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Question 1
Incorrect
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By the third day of wound healing, which sort of inflammatory cell has predominated:
Your Answer: Monocytes
Correct Answer: Macrophages
Explanation:The inflammatory phase of healing is sometimes called the lag phase because wound strength does not begin to return immediately. The inflammatory phase is completed within three days except in the presence of infection or other factors associated with impaired wound healing. Mononuclear leukocytes accumulate and are transformed into macrophages. The maturation of blood-derived monocytes into macrophages is heralded by several events, including secretion of vimentin, which is a structural filament protein involved in wound healing.
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This question is part of the following fields:
- Pathology
- Wound Healing
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Question 2
Correct
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Depression of the eyeball is primarily produced by which of the following muscles:
Your Answer: Inferior rectus and superior oblique
Explanation:Depression of the eyeball is produced by the inferior rectus and the superior oblique muscles.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 3
Correct
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Which of the following is NOT an effect of cytokine activity:
Your Answer: Opsonisation of bacteria for phagocytosis
Explanation:Cytokines are a family of chemical messengers, secreted by leucocytes, that act over short distances by binding specific receptors on target cell surfaces. They include: interleukins (act between leucocytes), interferons (inhibit replication of viruses within cells and activate macrophages and natural killer cells), growth factors, and tumour necrosis factors (kill tumour cells). Effects include: induction of fever and acute phase response, stimulation of leucocyte differentiation and maturation, leucocyte recruitment and activation and increased antibody production.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 4
Correct
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Which extraocular muscle is entrapped in a patient with a blowout fracture?
Your Answer: Inferior rectus
Explanation:A blowout fracture is an isolated fracture of the orbital walls without compromise of the orbital rims. The common mechanisms are falls, high-velocity ball-related sports, traffic accidents, and interpersonal violence.The frontal, ethmoidal, sphenoid, zygomatic, and lacrimal bones form the bony structures of the orbit. Medially, the maxillary and the lacrimal bone form the lacrimal fossa. Together with the lamina papyracea of the ethmoid bone, they form the medial wall. The sphenoid bone forms the posterior wall and houses the orbital canal. Lateral to the orbital canal lies the superior orbital fissure housing cranial nerves III, IV, V, and VI. The zygomatic bone forms the lateral wall. Superior and inferior borders are the frontal and maxillary bones. Located around the globe of the eye and attached to it are 6 extraocular muscles; the 4 rectus muscles and the superior and inferior oblique muscles. The fat and connective tissue around the globe help to reduce the pressure exerted by the extraocular muscles.The goal of treatment is to restore aesthetics and physiological function. The problem with orbital blowout fractures is that the volume of the orbit can be increased, resulting in enophthalmos and hypoglobus. In addition, the orbital tissue and inferior rectus muscle can become trapped by the bony fragments leading to diplopia, limitation of gaze, and tethering. Finally, the orbital injury can lead to retinal oedema, hyphema, and significant loss of vision.While some cases may be managed with conservative care, others may require some type of surgical intervention.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 5
Correct
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Regarding V/Q mismatch, which of the following statements is CORRECT:
Your Answer: In a true shunt, increasing inspired oxygen has no effect on improving hypoxaemia.
Explanation:Both ventilation and perfusion increase towards the lung base, because of the effects of gravity, but the gravitational effects are greater on perfusion than ventilation and therefore there is a regional variation in V/Q ratio from lung apex (high V/Q) to lung base (low V/Q). In a pure shunt, there is normal perfusion but absent ventilation and the V/Q ratio = 0. In a true shunt increasing oxygen fraction has no effect because the oxygen-enriched air fails to reach the shunted blood. An increased A-a gradient is seen in V/Q mismatch.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 6
Correct
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A patient with a stab wound to the axilla arrives to the emergency department. You notice weakness in elbow flexion and forearm supination during your assessment. Which of these nerves has been affected:
Your Answer: Musculocutaneous nerve
Explanation:The musculocutaneous nerve is relatively protected in the axilla, hence injury to it is uncommon. A stab wound in the axilla is the most prevalent source of damage. Because of the activities of the pectoralis major and deltoid, the brachioradialis, and the supinator muscles, arm flexion and forearm flexion and supination are diminished but not completely lost. Over the lateral part of the forearm, there is a lack of sensation.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 7
Correct
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A patient is referred for lung function tests on account of a history of breathlessness and cough.Which statement about lung volumes is correct?
