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  • Question 1 - A 23-year-old man acquires an infection in the pulp of his pinky finger....

    Incorrect

    • A 23-year-old man acquires an infection in the pulp of his pinky finger. What is the closest location to which this infection can spread?

      Your Answer: The distal interphalangeal joint

      Correct Answer: Proximal to the flexor retinaculum

      Explanation:

      The tendon sheath that runs from the little finger to the proximal part of the carpal tunnel poses a considerable risk of facilitating the spread of infections towards the proximal direction.

      Anatomy of the Hand: Fascia, Compartments, and Tendons

      The hand is composed of bones, muscles, and tendons that work together to perform various functions. The bones of the hand include eight carpal bones, five metacarpals, and 14 phalanges. The intrinsic muscles of the hand include the interossei, which are supplied by the ulnar nerve, and the lumbricals, which flex the metacarpophalangeal joints and extend the interphalangeal joint. The thenar eminence contains the abductor pollicis brevis, opponens pollicis, and flexor pollicis brevis, while the hypothenar eminence contains the opponens digiti minimi, flexor digiti minimi brevis, and abductor digiti minimi.

      The fascia of the palm is thin over the thenar and hypothenar eminences but relatively thick elsewhere. The palmar aponeurosis covers the soft tissues and overlies the flexor tendons. The palmar fascia is continuous with the antebrachial fascia and the fascia of the dorsum of the hand. The hand is divided into compartments by fibrous septa, with the thenar compartment lying lateral to the lateral septum, the hypothenar compartment lying medial to the medial septum, and the central compartment containing the flexor tendons and their sheaths, the lumbricals, the superficial palmar arterial arch, and the digital vessels and nerves. The deepest muscular plane is the adductor compartment, which contains adductor pollicis.

      The tendons of the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) enter the common flexor sheath deep to the flexor retinaculum. The tendons enter the central compartment of the hand and fan out to their respective digital synovial sheaths. The fibrous digital sheaths contain the flexor tendons and their synovial sheaths, extending from the heads of the metacarpals to the base of the distal phalanges.

    • This question is part of the following fields:

      • Musculoskeletal System And Skin
      11.4
      Seconds
  • Question 2 - A 28-year-old man arrives at the emergency department complaining of chest pain. The...

    Incorrect

    • A 28-year-old man arrives at the emergency department complaining of chest pain. The ECG strip shows an irregularly irregular tachycardia that is not in sinus rhythm.

      Where is the site of this pathology?

      Your Answer: Isolated discordance of the AV node

      Correct Answer: Discordance of electrical activity from the myocytes surrounding the pulmonary veins

      Explanation:

      Atrial fibrillation occurs when irregular electrical activity from the myocytes surrounding the pulmonary veins overwhelms the regular impulses from the sinus node. This leads to discordance of electrical activity in the atria, causing the irregularly irregular tachycardia characteristic of AF. It is important to note that AF is not caused by an absence of electrical activity in the atria or bundle of His.

      Atrial fibrillation (AF) is a heart condition that requires prompt management. The management of AF depends on the patient’s haemodynamic stability and the duration of the AF. For haemodynamically unstable patients, electrical cardioversion is recommended. For haemodynamically stable patients, rate control is the first-line treatment strategy, except in certain cases. Medications such as beta-blockers, calcium channel blockers, and digoxin are commonly used to control the heart rate. Rhythm control is another treatment option that involves the use of medications such as beta-blockers, dronedarone, and amiodarone. Catheter ablation is recommended for patients who have not responded to or wish to avoid antiarrhythmic medication. The procedure involves the use of radiofrequency or cryotherapy to ablate the faulty electrical pathways that cause AF. Anticoagulation is necessary before and during the procedure to reduce the risk of stroke. The success rate of catheter ablation varies, with around 50% of patients experiencing an early recurrence of AF within three months. However, after three years, around 55% of patients who have undergone a single procedure remain in sinus rhythm.

    • This question is part of the following fields:

      • Cardiovascular System
      64.8
      Seconds
  • Question 3 - A 42-year-old man is found to have a right-sided colon cancer and a...

    Incorrect

    • A 42-year-old man is found to have a right-sided colon cancer and a significant family history of colorectal and ovarian cancer. Upon genetic testing, he is diagnosed with hereditary non-polyposis colorectal cancer (HNPCC) caused by a mutation in the MSH2 gene. What is the role of this gene?

