-
Question 1
Incorrect
-
A 74-year-old man who has been diagnosed with atrial fibrillation and heart failure is being started on digoxin. What is the mechanism of action of digoxin?
Your Answer: Blocks Ca2+ release from the sarcoplasmic reticulum
Correct Answer:
Explanation:Digoxin works by inhibiting the Na+/K+ ATPase pump in cardiac myocytes. Here’s how it works:
- Inhibition of Na+/K+ ATPase: Digoxin binds to and inhibits the Na+/K+ ATPase pump, which is responsible for pumping sodium out of the cell and potassium into the cell.
- Increased intracellular sodium: Inhibition of this pump leads to an increase in intracellular sodium levels.
- Decreased activity of the sodium-calcium exchanger: The increased intracellular sodium reduces the activity of the sodium-calcium exchanger, which normally pumps calcium out of the cell in exchange for sodium.
- Increased intracellular calcium: As a result, intracellular calcium levels rise because less calcium is being extruded from the cell. The increased calcium is then stored in the sarcoplasmic reticulum.
- Enhanced contractility: During each action potential, more calcium is released from the sarcoplasmic reticulum into the cytoplasm, which enhances the contractility of the heart muscle (positive inotropic effect).
By increasing the force of contraction, digoxin helps improve cardiac output in patients with heart failure. Additionally, digoxin has vagomimetic effects, which can help control the heart rate in atrial fibrillation by increasing vagal tone and thereby reducing the conduction velocity through the atrioventricular node.
-
This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 2
Incorrect
-
Direct conduction from the atrium to the ventricles is prevented by:
Your Answer:
Correct Answer: Annulus fibrosus
Explanation:The annulus fibrosus disconnects the syncytium complex. The atria are rapidly activated however the activation peters out when the insulating layer-the annulus fibrosus-is reached.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 3
Incorrect
-
A 75 year old man was brought to the clinic by his wife because lately he has lost interest in activities he previously enjoyed. His wife is worried and claims he's generally withdrawn. What would exclude depression in favour of dementia?
Your Answer:
Correct Answer: Urinary incontinence
Explanation:Urinary incontinence is not a usual symptom of depression. A depressed patient is usually capable of maintaining control of his body sphincters. In dementia, however, urinary incontinence is an important and late symptom of the disease, non-related to any urinary tract pathology. It is rather related to the cognitive impairment caused by dementia.
-
This question is part of the following fields:
- Geriatrics
- Medicine
-
-
Question 4
Incorrect
-
A 23 year old male presents with a history of lower back pain for the last one year. Presence of which of the following features most likely points towards ankylosing spondylitis?
Your Answer:
Correct Answer: Bilateral erosion of sacroiliac joints on X-ray
Explanation:Bilateral erosions of the sacroiliac joints on pelvic radiographs of patients with ankylosing spondylitis are an important feature of the modified New York classification criteria. Although HLA-B27 is commonly associated with AS, it can also be found in normal individuals. Back stiffness is worse in the morning and gets better as the day progresses. Tenderness and limited lumbar motion can be associated with other spine problems as well and is not characteristic of rheumatoid arthritis.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 5
Incorrect
-
Question 6
Incorrect
-
Question 7
Incorrect
-
Where does secretin work in the pancreas?
Your Answer:
Correct Answer: Pancreatic ducts
Explanation:Secretin, a hormone produced by the duodenal S cells in response to the stomach chyme containing high hydrogen atom concentration (high acidity), is released into the blood stream; upon return to the digestive tract, secretion decreases gastric emptying, increases secretion of the pancreatic ductal cells, as well as stimulating pancreatic acinar cells to release their zymogenic juice.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 8
Incorrect
-
Which part of the neuron has the highest concentration of sodium channels per square millimetre of the cell membrane?
Your Answer:
Correct Answer: Nodes of Ranvier
Explanation:The nodes of Ranvier contain Na+/K+ ATPases, Na+/Ca2+ exchangers and a high density of Na+ channels. The estimated concentration of sodium channels in the node is of ∼1500/μm2.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 9
Incorrect
-
A 25-year-old male presented to accident and emergency 4 days ago, following an intentional paracetamol overdose. He had taken 20x 500mg tablets, all at once. He denies any alcohol intake. Blood investigations 4 hours after ingestion showed:Paracetamol: 14 mg/lINR: 1Liver enzymes: No abnormality detectedBilirubin: Mild elevationHe was seen by the mental health team and discharged. The blood investigations were repeated:Bilirubin: Within normal limitsUrea: 21 mmol/lCreatinine: 300 µmol/lWhat is the likely cause of these results?