Your Answer: The tidal volume is the volume of air drawn in and out of the lungs during normal breathing
Explanation:The tidal volume(TV) is the amount of air that moves in and out of the lungs with each respiratory cycle. In a healthy male, the usual volume is 0.5 L (,7 ml/kg body mass).The vital capacity(VC) is the maximum amount of air that can be exhaled following maximal inspiration. The usual volume in a healthy male is 4.5 L.The residual volume(RV) is the amount of air remaining in the lungs after maximum expiration. The usual volume in a healthy male is 1.0 L.The inspiratory reserve volume(IRV) is the maximum amount of air that can be breathed in forcibly after normal inspiration. The usual volume in a healthy male is 3.0 L.The expiratory reserve volume(ERV) is the volume of air that can be breathed out forcibly after normal expiration. The usual volume in a healthy male is 1.0 L.Total lung capacity(TLC) is the volume of air the lungs can accommodate. TLC = RV+VC. The usual volume in a healthy male is 5.5 L.
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 8
Incorrect
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All of the following statements are considered true regarding likelihood ratios, except:
Your Answer: They provide a way to estimate the pre-test probabilities of having a condition
Correct Answer: A likelihood ratio less than 1 indicates that the result is associated with the presence of the disease
Explanation:The Likelihood Ratio (LR) is the likelihood that a given test result would be expected in a patient with the target disorder compared to the likelihood that that same result would be expected in a patient without the target disorder.The LR is used to assess how good a diagnostic test is and to help in selecting an appropriate diagnostic tests or sequence of tests. They have advantages over sensitivity and specificity because they are less likely to change with the prevalence of the disorder, they can be calculated for several levels of the symptom/sign or test, they can be used to combine the results of multiple diagnostic test and they can be used to calculate post-test probability for a target disorder.A LR greater than 1 produces a post-test probability which is higher than the pre-test probability. An LR less than 1 produces a post-test probability which is lower than the pre-test probability. When the pre-test probability lies between 30 and 70 per cent, test results with a very high LR (say, above 10) rule in disease. An LR below 1 produces a post-test probability les than the pre-test probability. A very low LR (say, below 0.1) virtually rules out the chance that the patient has the disease.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 9
Incorrect
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A 72-year-old woman presents to your clinic with worsening oedema. She is a known case of ischaemic heart disease and heart failure.You decide to add a loop diuretic to her current drug regime to control the oedema. Of the following, what is a contraindication to using a loop diuretic?
Your Answer: Hypotension
Correct Answer: Anuria
Explanation:Loop diuretics are drugs used to manage and treat fluid overload associated with CHF, liver cirrhosis, and renal disease. The drugs commonly used are:FurosemideBumetanideTorsemideEthacrynic AcidLoop diuretics inhibit the Na-K-Cl pump in the ascending loop of Henle, resulting in salt-water excretion. This relieves congestion and reduces oedema. The contra-indications to the use of loop diuretics are:1. Anuria2. Comatose and precomatose states associated with liver cirrhosis3. Renal failure due to nephrotoxic or hepatotoxic drugs4. Severe hypokalaemia5. Severe hyponatremia6. History of hypersensitivity to furosemide, bumetanide, or torsemide (or sulphonamides)The following conditions or states are not contraindications, but loop diuretics needs to be used cautiously in these conditions:1. Diabetes (but hyperglycaemia less likely than with thiazides)2. Gout3. Hypotension (correct before initiation of treatment)4. Hypovolaemia (Correct before initiation of treatment)
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 10
Correct
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Regarding the glomerular filtration barrier, which of the following statements is CORRECT:
Your Answer: The main factor determining whether a substance is filtered or not is molecular weight.
Explanation:Molecular weight is the main factor in determining whether a substance is filtered or not – molecules < 7 kDa in molecular weight are filtered freely e.g. glucose, amino acids, urea, ions but larger molecules are increasingly restricted up to 70 kDa, above which filtration is insignificant. Negatively charged molecules are further restricted, as they are repelled by negative charges, particularly in the basement membrane. Albumin has a molecular weight of 69 kDa and is negatively charged, thus only very small amounts are filtered (and all of the filtered albumin is reabsorbed in the proximal tubule), whereas small molecules such as ions, glucose, amino acids and urea pass the filter without hindrance. This means that ultrafiltrate is virtually protein free, but otherwise has an identical composition of that of plasma. The epithelial lining of the Bowman's capsule consists of a single layer of cells called podocytes. The glomerular capillary endothelium is perforated by pores (fenestrations) which allow plasma components with a molecular weight of < 70 kDa to pass freely.
