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  • Question 1 - A 45-year-old man was admitted to critical care with urinary sepsis. He was...

    Incorrect

    • A 45-year-old man was admitted to critical care with urinary sepsis. He was intubated and ventilated and treated with intravenous fluids and antibiotics. About a week later, he developed an oxygen requirement, and the medical team observed crackles at the right base.

      What are the laboratory characteristics linked with Pseudomonas aeruginosa, as indicated by a sputum culture showing Gram-negative rod?

      Your Answer:

      Correct Answer: Non-lactose fermenting

      Explanation:

      Lab findings that suggest the presence of Pseudomonas aeruginosa include a gram-negative rod, non-lactose fermenting, and positive for oxidase. In this case, the patient likely acquired a nosocomial infection with Pseudomonas aeruginosa, which is a common cause of hospital-acquired pneumonia or ventilator-acquired pneumonia. It is important to note that Pseudomonas aeruginosa does not cause haemolysis, unlike Group A Streptococcus, which exhibits beta-haemolysis. Streptococcus pneumoniae, on the other hand, is a gram-positive coccus that causes alpha-haemolysis and is a less likely cause of hospital/ventilator-acquired pneumonia.

      Pseudomonas aeruginosa: A Gram-negative Rod Causing Various Infections

      Pseudomonas aeruginosa is a type of bacteria that is commonly found in the environment. It is a Gram-negative rod that can cause a range of infections in humans. Some of the infections it causes include chest infections, skin infections such as burns and wound infections, otitis externa, and urinary tract infections.

      In the laboratory, Pseudomonas aeruginosa is identified as a Gram-negative rod that does not ferment lactose and is oxidase positive. The bacteria produce both an endotoxin and exotoxin A. The endotoxin causes fever and shock, while exotoxin A inhibits protein synthesis by catalyzing ADP-ribosylation of elongation factor EF-2.

      Overall, Pseudomonas aeruginosa is a pathogenic bacteria that can cause a variety of infections in humans. Its ability to produce toxins makes it particularly dangerous and difficult to treat. Proper hygiene and infection control measures can help prevent the spread of this bacteria.

    • This question is part of the following fields:

      • General Principles
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  • Question 2 - A 45-year-old man with a history of asthma visits his doctor due to...

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    • A 45-year-old man with a history of asthma visits his doctor due to persistent symptoms despite using his inhaler. The doctor decides to prescribe a medication called salmeterol, which has a prolonged effect and works by relaxing the smooth muscles in the airways.

      What specific receptor does salmeterol target?

      Your Answer:

      Correct Answer: Beta-2 receptors

      Explanation:

      Formoterol acts on beta-2 receptors to cause smooth muscle relaxation and bronchodilation, while aclidinium is a muscarinic receptors antagonist which results in bronchodilation. Alpha-1 receptors cause vasoconstriction, increased peripheral resistance, increased blood pressure, and mydriasis, while beta-1 receptors lead to cardiac muscle contraction and can increase heart rate. Alpha-2 receptors cause vasoconstriction of certain blood vessels, suppression of norepinephrine release, and decreased motility of smooth muscle in the gastrointestinal tract.

      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: Îħ1, Îħ2, β1, and β2. Each receptor has a different potency order and primary action. The Îħ1 receptor responds equally to norepinephrine and epinephrine, causing smooth muscle contraction. The Îħ2 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.

    • This question is part of the following fields:

      • General Principles
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  • Question 3 - What is the primary process of growth that causes benign enlargement of the...

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    • What is the primary process of growth that causes benign enlargement of the prostate?

      Your Answer:

      Correct Answer: Hyperplasia

      Explanation:

      Benign Prostatic Hyperplasia

      Benign prostatic hyperplasia (BPH) is a common condition that affects men as they age. It is characterized by an increase in the number of cells in the prostate gland, which leads to its enlargement. This process is known as hyperplasia and is the main method for age-related prostate enlargement. BPH is caused by an increase in the number of exocrine glands and ducts, which are structurally normal.

      Hypertrophy, which is an increase in the size of cells, also plays a role in BPH, but to a lesser extent. It mainly affects the central (periurethral) zone of the prostate, causing urethral compression and the symptoms of bladder outlet obstruction. On the other hand, dysplasia, which is the abnormal growth of cells, is more likely to occur in the peripheral zone of the prostate. This area has the potential to develop into malignancy, making it important to monitor any changes in the prostate gland. the mechanisms behind BPH can help in the diagnosis and management of this condition.

    • This question is part of the following fields:

      • Clinical Sciences
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  • Question 4 - Which of the following structures separates the ulnar artery from the median nerve?...

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    • Which of the following structures separates the ulnar artery from the median nerve?

      Your Answer:

      Correct Answer: Pronator teres

      Explanation:

      It is located deeply to the pronator teres muscle, which creates a separation from the median nerve.

      Anatomy of the Ulnar Artery

      The ulnar artery is a blood vessel that begins in the middle of the antecubital fossa and runs obliquely downward towards the ulnar side of the forearm. It then follows the ulnar border to the wrist, where it crosses over the flexor retinaculum and divides into the superficial and deep volar arches. The artery is deep to the pronator teres, flexor carpi radialis, and palmaris longus muscles, and lies on the brachialis and flexor digitorum profundus muscles. At the wrist, it is superficial to the flexor retinaculum.

      The ulnar nerve runs medially to the lower two-thirds of the artery, while the median nerve is in relation with the medial side of the artery for about 2.5 cm before crossing over it. The artery also gives off a branch called the anterior interosseous artery.

      Understanding the anatomy of the ulnar artery is important for medical professionals, as it plays a crucial role in the blood supply to the forearm and hand.

    • This question is part of the following fields:

      • Musculoskeletal System And Skin
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  • Question 5 - You are asked to speak to a 72-year-old man in the respiratory clinic...

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    • You are asked to speak to a 72-year-old man in the respiratory clinic regarding his recent diagnosis of tuberculosis (TB). He originally presented with a 4-week history of productive cough and night sweats. Samples taken from a broncho-alveolar lavage showed a dense infiltration of macrophages which had formed a granuloma.

