-
Question 1
Correct
-
A 29-year-old woman with anaphylactic reaction to peanuts, had to use her EpiPen on the way to hospital.
What percentage of patients with anaphylactic reaction suffer a biphasic response?.Your Answer: 20%
Explanation:About 20% of patients that suffer an anaphylactic reaction suffer a biphasic response 4-6 hours after the initial response (sometimes up to 72 hours after).
-
This question is part of the following fields:
- General Pathology
- Pathology
-
-
Question 2
Correct
-
A 20-year-old female presents with painful wrist following a fall while skating. X-rays shows fracture of the ulna.
The initial phase of bone healing is?
Your Answer: Haematoma at the fracture site
Explanation:Haemorrhage occurs into the fracture site from the ruptured vessels in the bone marrow and those supplying the periosteum immediately after fracture. This hematoma formation is the first phase of bone healing.
The 4 stages of bone healing are:
Haematoma at the fracture site (provides a framework for healing)
Callus formation
Lamellar bone formation
Remodelling -
This question is part of the following fields:
- General Pathology
- Pathology
-
-
Question 3
Correct
-
Regarding the hard palate, which of the following statements is CORRECT:
Your Answer: Lymphatic vessels from the palate usually drain into deep cervical lymph nodes.
Explanation:Lymphatic vessels from the pharynx and palate drain into the deep cervical lymph nodes.
-
This question is part of the following fields:
- Anatomy
- Head And Neck
-
-
Question 4
Incorrect
-
A 32-year-old man is dehydrated as he presents with severe vomiting and diarrhoea. He urgently requires resuscitation with intravenous fluid administration. He is also administered metoclopramide.
Which of the following is the true mechanism of action of metoclopramide?Your Answer: 5-HT3 receptor agonism
Correct Answer: Dopamine receptor antagonism
Explanation:Metoclopramide is used to treat nausea and vomiting. It works by blocking the central and peripheral D2 (dopamine 2) receptors in the medullary chemoreceptor trigger zone in the vomiting centre (area postrema). It decreases the sensitivity of the visceral sensory nerves that transmit from the GI system to the vomiting centre. Blockade of inhibitory dopamine receptors in the GI tract may allow stimulatory actions of ACh at muscarinic synapses to predominate.
At high doses, metoclopramide also blocks type-2 serotonin receptors though the effect is much weaker.
-
This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
-
-
Question 5
Incorrect
-
Regarding codeine, which of the following statements is INCORRECT:
Your Answer: Codeine is metabolised to morphine which is responsible for its therapeutic effects.
Correct Answer: There is a reduced risk of toxicity in patients who are ultra-rapid metabolisers of codeine.
Explanation:Codeine phosphate is a weak opioid and can be used for the relief of mild to moderate pain where other painkillers such as paracetamol or ibuprofen have proved ineffective.Codeine is metabolised to morphine which is responsible for its therapeutic effects. Codeine 240 mg is approximately equivalent to 30 mg of morphine. The capacity to metabolise codeine can vary considerably between individuals; there is a marked increase in morphine toxicity in people who are ultra rapid metabolisers, and reduced therapeutic effect in poor codeine metabolisers. Codeine is contraindicated in patients of any age who are known to be ultra-rapid metabolisers of codeine (CYP2D6 ultra-rapid metabolisers).Codeine is also contraindicated in children under 12, and in children of any age who undergo the removal of tonsils or adenoids for the treatment of obstructive sleep apnoea due to reports of morphine toxicity.
-
This question is part of the following fields:
- Central Nervous System
- Pharmacology
-
-
Question 6
Correct
-
A 54-year-old man with a long history of poorly controlled hypertension complains of a headache and vision blurring today. In triage, his blood pressure is 210/192 mmHg. A CT head scan is scheduled to rule out the possibility of an intracranial haemorrhage. You make the diagnosis of hypertensive encephalopathy and rush the patient to reus to begin blood pressure-lowering treatment. He has a history of brittle asthma, for which he has been admitted to the hospital twice in the last year.
Which of the following is the patient's preferred drug treatment?Your Answer: 25% of the mean arterial pressure over the first hour
Explanation:End-organ damage (e.g. encephalopathy, intracranial haemorrhage, acute myocardial infarction or ischaemia, dissection, pulmonary oedema, nephropathy, eclampsia, papilledema, and/or angiopathic haemolytic anaemia) characterises a hypertensive emergency (also known as ‘accelerated hypertension’ or malignant hypertension’ It’s a life-threatening condition that necessitates rapid blood pressure reduction to avoid end-organ damage and a negative outcome.
Hypertensive encephalopathy is a syndrome that includes headaches, seizures, visual changes, and other neurologic symptoms in people who have high blood pressure. It is reversible if treated quickly, but it can progress to coma and death if not treated properly.