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This question is part of the following fields:
- Physiology
- Renal
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Question 11
Correct
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A 4-year old boy is taken to the emergency room after a sudden onset of coughing and wheezing. Further investigation reveals that he was drawing quietly in his room, when suddenly, he became anxious and started coughing. The parents also noted that the eraser on top of the pencil was missing.A plain radiographic chest imaging is conducted, and confirmed foreign body aspiration.Which of the following areas in the tracheobronchial tree is the most probable location of the aspirated eraser?
Your Answer: Right main bronchus
Explanation:In foreign body aspiration, the foreign body is more likely to enter the right main bronchus because it is shorter, wider and more vertical than the left main bronchus. In a patient who is standing or sitting, the foreign body tends to become lodged in the posterobasal segment of the inferior lobe of the right lung.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 12
Correct
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A patient with rash is examined. He has some redness of the skin that blanches when finger pressure is applied. What is the best description of this rash that you have found on examination?
Your Answer: Erythema
Explanation:Erythema is redness of the skin or mucous membranes caused by hyperaemia of superficial capillaries caused by skin injury, infection or inflammation. Erythema blanches when pressure is applied whereas ecchymosis, purpura and petechiae do not.Ecchymosis are discolouration of the skin or mucous membranes caused by extravasation of blood. They are usually red or purple in colour and measure greater than 1 cm in diameter and do not blanch on applying pressure. A macule is a flat, well circumscribed area of discoloured skin less than 1 cm in diameter with no changes in the thickness or texture of the skin. Petechiae are discolouration of the skin measuring less than 3 mm in diameterPurpura are discolouration of the skin measuring between 0.3 cm and 1 cm in diameter.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 13
Correct
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A 59-year-old woman presents with a history of tiredness and weight gain and a diagnosis of hypothyroidism is suspected.Which of these changes is likely to appear first in primary hypothyroidism?
Your Answer: Increased thyroid-stimulating hormone (TSH)
Explanation:The earliest biochemical change seen in hypothyroidism is an increase in thyroid-stimulating hormone (TSH) levels.Triiodothyronine (T3) and thyroxine (T4) levels are normal in the early stages.TBG levels are generally unchanged in primary hypothyroidism.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 14
Incorrect
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A 20-year-old male patient lives in a travelling community and has never received any vaccinations. He presents to you with fever.Which of these statements concerning indications and contraindications for vaccination is TRUE?
Your Answer: The BCG vaccination can be safely administered to patients with HIV
Correct Answer: Inactivated vaccines are safe in pregnancy
Explanation:All vaccines are contraindicated in individuals with: A confirmed anaphylactic reaction to a previous dose of the vaccine or a vaccine containing the same antigens.A confirmed anaphylactic reaction to a component in the vaccine e.g. neomycinThere is no evidence that vaccinating pregnant women with inactivated vaccine or toxoids harms the woman or foetus. The current protocol is that a child with history of egg allergy can be safely vaccinated with Fluenz tetra. However, if they had a previous severe anaphylaxis to egg requiring intensive care, then Flenz tetra is contraindicated. BCG, yellow fever or oral typhoid vaccinations are not safe in HIV positive patients.The normal times recommended for immunization of full-term babies should also be applied to premature infants and correction for gestational age should not be implemented.Concurrent antibiotic therapy is not a contraindication to vaccination.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 15
Correct
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Which of the following is the site of secretion of intrinsic factor:
Your Answer: Stomach
Explanation:Intrinsic factor is essential for the absorption of the small amounts of vitamin B12 normally present in the diet from the terminal ileum. The parietal cells of the stomach produce intrinsic factor, and following a gastrectomy, the absorption of vitamin B12 will be markedly reduced, and a deficiency state will exist.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 16
Incorrect
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Regarding a cohort study, which of the following statements is INCORRECT:
Your Answer: It is prospective.
Correct Answer: It is useful for rare diseases.
