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Question 1
Correct
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A patient with profuse watery diarrhoea was found to have C. difficile cytotoxin. Which of the following complications is NOT a typical complication of pseudomembranous colitis:
Your Answer: Volvulus
Explanation:Dehydration, electrolyte imbalance, acute kidney injury secondary to diarrhoea, toxic megacolon, bowel perforation, and sepsis secondary to intestinal infection are all possible complications of pseudomembranous colitis.
When the intestine twists around itself and the mesentery that supports it, an obstruction is created. This condition is known as a volvulus. Volvulus is caused by malrotation and other anatomical factors, as well as postoperative abdominal adhesions, and not by Clostridium difficile infection.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 2
Incorrect
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A 70-year-old woman presents with exacerbation of her chronic obstructive pulmonary disease (COPD), increased cough, wheeze and chest tightness. On examination, she is tachypnoeic and oxygen saturation is 86%. You plan to administer supplemental oxygen.
Which oxygen delivery system is most appropriate to use initially?Your Answer: Non-rebreather mask
Correct Answer: Venturi mask
Explanation:In life-threatening emergencies, oxygen should be started immediately otherwise, it should be prescribed like any other drug. The prescription should include a target saturation range.
Until blood gases can be measured, initial oxygen should be administered using a controlled concentration of 24% or 28%.
The ideal mask is a Venturi mask.The other mask are not ideal for initial use
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 3
Correct
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Which of the following is the most abundant peripheral blood leucocyte:
Your Answer: Neutrophils
Explanation:Neutrophils are the most abundant peripheral blood leucocyte, comprising about 50 – 70% of circulating white cells. Neutrophils have a characteristic dense nucleus consisting of between two and five lobes, and a pale cytoplasm with an irregular outline containing many fine pink-blue or grey-blue granules. The granules are divided into primary, which appear at the promyelocyte stage, and secondary, which appear at the myelocyte stage and predominate in the mature nucleus. Both types of granule are lysosomal in origin; the primary contains myeloperoxidase and other acid hydrolases; the secondary contains lactoferrin, lysozyme and other enzymes. The lifespan of neutrophils in the blood is only 6 – 10 hours. In response to tissue damage, cytokines and complement proteins, neutrophils migrate from the bloodstream to the site of insult within minutes, where they destroy pathogens by phagocytosis.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 4
Correct
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Which of the following is NOT a typical clinical feature of diabetic ketoacidosis:
Your Answer: Cheyne–Stokes respiration
Explanation:Clinical features of DKA:
Symptoms: Polyuria, polydipsia, thirst, lethargy, weight loss, nausea, vomiting, anorexia, abdominal pain, dehydration, headache, altered mental state
Signs: Dry mucous membranes, ketotic breath, tachycardia, hypotension, Kussmaul breathing, focal signs of precipitant e.g. infection -
This question is part of the following fields:
- Endocrine
- Physiology
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Question 5
Correct
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A GP is considering prescribing a non-steroidal anti-inflammatory (NSAID) for pain relief for a patient with a knee injury
Which of these statements about NSAIDs is NOT true?Your Answer: Side effects are less commonly seen with indomethacin than naproxen
Explanation:Most NSAIDs act as non-selective inhibitors of the enzyme cyclo-oxygenase (COX). They inhibit both COX-1 and COX-2 isoenzymes.
Only about 60% of patients will respond to any given NSAID.
It can take 21 days of treatment for a clinically appreciable reduction in inflammation to be apparent. If no improvement is seen after 21 days, the NSAID should be changed.
The use of NSAIDs in the 3rd trimester of pregnancy is associated with the following risks: delayed onset of labour, premature closure of ductus arteriosus and foetal kernicterus.
Side effects are lowest in Ibuprofen and highest in indomethacin. so side effects are more commonly seen with indomethacin than naproxen.
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This question is part of the following fields:
- Musculoskeletal Pharmacology
- Pharmacology
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Question 6
Incorrect
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A 7-year-old girl is admitted to the hospital with a persistently high temperature. To help her reduce her fever, you decide to give her paracetamol and ibuprofen.