      Your Answer: Regulatory GTPase

      Correct Answer: DNA mismatch repair

      Explanation:

      Colorectal cancer can be classified into three types: sporadic, hereditary non-polyposis colorectal carcinoma (HNPCC), and familial adenomatous polyposis (FAP). Sporadic colon cancer is believed to be caused by a series of genetic mutations, including allelic loss of the APC gene, activation of the K-ras oncogene, and deletion of p53 and DCC tumor suppressor genes. HNPCC, which is an autosomal dominant condition, is the most common form of inherited colon cancer. It is caused by mutations in genes involved in DNA mismatch repair, leading to microsatellite instability. The most common genes affected are MSH2 and MLH1. Patients with HNPCC are also at a higher risk of other cancers, such as endometrial cancer. The Amsterdam criteria are sometimes used to aid diagnosis of HNPCC. FAP is a rare autosomal dominant condition that leads to the formation of hundreds of polyps by the age of 30-40 years. It is caused by a mutation in the APC gene. Patients with FAP are also at risk of duodenal tumors. A variant of FAP called Gardner’s syndrome can also feature osteomas of the skull and mandible, retinal pigmentation, thyroid carcinoma, and epidermoid cysts on the skin. Genetic testing can be done to diagnose HNPCC and FAP, and patients with FAP generally have a total colectomy with ileo-anal pouch formation in their twenties.

    • This question is part of the following fields:

      • Gastrointestinal System
      28.4
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  • Question 4 - A 19-year-old male visits the clinic with concerns about his acne, which is...

    Correct

    • A 19-year-old male visits the clinic with concerns about his acne, which is causing him discomfort and affecting his emotional well-being. Despite using over-the-counter benzoyl peroxide, the lesions on his face, chest, and back persist. The GP decides to prescribe a combination of erythromycin and benzoyl peroxide as a topical treatment. What is the mechanism of action of erythromycin in treating acne?

      Your Answer: Binds to the 50S subunit of the ribosome

      Explanation:

      Macrolides, such as erythromycin, hinder protein synthesis by targeting the 50S subunit of ribosomes in bacteria. This action prevents the creation of proteins, leading to the eventual death of the bacterial cells.

      Quinolone antibiotics, like ciprofloxacin, work by inhibiting bacterial DNA gyrase, which is responsible for unwinding and duplicating bacterial DNA. By hindering this process, bacterial replication is impaired.

      Beta-lactam antibiotics, including penicillins and cephalosporins, damage the bacterial cell wall, ultimately leading to bacterial cell death.

      Trimethoprim works by inhibiting bacterial dihydrofolate reductase, which reduces the amount of purines available for DNA synthesis in bacteria. This reduction in DNA synthesis slows bacterial replication.

      Tetracyclines inhibit the 30S subunit of bacterial ribosomes, which also reduces protein synthesis and leads to bacterial cell death.

      Antibiotics work in different ways to kill or inhibit the growth of bacteria. The commonly used antibiotics can be classified based on their gross mechanism of action. The first group inhibits cell wall formation by either preventing peptidoglycan cross-linking (penicillins, cephalosporins, carbapenems) or peptidoglycan synthesis (glycopeptides like vancomycin). The second group inhibits protein synthesis by acting on either the 50S subunit (macrolides, chloramphenicol, clindamycin, linezolid, streptogrammins) or the 30S subunit (aminoglycosides, tetracyclines) of the bacterial ribosome. The third group inhibits DNA synthesis (quinolones like ciprofloxacin) or damages DNA (metronidazole). The fourth group inhibits folic acid formation (sulphonamides and trimethoprim), while the fifth group inhibits RNA synthesis (rifampicin). Understanding the mechanism of action of antibiotics is important in selecting the appropriate drug for a particular bacterial infection.

    • This question is part of the following fields:

      • General Principles
      19
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  • Question 5 - A 50-year-old man presents to a urology clinic with persistent haematuria. He has...

    Correct

    • A 50-year-old man presents to a urology clinic with persistent haematuria. He has a smoking history of 30 pack years and you suspect bladder cancer. After performing a cystoscopy and biopsy, the lesion is found to be malignant. What is the probable cell type?

      Your Answer: Transitional cell carcinoma

      Explanation:

      Bladder cancer is a common urological cancer that primarily affects males aged 50-80 years old. Smoking and exposure to hydrocarbons increase the risk of developing the disease. Chronic bladder inflammation from Schistosomiasis infection is also a common cause of squamous cell carcinomas in countries where the disease is endemic. Benign tumors of the bladder, such as inverted urothelial papilloma and nephrogenic adenoma, are rare. The most common bladder malignancies are urothelial (transitional cell) carcinoma, squamous cell carcinoma, and adenocarcinoma. Urothelial carcinomas may be solitary or multifocal, with papillary growth patterns having a better prognosis. The remaining tumors may be of higher grade and prone to local invasion, resulting in a worse prognosis.

      The TNM staging system is used to describe the extent of bladder cancer. Most patients present with painless, macroscopic hematuria, and a cystoscopy and biopsies or TURBT are used to provide a histological diagnosis and information on depth of invasion. Pelvic MRI and CT scanning are used to determine locoregional spread, and PET CT may be used to investigate nodes of uncertain significance. Treatment options include TURBT, intravesical chemotherapy, surgery (radical cystectomy and ileal conduit), and radical radiotherapy. The prognosis varies depending on the stage of the cancer, with T1 having a 90% survival rate and any T, N1-N2 having a 30% survival rate.

