a largely elevated lipase was discovered with a normal amylase level, and a diagnosis of chronic pancreatitis was made. This patient rarely drinks alcohol, and ultrasonography of the abdomen ruled out gallstones. The results of tests for autoimmune pancreatitis were negative. Twenty days later, imaging tests using magnetic resonance cholangiopancreatography (MRCP) revealed the cause of the chronic pancreatitis.
What was the most probable reason behind the chronic pancreatitis in this 23-year-old woman?Your Answer: Pancreas divisum
Explanation:Pancreas divisum is a condition where the dorsal and ventral buds of the pancreas fail to fuse in a portion of the population. This can lead to chronic pancreatitis due to insufficient drainage of pancreatic secretions through the minor papilla instead of the major papilla. Other causes of chronic pancreatitis include autoimmune pancreatitis and cystic fibrosis, but these have been ruled out in this case as the patient is a previously healthy individual with negative autoimmune antibodies. Acute pancreatitis can be caused by mumps or a Trinidadian scorpion bite.
Understanding Chronic Pancreatitis
Chronic pancreatitis is a condition characterized by inflammation that can affect both the exocrine and endocrine functions of the pancreas. While alcohol excess is the leading cause of this condition, up to 20% of cases are unexplained. Other causes include genetic factors such as cystic fibrosis and haemochromatosis, as well as ductal obstruction due to tumors, stones, and structural abnormalities.
Symptoms of chronic pancreatitis include pain that worsens 15 to 30 minutes after a meal, steatorrhoea, and diabetes mellitus. Abdominal x-rays and CT scans are used to detect pancreatic calcification, which is present in around 30% of cases. Functional tests such as faecal elastase may also be used to assess exocrine function if imaging is inconclusive.
Management of chronic pancreatitis involves pancreatic enzyme supplements, analgesia, and antioxidants. While there is limited evidence to support the use of antioxidants, one study suggests that they may be beneficial in early stages of the disease. Overall, understanding the causes and symptoms of chronic pancreatitis is crucial for effective management and treatment.
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This question is part of the following fields:
- Gastrointestinal System
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Question 45
Correct
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A 30-year-old woman has recently been diagnosed with epilepsy and is planning to start a family soon. She has come to see you, her GP, to discuss the treatment options for epilepsy and which medications are safe to take during pregnancy.
Which of the following drugs poses the highest risk of causing neural tube defects?Your Answer: Sodium valproate
Explanation:Women of childbearing potential should not be prescribed sodium valproate due to its high association with neural tube defects, as well as craniofacial abnormalities and distal digit hypoplasia. Among antiepileptics, it has the highest rate of causing these defects.
Harmful Drugs and Medical Conditions for Developing Fetuses
During pregnancy, certain drugs and medical conditions can harm the developing fetus. These harmful substances and conditions are known as teratogens. Some examples of teratogens include ACE inhibitors, alcohol, aminoglycosides, carbamazepine, chloramphenicol, cocaine, diethylstilbesterol, lithium, maternal diabetes mellitus, smoking, tetracyclines, thalidomide, and warfarin.
ACE inhibitors can cause renal dysgenesis and craniofacial abnormalities in the fetus. Alcohol consumption during pregnancy can lead to craniofacial abnormalities. Aminoglycosides can cause ototoxicity. Carbamazepine can result in neural tube defects and craniofacial abnormalities. Chloramphenicol can cause grey baby syndrome. Cocaine use during pregnancy can lead to intrauterine growth retardation and preterm labor. Diethylstilbesterol can cause vaginal clear cell adenocarcinoma. Lithium can result in Ebstein’s anomaly, which is an atrialized right ventricle. Maternal diabetes mellitus can cause macrosomia, neural tube defects, polyhydramnios, preterm labor, and caudal regression syndrome. Smoking during pregnancy can lead to preterm labor and intrauterine growth retardation. Tetracyclines can cause discolored teeth. Thalidomide can result in limb reduction defects. Valproate can cause neural tube defects and craniofacial abnormalities. Warfarin can lead to craniofacial abnormalities in the fetus.
It is important for pregnant women to avoid exposure to these harmful substances and conditions to ensure the healthy development of their fetus.
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This question is part of the following fields:
- General Principles
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Question 46
Correct
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A 42-year-old man falls onto an outstretched hand and is evaluated in the emergency department. During the examination, tenderness is noted in the base of his anatomical snuffbox upon palpation. What injury is most likely in this situation?
Your Answer: Scaphoid fracture
Explanation:If there is tenderness in the base of the anatomical snuffbox, a scaphoid fracture should be suspected as it is a common injury caused by a fall onto an outstretched hand. It is important to note that bony tenderness would not be a symptom of a tendon rupture.