Your Answer:
Correct Answer: Delayed paracetamol nephrotoxicity
Explanation:The most likely cause for these results is delayed paracetamol nephrotoxicity.The blood investigations of this patient are highly suggestive of acute kidney injury. Paracetamol overdose is well known to cause hepatotoxicity, but not for its delayed nephrotoxicity, especially in significant overdose. Appropriate monitoring of a patient’s blood tests is important.Management:NAC (N-Acetyl cysteine) has a clear role in preventing acetaminophen-induced liver necrosis. Although NAC has not been proven to be harmful to the kidney, its role in patients without hepatoxicity and only isolated renal dysfunction is uncertain.Other options:-There are no features in the history that are suggestive of dehydration and pre-renal AKI presenting in this manner in a 25-year-old would be very unusual.- Minimal change nephropathy typically presents with a nephrotic picture of kidney injury.- Berger’s more commonly presents with isolated haematuria.
-
This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 10
Incorrect
-
All of the following are Vitamin K-dependent clotting factors except:
Your Answer:
Correct Answer: Factor XI
Explanation:Activated Vitamin K is used to gamma carboxylate (and thus activate) certain enzymes involved in coagulation: Factors II, VII, IX, X, and protein C and protein S. Inability to activate the clotting cascade via these factors leads to the bleeding symptoms
-
This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 11
Incorrect
-
A 24 year old man presents to the clinic complaining of lower limb joint pain and lower backache for the past 2 weeks. He remembers getting a mild gastrointestinal infection while in Spain 6 weeks ago that settled spontaneously. There has been eye irritation that has now settled. Past surgical history includes an appendectomy 3 years back. Vital examination shows a temperature of 37.5 C. Lab results reveal a normal WBC and raised ESR. Which of the following is true?
Your Answer:
Correct Answer: Rheumatoid factor is likely to be negative
Explanation:Reactive arthritis, (formerly known as Reiter’s syndrome), is an autoimmune condition that occurs after a bacterial infection of the gastrointestinal or urinary tract. It is categorized as a seronegative spondylarthritis because of its association with HLA-B27. Reactive arthritis primarily affects young men and usually presents with musculoskeletal or extra‑articular symptoms. The characteristic triad consists of arthritis, conjunctivitis, and urethritis. The diagnosis is based on clinical features such as patient history and physical examination; there are no specific tests for reactive arthritis. Treatment is primarily symptomatic and consists of the administration of NSAIDs, as most patients recover spontaneously. extraarticular dermatologic manifestations include skin lesions of the glans resembling psoriasis (balanitis circinata); hyperkeratinisation of the palms and soles (keratoderma blenorrhagicum), oral ulcers. There usually is no rash and the diagnosis is unrelated to the presence of rheumatoid factor. This is a clinical diagnosis.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 12
Incorrect
-
Which of the following occurs during a Valsalva manoeuvre?
Your Answer:
Correct Answer: An initial rise in blood pressure
Explanation:The Valsalva maneuver involves forced expiration against a closed glottis. It has several phases, each affecting the cardiovascular system differently:
- Phase I: During the initial forced expiration against the closed glottis, there is a transient rise in intrathoracic pressure, which compresses the thoracic aorta and causes a brief increase in blood pressure.
- Phase II: Continued straining leads to decreased venous return to the heart, reducing cardiac output and causing a drop in blood pressure. This phase is characterized by a compensatory increase in heart rate.
- Phase III: Upon releasing the strain, there is a sudden drop in intrathoracic pressure, which momentarily decreases blood pressure.
- Phase IV: Blood pressure then rises rapidly as venous return to the heart is restored, leading to increased cardiac output. This is often followed by a reflex bradycardia (slow heart rate).
Given these phases, the most accurate statement about what occurs during the Valsalva maneuver is the initial rise in blood pressure (Phase I).
Other options explained:
- Forced inspiration against a closed glottis: Incorrect. The Valsalva maneuver involves forced expiration, not inspiration, against a closed glottis.
- Low intrathoracic pressures throughout: Incorrect. The Valsalva maneuver involves high intrathoracic pressures due to forced expiration.
- Disruption of autonomic function: Incorrect. The Valsalva maneuver affects autonomic function but does not disrupt it. Instead, it triggers autonomic responses to changes in blood pressure and heart rate.