      What cytokines are produced by this cell type?

      Your Answer:

      Correct Answer: Interleukin-1

      Explanation:

      Macrophages are the primary source of IL-1, which plays a crucial role in acute inflammation and the fever response. Th1 cells produce interferon-γ, which activates macrophages. IL-2, produced by T helper 1 cells, is essential for the growth and development of various immune cells, including T cells, B cells, and natural killer cells, to combat infections. T helper 2 cells produce IL-4, which aids in the proliferation and differentiation of B cells, while IL-5 stimulates the production of eosinophils.

      Overview of Cytokines and Their Functions

      Cytokines are signaling molecules that play a crucial role in the immune system. Interleukins are a type of cytokine that are produced by various immune cells and have specific functions. IL-1, produced by macrophages, induces acute inflammation and fever. IL-2, produced by Th1 cells, stimulates the growth and differentiation of T cell responses. IL-3, produced by activated T helper cells, stimulates the differentiation and proliferation of myeloid progenitor cells. IL-4, produced by Th2 cells, stimulates the proliferation and differentiation of B cells. IL-5, also produced by Th2 cells, stimulates the production of eosinophils. IL-6, produced by macrophages and Th2 cells, stimulates the differentiation of B cells and induces fever. IL-8, produced by macrophages, promotes neutrophil chemotaxis. IL-10, produced by Th2 cells, inhibits Th1 cytokine production and is known as an anti-inflammatory cytokine. IL-12, produced by dendritic cells, macrophages, and B cells, activates NK cells and stimulates the differentiation of naive T cells into Th1 cells.

      In addition to interleukins, there are other cytokines with specific functions. Tumor necrosis factor-alpha, produced by macrophages, induces fever and promotes neutrophil chemotaxis. Interferon-gamma, produced by Th1 cells, activates macrophages. Understanding the functions of cytokines is important in developing treatments for various immune-related diseases.

    • This question is part of the following fields:

      • General Principles
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  • Question 6 - A patient in her mid-40s complains of numbness on the left side of...

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    • A patient in her mid-40s complains of numbness on the left side of her face. During cranial nerve examination, it is discovered that the left, lower third of her face has lost sensation, which is the area controlled by the mandibular branch of the trigeminal nerve. Through which structure does this nerve branch pass?

      Your Answer:

      Correct Answer: Foramen ovale

      Explanation:

      The mandibular branch of the trigeminal nerve travels through the foramen ovale. Other nerves that pass through different foramina include the maxillary branch of the trigeminal nerve through the foramen rotundum, the glossopharyngeal, vagus, and accessory nerves through the foramen magnum, and the meningeal branch of the mandibular nerve through the foramen spinosum.

      Foramina of the Skull

      The foramina of the skull are small openings in the bones that allow for the passage of nerves and blood vessels. These foramina are important for the proper functioning of the body and can be tested on exams. Some of the major foramina include the optic canal, superior and inferior orbital fissures, foramen rotundum, foramen ovale, and jugular foramen. Each of these foramina has specific vessels and nerves that pass through them, such as the ophthalmic artery and optic nerve in the optic canal, and the mandibular nerve in the foramen ovale. It is important to have a basic understanding of these foramina and their contents in order to understand the anatomy and physiology of the head and neck.

    • This question is part of the following fields:

      • Neurological System
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  • Question 7 - A 21-year-old man is participating in a rugby game when he experiences a...

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    • A 21-year-old man is participating in a rugby game when he experiences a sharp pain in the posterolateral area of his right thigh. Which muscle group is the most probable source of the injury?

      Your Answer:

      Correct Answer: Long head of biceps femoris

      Explanation:

      The hamstring muscle group consists of three muscles: the biceps femoris, which is located on the lateral side, and the semitendinosus and semimembranosus, which are located on the medial side. While less common, it is possible for the gastrocnemius and soleus muscles to also experience a rupture.

      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.

    • This question is part of the following fields:

      • Musculoskeletal System And Skin
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  • Question 8 - What is the initial event that triggers puberty in girls? ...

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    • What is the initial event that triggers puberty in girls?

      Your Answer:

      Correct Answer: Nocturnal rise in luteinising hormone (LH)

      Explanation:

      Puberty is triggered by endocrine changes that begin years before visible changes occur. The initial event is an increase in nocturnal LH secretion under the stimulation of GnRH. LH patterns of secretion change over time, resembling the adult pattern. In females, increased secretion of GnRH, LH, FSH, and estrogen causes the development of secondary sexual characteristics, adrenarche, gonadarche, thelarche, and menarche. The growth spurt for girls occurs in mid-puberty around the age of 12.

    • This question is part of the following fields:

      • Paediatrics
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  • Question 9 - A female patient complains of continuous vaginal bleeding a month after undergoing a...

    Incorrect

    • A female patient complains of continuous vaginal bleeding a month after undergoing a hydatidiform mole evacuation. What could be the probable diagnosis?

      Your Answer:

      Correct Answer: Choriocarcinoma

      Explanation:

      The woman’s history of molar pregnancy suggests choriocarcinoma as a potential complication. Bleeding lasting one month after vaginal trauma, vaginitis, or uterine atony is not normal. Endometrial cancer is unlikely in women of childbearing age.

      Gestational trophoblastic disorders refer to a range of conditions that originate from the placental trophoblast. These disorders include complete hydatidiform mole, partial hydatidiform mole, and choriocarcinoma. Complete hydatidiform mole is a benign tumor of trophoblastic material that occurs when an empty egg is fertilized by a single sperm that duplicates its own DNA, resulting in all 46 chromosomes being of paternal origin. Symptoms of this disorder include bleeding in the first or early second trimester, exaggerated pregnancy symptoms, a large uterus for dates, and high levels of human chorionic gonadotropin (hCG) in the blood. Hypertension and hyperthyroidism may also be present. Urgent referral to a specialist center is necessary, and evacuation of the uterus is performed. Effective contraception is recommended to avoid pregnancy in the next 12 months. About 2-3% of cases may progress to choriocarcinoma. In partial mole, a normal haploid egg may be fertilized by two sperms or one sperm with duplication of paternal chromosomes, resulting in DNA that is both maternal and paternal in origin. Fetal parts may be visible, and the condition is usually triploid.