Any patient with suspected hypertensive encephalopathy should have an urgent CT scan to rule out an intracranial haemorrhage, as rapid blood pressure reduction could be dangerous in these circumstances.
The drug of choice is labetalol, which reduces blood pressure steadily and consistently without compromising cerebral blood flow.
An initial reduction of approximately 25% in mean arterial pressure (MAP) over an hour should be aimed for, followed by a further controlled MAP reduction over the next 24 hours. In patients who are unable to take beta-blockers, nicardipine can be used as a substitute. -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
-
-
Question 7
Correct
-
The action potential is generated by excitable tissues, which are specialized tissues that can generate a meaningful electrical signal. Local currents transport action potentials down the axons of neurons.
Which of the following claims about the action potential's conduction is correct?Your Answer: The areas of the membrane that have recently depolarised will not depolarise again due to the refractory period
Explanation:Local currents propagate action potentials down the axons of neurons. Following depolarization, this local current flow depolarizes the next axonal membrane, and when this region crosses the threshold, more action potentials are formed, and so on. Due to the refractory period, portions of the membrane that have recently depolarized will not depolarize again, resulting in the action potential only being able to go in one direction.
The square root of axonal diameter determines the velocity of the action potential; the axons with the biggest diameter have the quickest conduction velocities. When a neuron is myelinated, the speed of the action potential rises as well.
The myelin sheath is an insulating coating that surrounds certain neural axons. By increasing membrane resistance and decreasing membrane capacitance, the myelin coating increases conduction. This enables faster electrical signal transmission via a neuron, making them more energy-efficient than non-myelinated neuronal axons.
Nodes of Ranvier are periodic holes in a myelinate axon when there is no myelin and the axonal membrane is exposed. There are no gated ion channels in the portion of the axon covered by the myelin sheath, but there is a high density of ion channels in the Nodes of Ranvier. Action potentials can only arise at the nodes as a result of this.
Electrical impulses are quickly transmitted from one node to the next, causing depolarization of the membrane above the threshold and triggering another action potential, which is then transmitted to the next node. An action potential is rapidly conducted down a neuron in this manner. Saltatory conduction is the term for this. -
This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
-
-
Question 8
Correct
-
The ECG of a patient presenting with a history of intermittent palpitations has a prolonged QT interval.
Which of these can cause prolongation of the QT interval on the ECG?Your Answer: Hypomagnesaemia
Explanation:The causes of a prolonged QT interval include:
Hypomagnesaemia
Hypothermia
Hypokalaemia
Hypocalcaemia
Hypothyroidism
Jervell-Lange-Nielsen syndrome (autosomal dominant)
Romano Ward syndrome (autosomal recessive)
Ischaemic heart disease
Mitral valve prolapse
Rheumatic carditis
Erythromycin
Amiodarone
Quinidine
Tricyclic antidepressants
Terfenadine
Methadone
Procainamide
Sotalol -
This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
-
-
Question 9
Incorrect
-
A patient in the Emergency Department had a diagnosis of diabetic ketoacidosis (DKA) and you commence an insulin infusion. Which of these statements concerning endogenous insulin is true?
Your Answer: Glucagon inhibits insulin release
Correct Answer: Insulin has a short half-life of around 5-10 minutes
Explanation:Insulin, a peptide hormone, is produced in the pancreas by the beta-cells of the islets of Langerhans.
The beta-cells first synthesise an inactive precursor called preproinsulin which is converted to proinsulin by signal peptidases, which remove a signal peptide from the N-terminus.
Proinsulin is converted to insulin by the removal of the C-peptide.
Insulin has a short half-life in the circulation of about 5-10 minutes.
Glucagon and parasympathetic stimulation stimulates insulin release. -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
-
-
Question 10
Correct
-
A 34-year-old male is brought into the Emergency Department by the paramedics after a road traffic accident. After a quick triage, you establish that he will need to be intubated, and you ask for some ketamine to be prepared.
Which one of the following options regarding this drug is true?Your Answer: It is the only anaesthetic agent available that has analgesic, hypnotic, and amnesic properties
Explanation:Ketamine is a dissociative anaesthetic with analgesic, amnesic, and hypnotic effects. It is the only anaesthetic agent which causes all three of these effects.
Ketamine exerts its action by non-competitive antagonism at the NMDA (N-methyl-D-aspartate) receptor. Due to its analgesic property, Ketamine is given so that patients do not retain memories of short term procedures. Ketamine is used for the induction and maintenance of anaesthesia in general surgery and for treating burn wounds, battlefield injuries, and children who cannot tolerate other anaesthetic or analgesic agents.
It can be given by both intravenous and intramuscular routes. Ketamine causes cardiac stimulation by increasing the sympathetic tone. The major side effect is increased intracranial pressure as an increase in the sympathetic tone causes vasoconstriction and an increase in the MAP.