    • This question is part of the following fields:

      • Renal System
      36.4
      Seconds
  • Question 6 - An 80-year-old woman comes to the hospital complaining of chest pain, vomiting, and...

    Incorrect

    • An 80-year-old woman comes to the hospital complaining of chest pain, vomiting, and sweating for the past two hours. She has a medical history of hypertension and peripheral arterial disease. Despite using sublingual nitrate spray at home, the pain has not subsided. Upon admission, she is found to be tachycardic and tachypneic, but no other respiratory or cardiac abnormalities are detected. An ECG reveals ST segment elevation in leads II, III, and aVF, as well as ST segment depression in leads I and aVL. Which coronary artery is most likely affected?

      Your Answer:

      Correct Answer: Right coronary artery

      Explanation:

      The observed ECG alterations are indicative of an ischemic injury in the lower region of the heart. The ST depressions in leads I and aVL, which are located in the lateral wall, are common reciprocal changes that occur during an inferior myocardial infarction. Typically, the right coronary artery is the most probable site of damage in cases involving lesions in the lower wall.

      Understanding Acute Coronary Syndrome

      Acute coronary syndrome (ACS) is a term used to describe various acute presentations of ischaemic heart disease. It includes ST elevation myocardial infarction (STEMI), non-ST elevation myocardial infarction (NSTEMI), and unstable angina. ACS usually develops in patients with ischaemic heart disease, which is the gradual build-up of fatty plaques in the walls of the coronary arteries. This can lead to a gradual narrowing of the arteries, resulting in less blood and oxygen reaching the myocardium, causing angina. It can also lead to sudden plaque rupture, resulting in a complete occlusion of the artery and no blood or oxygen reaching the area of myocardium, causing a myocardial infarction.

      There are many factors that can increase the chance of a patient developing ischaemic heart disease, including unmodifiable risk factors such as increasing age, male gender, and family history, and modifiable risk factors such as smoking, diabetes mellitus, hypertension, hypercholesterolaemia, and obesity.

      The classic and most common symptom of ACS is chest pain, which is typically central or left-sided and may radiate to the jaw or left arm. Other symptoms include dyspnoea, sweating, and nausea and vomiting. Patients presenting with ACS often have very few physical signs, and the two most important investigations when assessing a patient with chest pain are an electrocardiogram (ECG) and cardiac markers such as troponin.

      Once a diagnosis of ACS has been made, treatment involves preventing worsening of the presentation, revascularising the vessel if occluded, and treating pain. For patients who’ve had a STEMI, the priority of management is to reopen the blocked vessel. For patients who’ve had an NSTEMI, a risk stratification tool is used to decide upon further management. Patients who’ve had an ACS require lifelong drug therapy to help reduce the risk of a further event, which includes aspirin, a second antiplatelet if appropriate, a beta-blocker, an ACE inhibitor, and a statin.

    • This question is part of the following fields:

      • Cardiovascular System
      0
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  • Question 7 - A 67-year-old man patient with a history of recurrent renal stones is referred...

    Incorrect

    • A 67-year-old man patient with a history of recurrent renal stones is referred to an endocrinologist for further investigations. The doctor performs a series of investigations, which includes the following results:

      Calcium 2.9 mmol/L (2.1-2.6)
      Phosphate 0.7 mmol/L (0.8-1.4)
      Magnesium 0.8 mmol/L (0.7-1.0)
      Thyroid stimulating hormone (TSH) 3.9 mU/L (0.5-5.5)
      Free thyroxine (T4) 17.5 pmol/L (9.0 - 18)
      Amylase 110 U/L (70 - 300)
      Uric acid 0.42 mmol/L (0.18 - 0.48)
      Creatine kinase 130 U/L (35 - 250)

      What is the most likely cause of this abnormality in the patient's test results?

      Your Answer:

      Correct Answer: Parathyroid hormone (PTH)

      Explanation:

      The regulation of calcium metabolism is mainly controlled by PTH and calcitriol. The patient is exhibiting symptoms of hyperparathyroidism, which is caused by excessive levels of parathyroid hormone leading to high serum calcium levels. This can result in recurrent renal stones, as well as other symptoms such as abdominal pain, fatigue, and confusion.

      Antidiuretic hormone, which promotes water retention in the body, does not directly affect calcium metabolism and is therefore not the correct answer.

      An excess of calcitriol would cause abnormally low levels of serum calcium, which does not match the clinical presentation in this case.

      Gonadotropin-releasing hormone stimulates the secretion of LH and FSH from the anterior pituitary gland and is not expected to affect calcium and phosphate levels.