    • This question is part of the following fields:

      • Reproductive System
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  • Question 10 - A 50-year-old obese woman presents with right upper quadrant abdominal pain, nausea and...

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    • A 50-year-old obese woman presents with right upper quadrant abdominal pain, nausea and vomiting. She has a family history of gallstone disease. Upon physical examination, a positive Murphy's sign is observed. An abdominal ultrasound reveals gallstones in the thickened gallbladder. The surgeon opts for a laparoscopic cholecystectomy to remove the gallbladder. During the procedure, the surgeon identifies and dissects the hepatobiliary triangle to safely ligate and divide two structures.

      What are the two structures being referred to in the above scenario?

      Your Answer:

      Correct Answer: Cystic duct and cystic artery

      Explanation:

      During laparoscopic cholecystectomy, the hepatobiliary triangle plays a crucial role in ensuring the safe ligation and division of the cystic duct and cystic artery. Surgeons must carefully dissect this area to identify these structures and avoid any potential biliary complications.

      The hepatobiliary triangle is bordered by the common hepatic duct, which is formed by the union of the common bile duct and cystic duct. The cystic artery branches off from the right hepatic artery, while Lund’s node serves as the sentinel lymph node of the gallbladder.

      The accessory duct is considered auxiliary to the biliary tree, and the left and right hepatic ducts merge into the common hepatic duct. The gastroduodenal artery arises from the common hepatic artery, and the cystic vein helps distinguish between the cystic and common hepatic ducts during surgery, but is not ligated.

      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 11 - A 28-year-old man has just begun taking haloperidol and is worried about developing...

    Incorrect

    • A 28-year-old man has just begun taking haloperidol and is worried about developing Parkinsonism due to some motor symptoms he has been experiencing. What sign during the examination would suggest a different diagnosis?

      Your Answer:

      Correct Answer: Babinski's sign

      Explanation:

      Extrapyramidal symptoms such as akathisia, bradykinesia, dystonia, and tardive dyskinesia are commonly observed in Parkinsonian conditions. Babinski’s sign, which is the upward movement of the big toe upon stimulation of the sole of the foot, is normal in infants but may indicate upper motor neuron dysfunction in older individuals. The presence of these symptoms suggests a possible diagnosis of Parkinsonism, as discussed in the case.

      Parkinsonism is a condition that can be caused by various factors. One of the most common causes is Parkinson’s disease, which is a degenerative disorder of the nervous system. Other causes include drug-induced Parkinsonism, which can occur as a side effect of certain medications such as antipsychotics and metoclopramide. Progressive supranuclear palsy, multiple system atrophy, Wilson’s disease, post-encephalitis, dementia pugilistica, and exposure to toxins such as carbon monoxide and MPTP can also lead to Parkinsonism.

      It is important to note that not all medications that can cause Parkinsonism have the same effect. For example, domperidone does not cross the blood-brain barrier and therefore does not cause extrapyramidal side-effects. Parkinsonism can have a significant impact on a person’s quality of life, and it is important to identify the underlying cause in order to provide appropriate treatment and management. With proper care and management, individuals with Parkinsonism can lead fulfilling lives.

    • This question is part of the following fields:

      • Neurological System
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  • Question 12 - A 25-year-old woman is seeking your assistance in getting a referral to a...

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    • A 25-year-old woman is seeking your assistance in getting a referral to a clinical geneticist. She has a family history of Huntington's disease, with her grandfather having died from the condition and her father recently being diagnosed. She wants to learn more about the disease and its genetic inheritance. Which of the following statements is accurate?

      Your Answer:

      Correct Answer: Huntington's disease is caused by a defect on chromosome 4

      Explanation:

      The cause of Huntington’s disease is a flaw in the huntingtin gene located on chromosome 4, resulting in a degenerative and irreversible neurological disorder. It is inherited in an autosomal dominant pattern and affects both genders equally.

      Huntington’s disease is a genetic disorder that causes progressive and incurable neurodegeneration. It is inherited in an autosomal dominant manner and is caused by a trinucleotide repeat expansion of CAG in the huntingtin gene on chromosome 4. This can result in the phenomenon of anticipation, where the disease presents at an earlier age in successive generations. The disease leads to the degeneration of cholinergic and GABAergic neurons in the striatum of the basal ganglia, which can cause a range of symptoms.

      Typically, symptoms of Huntington’s disease develop after the age of 35 and can include chorea, personality changes such as irritability, apathy, and depression, intellectual impairment, dystonia, and saccadic eye movements. Unfortunately, there is currently no cure for Huntington’s disease, and it usually results in death around 20 years after the initial symptoms develop.

    • This question is part of the following fields:

      • Neurological System
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  • Question 13 - A 5-year-old girl with Down's syndrome is being evaluated for chronic constipation. An...

    Incorrect

    • A 5-year-old girl with Down's syndrome is being evaluated for chronic constipation. An abdominal ultrasound revealed an incidental finding of a small left kidney. Which structure is most likely to have been affected during embryological development?

      Your Answer:

      Correct Answer: Ureteric bud

      Explanation:

      The ureteric bud is responsible for the development of the ureter, renal pelvis, collecting duct, and calyces in the kidney. It should be noted that the metanephrogenic blastema also plays a role in kidney development by giving rise to the glomerulus and renal tubules. However, the paramesonephric duct and urogenital sinus are not involved in kidney development, as they give rise to structures related to genitalia. Similarly, the bulbourethral glands and ductus deferens are also associated with genitalia and not the kidneys. In males, the ductus deferens is responsible for transporting sperm to the epididymis.

      Urogenital Embryology: Development of Kidneys and Genitals

      During embryonic development, the urogenital system undergoes a series of changes that lead to the formation of the kidneys and genitals. The kidneys develop from the pronephros, which is rudimentary and non-functional, to the mesonephros, which functions as interim kidneys, and finally to the metanephros, which starts to function around the 9th to 10th week. The metanephros gives rise to the ureteric bud and the metanephrogenic blastema. The ureteric bud develops into the ureter, renal pelvis, collecting ducts, and calyces, while the metanephrogenic blastema gives rise to the glomerulus and renal tubules up to and including the distal convoluted tubule.