-
This question is part of the following fields:
- Anaesthesia
- Pharmacology
-
-
Question 11
Incorrect
-
A patient presents with increased breathlessness and worsening of his chronic cough and. He has a chronic lung disorder and is on long-term oxygen therapy (LTOT). Which of these is an indication for LTOT?
Your Answer: A patient with interstitial lung disease with PaO2 8.5 kPa when stable
Correct Answer: A non-smoker with COPD and a PaO2 of 7.5 kPa when stable with secondary polycythaemia
Explanation:Long-term administration of oxygen, usually at least 15 hours daily, improves survival in COPD patients who have severe hypoxaemia.
Long-term oxygen therapy should be considered in:
A non-smoker with COPD and a PaO2<7.3 kPa when stable
A non-smoker with COPD and PaO27.3–8 kPa when stable and with secondary polycythaemia, peripheral oedema, or evidence of pulmonary hypertension
Severe chronic asthma with PaO2<7.3 kPa or persistent disabling breathlessness
A patient with Interstitial lung disease with PaO2<8 kPa and in patients with PaO2>8 kPa with disabling dyspnoea
A patient with cystic fibrosis when PaO2<7.3 kPa or if PaO27.3–8 kPa in the presence of secondary polycythaemia, nocturnal hypoxaemia, pulmonary hypertension, or peripheral oedema
Pulmonary hypertension, without parenchymal lung involvement when PaO2<8 kPa
Neuromuscular or skeletal disorders, after specialist assessment
Obstructive sleep apnoea despite continuous positive airways pressure therapy, after specialist assessment
Pulmonary malignancy or other terminal disease with disabling dyspnoea
Heart failure with daytime PaO2<7.3 kPa when breathing air or with nocturnal hypoxaemia
-
This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
-
-
Question 12
Incorrect
-
Which statement accurately describes the osmolality in the various parts of the Henle Loop?
Your Answer: The osmolality of tubular fluid increases as it passes through the descending limb to a maximum of approximately 2000 mOsm
Correct Answer: The osmolality of fluid in the descending loop equals that of the peritubular fluid
Explanation:The Loop of Henle connects the proximal tubule to the distal convoluted tubule and lies parallel to the collecting ducts. It consists of three major segments, including the descending thin limb, the ascending thin limb, and the ascending thick limb. These segments are differentiated based on structure, anatomic location, and function.
The main function of the loop of Henle is to recover water and sodium chloride from urine. When fluid enters the loop of Henle, it has an osmolality of approximately 300 mOsm, and the main solute is sodium.
The thin descending limb has a high water permeability but a low ion permeability. Because it lacks solute transporters, it cannot reabsorb sodium. Aquaporin 1 (AQP1) channels are used to passively absorb water in this area. The peritubular fluid becomes increasingly concentrated as the loop descends into the medulla, causing water to osmose out of the tubule. The tubular fluid in this area now equalizes to the osmolality of the peritubular fluid, to a maximum of approximately 1200 mOsm in a long medullary loop of Henle and 600 mOsm in a short cortical loop of Henle.
The thin ascending limb is highly permeable to ions and impermeable to water. It allows the passive movement of sodium, chloride, and urea down their concentration gradients, so urea enters the tubule and sodium and chloride leave. Reabsorption occurs paracellularly due to the difference in osmolarity between the tubule and the interstitium.
The thick ascending limb is also impermeable to water but actively transports sodium, potassium, and chloride out of the tubular fluid. The osmolality of the tubular fluid is lower compared to the surrounding peritubular fluid. This area is water impermeable. This results in tubular fluid leaving the loop of Henle with an osmolality of approximately 100 mOsm, which is lower than the osmolality of the fluid entering the loop, and urea being the solute.
-
This question is part of the following fields:
- Physiology
- Renal Physiology
-
-
Question 13
Correct
-
A patient with a high potassium level is at risk of going into cardiac arrest. What changes in the ECG may indicate the incident of cardiac arrest in this patient?
Your Answer: Peaked T waves and broad QRS complex
Explanation:Severe hyperkalaemia can result in a heart attack or a life-threatening arrhythmia.
T waves become narrow-based, pointed, and tall if hyperkalaemia is not treated.
The QRS complex widens and eventually merges with the T wave, resulting in a classic sine-wave electrocardiogram. Ventricular fibrillation and asystole are likely to follow.
-
This question is part of the following fields:
- Physiology
- Renal
-
-
Question 14
Incorrect
-
Regarding the management of gout, which of the following statements is CORRECT:
Your Answer: Ibuprofen is the NSAID of choice in treating acute gout.
Correct Answer: Allopurinol may cause an acute attack of gout when first started.