      Hormones Controlling Calcium Metabolism

      Calcium metabolism is primarily controlled by two hormones, parathyroid hormone (PTH) and 1,25-dihydroxycholecalciferol (calcitriol). Other hormones such as calcitonin, thyroxine, and growth hormone also play a role. PTH increases plasma calcium levels and decreases plasma phosphate levels. It also increases renal tubular reabsorption of calcium, osteoclastic activity, and renal conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol. On the other hand, 1,25-dihydroxycholecalciferol increases plasma calcium and plasma phosphate levels, renal tubular reabsorption and gut absorption of calcium, osteoclastic activity, and renal phosphate reabsorption. It is important to note that osteoclastic activity is increased indirectly by PTH as osteoclasts do not have PTH receptors. Understanding the actions of these hormones is crucial in maintaining proper calcium metabolism in the body.

    • This question is part of the following fields:

      • General Principles
      0
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  • Question 8 - The emergency buzzer is activated for a 32-year-old woman in labour. Despite gentle...

    Incorrect

    • The emergency buzzer is activated for a 32-year-old woman in labour. Despite gentle traction, the midwife is unable to deliver the foetal shoulders after the head is delivered during a vaginal cephalic delivery. What is the most probable risk factor for this labour complication?

      Your Answer:

      Correct Answer: Foetal macrosomia

      Explanation:

      Shoulder dystocia is the labour complication discussed in this case, and it is more likely to occur in cases of foetal macrosomia. This is because larger babies have a greater shoulder diameter, making it more difficult for the shoulders to pass through the pelvic outlet.

      Maternal pre-eclampsia is a risk factor for small for gestational age (SGA) pregnancies, but it is not directly linked to shoulder dystocia.

      Obstetric cholestasis is a liver disorder that can occur during pregnancy, but it does not increase the risk of shoulder dystocia.

      While a previous caesarean section may increase the likelihood of placenta praevia, placenta accreta, or uterine rupture, it is not a direct risk factor for shoulder dystocia.

      A previous post-term delivery may increase the likelihood of future post-term deliveries, but it does not directly increase the risk of shoulder dystocia.

      Shoulder dystocia is a complication that can occur during vaginal delivery when the body of the fetus cannot be delivered after the head has already been delivered. This is usually due to the anterior shoulder of the fetus becoming stuck on the mother’s pubic bone. Shoulder dystocia can cause harm to both the mother and the baby.

      There are several risk factors that increase the likelihood of shoulder dystocia, including fetal macrosomia (large baby), high maternal body mass index, diabetes mellitus, and prolonged labor.

      If shoulder dystocia is identified, it is important to call for senior medical assistance immediately. The McRoberts’ maneuver is often used to help deliver the baby. This involves flexing and abducting the mother’s hips to increase the angle of the pelvis and facilitate delivery. An episiotomy may be performed to provide better access for internal maneuvers, but it will not relieve the bony obstruction. Symphysiotomy and the Zavanelli maneuver are not recommended as they can cause significant harm to the mother. Oxytocin administration is not effective in treating shoulder dystocia.

      Complications of shoulder dystocia can include postpartum hemorrhage and perineal tears for the mother, and brachial plexus injury or neonatal death for the baby. It is important to manage shoulder dystocia promptly and effectively to minimize these risks.

    • This question is part of the following fields:

      • Reproductive System
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  • Question 9 - A woman presents with symptoms of agalactorrhoea, amenorrhoea, intolerance to cold, constipation, and...

    Incorrect

    • A woman presents with symptoms of agalactorrhoea, amenorrhoea, intolerance to cold, constipation, and weight loss six months after giving birth. She experienced postpartum bleeding during delivery and has now been diagnosed with hypopituitarism. What could be the possible reason for this condition?

      Your Answer:

      Correct Answer: Sheehan's syndrome

      Explanation:

      Sheehan’s syndrome is a condition that arises from pituitary ischaemia, which is caused by blood loss during or after childbirth. The syndrome is characterized by symptoms that indicate global hypopituitarism, including agalactorrhoea (lack of prolactin), amenorrhoea (lack of FSH and LH), cold intolerance and constipation (lack of thyroid hormones), and weight loss (lack of steroid hormones).

      Malignancy is an uncommon cause of hypopituitarism.

      While pituitary adenoma is a frequent cause of hypopituitarism, it is unlikely to be the cause of this patient’s symptoms, given that they occurred after childbirth. Pituitary adenoma may also present with symptoms related to mass effect, such as headache and bilateral hemianopia.