What are the effects of paracetamol and ibuprofen on fever?Your Answer: Reduction in interleukin synthesis
Correct Answer: Reduction in prostaglandin synthesis
Explanation:Interleukin-1, which is released by leukocytes and acts on the thermoregulatory centre of the hypothalamus, causes fever. Because prostaglandins mediate this process, antipyretics such as NSAIDs, paracetamol, and aspirin reduce prostaglandin levels by inhibiting cyclooxygenase enzymes. Malignant disease secretes interleukins, which cause the B-symptoms seen in lymphoma, for example. Bacterial toxins can also cause interleukins to be produced.
Pyrexia of unknown origin (PUO) is defined as a fever of greater than 38.3 degrees Celsius that lasts for more than 2-3 weeks with no clear diagnosis despite extensive investigation.
Investigation necessitates a thorough understanding of the conditions that can cause febrile illness, which may be missed during an initial investigation, as well as a thorough history, examination, and investigation centred on that list.
Pyrexia of unknown origin has a wide differential diagnosis, which includes:
Infection
Bacterial
Pyogenic abscess
Tuberculosis
Infective endocarditis
Brucellosis
Lyme disease
Viral
HIV
Epstein Barr Virus
Cytomegalovirus
Parasite
Toxoplasmosis
Malignancy
Leukaemia
Lymphoma
Renal cell carcinoma
Hepatocellular carcinoma
Vasculitides
Still’s disease
Granulomatosis with polyangiitis (formerly Wegener’s)
Systemic lupus erythematosus
Giant cell arteritis
Rheumatoid arthritis
Polymyalgia rheumatica
Miscellaneous
Drug induced fevers
Familial Mediterranean fever
Thyrotoxicosis
Inflammatory bowel disease
Sarcoidosis
Factitious fever
Exaggerated normal circadian fluctuationThe patient might need to be admitted to the hospital for observation and further investigation. Because infection is still a possibility, blood cultures should be repeated on a regular basis, and inflammatory markers should be closely monitored. CT, PET, and MRI imaging have largely replaced diagnostic laparotomy as a diagnostic tool.
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This question is part of the following fields:
- Pathology
- Pathology Of Infections
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Question 7
Correct
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Which of the following is the primary indication for loop diuretics?
Your Answer: Acute pulmonary oedema
Explanation:Loop diuretics have long been the cornerstone of pulmonary oedema treatment, with furosemide being the most commonly used of these drugs. Premedication with drugs that decrease preload (e.g., nitro-glycerine [NTG]) and afterload (e.g., angiotensin-converting enzyme [ACE] inhibitors) before the administration of loop diuretics can prevent adverse hemodynamic changes.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 8
Correct
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During her pregnancy, a 28-year-old lady was given an antibiotic. The neonate is born with bilateral deafness as a result of this.
From the  following antibiotics, which one is most likely to cause this side effect?Your Answer: Gentamicin
Explanation:Aminoglycosides cross the placenta and are linked to poisoning of the 8th cranial nerve in the foetus, as well as permanent bilateral deafness.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 9
Incorrect
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A 47-year-old woman comes in with palpitations that have been bothering her for the past four days. Her haemodynamics are normal, but her heart rate is currently 150 beats per minute. An ECG is performed, which reveals that she is experiencing atrial flutter. The patient is examined by a cardiology registrar, who recommends starting her on verapamil to control her ventricular rate while she waits for cardioversion.
In these circumstances, which of the following is a contraindication to the use of verapamil?Your Answer: Aortic stenosis
Correct Answer: Acute porphyria
Explanation:In most cases of atrial flutter, ventricular rate control is used as a stopgap measure until sinus rhythm is restored. A beta-blocker (e.g. bisoprolol), diltiazem, or verapamil can be used to reduce the rate of contractions in the heart.