Explanation:Allopurinol is a treatment for the prevention of gout. The initiation of treatment may precipitate an acute attack, and should be covered with an NSAID or colchicine, continued for at least one month after the hyperuricaemia has been corrected. Colchicine is not indicated for long term prevention of gout. NSAIDs are first line for acute gout; colchicine is an alternative in whom NSAIDs are contraindicated, not tolerated or ineffective (including in people taking anticoagulants). Ibuprofen is not recommended for acute gout, given it has only weak anti-inflammatory properties; naproxen, diclofenac or indometacin are indicated instead.
-
This question is part of the following fields:
- Musculoskeletal
- Pharmacology
-
-
Question 15
Incorrect
-
A 50-year-old woman with painful joints had some blood tests done with her GP. The test showed she had anti-double stranded DNA antibodies.
Which one of these disorders is most likely to be associated with anti-double stranded DNA antibodies?Your Answer: Polymyositis
Correct Answer: Systemic lupus erythematosus (SLE)
Explanation:CREST syndrome is usually associated with anti-centromere antibodies.
Primary biliary cirrhosis is associated with anti-mitochondrial antibodies.
Sjogren’s syndrome is associated with anti-Ro and anti-La antibodies.
Polymyositis is associated with anti-Jo1 antibodies.
Anti-double stranded DNA antibodies are highly characteristic of systemic lupus erythematosus (SLE). They are a group of anti-nuclear antibodies (ANA) that target double stranded DNA and are implicated in the pathogenesis of lupus nephritis.
-
This question is part of the following fields:
- General Pathology
- Pathology
-
-
Question 16
Incorrect
-
Which of the following best describes a pathogen:
Your Answer: An organism that is part of the normal flora
Correct Answer: An organism that is capable of causing disease
Explanation:A pathogen is an organism that is capable of causing disease.
-
This question is part of the following fields:
- Microbiology
- Principles
-
-
Question 17
Incorrect
-
A 45-year old man presented to the emergency room with complains of chest pain and breathlessness. Upon history taking and examination, it was discovered that he had a right-sided spontaneous pneumothorax and had a failed attempt at pleural aspiration. The pneumothorax is still considerable in size, but he remains breathless. A Seldinger chest drain was inserted but it started to drain frank blood shortly after.
Which of the following complications is most likely to have occurred?Your Answer: Pulmonary laceration
Correct Answer: Intercostal artery laceration
Explanation:Injury to the intercostal artery (ICA) is an infrequent but potentially life-threatening complication of all pleural interventions.
Traditional anatomy teaching describes the ICA as lying in the intercostal groove, protected by the flange of the rib. This is the rationale behind the recommendation to insert needles just above the superior border of the rib. Current recommendations for chest drain insertion suggest that drains should be inserted in the ‘safe triangle’ in order to avoid the heart and the mediastinum and be above the level of the diaphragm.
The safe triangle is formed anteriorly by the lateral border of the pectoralis major, laterally by the lateral border of the latissimus dorsi, inferiorly by the line of the fifth intercostal space and superiorly by the base of the axilla. Imaging guidance also aids in the safety of the procedure.
-
This question is part of the following fields:
- Anatomy
- Thorax
-
-
Question 18
Incorrect
-
You review a 37-year-old man with a history of intravenous drug abuse who admits to sharing needles in the past. He has a flu-like illness and a rash. Concerned he may be experiencing an HIV seroconversion illness, you order a test.
Which of these tests is most reliably used to diagnose HIV at this stage?
Your Answer: ELISA antibody test
Correct Answer: p24 antigen test
Explanation:Serum concentrations of the p24 antigen are usually high in the first few weeks after human immunodeficiency virus (HIV) infection and testing for p24 antigen is therefore a useful way of diagnosing very early infection. P24 is the viral protein that makes up most of the core of the HIV.
ELISA and other antibody tests, though a very sensitive way of detecting the presence of HIV, cannot be used in the early stages of the disease. This is because of the window period of 6-12 weeks before antibodies are produced. These tests will be negative during a seroconversion illness.
The ‘rapid HIV test’ is an HIV antibody test. It will also be negative during the ‘window period’ since it takes time for antibodies to be produced. It is called the ‘rapid test’ as it can detect antibodies in blood or saliva much quicker than the other antibody tests and results are often back within 20 minutes.
CD4 and CD8 counts are usually normal in the early stages of the HIV infection and cannot be used in this case.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 19
Incorrect
-
You see a patient in the ED with photophobia, petechial rash, headache and neck stiffness, and suspect a diagnosis of meningococcal meningitis.
What is the most appropriate initial management?
Your Answer: Send blood cultures and await results
Correct Answer: Give ceftriaxone 2 g IV
Explanation:Treatment should be commenced with antibiotics immediately before laboratory confirmation due to the potentially life-threatening nature of the disease.