      Understanding Hypopituitarism: Causes, Symptoms, and Management

      Hypopituitarism is a medical condition that occurs when the pituitary gland fails to produce enough hormones. This can be caused by various factors such as compression of the gland by non-secretory pituitary macroadenoma, pituitary apoplexy, Sheehan’s syndrome, hypothalamic tumors, trauma, iatrogenic irradiation, and infiltrative diseases like hemochromatosis and sarcoidosis. The symptoms of hypopituitarism depend on which hormones are deficient. For instance, low ACTH can cause tiredness and postural hypotension, while low FSH/LH can lead to amenorrhea, infertility, and loss of libido. Low TSH can cause constipation and feeling cold, while low GH can result in short stature if it occurs during childhood. Low prolactin can cause problems with lactation.

      To diagnose hypopituitarism, hormone profile testing and imaging are usually conducted. Treatment involves addressing the underlying cause, such as surgical removal of pituitary macroadenoma, and replacement of deficient hormones. It is important to manage hypopituitarism promptly to prevent complications and improve the patient’s quality of life.

    • This question is part of the following fields:

      • Renal System
      0
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  • Question 10 - A boy dashes to catch a bus.
    What adjustments does his body undergo...

    Incorrect

    • A boy dashes to catch a bus.
      What adjustments does his body undergo for this brief physical activity?

      Your Answer:

      Correct Answer: Increased blood flow to skin

      Explanation:

      Phases of Physiological Response to Exercise

      Regular exercise triggers a series of physiological responses in the body. These responses can be divided into three phases: stress reaction, resistance reaction, and adaptation reaction. The stress reaction is the initial response to short-term exercise. During this phase, the body increases sympathetic activity, reduces parasympathetic activity, and redirects blood flow to muscles and skin for cooling. Respiration becomes deeper and metabolic buffering responds to the generation of lactic acid through anaerobic respiration.

      As exercise continues, the resistance reaction takes over. This phase occurs minutes to hours after the initiation of exercise and involves the release of hormones such as ACTH, cortisol, growth hormone, and adrenaline. Finally, the adaptation reaction develops over days to weeks of regular exercise. During this phase, genes are activated in exercising tissues, promoting increases in strength, speed, and endurance.

      Overall, the phases of physiological response to exercise can help individuals tailor their exercise routines to achieve their desired outcomes. By gradually increasing the intensity and duration of exercise, individuals can promote the adaptation reaction and achieve long-term improvements in their physical fitness.

    • This question is part of the following fields:

      • Clinical Sciences
      0
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  • Question 11 - A 63-year-old man presents with a 5-month history of non-specific back pain, fatigue...

    Incorrect

    • A 63-year-old man presents with a 5-month history of non-specific back pain, fatigue and loss of appetite. He has a medical history of type 2 diabetes mellitus controlled with diet, chronic obstructive pulmonary disease, and seasonal affective disorder. He has a 30 pack-year smoking history. On examination, his vital signs are within normal limits except for saturations of 94% on room air. A chest x-ray shows hyperinflated lung fields bilaterally, unchanged from a previous x-ray. Blood tests and urine analysis reveal a positive urinary Bence-Jones protein. Based on these findings, what is the most likely diagnosis?

      Your Answer:

      Correct Answer: Multiple myeloma

      Explanation:

      The diagnosis of multiple myeloma can be supported by the presence of Bence-Jones protein on urinary analysis, although it is not always necessary. This haematological malignancy of plasma cells is characterized by bone pain and lytic bone lesions. Hypercalcaemia can also indicate the presence of multiple myeloma.

      Ankylosing spondylitis is a chronic inflammatory arthritis that typically affects young men and is associated with HLA-B27. Symptoms include early-morning back pain that improves with exercise, and an elevated ESR may be observed.

      Chronic myeloid leukaemia (CML) is a haematological malignancy that is linked to genetic translocation on chromosome 9 (Philadelphia chromosome). It is characterized by high white cell count, splenomegaly, and blast cells seen on marrow biopsy.

      Gastric and pancreatic cancer may present with non-specific symptoms such as fatigue, weight loss, loss of appetite, and abdominal fullness or pain. Biochemistry may be normal or show raised inflammatory markers, and diagnosis is confirmed through biopsy following imaging.

      Understanding Multiple Myeloma: Features and Investigations

      Multiple myeloma is a type of cancer that affects the plasma cells in the bone marrow. It is most commonly found in patients aged 60-70 years. The disease is characterized by a range of symptoms, which can be remembered using the mnemonic CRABBI. These include hypercalcemia, renal damage, anemia, bleeding, bone lesions, and increased susceptibility to infection. Other features of multiple myeloma include amyloidosis, carpal tunnel syndrome, neuropathy, and hyperviscosity.

      To diagnose multiple myeloma, a range of investigations are required. Blood tests can reveal anemia, renal failure, and hypercalcemia. Protein electrophoresis can detect raised levels of monoclonal IgA/IgG proteins in the serum, while bone marrow aspiration can confirm the diagnosis if the number of plasma cells is significantly raised. Imaging studies, such as whole-body MRI or X-rays, can be used to detect osteolytic lesions.