      In males, the mesonephric duct (Wolffian duct) gives rise to the seminal vesicles, epididymis, ejaculatory duct, and ductus deferens. The paramesonephric duct (Mullerian duct) degenerates by default. In females, the paramesonephric duct gives rise to the fallopian tube, uterus, and upper third of the vagina. The urogenital sinus gives rise to the bulbourethral glands in males and Bartholin glands and Skene glands in females. The genital tubercle develops into the glans penis and clitoris, while the urogenital folds give rise to the ventral shaft of the penis and labia minora. The labioscrotal swelling develops into the scrotum in males and labia majora in females.

      In summary, the development of the urogenital system is a complex process that involves the differentiation of various structures from different embryonic tissues. Understanding the embryology of the kidneys and genitals is important for diagnosing and treating congenital abnormalities and disorders of the urogenital system.

    • This question is part of the following fields:

      • General Principles
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  • Question 14 - A 49-year-old male presents to the emergency department with severe back pain. He...

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    • A 49-year-old male presents to the emergency department with severe back pain. He rates this pain as 7/10. His past medical history includes asthma, for which he takes salbutamol inhalers, and constipation. Although he usually takes laxatives, these were stopped following a few recent episodes of bloody diarrhoea. A significant family history exists for cardiovascular disease, and he neither smokes nor drinks alcohol. On examination, there is symmetrical, ascending weakness in the lower limbs. No further abnormalities were identified on examination.

      Which organism is most likely associated with his current condition?

      Your Answer:

      Correct Answer: Campylobacter jejuni

      Explanation:

      Guillain-Barre syndrome is most commonly triggered by Campylobacter jejuni infection. It is important to suspect Guillain-Barre syndrome in patients with back pain, preceding gastrointestinal infection, and symmetrical, ascending weakness on examination. In addition to Guillain-Barre syndrome, Campylobacter jejuni is also associated with reactive arthritis. The other options listed may cause bloody diarrhea but are not typically associated with Guillain-Barre syndrome. Clostridium difficile is associated with antibiotic use, EHEC is associated with undercooked meat, and Entamoeba histolytica is associated with recent travel abroad.

      Understanding Guillain-Barre Syndrome and Miller Fisher Syndrome

      Guillain-Barre syndrome is a condition that affects the peripheral nervous system and is often triggered by an infection, particularly Campylobacter jejuni. The immune system attacks the myelin sheath that surrounds nerve fibers, leading to demyelination. This results in symptoms such as muscle weakness, tingling sensations, and paralysis.

      The pathogenesis of Guillain-Barre syndrome involves the cross-reaction of antibodies with gangliosides in the peripheral nervous system. Studies have shown a correlation between the presence of anti-ganglioside antibodies, particularly anti-GM1 antibodies, and the clinical features of the syndrome. In fact, anti-GM1 antibodies are present in 25% of patients with Guillain-Barre syndrome.

      Miller Fisher syndrome is a variant of Guillain-Barre syndrome that is characterized by ophthalmoplegia, areflexia, and ataxia. This syndrome typically presents as a descending paralysis, unlike other forms of Guillain-Barre syndrome that present as an ascending paralysis. The eye muscles are usually affected first in Miller Fisher syndrome. Studies have shown that anti-GQ1b antibodies are present in 90% of cases of Miller Fisher syndrome.

      In summary, Guillain-Barre syndrome and Miller Fisher syndrome are conditions that affect the peripheral nervous system and are often triggered by infections. The pathogenesis of these syndromes involves the cross-reaction of antibodies with gangliosides in the peripheral nervous system. While Guillain-Barre syndrome is characterized by muscle weakness and paralysis, Miller Fisher syndrome is characterized by ophthalmoplegia, areflexia, and ataxia.

    • This question is part of the following fields:

      • Neurological System
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  • Question 15 - A 59-year-old male patient visits his physician complaining of a recent cough that...

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    • A 59-year-old male patient visits his physician complaining of a recent cough that is producing green sputum. The doctor suspects a lower respiratory tract infection and initiates treatment with ceftriaxone. What is the mode of action of this medication?

      Your Answer:

      Correct Answer: Inhibits cell wall formation

      Explanation:

      Ceftriaxone is a cephalosporin antibiotic that works by inhibiting cell wall formation through the prevention of peptidoglycan cross-linking. This mechanism is similar to other beta-lactam antibiotics like penicillins and carbapenems. It is important to note that cephalosporins do not inhibit RNA synthesis, folic acid synthesis, protein synthesis, or DNA synthesis, which are mechanisms of action for other types of antibiotics such as Rifampicin, sulphonamides and trimethoprim, macrolides, aminoglycosides, tetracyclines, and quinolones, respectively.

      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
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  • Question 16 - What clinical sign in a newborn would indicate a plasma glucose level below...

    Incorrect

    • What clinical sign in a newborn would indicate a plasma glucose level below the normal range of 2.2 mmol/L, such as 1.6 mmol/L?

      Your Answer:

      Correct Answer: Hypotonia

      Explanation:

      Hypoglycaemia: Symptoms and Diagnosis

      Hypoglycaemia occurs when the blood glucose level falls below the typical fasting level. This condition is diagnosed when Whipple’s triad is satisfied, which includes the presence of hypoglycaemia, symptoms consistent with hypoglycaemia, and resolution of symptoms when the blood glucose level normalises. Symptoms of hypoglycaemia are caused by sympathetic activity and disrupted central nervous system function due to inadequate glucose.

      Assessing hypoglycaemia in neonates and infants can be challenging as they cannot communicate early symptoms. Infants may experience hypotonia, jitteriness, seizures, poor feeding, apnoea, and lethargy. On the other hand, adults and older children may experience tremor, sweating, nausea, lightheadedness, hunger, and disorientation. Severe hypoglycaemia can cause confusion, aggressive behaviour, and reduced consciousness.