In a hospital setting, 2g of IV ceftriaxone (80 mg/kg for a child) or IV cefotaxime (2 g adult; 80 mg/kg child) are the drugs of choice.
In the prehospital setting, IM benzylpenicillin can be given as an alternative. -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 20
Incorrect
-
A 27-year-old man was sent to the emergency department by ambulance with suspected anaphylaxis. What is the best first-line treatment for this patient?
Your Answer: 5 mg of adrenaline intramuscularly
Correct Answer: 500 micrograms of adrenaline intramuscularly
Explanation:Anaphylaxis is the sudden onset of systemic hypersensitivity due to IgE-mediated chemical release from mast cells and basophils.
If anaphylaxis is suspected, 500 micrograms of adrenaline should be administered promptly (0.5 ml of 1:1000 solution).
In anaphylaxis, the intramuscular route is the most immediate approach; the optimal site is the anterolateral aspect of the middle part of the thigh.
Intravenous adrenaline should only be given by people who are well-versed in the use and titration of vasopressors in their routine clinical practice.
-
This question is part of the following fields:
- Pharmacology
- Respiratory
-
-
Question 21
Incorrect
-
A lung function test is being performed on a male patient. For this patient, which of the following volumes for functional residual capacity is considered a normal result?
Your Answer: 0.5 L
Correct Answer: 2.0 L
Explanation:The volume of air that remains in the lungs after a single breath is known as functional residual capacity (FRC). It is calculated by combining the expiratory reserve volume and residual volume. In a 70 kg, average-sized male, a normal functional residual capacity is approximately 2100 mL.
-
This question is part of the following fields:
- Physiology
- Respiratory Physiology
-
-
Question 22
Incorrect
-
A 29-year-old male presents with a 3-day history of bloody diarrhoea and abdominal pain.
All the following are causes of infectious bloody diarrhoea EXCEPT?
Your Answer: Salmonella enterica
Correct Answer: Enterotoxigenic Escherichia coli
Explanation:Infective causes of bloody diarrhoea include:
Salmonella spp
Campylobacter spp
Schistosomiasis
Entamoeba histolytica (Amoebiasis )
Shigella spp
Clostridium difficile
Yersinia spp
Enteroinvasive Escherichia coliEnterotoxigenic Escherichia coli is non-invasive and does not cause inflammation of the gut and bloody diarrhoea. It presents with copious watery diarrhoea and usually are not associated with abdominal cramping.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 23
Correct
-
Regarding cortical areas, which one is found in the posterior part of the inferior frontal gyrus?
Your Answer: Broca’s area
Explanation:Broca’s area is involved in the expressive aspects of spoken and written language (production of sentences constrained by the rules of grammar and syntax). It corresponds to the opercular and triangular parts of the inferior frontal gyrus (BA 44 and 45). These areas are defined by two rami (branches) of the lateral sulcus (one ascending, one horizontal) which ‘slice into’ the inferior frontal gyrus. In keeping with its role in speech and language, Broca’s area is immediately anterior to the motor and premotor representations of the face, tongue and larynx. A homologous area in the opposite hemisphere is involved in non-verbal communication such as facial expression, gesticulation and modulation of the rate, rhythm and intonation of speech.
-
This question is part of the following fields:
- Anatomy
- Central Nervous System
-
-
Question 24
Correct
-
A 27-year-old athlete presents with buttock pain after tearing his gluteus maximus muscle.
In which of the following nerves is the gluteus maximus muscle innervated by?Your Answer: Inferior gluteal nerve
Explanation:The gluteal muscles are a group of muscles that make up the buttock area. These muscles include: gluteus maximus, gluteus medius. and gluteus minimus.
The gluteus maximus is the most superficial as well as largest of the three muscles and makes up most of the shape and form of the buttock and hip area. It is a thick, fleshy muscle with a quadrangular shape. It is a large muscle and plays a prominent role in the maintenance of keeping the upper body erect.
The innervation of the gluteus maximus muscle is from the inferior gluteal nerve. -
This question is part of the following fields:
- Anatomy
- Lower Limb
-
-
Question 25
Correct
-
Regarding the refractory period, which of the following statements is INCORRECT:
Your Answer: Action potentials can occur in the relative refractory period but the amplitude of the action potential is smaller.
Explanation:Following the action potential, Na+channels remain inactive for a time in a period known as the absolute refractory period where they cannot be opened by any amount of depolarisation. Following this there is a relative refractory period where the temporary hyperpolarisation (due to delayed closure of rectifier K+channels) makes the cell more difficult to depolarise and an action potential can be generated only in response to a larger than normal stimulus. The refractory period limits the frequency at which action potentials can be generated, and ensures that, once initiated, an action potential can travel only in one direction. An action potential is an all or nothing response so the amplitude of the action potential cannot be smaller.