      The diagnostic criteria for multiple myeloma require one major and one minor criteria or three minor criteria in an individual who has signs or symptoms of the disease. Major criteria include the presence of plasmacytoma, 30% plasma cells in a bone marrow sample, or elevated levels of M protein in the blood or urine. Minor criteria include 10% to 30% plasma cells in a bone marrow sample, minor elevations in the level of M protein in the blood or urine, osteolytic lesions, or low levels of antibodies in the blood. Understanding the features and investigations of multiple myeloma is crucial for early detection and effective treatment.

    • This question is part of the following fields:

      • Haematology And Oncology
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  • Question 12 - Which one of the following statements relating to the posterior cerebral artery is...

    Incorrect

    • Which one of the following statements relating to the posterior cerebral artery is false?

      Your Answer:

      Correct Answer: It is connected to the circle of Willis via the superior cerebellar artery

      Explanation:

      The bifurcation of the basilar artery gives rise to the posterior cerebral arteries, which are linked to the circle of Willis through the posterior communicating artery.

      These arteries provide blood supply to the occipital lobe and a portion of the temporal lobe.

      The Circle of Willis is an anastomosis formed by the internal carotid arteries and vertebral arteries on the bottom surface of the brain. It is divided into two halves and is made up of various arteries, including the anterior communicating artery, anterior cerebral artery, internal carotid artery, posterior communicating artery, and posterior cerebral arteries. The circle and its branches supply blood to important areas of the brain, such as the corpus striatum, internal capsule, diencephalon, and midbrain.

      The vertebral arteries enter the cranial cavity through the foramen magnum and lie in the subarachnoid space. They then ascend on the anterior surface of the medulla oblongata and unite to form the basilar artery at the base of the pons. The basilar artery has several branches, including the anterior inferior cerebellar artery, labyrinthine artery, pontine arteries, superior cerebellar artery, and posterior cerebral artery.

      The internal carotid arteries also have several branches, such as the posterior communicating artery, anterior cerebral artery, middle cerebral artery, and anterior choroid artery. These arteries supply blood to different parts of the brain, including the frontal, temporal, and parietal lobes. Overall, the Circle of Willis and its branches play a crucial role in providing oxygen and nutrients to the brain.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 13 - A motorcyclist in his mid-twenties has been in a road traffic accident resulting...

    Incorrect

    • A motorcyclist in his mid-twenties has been in a road traffic accident resulting in severe injuries to his right shoulder. Upon examination, his shoulder is adducted and medially rotated, while his elbow is fully extended and his forearm is pronated. What is the most probable diagnosis?

      Your Answer:

      Correct Answer: C5, C6 root lesion

      Explanation:

      The individual is experiencing Erb’s palsy due to a lesion in the C5 and C6 roots. This condition is often linked to birth injuries that occur when a baby experiences shoulder dystocia. Symptoms include the waiter’s tip position, inability to raise the shoulder (due to paralysis of the deltoid and supraspinatus muscles), inability to externally rotate the shoulder (due to paralysis of the infraspinatus muscle), inability to flex the elbow (due to paralysis of the biceps, brachialis, and brachioradialis muscles), and inability to supinate the forearm (due to paralysis of the biceps muscle).

      Understanding the Brachial Plexus and Cutaneous Sensation of the Upper Limb

      The brachial plexus is a network of nerves that originates from the anterior rami of C5 to T1. It is divided into five sections: roots, trunks, divisions, cords, and branches. To remember these sections, a common mnemonic used is Real Teenagers Drink Cold Beer.

      The roots of the brachial plexus are located in the posterior triangle and pass between the scalenus anterior and medius muscles. The trunks are located posterior to the middle third of the clavicle, with the upper and middle trunks related superiorly to the subclavian artery. The lower trunk passes over the first rib posterior to the subclavian artery. The divisions of the brachial plexus are located at the apex of the axilla, while the cords are related to the axillary artery.

      The branches of the brachial plexus provide cutaneous sensation to the upper limb. This includes the radial nerve, which provides sensation to the posterior arm, forearm, and hand; the median nerve, which provides sensation to the palmar aspect of the thumb, index, middle, and half of the ring finger; and the ulnar nerve, which provides sensation to the palmar and dorsal aspects of the fifth finger and half of the ring finger.

      Understanding the brachial plexus and its branches is important in diagnosing and treating conditions that affect the upper limb, such as nerve injuries and neuropathies. It also helps in understanding the cutaneous sensation of the upper limb and how it relates to the different nerves of the brachial plexus.

    • This question is part of the following fields:

      • Neurological System
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  • Question 14 - You eagerly begin your second laparoscopic cholecystectomy and encounter unexpected difficulties with the...