Explanation:A cohort study is a longitudinal, prospective, observational study that follows a defined group (cohort) matched to unexposed controls for a set period of time and investigates the effect of exposure to a risk factor on a particular future outcome. The usual outcome measure is the relative risk (risk ratio). A large sample size is required for a rare outcome of interest so it is not useful for rare diseases.
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This question is part of the following fields:
- Evidence Based Medicine
- Study Methodology
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Question 17
Correct
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Bile acids are essential for the digestion and absorption of which of the following:
Your Answer: Lipids and fat-soluble vitamins
Explanation:Bile acids are synthesised from cholesterol by hepatocyte and excreted into bile. Bile acids are essential for lipid digestion and absorption. Of the bile acids excreted into the intestine, about 95% are reabsorbed into the portal circulation by active transport mechanisms in the distal ileum and recycled by the liver. Many of the bile salts are reabsorbed unaltered, some are converted by intestinal bacteria into secondary bile acids (deoxycholic acid and lithocholic acid) and then reabsorbed and a small proportion escapes reabsorption and is excreted in the faeces.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 18
Incorrect
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An 80-year-old female complains of chest pain characteristic of angina. A dose of glyceryl trinitrate (GTN) is administered that resolves the chest pain rapidly. Which ONE of the following is released on the initial metabolism of GTN?
Your Answer: Nitric oxide
Correct Answer: Nitrite ions
Explanation:Angina pectoris is the most common symptom of ischemic heart disease and presents with chest pain relieved by rest and nitro-glycerine. Nitrates are the first-line treatment to relieve chest pain caused by angina. The commonly used nitrates are: 1. Glyceryl trinitrate 2. Isosorbide dinitrate The nitrate drugs are metabolized in the following steps: 1. Release Nitrite ions (NO2-), which are then converted to nitric oxide (NO) within cells. 2. NO activates guanylyl cyclase, which causes an increase in the intracellular concentration of cyclic guanosine-monophosphate (cGMP) in vascular smooth muscle cells. 3. Relaxation of vascular smooth muscle.Although nitrates are potent coronary vasodilators, their principal benefit in the management of angina results from a predominant mechanism of venous dilation:- Bigger veins hold more blood- Takes blood away from the left ventricle- Lowers LVEDV (preload), LA pressure- Less pulmonary oedema → improved dyspnoea
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 19
Correct
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A 29 year old man presents to ED followed an alleged assault whilst out drinking. He received blunt trauma to his right axilla. He is complaining of difficulty abducting his right arm above the level of his shoulder, and on inspection, the inferior angle of his right scapula protrudes more than that of his left scapula. Which of the following nerves has most likely been affected:
Your Answer: Long thoracic nerve
Explanation:Damage to the long thoracic nerve results in weakness/paralysis of the serratus anterior muscle causing difficulty abducting the upper limb above 90 degrees and giving a ‘winged ‘ scapula appearance where the medial border, particularly the inferior angle, of the scapula moves laterally and posteriorly away from the thoracic wall (this becomes more pronounced if the patient presses the upper limb against a wall).
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 20
Correct
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Which of the following could denote a diagnosis of acquired immunodeficiency syndrome (AIDS) in a patient infected with HIV:
Your Answer: CD4 count < 200 cells/uL
Explanation:A diagnosis of AIDS can be made in a patient infected with HIV if the patient has a CD4 count < 200 cells/uL, or an AIDS-defining illness. Antiretroviral treatment should be considered in patients with CD4 counts < 350 cells/uL. Oral candidiasis is not an AIDS defining illness – candidiasis of the bronchi, trachea or lungs or of the oesophagus is an AIDS defining illness. A positive p24 antigen test seen in early HIV infection and does not indicate the development of AIDS.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 21
Correct
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Which of the following does NOT increase free ionised calcium levels:
Your Answer: Calcitonin
Explanation:Calcium homeostasis is primarily controlled by three hormones: parathyroid hormone, activated vitamin D and calcitonin.Parathyroid hormone acts on the kidneys to increase calcium reabsorption in the distal tubule by activating Ca2+entry channels in the apical membrane and the Ca2+ATPase pump in the basolateral membrane (and to decrease phosphate reabsorption in the proximal tubule).Activated vitamin D acts to increase calcium reabsorption in the distal tubule via activation of a basolateral Ca2+ATPase pump (and to increase phosphate reabsorption).Calcitonin acts to inhibit renal reabsorption of calcium (and phosphate).