-
This question is part of the following fields:
- Basic Cellular
- Physiology
-
-
Question 26
Incorrect
-
Approximately what proportion of lymphocytes are B-cells:
Your Answer: 0.35
Correct Answer: 0.2
Explanation:B-cells (20% of lymphocytes) mature in the bone marrow and circulate in the peripheral blood until they undergo recognition of antigen. B-cell immunoglobulin molecules synthesised in the cell are exported and bound to the surface membrane to become the B-cell receptor (BCR) which can recognise and bind to a specific antigen (either free or presented by APCs). The BCR is also important for antigen internalisation, processing and presentation to T helper cells. Most antibody responses require help from antigen-specific T helper cells (although some antigens such as polysaccharide can lead to T-cell independent B-cell antibody production). When the B-cell is activated, the receptor itself is secreted as free soluble immunoglobulin and the B-cell matures into a memory B-cell or a plasma cell (a B-cell in its high-rate immunoglobulin secreting state). Plasma cells are non-motile and are found predominantly in the bone marrow or spleen. Most plasma cells are short-lived (1 – 2 weeks) but some may survive much longer. A proportion of B-cells persist as memory cells, whose increased number and rapid response underlies the augmented secondary response of the adaptive immune system.
-
This question is part of the following fields:
- Immune Responses
- Pathology
-
-
Question 27
Correct
-
Which of the following microbes is spread by a vector:
Your Answer: Plasmodium falciparum
Explanation:The female Anopheles mosquito is the vector for Plasmodium falciparum transmission. Treponema pallidum is transmitted through sexual transmission or direct skin contact. Clostridium perfringens is spread by direct skin contact or through oral-faecal route. The oral-faecal pathway is how Vibrio cholerae spreads. Mycoplasma tuberculosis is spread via the airborne route.
-
This question is part of the following fields:
- Microbiology
- Principles
-
-
Question 28
Incorrect
-
A patient suffers a stab wound to the neck. The entry point of the blade is situated within the anterior triangle of the neck.
Which of the following muscles is most likely to be involved? Select ONE answer only.Your Answer: Platysma
Correct Answer: Sternohyoid
Explanation:The anterior triangle is the triangular area of the neck found anteriorly to the sternocleidomastoid muscle. It is formed by the anterior border of sternocleidomastoid laterally, the median line of the neck medially and by the inferior border of the mandible superiorly. The apex of the anterior triangle extends towards the manubrium sterni. The anterior triangle contains:
Muscles: thyrohyoid, sternothyroid, sternohyoid muscles
Organs: thyroid gland, parathyroid glands, larynx, trachea, esophagus, submandibular gland, caudal part of the parotid gland
Arteries: superior and inferior thyroid, common carotid, external carotid, internal carotid artery (and sinus), facial, submental, lingual arteries
Veins: anterior jugular veins, internal jugular, common facial, lingual, superior thyroid, middle thyroid veins, facial vein, submental vein, lingual veins
Nerves: vagus nerve (CN X), hypoglossal nerve (CN XII), part of sympathetic trunk, mylohyoid nerveThe posterior triangle is a triangular area found posteriorly to the sternocleidomastoid muscle. It has three borders; anterior, posterior and inferior borders. The anterior border is the posterior margin of the sternocleidomastoid muscle. The posterior border is the anterior margin of the trapezius muscle, while the inferior border is the middle one-third of the clavicle. The investing layer of deep cervical fascia and integument forms the roof of the space, while the floor is covered with the prevertebral fascia along with levator scapulae, splenius capitis and the scalene muscles. The inferior belly of omohyoid subdivides the posterior triangle into a small supraclavicular, and a large occipital, triangle.
Contents:
Vessels: the third part of the subclavian artery, suprascapular and transverse cervical branches of the thyrocervical trunk, external jugular vein, lymph nodes
Nerves: accessory nerve (CN XI), the trunks of the brachial plexus, fibers of the cervical plexus -
This question is part of the following fields:
- Anatomy
- Head And Neck
-
-
Question 29
Correct
-
Which of the following neurotransmitter and receptor combinations is present at the neuromuscular junction:
Your Answer: Acetylcholine acting at nicotinic receptors
Explanation:At the neuromuscular junction, acetylcholine is released from the prejunctional membrane which acts on cholinergic nicotinic receptors on the postjunctional membrane.
-
This question is part of the following fields:
- Basic Cellular
- Physiology
-
-
Question 30
Incorrect
-
One of your patients has been infected by an obligate pathogen and presents with features of this condition.
Which of these is an example of an obligate pathogen?
Your Answer: Pseudomonas aeruginosa
Correct Answer: Trepenoma pallidum
Explanation:Treponema pallidum is an obligate pathogen. Obligate pathogens are almost always associated with disease and usually cannot survive outside of the body for long periods of time. Examples include and HIV.