    Incorrect

    • You eagerly begin your second laparoscopic cholecystectomy and encounter unexpected difficulties with the anatomy of Calots triangle. While attempting to apply a haemostatic clip, you accidentally tear the cystic artery, resulting in profuse bleeding. What is the most probable source of this bleeding?

      Your Answer:

      Correct Answer: Right hepatic artery

      Explanation:

      The most frequent scenario is for the cystic artery to originate from the right hepatic artery, although there are known variations in the anatomy of the gallbladder’s blood supply.

      The gallbladder is a sac made of fibromuscular tissue that can hold up to 50 ml of fluid. Its lining is made up of columnar epithelium. The gallbladder is located in close proximity to various organs, including the liver, transverse colon, and the first part of the duodenum. It is covered by peritoneum and is situated between the right lobe and quadrate lobe of the liver. The gallbladder receives its arterial supply from the cystic artery, which is a branch of the right hepatic artery. Its venous drainage is directly to the liver, and its lymphatic drainage is through Lund’s node. The gallbladder is innervated by both sympathetic and parasympathetic nerves. The common bile duct originates from the confluence of the cystic and common hepatic ducts and is located in the hepatobiliary triangle, which is bordered by the common hepatic duct, cystic duct, and the inferior edge of the liver. The cystic artery is also found within this triangle.

    • This question is part of the following fields:

      • Gastrointestinal System
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  • Question 15 - What is the composition of nails? ...

    Incorrect

    • What is the composition of nails?

      Your Answer:

      Correct Answer: Keratin

      Explanation:

      Skin, Collagen, and Other Components of Tissue

      The epidermis is composed of keratinocytes that become less cellular and harder as they move towards the surface. The nail bed is a specialized area of skin that produces hardened plates of keratin to form nails. Type I collagen is the primary structural collagen that helps form bone, cartilage, and tendons. Ehlers-Danlos syndrome is a condition where Type I collagen is defective. Type IV collagen is the primary structural collagen in the basement membrane and is defective in Alport’s syndrome. Hyaluronic acid is a glycosaminoglycan and a major component of the ground substance that surrounds cells. Fibrin is an insoluble protein that cross-links to form clots as part of haemostasis.

      Overall, these components play important roles in the structure and function of tissues in the body. their functions and potential defects can aid in the diagnosis and treatment of various conditions.

    • This question is part of the following fields:

      • Histology
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  • Question 16 - You come across a young woman who has recently been diagnosed with schizophrenia....

    Incorrect

    • You come across a young woman who has recently been diagnosed with schizophrenia. She is curious about what her future may look like with the condition.

      Your Answer:

      Correct Answer: Associated with a poor prognosis

      Explanation:

      A prodromal phase characterized by social withdrawal is linked to a negative prognosis in individuals with schizophrenia.

      Schizophrenia is a mental disorder that can have varying outcomes for individuals. There are certain factors that have been associated with a poor prognosis, meaning a less favorable outcome. These factors include a strong family history of the disorder, a gradual onset of symptoms, a low IQ, a prodromal phase of social withdrawal, and a lack of an obvious precipitant for the onset of symptoms. It is important to note that these factors do not guarantee a poor outcome, but they may increase the likelihood of it. It is also important to seek treatment and support regardless of these factors, as early intervention and ongoing care can greatly improve outcomes for individuals with schizophrenia.

    • This question is part of the following fields:

      • Psychiatry
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  • Question 17 - A child with severe hydrocephalus is exhibiting a lack of upward gaze. What...

    Incorrect

    • A child with severe hydrocephalus is exhibiting a lack of upward gaze. What specific area of the brain is responsible for this impairment?

      Your Answer:

      Correct Answer: Superior colliculi

      Explanation:

      The superior colliculi play a crucial role in upward gaze and are located on both sides of the tectal or quadrigeminal plate. Damage or compression of the superior colliculi, such as in severe hydrocephalus, can result in the inability to look up, known as sunsetting of the eyes.

      The optic chiasm serves as the connection between the anterior and posterior optic pathways. The nasal fibers of the optic nerves cross over at the chiasm, leading to monocular visual field deficits with anterior pathway lesions and binocular visual field deficits with posterior pathway lesions.

      The lateral geniculate body in the thalamus is where the optic tract connects with the optic radiations, while the inferior colliculi and medial geniculate bodies are responsible for processing auditory stimuli.

      Understanding the Diencephalon: An Overview of Brain Anatomy

      The diencephalon is a part of the brain that is located between the cerebral hemispheres and the brainstem. It is composed of several structures, including the thalamus, hypothalamus, epithalamus, and subthalamus. Each of these structures plays a unique role in regulating various bodily functions and behaviors.

      The thalamus is responsible for relaying sensory information from the body to the cerebral cortex, which is responsible for processing and interpreting this information. The hypothalamus, on the other hand, is involved in regulating a wide range of bodily functions, including hunger, thirst, body temperature, and sleep. It also plays a role in regulating the release of hormones from the pituitary gland.