- No change: Incorrect. The Valsalva maneuver causes significant changes in blood pressure and heart rate.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 13
Incorrect
-
During which phase of the cell cycle does transcription of DNA synthesis molecules occur?
Your Answer:
Correct Answer: S
Explanation:DNA synthesis occurs in the S phase of the cell cycle. In the G1 phase the cell prepares to divide. In G2 the cellular organelles divide and in the M phase mitosis occur. In the G0 phase the cell becomes quiescent and does not divide further.
Interphase is composed of G1 phase (cell growth), followed by S phase (DNA synthesis), followed by G2 phase (cell growth). At the end of interphase comes the mitotic phase, which is made up of mitosis and cytokinesis and leads to the formation of two daughter cells.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 14
Incorrect
-
Role of bile salts in digestion of fats include
Your Answer:
Correct Answer: Reduce surface tension, emulsification and transportation
Explanation:Bile acts to some extent as a surfactant reducing surface tension, helping to emulsify the lipids in food. Bile salt anions are hydrophilic on one side and hydrophobic on the other side; consequently, they tend to aggregate around droplets of lipids (triglycerides and phospholipids) to form micelles, with the hydrophobic sides towards the fat and hydrophilic sides facing outwards. The hydrophilic sides are negatively charged, and this charge prevents fat droplets coated with bile from re-aggregating into larger fat particles.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 15
Incorrect
-
Which one of the following neurotransmitters is considered a monoamine?
Your Answer:
Correct Answer: Dopamine
Explanation:Monoamines are a class of neurotransmitters that include:
- Dopamine: A neurotransmitter involved in reward, motivation, and motor control.
- Norepinephrine: A neurotransmitter involved in arousal, attention, and stress responses.
- Serotonin: Although not listed in the options, it is another key monoamine involved in mood regulation.
The other neurotransmitters listed are not monoamines:
- Acetylcholine: This is a different type of neurotransmitter involved in muscle activation and various brain functions.
- GABA (gamma-aminobutyric acid): This is the main inhibitory neurotransmitter in the central nervous system.
- Glutamate: This is the main excitatory neurotransmitter in the central nervous system.
- Glycine: An inhibitory neurotransmitter in the central nervous system.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 16
Incorrect
-
What is troponin?
Your Answer:
Correct Answer: A component of thin filaments
Explanation:Skeletal muscle cytoplasmic proteins include myosin and actin (also known as thick and thin filaments, respectively) which are arranged in a repeating unit called a sarcomere. Troponin is a component of thin filaments (along with tropomyosin), and is the protein to which calcium binds.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 17
Incorrect
-
Which statement about the 2nd heart sound is true?
Your Answer:
Correct Answer: It is caused by closure of the aortic and pulmonary valves.
Explanation:The second heart sound is produced due to closure of the aortic and pulmonary valves. It is a high pitched dub sound.
Normally the aortic closure sound (A2) occurs prior to the pulmonic closure sound (P2), and the interval between the two (splitting) widens on inspiration and narrows on expiration. With quiet respiration, A2 will normally precede P2 by 0.02 to 0.08 second (mean, 0.03 to 0.04 sec) with inspiration. In younger subjects inspiratory splitting averages 0.04 to 0.05 second during quiet respiration. With expiration, A2 and P2 may be superimposed and are rarely split as much as 0.04 second. If the second sound is split by greater than 0.04 second on expiration, it is usually abnormal. Therefore, the presence of audible splitting during expiration (i.e., the ability to hear two distinct sounds during expiration) is of greater significance at the bedside in identifying underlying cardiac pathology than is the absolute inspiratory increase in the A2–P2 interval.
The respiratory variation of the second heart sound can be categorized as follows: (1) normal (physiologic) splitting; (2) persistent (audible expiratory) splitting, with normal respiratory variation; (3) persistent splitting without respiratory variation (fixed splitting); and (4) reversed (paradoxical) splitting.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 18
Incorrect
-
Efferent innervation of the muscle spindle is supplied by which type of motor neuron?
Your Answer:
Correct Answer: Gama – motor neuron
Explanation:The muscle spindle is supplied by both sensory and motor nerves. Sensory supply is via Type Ia fibers whereas the motor supply is via gamma motor neurons.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 19
Incorrect
-
During which phase of the cardiac cycle does most of the ventricular filling occur?