Staphylococcus aureus and Bacteroides fragilis are conditional pathogens. These are pathogens that usually cause disease only if certain conditions are met.
Pneumocystis jiroveci and Pseudomonas aeruginosa, are opportunistic pathogens. These are pathogens that can only cause disease in an immunocompromised host or under unusual circumstances.
-
This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
-
-
Question 31
Correct
-
Which of the following statements accurately describes the extensor indicis muscle?
Your Answer: It lacks the juncturae tendinum
Explanation:Extensor indicis is a narrow, elongated muscle found in the posterior compartment of the forearm. It belongs to the deep extensors of the forearm, together with supinator, abductor pollicis longus, extensor pollicis longus, and extensor pollicis brevis muscles. It lacks the juncturae tendinum, which connects the extensor digitorum on the dorsal aspect of the hand.
Extensor indicis can be palpated by applying deep pressure over the lower part of the ulna while the index finger is extended. The main function of extensor indicis involves the extension of the index finger at the metacarpophalangeal and interphalangeal joints. As the index finger is one of the few fingers that have their own separate extensor muscle, it is able to extend independently from other fingers. Additionally, extensor indicis muscle produces a weak extension of the wrist.
Extensor indicis receives its nervous supply from posterior interosseous nerve, a branch of the radial nerve derived from spinal roots C7 and C8. The skin overlying the muscle is supplied by the same nerve, with fibres that stem from the spinal roots C6 and C7.
The superficial surface of the extensor indicis receives arterial blood supply from posterior interosseous branch of the ulnar artery, whereas its deep surface receives blood from perforating branches of the anterior interosseous artery.
-
This question is part of the following fields:
- Anatomy
- Upper Limb
-
-
Question 32
Correct
-
When inserting a Seldinger chest drain for management of pneumothorax, the 'safe triangle' should be identified. Which of the following forms the inferior border of the 'safe triangle'?
Your Answer: 5 th intercostal space
Explanation:Care and management of the thoracostomy tubes (chest tubes) are subject to the direction and practice pattern of the responsible physician. Therefore, it is difficult to make a “one size fits all” set of instructions about the specific management recommendations for all chest tubes. It is recommended to discuss specific expectations for management with the patient’s attending physician. Facility specific Clinical Practice Guidelines (CPGs) may provide further guidance for one’s practice.
Placement of the appropriately sized chest tube is performed on the affected side. The typical landmark for placement is the 4th or 5th intercostal space (nipple line for males, inframammary fold for females) at the anterior axillary line. The space above the 5th intercostal space and below the base of the axilla that is bordered posteriorly by the trapezius and anteriorly by the pectoralis muscle has recently been described as the safe triangle. Tubes are positioned anteriorly for pneumothoraces and posteriorly for fluid processes.
-
This question is part of the following fields:
- Anatomy
- Thorax
-
-
Question 33
Incorrect
-
Which of the following statements is correct regarding homeostasis?
Your Answer: The set point is a fixed value which homeostasis must maintain.
Correct Answer: In negative feedback mechanisms, effectors always act to move the variable in the opposite direction to the change that was originally detected.
Explanation:The vast majority of systems within the body work by negative feedback mechanisms. This negative feedback refers to the way that effectors act to move the variable in the opposite direction to the change that was originally detected. Because there is an inherent time delay between detecting a change in a variable and effecting a response, the negative feedback mechanisms cause oscillations in the variable they control. There is a narrow range of values within which a normal physiological function occurs and this is called the ‘set point’. The release of oxytocin in childbirth is an example of positive feedback.
-
This question is part of the following fields:
- Basic Cellular
- Physiology
-
-
Question 34
Correct
-
Which of the following clinical features would you least expect to see in a lesion of the frontal lobe:
Your Answer: Contralateral homonymous hemianopia with macular sparing
Explanation:Contralateral homonymous hemianopia with macular sparing results from damage to the primary visual cortex of the occipital lobe. Incontinence may occur due to damage of the cortical micturition centre in the prefrontal cortex. Primitive reflexes and inability to problem solve may occur due to damage to the prefrontal cortex. Motor weakness of the contralateral limb with UMN signs may occur due to damage of the primary motor cortex.
-
This question is part of the following fields:
- Anatomy
- Central Nervous System
-
-
Question 35
Incorrect
-
Which of the following is considered an example of an observational study?
Your Answer: Single-blind trial
Correct Answer: Cohort study
Explanation:The two most common types of observational studies are cohort studies and case-control studies; a third type is cross-sectional studies.
-
This question is part of the following fields:
- Evidence Based Medicine
-
-
Question 36
Correct
-
A 75-year-old man with rheumatoid arthritis had gained weight, developed resistant hypertension, muscle weakness, and ankle oedema. This patient is most likely suffering from what condition?