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This question is part of the following fields:
- Physiology
- Renal
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Question 22
Correct
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An elderly female has a bacterial infection and you are asked to prescribe an antibiotic to her. This antibiotic is a nucleic acid synthesis inhibitor.Which of the following antimicrobial drugs will be prescribed to this patient?
Your Answer: Metronidazole
Explanation:Metronidazole and the other 5-nitroimidazole agents inhibit nucleic acid synthesis by forming toxic free radical metabolites in the bacterial cell that damage DNA. Vancomycin inhibits cell wall peptidoglycan formation by binding the D-Ala-D-Ala portion of cell wall precursors. Erythromycin inhibits protein synthesis and blocks translocation by binding to the 23S rRNA of the 50S ribosomal subunit.Chloramphenicol blocks peptidyl transferase at 50S ribosomal subunit.Gentamicin, an aminoglycoside antibiotic, acts by binding to the 30S subunit of the bacterial ribosome inhibiting the binding of aminoacyl-tRNA and thus preventing initiation of protein synthesis.An overview of the different mechanisms of action of the various types of antimicrobial agents is shown below:1. Inhibition of cell wall synthesis- Penicillins- Cephalosporins- Vancomycin2. Disruption of cell membrane function- Polymyxins- Nystatin- Amphotericin B3. Inhibition of protein synthesis- Macrolides- Aminoglycosides- Tetracyclines- Chloramphenicol4. Inhibition of nucleic acid synthesis- Quinolones- Trimethoprim- 5-nitroimidazoles- Rifampicin5. Anti-metabolic activity- Sulphonamides- Isoniazid
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 23
Correct
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Which of the following cervical nerves is likely to be affected if your patient is complaining of elbow extension weakness and loss of sensation in her middle finger? She also has pain and tenderness in her cervical region, which is caused by a herniated disc, all after a whiplash-type injury in a car accident.
Your Answer: C7
Explanation:A C7 spinal nerve controls elbow extension and some finger extension. Damage to this nerve can result in a burning pain in the shoulder blade or back of the arms. The ability to extend shoulders, arms, and fingers may also be affected. Dexterity may also be compromised in the hands or fingers.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 24
Correct
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You evaluate a 80-year-old man who has a history of persistent heart failure and discover that he has generalised oedema.Which of the following claims regarding capillary hydrostatic pressure (P c) is false?
Your Answer: P c increases along the length of the capillary, from arteriole to venule
Explanation:The capillary hydrostatic pressure (Pc) is normally between 15 and 30 millimetres of mercury. Pc Decreases along the capillary’s length, mirroring the arteriolar and venule pressures proximally and distally.Pc is determined by the ratio of arteriolar resistance (RA) to venular resistance (RV).When the RA/RV ratio is high, the pressure drop across the capillary is modest, and Pcis is close to venule pressure.When the ratio of RA/RV is low, the pressure drop across the capillary is considerable, and Pcis is close to arteriolar pressure.Pcis closer to the venule pressure and thus more responsive to changes in venous pressure than arteriolar pressure when RA/RV is high.Pcis the major force behind fluid pushing out of the capillary bed and into the interstitium.It is also the most variable of the forces affecting fluid transport at the capillary, partly because sympathetic-mediated arteriolar vasoconstriction varies.