      Neonates with prematurity, poor feeding, or born to mothers with diabetes, gestational diabetes, or eclampsia are at high risk of hypoglycaemia. Many neonates or infants with hypoglycaemia will secrete inappropriately high amounts of insulin, such as neonatal transient hyperinsulinism or persistent hyperinsulinism. Neonates born to diabetic mothers have hyperinsulinism, which developed in utero following exposure to high amounts of glucose from the mother that cross the placenta. This usually settles within several days.

    • This question is part of the following fields:

      • Clinical Sciences
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  • Question 17 - A 32-year-old male complains of a sudden onset of severe headache that has...

    Incorrect

    • A 32-year-old male complains of a sudden onset of severe headache that has been ongoing for an hour. He has no significant medical history. Upon examination, he appears to be in pain, with a pulse rate of 106 bpm, blood pressure of 138/70 mmHg, and a temperature of 37°C. He also exhibits neck stiffness and mild photophobia, but no specific neurological deficit is observed. What is the probable diagnosis?

      Your Answer:

      Correct Answer: Subarachnoid haemorrhage

      Explanation:

      Sudden and Severe Headache with Meningism: Possible Subarachnoid Haemorrhage

      This young male is experiencing a sudden and severe headache with meningism, which may indicate subarachnoid haemorrhage. To confirm the diagnosis, the presence of red cells in the cerebrospinal fluid (CSF) or xanthochromia in the CSF may be demonstrated. Meningitis is unlikely due to the acute onset of headache and apyrexia, while subdural haematomas are not common unless there is associated trauma. On the other hand, HSV meningitis typically affects the temporal lobe and may cause symptoms of memory or personality changes.

      Overall, a sudden and severe headache with meningism should be taken seriously as it may indicate a potentially life-threatening condition such as subarachnoid haemorrhage. Prompt diagnosis and treatment are crucial to prevent further complications and improve the patient’s prognosis.

    • This question is part of the following fields:

      • Neurological System
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  • Question 18 - You are evaluating a 67-year-old woman with breast cancer in an oncology center...

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    • You are evaluating a 67-year-old woman with breast cancer in an oncology center who is experiencing decreased sensation in her fingers and toes. She has just commenced vincristine therapy and is curious if her symptoms could be related to the medication.

      During which phase of the cell cycle does this drug exert its action?

      Your Answer:

      Correct Answer: Metaphase

      Explanation:

      During metaphase, Vincristine, a dimeric catharanthus alkaloid, binds to tubulin and disrupts microtubules in actively dividing cells. This action makes it an effective treatment for cancers such as leukaemias, lymphomas, and advanced-stage breast cancer. However, its use is limited by its neurotoxicity, which mainly manifests as peripheral neuropathy. Vincristine’s toxicity affects small sensory fibres and causes axonal neuropathy due to the disruption of microtubules within axons and interference with axonal transport. Paraesthesia in the fingertips and feet is usually the earliest symptom experienced by patients, and almost all patients experience some degree of neuropathy.

      Mitosis: The Process of Somatic Cell Division

      Mitosis is a type of cell division that occurs in somatic cells during the M phase of the cell cycle. This process allows for the replication and growth of tissues by producing genetically identical diploid daughter cells. Before mitosis begins, the cell prepares itself during the S phase by duplicating its chromosomes. The phases of mitosis include prophase, prometaphase, metaphase, anaphase, telophase, and cytokinesis. During prophase, the chromatin in the nucleus condenses, and during prometaphase, the nuclear membrane breaks down, allowing microtubules to attach to the chromosomes. In metaphase, the chromosomes align at the middle of the cell, and in anaphase, the paired chromosomes separate at the kinetochores and move to opposite sides of the cell. Telophase occurs when chromatids arrive at opposite poles of the cell, and cytokinesis is the final stage where an actin-myosin complex in the center of the cell contacts, resulting in it being pinched into two daughter cells.

    • This question is part of the following fields:

      • General Principles
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  • Question 19 - A 30-year-old male runner visits his doctor with a rough, hard, warty growth...

    Incorrect

    • A 30-year-old male runner visits his doctor with a rough, hard, warty growth on the sole of his foot. He has observed a tiny black spot in the center of the wart. The lesion has been there for 8 weeks.

      What is the probable cause of his condition?

      Your Answer:

      Correct Answer: Human papillomavirus

      Explanation:

      The human papillomavirus is responsible for causing plantar warts, which are non-cancerous and typically resolve on their own. These warts are more common in individuals who frequent public showers, as the warm and damp environment is conducive to their growth. They are characterized by a rough and thickened surface, often with small black spots resulting from clotted blood vessels.

      Understanding Viral Warts: When to Seek Treatment

      Viral warts are a common skin condition caused by the human papillomavirus (HPV). While they are generally harmless, they can be painful and unsightly, leading some patients to seek treatment. However, in most cases, treatment is not necessary as warts will typically resolve on their own within a few months to two years. In fact, it can take up to 10 years for warts to disappear in adults.

      It is important to note that while viral warts are not a serious medical concern, they can be contagious and easily spread through skin-to-skin contact or contact with contaminated surfaces. Therefore, it is important to practice good hygiene and avoid sharing personal items such as towels or razors with others to prevent the spread of warts.

    • This question is part of the following fields:

      • Musculoskeletal System And Skin
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  • Question 20 - Which cell type gives rise to all germ cells through differentiation? ...

    Incorrect

    • Which cell type gives rise to all germ cells through differentiation?

      Your Answer:

      Correct Answer: Epiblast

      Explanation:

      Embryonic Development and Tissue Formation

      During embryonic development, the epiblast layer, which originates from the inner cell mass, is located above the hypoblast. As the process of gastrulation occurs, the epiblast layer differentiates into three embryonic germ layers, namely the ectoderm, endoderm, and mesoderm. The ectoderm is responsible for forming various bodily systems such as the brain, retina, and anal canal. On the other hand, the mesoderm gives rise to the myotome, which is a tissue formed from somites that forms the body muscle wall. Additionally, the sclerotome, which is also part of the somite, develops to form most of the skull and vertebrae.

      Furthermore, a dermatome is an area of skin that is supplied by a single spinal nerve. These dermatomes are important in the diagnosis of certain medical conditions that affect the skin. the different tissues formed during embryonic development is crucial in comprehending the various bodily systems and functions.