      The epithalamus is a small structure that is involved in regulating the sleep-wake cycle and the production of melatonin, a hormone that helps to regulate sleep. The subthalamus is involved in regulating movement and is part of the basal ganglia, a group of structures that are involved in motor control.

      Overall, the diencephalon plays a crucial role in regulating many of the body’s essential functions and behaviors. Understanding its anatomy and function can help us better understand how the brain works and how we can maintain optimal health and well-being.

    • This question is part of the following fields:

      • Neurological System
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  • Question 18 - A 32-year-old man suffers an injury from farm machinery resulting in a laceration...

    Incorrect

    • A 32-year-old man suffers an injury from farm machinery resulting in a laceration at the superolateral aspect of the popliteal fossa and a laceration of the medial aspect of the biceps femoris. What is the most vulnerable underlying structure to injury in this case?

      Your Answer:

      Correct Answer: Common peroneal nerve

      Explanation:

      The greatest risk of injury lies with the common peroneal nerve, which is located beneath the medial aspect of the biceps femoris. Although not mentioned, the tibial nerve may also be affected by this type of injury. The sural nerve branches off at a lower point.

      The common peroneal nerve originates from the dorsal divisions of the sacral plexus, specifically from L4, L5, S1, and S2. This nerve provides sensation to the skin and fascia of the anterolateral surface of the leg and dorsum of the foot, as well as innervating the muscles of the anterior and peroneal compartments of the leg, extensor digitorum brevis, and the knee, ankle, and foot joints. It is located laterally within the sciatic nerve and passes through the lateral and proximal part of the popliteal fossa, under the cover of biceps femoris and its tendon, to reach the posterior aspect of the fibular head. The common peroneal nerve divides into the deep and superficial peroneal nerves at the point where it winds around the lateral surface of the neck of the fibula in the body of peroneus longus, approximately 2 cm distal to the apex of the head of the fibula. It is palpable posterior to the head of the fibula. The nerve has several branches, including the nerve to the short head of biceps, articular branch (knee), lateral cutaneous nerve of the calf, and superficial and deep peroneal nerves at the neck of the fibula.

    • This question is part of the following fields:

      • Neurological System
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  • Question 19 - How can this question be restated? ...

    Incorrect

    • How can this question be restated?

      Your Answer:

      Correct Answer: NMDA receptors are ligand gated ion channels

      Explanation:

      Different Types of Receptors in the Body

      There are various types of receptors in the body that play important roles in different physiological processes. One type of receptor is the 5HT3 receptor, which is a ligand gated ion channel. This means that it opens and closes in response to the binding of a specific ligand, allowing ions to flow in and out of the cell. Another type of receptor is the aldosterone receptor, which is a steroid receptor. This receptor binds to the hormone aldosterone and regulates the body’s electrolyte balance.

      The β2 adrenoreceptor is another type of receptor, which is a g protein coupled receptor. This receptor is activated by the hormone adrenaline and plays a role in regulating heart rate and bronchodilation. Finally, the insulin receptor is a tyrosine receptor kinase. This receptor is activated by the hormone insulin and plays a crucial role in regulating glucose metabolism in the body. the different types of receptors in the body is important for how different physiological processes are regulated.

    • This question is part of the following fields:

      • Pharmacology
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  • Question 20 - A newly diagnosed patient with acute myeloid leukaemia (AML) is about to begin...

    Incorrect

    • A newly diagnosed patient with acute myeloid leukaemia (AML) is about to begin treatment. What would be a favorable prognostic factor for this individual?

      Your Answer:

      Correct Answer: Acute promyelocytic leukaemia (APML) subtype

      Explanation:

      Prognostic Factors in Acute Myeloid Leukemia

      Acute myeloid leukemia (AML) is a type of cancer that affects the blood and bone marrow. The APML subtype of AML has a higher five-year survival rate of 70% compared to the average rate of 25%. However, it is a medical emergency upon presentation due to the risk of coagulopathy, tumor lysis, and life-threatening infections. Urgent treatment with ATRA chemotherapy is necessary. Younger patients tend to have a better prognosis and can tolerate intensive chemotherapy better. Certain cytogenetic changes, such as t(15;17) in APML and t(8;21) and inv(16), are associated with a favorable prognosis. However, complex cytogenetics are not. A performance status of 3, which indicates that an individual spends more than 50% of the day in bed, is not ideal for intensive chemotherapy. AML that arises from a pre-existing condition, such as a myeloproliferative neoplasm, has a worse prognosis than AML that arises de novo.

      Overall, the prognostic factors in AML is crucial for determining the appropriate treatment plan and predicting outcomes.

    • This question is part of the following fields:

      • Haematology And Oncology
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