Your Answer:
Correct Answer: Ventricular diastole
Explanation:During the phase of ventricular diastole when the heart muscle relaxes and all the valves are open, blood flows easily into the heart. This is the phase of rapid ventricular filling. During isovolumetric contraction and relaxation the volume of blood in the heart does not change. During ventricular ejection blood enters into the aorta and pulmonary vessels.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 20
Incorrect
-
The cerebellum consists of which three cell layers?
Your Answer:
Correct Answer: Granular, purkinje, molecular
Explanation:The cerebellar cortex consist of 3 layers; the molecular layer, the granular cell layer and the Purkinje cell layer in the middle.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 21
Incorrect
-
Which of the following causes an increase in venous return?
Your Answer:
Correct Answer: An increase in the negative intra-thoracic pressure
Explanation:During inspiration, intrathoracic pressure becomes more negative and intra-abdominal pressure more positive. This increases the venous pressure gradient from abdomen to thorax and promotes filling of the central veins.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 22
Incorrect
-
Question 23
Incorrect
-
Number of cases that are infected at a specific point in time
Your Answer:
Correct Answer: Prevalence
Explanation:Prevalence in epidemiology is the proportion of a population found to have a condition (typically a disease or a risk factor such as smoking or seat-belt use). It is arrived at by comparing the number of people found to have the condition with the total number of people studied, and is usually expressed as a fraction, as a percentage or as the number of cases per 10,000 or 100,000 people. Point prevalence is the proportion of a population that has the condition at a specific point in time. Period prevalence is the proportion of a population that has the condition at some time during a given period (e.g., 12 month prevalence), and includes people who already have the condition at the start of the study period as well as those who acquire it during that period. Lifetime prevalence (LTP) is the proportion of a population that at some point in their life (up to the time of assessment) have experienced the condition
-
This question is part of the following fields:
- Infectious Diseases
- Medicine
-
-
Question 24
Incorrect
-
When one of the two copies of the autosomes has a mutation and the protein produced by the normal form of the gene cannot compensate. The affected individual has an:
Your Answer:
Correct Answer: Autosomal dominant disorder
Explanation:An autosomal dominant trait will be expressed no matter the consequence. If one chromosome has a mutation the other will not be able to compensate for the mutation hence the protein formed will be mutated and will not function properly.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 25
Incorrect
-
Question 26
Incorrect
-
Regarding cardiac muscle contractility, the afterload refers to:
Your Answer:
Correct Answer: The resistance against which blood is expected
Explanation:The afterload for the left ventricle is the aortic pressure. Hence it is this pressure that offers resistance against which the blood is to be expelled from the heart.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 27
Incorrect
-
Which of the following is a product of D cells
Your Answer:
Correct Answer: Somatostatin
Explanation:Somatostatin is secreted by D cells, HCL and intrinsic factor secreted by parietal cells. Trefoil peptides are secreted by mucus secreting goblet cells and gastrin releasing peptide (grp) by post-ganglionic fibers of the vagus nerve (which innervate the G cells of the stomach).
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 28
Incorrect
-
The pathway responsible for the discriminative aspect of pain, is called the:
Your Answer:
Correct Answer: Neospinothalamic tract
Explanation:The spinothalamic tract is an ascending or a sensory tract, responsible for transmission of pain and temperature. The neospinothalamic tract is responsible for fast pain or discriminative pain whereas the palaeospinothalamic tract is responsible for transmission of slow pain.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 29
Incorrect
-
Which enzyme is responsible for the formation of the active endopeptidases from their inactive precursors?
Your Answer:
Correct Answer: Enterokinase
Explanation:Enterokinase is a brush border enzyme of the duodenum that activates proteolytic enzymes for further digestion of proteins. Trypsinogen is converted to trypsin by the action of enterokinase. Trypsin and chymotrypsin are secreted by the pancreatic acinar cells and are enzymes that aid in protein digestion. Pepsin is secreted by chief cells of gastric mucosa. Procarboxydase is the inactive form of carboxypeptidase which is converted to its active form by trypsin and is secreted by pancreatic acinar cells.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 30
Incorrect
-
The hyperpolarization phase of pacemaker cells is dominated by ____ current.
Your Answer:
Correct Answer: K+
Explanation:The hyperpolarization phase is a continuation of the repolarization phase but the membrane potential dips below the resting membrane potential. This results due to the fact that the K+ channels take a longer time to close than the Na+ channels. Hence efflux of the K+ will result in hyperpolarization.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
00
Correct
00
Incorrect
00
:
00
:
00
Session Time
00
:
00
Average Question Time (
Secs)