    • This question is part of the following fields:

      • Clinical Sciences
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  • Question 21 - A 27-year-old woman from a rural town in Central America delivers a baby...

    Incorrect

    • A 27-year-old woman from a rural town in Central America delivers a baby at 37 weeks' gestation without any antenatal care. She had fallen ill during early pregnancy after consuming undercooked meat and received treatment with antibiotics from a local doctor. The neonatologist sent the baby's serum for PCR analysis, which revealed the presence of Toxoplasmosis gondii DNA. What are the probable clinical manifestations in this newborn?

      Your Answer:

      Correct Answer: Chorioretinitis, intracranial calcifications, hydrocephalus

      Explanation:

      The presence of congenital toxoplasmosis was confirmed by the PCR test on the baby’s serum. This condition is characterized by the classic triad of chorioretinitis, intracranial calcifications, and hydrocephalus.

      In contrast, congenital rubella syndrome is identified by the triad of cataracts, cochlear defects, and cardiac defects. Meanwhile, maculopapular rashes on the hands and soles are indicative of congenital syphilis, while periventricular calcifications, chorioretinitis, and sensorineural hearing loss are associated with congenital CMV infection.

      Congenital Toxoplasmosis: Effects on Neurological and Ophthalmic Health

      Congenital toxoplasmosis is a condition that occurs when a pregnant woman passes the Toxoplasma gondii parasite to her unborn child. This can result in a range of health issues, particularly affecting the neurological and ophthalmic systems.

      Neurological damage is a common feature of congenital toxoplasmosis, with cerebral calcification and hydrocephalus being two potential outcomes. Cerebral calcification refers to the buildup of calcium deposits in the brain, which can lead to seizures, developmental delays, and other neurological problems. Hydrocephalus, on the other hand, is a condition in which there is an excess of cerebrospinal fluid in the brain, causing pressure and potentially leading to brain damage.

      In addition to neurological damage, congenital toxoplasmosis can also cause ophthalmic damage. Chorioretinitis, a condition in which the retina becomes inflamed, is a common outcome. This can lead to vision loss and other eye-related problems. Retinopathy and cataracts are also potential effects of congenital toxoplasmosis.

      Overall, congenital toxoplasmosis can have significant impacts on a child’s health, particularly in terms of neurological and ophthalmic function. Early detection and treatment are crucial for minimizing the potential long-term effects of this condition.

    • This question is part of the following fields:

      • General Principles
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  • Question 22 - Jill, a 24-year-old female, falls on an outstretched hand and is diagnosed with...

    Incorrect

    • Jill, a 24-year-old female, falls on an outstretched hand and is diagnosed with a scaphoid fracture. During examination, she exhibits tenderness in the anatomical snuffbox. What structures form the lateral border of the anatomical snuffbox?

      Your Answer:

      Correct Answer: Extensor pollicis brevis and the ABductor pollicis longus tendons

      Explanation:

      The lateral border of the anatomical snuffbox is formed by the tendons of the extensor pollicis brevis and the abductor pollicis longus, not the muscles.

      To remember the borders, use the phrase Brevis sandwich which stands for the abductor pollicis longus tendons, extensor pollicis brevis, and extensor pollicis longus.

      The Anatomical Snuffbox: A Triangle on the Wrist

      The anatomical snuffbox is a triangular depression located on the lateral aspect of the wrist. It is bordered by tendons of the extensor pollicis longus, extensor pollicis brevis, and abductor pollicis longus muscles, as well as the styloid process of the radius. The floor of the snuffbox is formed by the trapezium and scaphoid bones. The apex of the triangle is located distally, while the posterior border is formed by the tendon of the extensor pollicis longus. The radial artery runs through the snuffbox, making it an important landmark for medical professionals.

      In summary, the anatomical snuffbox is a small triangular area on the wrist that is bordered by tendons and bones. It is an important landmark for medical professionals due to the presence of the radial artery.

    • This question is part of the following fields:

      • Musculoskeletal System And Skin
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  • Question 23 - A 67-year-old man is brought to the emergency department by his son, complaining...

    Incorrect

    • A 67-year-old man is brought to the emergency department by his son, complaining of severe chest pain. An immediate ECG shows widespread ST elevation in the anterolateral chest leads. He is given aspirin, prasugrel, morphine, metoclopramide, and nitrates and is taken to the PCI lab. The attending cardiologist recommends starting him on abciximab to prevent further ischemic events. What is the mechanism of action of this drug?

      Your Answer:

      Correct Answer: Glycoprotein IIb/IIIa inhibitor

      Explanation:

      Heparin activates antithrombin III, while Prasugrel inhibits P2Y12 ADP and Abciximab inhibits glycoprotein IIb/IIIa. Dabigatran and Rivaroxaban both directly inhibit thrombin and factor X, respectively.

      Monoclonal antibodies are becoming increasingly important in the field of medicine. They are created using a technique called somatic cell hybridization, which involves fusing myeloma cells with spleen cells from an immunized mouse to produce a hybridoma. This hybridoma acts as a factory for producing monoclonal antibodies.

      However, a major limitation of this technique is that mouse antibodies can be immunogenic, leading to the formation of human anti-mouse antibodies. To overcome this problem, a process called humanizing is used. This involves combining the variable region from the mouse body with the constant region from a human antibody.

      There are several clinical examples of monoclonal antibodies, including infliximab for rheumatoid arthritis and Crohn’s, rituximab for non-Hodgkin’s lymphoma and rheumatoid arthritis, and cetuximab for metastatic colorectal cancer and head and neck cancer. Monoclonal antibodies are also used for medical imaging when combined with a radioisotope, identifying cell surface markers in biopsied tissue, and diagnosing viral infections.

    • This question is part of the following fields:

      • General Principles
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  • Question 24 - A 25-year-old male is getting a routine check-up from his family doctor before...

    Incorrect

    • A 25-year-old male is getting a routine check-up from his family doctor before starting a new workout regimen at the gym. He has a clean medical history and does not smoke or drink. He is currently pursuing a graduate degree in political science. The doctor orders a CBC and other tests.