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 25
Correct
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Which of the following is a primary action of calcitonin:
Your Answer: Decreased bone resorption through inhibition of osteoclast activity
Explanation:Calcitonin is a 32 amino acid polypeptide that is primarily synthesised and released by the parafollicular cells (C-cells) of the thyroid gland in response to rising or high levels of plasma Ca2+ions. Its primary role is to reduce the plasma calcium concentration, therefore opposing the effects of parathyroid hormone.Secretion of calcitonin is stimulated by:- Increased plasma calcium concentration- Gastrin- Pentagastrin- The main actions of calcitonin are:- Inhibition of osteoclastic activity (decreasing calcium and phosphate resorption from bone)- Stimulation of osteoblastic activity- Decreases renal calcium reabsorption- Decreases renal phosphate reabsorption
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 26
Correct
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Which of the following is an ECG change typically associated with hyperkalaemia:
Your Answer: Wide QRS complex
Explanation:Hyperkalaemia causes a rapid reduction in resting membrane potential leading to increased cardiac depolarisation and muscle excitability. This in turn results in ECG changes which can rapidly progress to ventricular fibrillation or asystole. Very distinctive ECG changes that progressively change as the K+level increases:K+>5.5 mmol/l – peaked T waves (usually earliest sign of hyperkalaemia), repolarisation abnormalitiesK+>6.5 mmol/l – P waves widen and flatten, PR segment lengthens, P waves eventually disappearK+>7.0 mmol/l – Prolonged QRS interval and bizarre QRS morphology, conduction blocks (bundle branch blocks, fascicular blocks), sinus bradycardia or slow AF, development of a sine wave appearance (a pre-terminal rhythm)K+>9.0 mmol/l – Cardiac arrest due to asystole, VF or PEA with a bizarre, wide complex rhythm.
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This question is part of the following fields:
- Physiology
- Renal
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Question 27
Incorrect
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A 38-year-old woman presented to the emergency room after an incident of slipping and falling onto her back and left hip. Upon physical examination, it was noted that she has pain on hip flexion, but normal hip adduction. Which of the following muscles was most likely injured in this case?
Your Answer: Pectinius
Correct Answer: Sartorius
Explanation:The hip adductors are a group of five muscles located in the medial compartment of the thigh. These muscles are the adductor longus, adductor brevis, adductor magnus, gracilis, and pectineus.The hip flexors consist of 5 key muscles that contribute to hip flexion: iliacus, psoas, pectineus, rectus femoris, and sartorius.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 28
Correct
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A blood culture was performed from a sample taken from a patient. It was noted that a Gram-positive coccus organism was grown.Among the following microorganisms, which is considered an example of a Gram-positive coccus?
Your Answer: Staphylococcus aureus
Explanation:Bacillus cereus = Gram-positive bacillusNeisseria meningitidis = Gram-negative coccusSalmonella enterica & Escherichia coli = Gram-negative bacilliIn Gram staining, crystal violet is a purple stain that is used to stain the bacteria first. The stained bacteria are decolorized and then stained with a red stain, which is safranin. Bacteria with thick cell walls keep the purple stain and are called Gram-positive. Thin-walled bacteria are easily decolorized so when safranin, the red stain, is placed on the organisms, they become red or Gram-negative. The Staphylococci that are associated with infections in humans are colonizers of various skin and mucosal surfaces. Because the carrier state is common among the human population, infections are frequently acquired when the colonizing strain gains entrance to a normally sterile site as a result of trauma or abrasion to the skin or mucosal surface.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 29
Correct
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Antidiuretic hormone (ADH) has which of the following effects:
Your Answer: Increases urine osmolality
Explanation:ADH binds V2 receptors on renal principal cells in the late distal tubule and collecting ducts, raising cAMP levels and causing intracellular vesicles to fuse with the apical membrane. In their membrane these vesicles have water channels called aquaporins, which increase the water permeability allowing greater water reabsorption and concentration of urine. ADH also binds to V1 receptor receptors on vascular smooth muscle, causing vasoconstriction and enhancing the effect of aldosterone on sodium reabsorption in the distal tubule. ADH release is stimulated primarily by raised plasma osmolality detected by osmoreceptors in the anterior hypothalamus. Other factors that increase ADH release include: extracellular fluid volume depletion, angiotensin II, nausea, pain, stress, exercise, emotion, hypoglycaemia. ADH release is inhibited by low plasma osmolality, alcohol, caffeine, glucocorticoids and atrial natriuretic peptide (ANP). ADH deficiency (or an inadequate response to ADH) results in diabetes insipidus. Excess levels of ADH results in syndrome of inappropriate ADH secretion (SIADH).
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 30
Incorrect
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A 17-year-old male presenting in the department has a history of C3 deficiency.C3 deficiency is associated with all of the following EXCEPT?
Your Answer: Membranous glomerulonephritis
Correct Answer: Hereditary angioedema
Explanation:C1-inhibitor deficiency is the cause of hereditary angioedema not C3 deficiency,All the other statements are correct
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This question is part of the following fields:
- General Pathology
- Pathology
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SESSION STATS - PERFORMANCE PER SPECIALTY