Electrical cardioversion, pharmacological cardioversion, and catheter ablation can all be used to return the heart to a normal rhythm. Cardioversion should not be attempted until the patient has been fully anticoagulated for at least three weeks if the duration of atrial flutter is unknown or it has lasted longer than 48 hours. Emergency electrical cardioversion is the treatment of choice when there is a sudden onset of symptoms and haemodynamic compromise. For recurrent atrial flutter, catheter ablation is preferred.Verapamil is a calcium-channel blocker that is non-dihydropyridine phenylalkylamine and can be used to treat supraventricular arrhythmias. It’s a calcium channel blocker with a high negative inotropic effect that lowers cardiac output, slows the heart rate, and may impair atrioventricular conduction. At high doses, it can cause heart failure, exacerbate conduction disorders, and cause hypotension.
Adults should take 240-480 mg of verapamil in 2-3 divided doses. 5-10 mg IV over 30 seconds is the corresponding intravenous (IV) dose. After an IV injection, the peak effect lasts 3-5 minutes, and the action lasts 10-20 minutes.
Verapamil should not be taken with beta-blockers like atenolol or quinidine because the combination of their negatively inotropic and negatively chronotropic effects can result in severe hypotension, bradycardia, impaired atrioventricular conduction, heart failure (due to impaired cardiac contractility), and sinus arrest.
The use of verapamil is contraindicated in the following situations:
Acute porphyrias are a type of porphyria that occurs suddenly.
Accessory conducting pathways are linked to atrial flutter or fibrillation (e.g. Wolff-Parkinson-White-syndrome)
Bradycardia
Shock caused by the heart
Insufficiency of the heart (with reduced ejection fraction)
Left ventricular function has been significantly harmed in the past (even if controlled by therapy)
Hypotension (blood pressure less than 90 mmHg)
AV block in the second and third degrees
Sinusitis is a condition in which the sinuses become
Sino-atrial occlusion -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 10
Correct
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A 32-year old male patient has been diagnosed with meningococcal meningitis and was given appropriate treatments. Because he is a family man, he fears that he might transmit the infection to the rest of his family members.
The causative agent of meningococcal meningitis is spread via what mode of transmission?Your Answer: Respiratory droplet route
Explanation:N. meningitidis, the causative agent of meningococcal meningitis, is considered both a commensal and a pathogen. It can be found in the surfaces of mucous membranes such as the nasopharynx and oropharynx. With this, it can be transmitted from a carrier to a new host via respiratory droplet secretions.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 11
Correct
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A 60-year-old male presents to the genitourinary clinic with dysuria and urinary frequency complaints. He has a past medical history of benign prostate enlargement, for which he has been taking tamsulosin. There is blood, protein, leucocytes, and nitrites on a urine dipstick. Fresh blood tests were sent, and his estimated GFR is calculated to be >60 ml/minute. A urinary tract infection (UTI) diagnosis is made, and he is prescribed antibiotics. Out of the following, which antibiotic is most appropriate to be prescribed to this patient?
Your Answer: Ciprofloxacin
Explanation:URINARY TRACT INFECTIONS IN ADULT MEN
Symptomatic urinary tract infections are much less common in men than in women, and all UTIs
in men are considered complicated UTIs. Men with UTIs should be evaluated for predisposing or
causative factors.Uncomplicated cystitis
- Fosfomycin, oral, 3 g as a single dose.
If fosfomycin is unavailable:
- Nitrofurantoin, oral, 100 mg 6 hourly for 5 days.
Do not use nitrofurantoin or fosfomycin if there is any suspicion of early pyelonephritis as they do
not achieve adequate renal tissue levels.
If there are any factors precluding the use of the above agents, then a beta-lactam should be used.
Options include:
Cefixime 200 mg PO 12 hourly for 7 days
OR
Cefpodoxime 100 mg PO 12 hourly for 7 daysComplicated cystitis
Adults- Ciprofloxacin 500 mg PO 12 hourly
OR - Levofloxacin 750 mg PO once daily
Empiric antibiotic therapy should be changed based upon the bacteria isolated and its
antimicrobial susceptibility.