      The patient returns to the doctor's office a week later for the test results. The CBC shows that his platelet count is low. However, he does not have any signs of bleeding from his nose or mouth, and there are no rashes on his skin.

      The doctor suspects that this may be due to platelet in vitro agglutination.

      What could have caused this condition?

      Your Answer:

      Correct Answer: Ethylenediaminetetraacetic acid (EDTA)

      Explanation:

      EDTA is known to induce pseudothrombocytopenia, which is a condition where platelet counts are falsely reported as low due to EDTA-dependent platelet aggregation. On the other hand, sodium fluoride inhibits glycolysis and prevents enzymes from functioning, leading to the depletion of substrates like glucose during storage. While sodium citrate, sodium oxalate, and lithium heparin are all anticoagulants commonly found in vacutainers, they are not linked to thrombocytopenia.

      Causes of Thrombocytopenia

      Thrombocytopenia is a medical condition characterized by a low platelet count in the blood. The severity of thrombocytopenia can vary, with some cases being more severe than others. Severe thrombocytopenia can be caused by conditions such as immune thrombocytopenia (ITP), disseminated intravascular coagulation (DIC), thrombotic thrombocytopenic purpura (TTP), and haematological malignancy. On the other hand, moderate thrombocytopenia can be caused by heparin-induced thrombocytopenia (HIT), drug-induced factors such as quinine, diuretics, sulphonamides, aspirin, and thiazides, alcohol, liver disease, hypersplenism, viral infections such as EBV, HIV, and hepatitis, pregnancy, SLE/antiphospholipid syndrome, and vitamin B12 deficiency. It is important to note that pseudothrombocytopenia can also occur as a result of using EDTA as an anticoagulant.

    • This question is part of the following fields:

      • Haematology And Oncology
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  • Question 25 - A 55-year-old man with a smoking history of over 30 years presented to...

    Incorrect

    • A 55-year-old man with a smoking history of over 30 years presented to the emergency department with acute confusion and disorientation. He was unable to recognize his family members and relatives. He had been experiencing unexplained weight loss, loss of appetite, and occasional episodes of haemoptysis for the past few months. Urgent blood tests were performed, revealing abnormal levels of electrolytes and renal function.

      Based on the likely diagnosis, what is the mechanism of action of the hormone that is being secreted excessively in this case?

      Your Answer:

      Correct Answer: Insertion of aquaporin-2 channels

      Explanation:

      Antidiuretic hormone (ADH) plays a crucial role in promoting water reabsorption by inserting aquaporin-2 channels in principal cells. In small-cell lung cancer patients, decreased serum sodium levels are commonly caused by the paraneoplastic syndrome of inadequate ADH secretion (SIADH) or ADH released during the initial lysis of tumour cells after chemotherapy. It is important to note that arteriolar vasodilation, promoting water excretion, decreased urine osmolarity, and increased portal blood flow are not functions of ADH.

      Understanding Antidiuretic Hormone (ADH)

      Antidiuretic hormone (ADH) is a hormone that is produced in the supraoptic nuclei of the hypothalamus and released by the posterior pituitary gland. Its primary function is to conserve body water by promoting water reabsorption in the collecting ducts of the kidneys through the insertion of aquaporin-2 channels.

      ADH secretion is regulated by various factors. An increase in extracellular fluid osmolality, a decrease in volume or pressure, and the presence of angiotensin II can all increase ADH secretion. Conversely, a decrease in extracellular fluid osmolality, an increase in volume, a decrease in temperature, or the absence of ADH can decrease its secretion.

      Diabetes insipidus (DI) is a condition that occurs when there is either a deficiency of ADH (cranial DI) or an insensitivity to ADH (nephrogenic DI). Cranial DI can be treated with desmopressin, which is an analog of ADH.

      Overall, understanding the role of ADH in regulating water balance in the body is crucial for maintaining proper hydration and preventing conditions like DI.

    • This question is part of the following fields:

      • Endocrine System
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  • Question 26 - A 67-year-old female smoker with a two-month history of worsening shortness of breath...

    Incorrect

    • 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:

      Correct 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.

    • This question is part of the following fields:

      • Respiratory System
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  • Question 27 - A 50-year-old man is brought to the acute medical ward with red flag...

    Incorrect

    • A 50-year-old man is brought to the acute medical ward with red flag sepsis, possibly originating from the urinary tract. Upon arrival, his blood pressure is recorded as 90/60mmHg, and he exhibits cool, mottled skin peripherally. To increase his preload and stroke volume, a fluid bolus is administered. What other physiological parameter is likely to be observed?

      Your Answer:

      Correct Answer: Increased pulse pressure

      Explanation:

      When stroke volume increases, pulse pressure also increases. This is important to consider in the management of shock, where intravenous fluids can increase preload and stroke volume. Factors that affect stroke volume include preload, cardiac contractility, and afterload. Pulse pressure can be calculated by subtracting diastolic blood pressure from systolic blood pressure.

      Decreased cardiac output is not a result of increased stroke volume, as cardiac output is calculated by multiplying stroke volume by heart rate. An increase in stroke volume would actually lead to an increase in cardiac output.

      Similarly, decreased mean arterial pressure is not a result of increased stroke volume, as mean arterial pressure is calculated by multiplying cardiac output by total peripheral resistance. An increase in stroke volume would lead to an increase in mean arterial pressure.

      Lastly, increased heart rate is not a direct result of increased stroke volume, as heart rate is calculated by dividing cardiac output by stroke volume. An increase in stroke volume would actually lead to a decrease in heart rate.

      Cardiovascular physiology involves the study of the functions and processes of the heart and blood vessels. One important measure of heart function is the left ventricular ejection fraction, which is calculated by dividing the stroke volume (the amount of blood pumped out of the left ventricle with each heartbeat) by the end diastolic LV volume (the amount of blood in the left ventricle at the end of diastole) and multiplying by 100%. Another key measure is cardiac output, which is the amount of blood pumped by the heart per minute and is calculated by multiplying stroke volume by heart rate.