The scaphoid bone has various articular surfaces for different bones in the wrist. It has a concave surface for the head of the capitate and a crescentic surface for the lunate. The proximal end has a wide convex surface for the radius, while the distal end has a tubercle that can be felt. The remaining articular surface faces laterally and is associated with the trapezium and trapezoid bones. The narrow strip between the radial and trapezial surfaces and the tubercle gives rise to the radial collateral carpal ligament. The tubercle also receives part of the flexor retinaculum and is the only part of the scaphoid bone that allows for the entry of blood vessels. However, this area is commonly fractured and can lead to avascular necrosis.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 47
Incorrect
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A 35-year-old man visits his GP complaining of abdominal pain and diarrhoea that have persisted for 2 days. He mentions that his children noticed an unusual rash on the soles of his feet. The GP discovers that he recently returned from a 6-week business trip to Thailand.
Upon examination, the GP observes papulovesicular lesions on the soles of both feet and a soft abdomen with no rebound tenderness or guarding. The patient is also wheezing slightly, and his temperature is recorded at 38.4ºC.
Which helminths are most likely responsible for this man's symptoms?Your Answer: Enterobius vermicularis
Correct Answer: Strongyloides stercoralis
Explanation:The patient is exhibiting symptoms of strongyloidiasis, which is caused by Strongyloides stercoralis. This includes abdominal pain, diarrhoea, and weight loss, as well as papulovesicular lesions on the soles of the feet and an urticarial rash. Respiratory symptoms may also occur due to the migration of filariform larvae. Pinworm, or Enterobius vermicularis, typically presents with perianal itching and is most common in children. Onchocerca volvulus causes onchocerciasis, which is prevalent in Africa and can lead to severe itching and blindness. Schistosoma haematobium causes schistosomiasis, the most common parasitic infection in humans, which affects the urinary tract and presents with haematuria.
Helminths are a group of parasitic worms that can infect humans and cause various diseases. Nematodes, also known as roundworms, are one type of helminth. Strongyloides stercoralis is a type of roundworm that enters the body through the skin and can cause symptoms such as diarrhea, abdominal pain, and skin lesions. Treatment for this infection typically involves the use of ivermectin or benzimidazoles. Enterobius vermicularis, also known as pinworm, is another type of roundworm that can cause perianal itching and other symptoms. Diagnosis is made by examining sticky tape applied to the perianal area. Treatment typically involves benzimidazoles.
Hookworms, such as Ancylostoma duodenale and Necator americanus, are another type of roundworm that can cause gastrointestinal infections and anemia. Treatment typically involves benzimidazoles. Loa loa is a type of roundworm that is transmitted by deer fly and mango fly and can cause red, itchy swellings called Calabar swellings. Treatment involves the use of diethylcarbamazine. Trichinella spiralis is a type of roundworm that can develop after eating raw pork and can cause fever, periorbital edema, and myositis. Treatment typically involves benzimidazoles.
Onchocerca volvulus is a type of roundworm that causes river blindness and is spread by female blackflies. Treatment involves the use of ivermectin. Wuchereria bancrofti is another type of roundworm that is transmitted by female mosquitoes and can cause blockage of lymphatics and elephantiasis. Treatment involves the use of diethylcarbamazine. Toxocara canis, also known as dog roundworm, is transmitted through ingestion of infective eggs and can cause visceral larva migrans and retinal granulomas. Treatment involves the use of diethylcarbamazine. Ascaris lumbricoides, also known as giant roundworm, can cause intestinal obstruction and occasionally migrate to the lung. Treatment typically involves benzimidazoles.
Cestodes, also known as tapeworms, are another type of helminth. Echinococcus granulosus is a tapeworm that is transmitted through ingestion of eggs in dog feces and can cause liver cysts and anaphylaxis if the cyst ruptures
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This question is part of the following fields:
- General Principles
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Question 48
Incorrect
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African farmers in their 40s often develop massively swollen legs and scrotum enlargement associated with frequent mosquito bites. The oedema is non-pitting, and the scrotum transilluminates. What is the most likely organism responsible for these symptoms?
Your Answer: Diphyllobothrium latum
Correct Answer: Wuchereria bancrofti
Explanation:African farmer experiences significant swelling in his legs and scrotum.