Treat for a total of 7–14 days -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 12
Correct
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Which of the following is where the rectovesical fascia is located:
Your Answer: Between the fundus of the bladder and the ampulla of the rectum
Explanation:In a triangular area between the vasa deferentia, the bladder and rectum are separated only by rectovesical fascia, commonly known as Denonvillier’s fascia.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 13
Incorrect
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Atrial natriuretic peptide (ANP) acts to cause all of the following effects EXCEPT for:
Your Answer: Inhibits renin release
Correct Answer: Vasoconstricts the afferent arteriole
Explanation:ANP acts to:
Inhibit Na+ reabsorption in the distal nephron (through inhibition of ENaC in principal cells)
Suppress the production of renin
Suppress the production of aldosterone
Suppress the production of ADH
Cause renal vasodilation, increasing the glomerular filtration rate -
This question is part of the following fields:
- Physiology
- Renal
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Question 14
Correct
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The most important Complement protein for antigen opsonization is:
Your Answer: C3b
Explanation:Phagocytosis is largely responsible for depletion of cells coated with antibodies. Cells opsonized by IgG antibodies are recognized by phagocyte Fc receptors, which are specific for the Fc portions of some IgG subclasses. In addition, when IgM or IgG antibodies are deposited on the surfaces of cells, they may activate the complement system by the classical pathway. Complement activation generates by-products, mainly C3b and C4b, which are deposited on the surfaces of the cells and recognized by phagocytes that express receptors for these proteins. The net result is phagocytosis of the opsonized cells and their destruction.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 15
Correct
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Naloxone is a reversal agent for which of the following groups of drugs:
Your Answer: Opioids
Explanation:Naloxone is a specific antagonist of mu(ÎĽ)-opioid receptors, the specific antidote for opioid overdose and will reverse respiratory depression and coma if given at sufficient dosage. The initial dose is usually 0.8 mg (2 mL) intravenously (the dose range suggested by BNF is 0.4-2 mg). It can also be given by intramuscular injection if the intravenous route is not feasible.
As naloxone has a shorter duration of action than most opioids, close monitoring and repeated injections are necessary according to the respiratory rate and depth of coma. The dose is generally repeated every 2-3 minutes to a maximum of 10 mg. When repeated doses are needed, naloxone may be given by a continuous infusion adjusted according to the vital signs. Initially, the infusion rate can be set at 60% of the initial resuscitative IV dose per hour.
In opioid addicts, naloxone administration may precipitate a withdrawal syndrome with abdominal cramps, nausea and diarrhoea, but these usually settle within 2 hours. -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 16
Incorrect
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Monoamine oxidase is primarily involved in the degradation of which of the following:
Your Answer: Adrenocorticotropic hormone
Correct Answer: Noradrenaline
Explanation:Catecholamines are broken down extracellularly and in the liver by catechol-O-methyltransferase (COMT) and intracellularly by monoamine oxidase (MAO).
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 17
Correct
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Which of the following is NOT one of insulin's actions:
Your Answer: Increased gluconeogenesis
Explanation:Insulin has a number of effects on glucose metabolism, including:
Inhibition of glycogenolysis and gluconeogenesis
Increased glucose transport into fat and muscle
Increased glycolysis in fat and muscle
Stimulation of glycogen synthesis
By inhibiting gluconeogenesis, insulin maintains the availability of amino acids as substrates for protein synthesis. Thus, insulin supports protein synthesis through direct and indirect mechanisms. -
This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 18
Incorrect
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Diagnosis of HIV is predominantly made through which of the following:
Your Answer: Viral PCR
Correct Answer: Antibody detection
Explanation:Diagnosis of HIV is predominantly made through detection of HIV antibody and p24 antigen. Viral load (viral PCR) and CD4 count are used to monitor progression of disease.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 19
Correct
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A patient complains of headache and visual loss. CT scan demonstrates a lesion of the temporal lobe. What type of visual field defect would you most expect to see in this patient:
Your Answer: Contralateral homonymous superior quadrantanopia
Explanation:Axons from the lateral geniculate nucleus (LGN) carry visual information, via the upper and lower optic radiations, to the visual cortex in the occipital lobe:
The upper optic radiation carries fibres from the superior retinal quadrants (corresponding to the inferior visual field quadrants) and travels through the parietal lobe to reach the visual cortex.