      Pulse pressure is another important measure of cardiovascular function, which is the difference between systolic pressure (the highest pressure in the arteries during a heartbeat) and diastolic pressure (the lowest pressure in the arteries between heartbeats). Factors that can increase pulse pressure include a less compliant aorta (which can occur with age) and increased stroke volume.

      Finally, systemic vascular resistance is a measure of the resistance to blood flow in the systemic circulation and is calculated by dividing mean arterial pressure (the average pressure in the arteries during a heartbeat) by cardiac output. Understanding these measures of cardiovascular function is important for diagnosing and treating cardiovascular diseases.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 28 - You are investigating the impact of HIV on T-cells during their maturation process....

    Incorrect

    • You are investigating the impact of HIV on T-cells during their maturation process. Which organ sample is necessary to meet the criteria of your research?

      Your Answer:

      Correct Answer: Thymus

      Explanation:

      The thymus is where T-cells undergo maturation, while they are produced in the bone marrow. Once mature, they can be found in the spleen and lymph nodes where they interact with antigen presenting cells. To investigate the impact of HIV on T-cell maturation, a thymus sample is necessary.

      Understanding the Lymphatic System

      The lymphatic system is composed of primary and secondary lymphatic organs, as well as lymph vessels. The primary lymphatic organs are the thymus and red bone marrow, which are responsible for the formation and maturation of lymphocytes. These organs contain pluripotent cells that give rise to immunocompetent B cells and pre-T cells. To become mature T cells, pre-T cells must migrate to the thymus.

      On the other hand, secondary lymphatic organs include lymph nodes, the spleen, tonsils, mucosa-associated lymphoid tissue (MALT), and Peyer’s patches. These organs filter lymphocytes and activate them to mount an immune response. Understanding the lymphatic system is crucial in comprehending how the body’s immune system works. By knowing the different organs and their functions, we can appreciate how the body fights off infections and diseases.

    • This question is part of the following fields:

      • Haematology And Oncology
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  • Question 29 - A 67-year-old woman visits the anticoagulation clinic for her regular INR test. She...

    Incorrect

    • A 67-year-old woman visits the anticoagulation clinic for her regular INR test. She has a medical history of deep vein thrombosis and pulmonary embolism and is currently taking warfarin for life. During this visit, her INR level is found to be 4.4, which is higher than her target of 3.0. Upon further inquiry, she reveals that she had been prescribed antibiotics by her GP recently. Can you identify the clotting factors that warfarin affects?

      Your Answer:

      Correct Answer: Factors II, VII, IX, X

      Explanation:

      Warfarin is an oral anticoagulant that is widely used to prevent blood clotting in various medical conditions, including stroke prevention in atrial fibrillation and venous thromboembolism. Warfarin primarily targets the Vitamin K dependent clotting factors, which include factors II, VII, IX, and X.

      To monitor the effectiveness of warfarin therapy, the International Normalized Ratio (INR) is used. However, the INR can be affected by drug interactions, such as those with antibiotics. Therefore, it is important to be aware of the common drug interactions associated with warfarin.

      Understanding Warfarin: Mechanism of Action, Indications, Monitoring, Factors, and Side-Effects

      Warfarin is an oral anticoagulant that has been widely used for many years to manage venous thromboembolism and reduce stroke risk in patients with atrial fibrillation. However, it has been largely replaced by direct oral anticoagulants (DOACs) due to their ease of use and lack of need for monitoring. Warfarin works by inhibiting epoxide reductase, which prevents the reduction of vitamin K to its active hydroquinone form. This, in turn, affects the carboxylation of clotting factor II, VII, IX, and X, as well as protein C.

      Warfarin is indicated for patients with mechanical heart valves, with the target INR depending on the valve type and location. Mitral valves generally require a higher INR than aortic valves. It is also used as a second-line treatment after DOACs for venous thromboembolism and atrial fibrillation, with target INRs of 2.5 and 3.5 for recurrent cases. Patients taking warfarin are monitored using the INR, which may take several days to achieve a stable level. Loading regimes and computer software are often used to adjust the dose.

      Factors that may potentiate warfarin include liver disease, P450 enzyme inhibitors, cranberry juice, drugs that displace warfarin from plasma albumin, and NSAIDs that inhibit platelet function. Warfarin may cause side-effects such as haemorrhage, teratogenic effects, skin necrosis, temporary procoagulant state, thrombosis, and purple toes.

      In summary, understanding the mechanism of action, indications, monitoring, factors, and side-effects of warfarin is crucial for its safe and effective use in patients. While it has been largely replaced by DOACs, warfarin remains an important treatment option for certain patients.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 30 - A young woman with a history of intravenous drug use presents to the...

    Incorrect

    • A young woman with a history of intravenous drug use presents to the emergency department with cellulitis of her arm. Upon admission, a blood culture is obtained and reveals the growth of a Gram-positive coccus that forms clusters. What molecular tests would be most beneficial in identifying this bacterium?

      Your Answer:

      Correct Answer: Coagulase

      Explanation:

      Staphylococcus species can be sub-grouped based on the presence of coagulase. The presence of coagulase determines the two most common groups of staphylococci. Staphylococcus aureus is a coagulase positive staphylococcus, while Staphylococcus epidermis is the most common coagulase negative staphylococcus.

      Understanding Staphylococci: Common Bacteria with Different Types

      Staphylococci are a type of bacteria that are commonly found in the human body. They are gram-positive cocci and are facultative anaerobes that produce catalase. While they are usually harmless, they can also cause invasive diseases. There are two main types of Staphylococci that are important to know: Staphylococcus aureus and Staphylococcus epidermidis.

      Staphylococcus aureus is coagulase-positive and is known to cause skin infections such as cellulitis, abscesses, osteomyelitis, and toxic shock syndrome. On the other hand, Staphylococcus epidermidis is coagulase-negative and is often the cause of central line infections and infective endocarditis.

      It is important to understand the different types of Staphylococci and their potential to cause disease in order to properly diagnose and treat infections. By identifying the type of Staphylococci present, healthcare professionals can determine the appropriate course of treatment and prevent the spread of infection.

    • This question is part of the following fields:

      • General Principles
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SESSION STATS - PERFORMANCE PER SPECIALTY

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