Helminths are a group of parasitic worms that can infect humans and cause various diseases. Nematodes, also known as roundworms, are one type of helminth. Strongyloides stercoralis is a type of roundworm that enters the body through the skin and can cause symptoms such as diarrhea, abdominal pain, and skin lesions. Treatment for this infection typically involves the use of ivermectin or benzimidazoles. Enterobius vermicularis, also known as pinworm, is another type of roundworm that can cause perianal itching and other symptoms. Diagnosis is made by examining sticky tape applied to the perianal area. Treatment typically involves benzimidazoles.
Hookworms, such as Ancylostoma duodenale and Necator americanus, are another type of roundworm that can cause gastrointestinal infections and anemia. Treatment typically involves benzimidazoles. Loa loa is a type of roundworm that is transmitted by deer fly and mango fly and can cause red, itchy swellings called Calabar swellings. Treatment involves the use of diethylcarbamazine. Trichinella spiralis is a type of roundworm that can develop after eating raw pork and can cause fever, periorbital edema, and myositis. Treatment typically involves benzimidazoles.
Onchocerca volvulus is a type of roundworm that causes river blindness and is spread by female blackflies. Treatment involves the use of ivermectin. Wuchereria bancrofti is another type of roundworm that is transmitted by female mosquitoes and can cause blockage of lymphatics and elephantiasis. Treatment involves the use of diethylcarbamazine. Toxocara canis, also known as dog roundworm, is transmitted through ingestion of infective eggs and can cause visceral larva migrans and retinal granulomas. Treatment involves the use of diethylcarbamazine. Ascaris lumbricoides, also known as giant roundworm, can cause intestinal obstruction and occasionally migrate to the lung. Treatment typically involves benzimidazoles.
Cestodes, also known as tapeworms, are another type of helminth. Echinococcus granulosus is a tapeworm that is transmitted through ingestion of eggs in dog feces and can cause liver cysts and anaphylaxis if the cyst ruptures
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This question is part of the following fields:
- General Principles
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Question 49
Correct
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As a GP, you are evaluating a 35-year-old female patient who has been experiencing a persistent burning sensation in her epigastrium that is temporarily relieved by eating meals. Your initial suspicion of H. pylori infection was ruled out by a negative serology test, and a two-week trial of full-dose proton pump inhibitor and triple eradication therapy failed to alleviate her symptoms. An endoscopy revealed multiple duodenal ulcers, and upon further questioning, the patient disclosed that her mother has a pituitary tumor. Which hormone is most likely to be elevated in this patient?
Your Answer: Gastrin
Explanation:Zollinger-Ellison Syndrome and Gastrinoma
Zollinger-Ellison syndrome is a familial condition that predisposes individuals to benign or malignant tumors of the pituitary and pancreas with parathyroid hyperplasia causing hyperparathyroidism. This autosomal dominant inherited syndrome should be considered in patients who present with unusual endocrine tumors, especially if they are relatively young at diagnosis or have a relevant family history.
One manifestation of Zollinger-Ellison syndrome is the development of a pancreatic tumor called a gastrinoma, which secretes the hormone gastrin. Gastrin stimulates the release of hydrochloric acid from parietal cells in the stomach, which optimizes conditions for protein digesting enzymes. However, excessive production of gastrin can occur in gastrinomas, leading to excessive HCL production that can denature the mucosa and submosa of the gastrointestinal tract, causing symptoms, ulceration, and even perforation of the duodenum.
While other pancreatic tumors can also produce hormones such as insulin or glucagon, the symptoms and clinical findings in this case suggest a diagnosis of gastrinoma. Cholecystokinin and somatostatin are hormones that have inhibitory effects on HCL secretion and do not fit with the clinical picture. Cholecystokinin also produces the feeling of satiety.
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This question is part of the following fields:
- Gastrointestinal System
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Question 50
Correct
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A 32-year-old female patient visits the GP with a concern about her middle finger's inability to flex at the end. During the examination, it is observed that she cannot bend the distal interphalangeal joint of her middle finger.
Which muscle is accountable for this movement?Your Answer: Flexor digitorum profundus
Explanation:The correct answer is that the flexor digitorum profundus muscle is responsible for flexing the distal interphalangeal joint. The other options, such as the flexor digitorum superficialis and flexor pollicis longus, are responsible for different movements and are therefore incorrect. The palmar interossei are also not responsible for flexion at the distal interphalangeal joint. Lastly, there is no such muscle as the flexor digiti medius.
The forearm flexor muscles include the flexor carpi radialis, palmaris longus, flexor carpi ulnaris, flexor digitorum superficialis, and flexor digitorum profundus. These muscles originate from the common flexor origin and surrounding fascia, and are innervated by the median and ulnar nerves. Their actions include flexion and abduction of the carpus, wrist flexion, adduction of the carpus, and flexion of the metacarpophalangeal and interphalangeal joints.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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