The lower optic radiation carries fibres from the inferior retinal quadrants (corresponding to the superior visual field quadrants) and travels through the temporal lobe to reach the visual cortex of the occipital lobe. -
This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 20
Correct
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Which of the following anatomical structures is most likely the cause of oedema and erythema of the arm in a patient who underwent modified radical mastectomy and radiotherapy?
Your Answer: Axillary lymph nodes
Explanation:Arm oedema is one of the sequelae after breast cancer surgery and radiation therapy. Arm oedema in the breast cancer patient is caused by interruption of the axillary lymphatic system by surgery or radiation therapy, which results in the accumulation of fluid in subcutaneous tissue in the arm, with decreased distensibility of tissue around the joints and increased weight of the extremity. Chronic inflammatory changes result in both subcutaneous and lymph vessel fibrosis.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 21
Incorrect
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Question 22
Correct
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A 43 year old lady who has a previous medical history of hyperthyroidism presents to the emergency room with sweating, palpitations and agitation. On examination, she is tachycardic, hypertensive and hyperpyrexic. She recently had a stomach bug and has not been able to take her medication regularly. The best medication to immediately treat her symptoms is which of the following?
Your Answer: Propranolol
Explanation:There is a high suspicion of a thyroid crisis in this patient and emergent treatment should be initiated even before the results of TFT’s have returned. Antiadrenergic drugs like IV propranolol should be administered immediately to minimise sympathomimetic symptoms. Antithyroid medications like propylthiouracil or carbimazole should be administered to block further synthesis of thyroid hormones. After thionamide therapy has been started to prevent stimulation of new hormone synthesis, there should then be delayed administration of oral iodine solution. Hydrocortisone administration is also recommended as it treats possible relative adrenal insufficiency while also decreases peripheral conversion of T4 to T3.
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This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 23
Incorrect
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A 56-year-old man presents with pneumonia 8 days after being admitted for an open fracture of his tibia and fibula. Upon history taking and observation, it was established that he has no known drug allergies, has coarse left basal crackles and evidence of consolidation in the left lower lobe based on his chest X-ray.
Which of the following antibacterial agents would be the most appropriate to prescribe according to the latest NICE guidelines?Your Answer: Co-amoxiclav
Correct Answer: Ciprofloxacin
Explanation:The current NICE guidelines for hospital-acquired pneumonia are as follow:
– First-choice oral antibiotic if non‑severe symptoms or signs, and not at higher risk of resistance (guided by microbiological results when available): co-amoxiclav– Alternative oral antibiotics if non‑severe symptoms or signs, and not at higher risk of resistance, for penicillin allergy or if co‑amoxiclav unsuitable (based on specialist microbiological advice and local resistance data): doxycycline, cefalexin, co-trimoxazole, levofloxacin
– First-choice intravenous antibiotics if severe symptoms or signs (for example, symptoms or signs of sepsis) or at higher risk of resistance (based on specialist microbiological advice and local resistance data): piperacillin with tazobactam, ceftazidime, ceftriaxone, cefuroxime, meropenem, ceftazidime with avibactam, levofloxacin
– Antibiotics to be added if suspected or confirmed methicillin-resistant Staphylococcus aureus infection (dual therapy with a first-choice intravenous antibiotic): vancomycin, teicoplanin, linezolid
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 24
Correct
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A 50-year-old man, known hypertensive on amlodipine has been visiting his GP with symptoms of headache, tiredness, and muscle weakness. His blood test today shows a low potassium level of 2.8 mmol/L, and a slightly raised sodium level at 147 mmol/L.
What is the MOST LIKELY diagnosis?
Your Answer: Conn’s syndrome
Explanation:When there are excessive levels of aldosterone independent of the renin-angiotensin aldosterone axis, primary hyperaldosteronism occurs. Secondary hyperaldosteronism occurs due to high renin levels.