Your Answer: Cushing's syndrome
Explanation:Overuse of cortisol medication, as seen in the treatment of patients with chronic asthma or rheumatoid arthritis, can cause Cushing’s syndrome.
Weight gain, thin arms and legs, a round face, increased fat around the base of the neck, a fatty hump between the shoulders, easy bruising, wide purple stretch marks primarily on the abdomen, breasts, hips, and under the arms, weak muscles, hirsutism, hypertension, erectile dysfunction, osteoporosis, frontal alopecia, acne, depression, poor wound healing, and polycythaemia are all clinical features of Cushing’s syndrome.
-
This question is part of the following fields:
- Endocrine
- Physiology
-
-
Question 37
Correct
-
Which one these is an example of a cause of an exudate?
Your Answer: Subphrenic abscess
Explanation:An exudate is an inflammatory fluid emanating from the intravascular space due to changes in the permeability of the surrounding microcirculation.
Some common causes of exudates are: pneumonia, empyema, lung cancer, breast cancer, cancer of the pleura, SLE, rheumatoid arthritis, pericarditis, subphrenic abscess, chylothorax.
Myxoedema, nephrotic syndrome, congestive cardiac failure, and liver cirrhosis all cause TRANSUDATE.
-
This question is part of the following fields:
- General Pathology
- Pathology
-
-
Question 38
Correct
-
Which of the following is the most potent stimulus of fibrinolysis:
Your Answer: Tissue plasminogen activator
Explanation:Fibrinolysis is a normal haemostatic response to vascular injury. Plasminogen, a proenzyme in blood and tissue fluid, is converted to plasmin by activators either from the vessel wall (intrinsic activation) or from the tissues (extrinsic activation). The most important route follows the release of tissue plasminogen activator (TPA) from endothelial cells.
-
This question is part of the following fields:
- Basic Cellular
- Physiology
-
-
Question 39
Incorrect
-
The syndrome of inappropriate antidiuresis due to excessive antidiuretic hormone (ADH) secretion is diagnosed in a male patient with a history of recurrent hyponatraemia.
Which of the following produces ADH?Your Answer: Anterior pituitary
Correct Answer: Hypothalamus
Explanation:Antidiuretic hormone (ADH), commonly known as vasopressin, is a peptide hormone that controls how much water the body retains.
It is produced in the magnocellular and parvocellular neurosecretory cells of the paraventricular nucleus and supraoptic nucleus in the hypothalamus from a prohormone precursor. It is subsequently carried to the posterior pituitary via axons and stored in vesicles.
The secretion of ADH from the posterior pituitary is regulated by numerous mechanisms:
Increased plasma osmolality: Osmoreceptors in the hypothalamus detect an increase in osmolality and trigger ADH release.Stretch receptors in the atrial walls and big veins detect a decrease in atrial pressure as a result of this (cardiopulmonary baroreceptors). ADH release is generally inhibited by atrial receptor firing, but when the atrial receptors are stretched, the firing reduces and ADH release is promoted.
Hypotension causes baroreceptor firing to diminish, resulting in increased sympathetic activity and ADH release.
An increase in angiotensin II stimulates angiotensin II receptors in the hypothalamus, causing ADH production to increase.The main sites of action for ADH are:
The kidney is made up of two parts. ADH’s main job is to keep the extracellular fluid volume under control. It increases permeability to water by acting on the renal collecting ducts via V2 Receptors (via a camp-dependent mechanism). This leads to a decrease in urine production, an increase in blood volume, and an increase in arterial pressure as a result.Vascular system: Vasoconstriction is a secondary function of ADH. ADH causes vasoconstriction via binding to V1 Receptors on vascular smooth muscle (via the IP3 signal transduction pathway). An increase in arterial pressure occurs as a result of this.
-
This question is part of the following fields:
- Physiology
- Renal Physiology
-
-
Question 40
Correct
-
Regarding the renin-angiotensin-aldosterone system (RAAS), which of the following statements is CORRECT:
Your Answer: Angiotensin II has a predominant vasoconstrictor effect on the efferent arteriole.
Explanation:Angiotensin II constricts both the afferent and efferent arterioles, but preferentially increases efferent resistance. The net effect of the more prominent increase in efferent tone is that the intraglomerular pressure is stable or increased, thereby tending to maintain or even raise the GFR. Renin is produced by granular cells of the juxtaglomerular apparatus. Renin cleaves plasma angiotensinogen (produced in the liver) into angiotensin I. Angiotensin I is converted by angiotensin-converting enzyme (ACE) on pulmonary endothelial cells to angiotensin II. Angiotensin II acts to potentiate sympathetic activity (positive feedback).
-
This question is part of the following fields:
- Physiology
- Renal
-
SESSION STATS - PERFORMANCE PER SPECIALTY