Causes of primary hyperaldosteronism include:
Conn’s syndrome
Adrenal hyperplasia
Adrenal cancer
Familial aldosteronismCauses of secondary hyperaldosteronism include:
Renal vasoconstriction
Oedematous disorders
Drugs – diuretics
Obstructive renal artery diseaseAlthough patients are usually asymptomatic, when clinical features are present, classically hyperaldosteronism presents with:
Hypokalaemia
Sodium levels can be normal or slightly raised
Hypertension
Metabolic alkalosis
Less common, clinical features are:
Lethargy
Headaches
Intermittent paraesthesia
Polyuria and polydipsia
Muscle weakness (from persistent hypokalaemia)
Tetany and paralysis (rare) -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 25
Correct
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A 55-year-old woman was complaining of headaches. On examination, the patient is found to have weakness on the left side of her body and her eyes are deviated towards the right hand side. These are signs of damage to which of the following areas?
Your Answer: Frontal lobe
Explanation:Some potential symptoms of frontal lobe damage can include loss of movement, either partial or complete, on the opposite side of the body.
In the patient’s case, it is a result of motor cortex damage on the right side since her left side of the body is affected. The conjugate eye deviation symptom towards the side of the lesion is a result of damage to the frontal eye field.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 26
Correct
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A 35-year-old man, who was feeling unwell after his return from a business trip, was diagnosed with a disease that is known to be transmitted by a vector.
Among the following microorganisms, which of the following has a mode of transmission of being vector-borne?Your Answer: Plasmodium falciparum
Explanation:Plasmodium falciparum is a parasite that is vector-borne which is transmitted by the female Anopheles mosquito.
Bordetella pertussis is transmitted through the respiratory tract, via respiratory droplets or direct contact with infectious secretions.
Mycobacterium tuberculosis is transmitted via inhalation of infected respiratory droplets.
HIV may be transmitted via sexual contact, vertical transmission from mothers to infants, and among injection drug users sharing infected needles, as well as through transfusion of infected blood products.
Treponema pallidum transmission normally occurs during direct sexual contact with an individual who has an active primary or secondary syphilitic lesion.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 27
Correct
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Which statement regarding skeletal muscle is true?
Your Answer: Myosin is the major constituent of the thick filament
Explanation:Myosin is the major constituent of the thick filament.
Actin is the major constituent of the THIN filament.
Thin filaments consist of actin, tropomyosin and troponin in the ratio 7:1:1.
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 28
Correct
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The causative organism for an infection in a patient you are reviewing is a facultative anaerobe.
Which of these is a facultative anaerobic organism?Your Answer: Staphylococcus aureus
Explanation:Facultative anaerobic bacteria make energy in the form of ATP by aerobic respiration in an oxygen rich environment and can switch to fermentation in an oxygen poor environment.
Examples of facultative anaerobes are:
Staphylococcus spp.
Listeria spp.
Streptococcus spp.
Escherichia coliMycobacterium tuberculosis, and Pseudomonas aeruginosa are obligate aerobe. They require oxygen to grow
Campylobacter jejuni and Clostridium spp are obligate anaerobes.
They live and grow in the absence of oxygen. -
This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 29
Correct
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You suspect that your patient with polycystic kidney disease has developed a berry aneurysm as a complication of his disease. The patient complains of a sudden, severe headache. You are guessing subarachnoid haemorrhage secondary to a ruptured berry aneurysm as the cause of his severe headaches. What is the most likely location of his aneurysm?
Your Answer: Anterior communicating artery
Explanation:One of the complications that polycystic kidney disease may cause is the development of a brain aneurysm.
A berry aneurysm is the most common type of brain aneurysm.
The Circle of Willis, where the major blood vessels meet at the base of the brain, is where it usually appears. The most common junctions of the Circle of Willis where an aneurysm may occur include the anterior communicating artery (35%), internal carotid artery (30%), the posterior communicating artery and the middle cerebral artery (22%), and finally, the posterior circulation sites, most commonly the basilar artery tip.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 30
Incorrect
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Antidiuretic hormone (ADH) has which of the following effects:
Your Answer: Increases water excretion by inhibiting reabsorption of sodium in the distal convoluted tubule
Correct 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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SESSION STATS - PERFORMANCE PER SPECIALTY
