-
Question 1
Incorrect
-
A 70 year old man who has a previous history of small cell lung cancer was found to have severe hyponatraemia on a recent blood test and he is sent to the emergency room. In the nephron, where is the likely cause of this abnormality?
Your Answer: Proximal Tubule
Correct Answer: Distal nephron
Explanation:In the cancer patient, hyponatremia is usually caused by the syndrome of inappropriate antidiuretic hormone (SIADH). This develops more frequently with small cell lung cancer (SCLC) than with other malignancies. The pathogenesis of this is as a result of the process whereby ADH binds V2 receptors on renal principal cells in the late distal tubule and collecting ducts, resulting in elevation of cAMP levels. Increased cAMP levels cause fusion of intracellular vesicles with the apical membrane. There are water channels called aquaporins in their membranes of these vesicles, and these increase the water permeability, thus facilitating increased water reabsorption and urine concentration. Thus, by increasing water retention, ADH causes blood to be diluted, which then decreases the concentration of solutes like sodium.
-
This question is part of the following fields:
- Endocrine
- Physiology
-
-
Question 2
Incorrect
-
An 18-year-old patient was brought to the ER after falling off of his skateboard. He is unable to flex the distal interphalangeal joint of his index finger. You suspect that he suffers from a supracondylar fracture. Which of the following conditions would confirm supracondylar fracture?
Your Answer: Loss of sensation over the lateral dorsum of the hand.
Correct Answer: Inability to oppose the thumb
Explanation:A supracondylar fracture is a fracture that occurs through the thin section of the distal humerus above the growth plate.
A supracondylar fracture is most usually associated with median nerve injury. A medial nerve damage causes paralysis of the thenar muscles, as well as loss of thumb opposition.
-
This question is part of the following fields:
- Anatomy
- Upper Limb
-
-
Question 3
Incorrect
-
The functional residual capacity (FRC) will be decreased in which of the following:
Your Answer: Asthma
Correct Answer: Pulmonary fibrosis
Explanation:Factors decreasing FRC:
Restrictive ventilatory defects e.g. pulmonary fibrosis
Posture – lying supine
Increased intra-abdominal pressure (e.g. obesity, pregnancy, ascites)
Reduced muscle tone of diaphragm e.g. muscle relaxants in anaesthesia, neuromuscular disease -
This question is part of the following fields:
- Physiology
- Respiratory
-
-
Question 4
Incorrect
-
If the afferent arteriole's diameter is smaller than the efferent arteriole's diameter in the glomerulus:
Your Answer: There will be no change in the glomerular filtration rate
Correct Answer: The net filtration pressure will decrease
Explanation:The relative resistance of the afferent and efferent arterioles substantially influences glomerular capillary hydrostatic pressure and consequently GFR. Filtration is forced through the filtration barrier due to high pressure in the glomerular capillaries. Afferent arteriolar constriction lowers this pressure while efferent arteriolar constriction raises it.
-
This question is part of the following fields:
- Physiology
- Renal
-
-
Question 5
Incorrect
-
On which of the following types of receptors does loperamide act?
Your Answer: Dopamine receptors
Correct Answer: Opioid receptors
Explanation:Loperamide inhibits acetylcholine release from the myenteric plexus acts by action on opioid mu-receptors, and this then reduces bowel motility. The intestinal transit time is increased, thereby facilitating water reabsorption.
-
This question is part of the following fields:
- Gastrointestinal
- Pharmacology
-
-
Question 6
Incorrect
-
Aldin is a 24-year-old male patient who arrives at the emergency department diagnosed with psittacosis based on his symptoms and history of being a pigeon enthusiast. Which of the following is the causative bacteria of psittacosis?
Your Answer: Francisella tularensis
Correct Answer: Chlamydia psittaci
Explanation:Chlamydia psittaci is a microorganism that is commonly found in birds.
These bacteria can infect people and cause psittacosis. Psittacosis is an infectious disease that may cause high fever and pneumonia associated with headaches, altered mental state, and hepatosplenomegaly.
-
This question is part of the following fields:
- Infections
- Microbiology
-
-
Question 7
Incorrect
-
All of the following statement are correct regarding endothelium derived nitric oxide except:
Your Answer: The basal production of NO continuously modulates vascular resistance.
Correct Answer: Nitric oxide production is inhibited by local mediators such as bradykinin, histamine and serotonin.
Explanation:Factors that elevate intracellular Ca2+ increase nitric oxide (NO) production by the endothelium included local mediators such as histamine and serotonin, bradykinin, and some neurotransmitters like substance P. NO production is also stimulated by increased flow (shear stress) and additionally activates prostacyclin synthesis. As a result of basal production of NO, there is continuous modulation of vascular resistance and as a result, there is increased production of nitric oxide acts which causes vasodilation. Platelet activation and thrombosis are inhibited by nitric oxide.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 8
Correct
-
The renal team is currently prescribing erythropoietin to a patient with chronic kidney disease.
Which of the following statements about erythropoietin is correct?Your Answer: It protects red blood cell progenitors from apoptosis
Explanation:Erythropoietin is a glycoprotein hormone that regulates the formation of red blood cells (red cell production). It is mostly produced by interstitial fibroblasts in the kidney, which are located near the PCT. It is also produced in the liver’s perisinusoidal cells, however this is more common during the foetal and perinatal periods.
The kidneys produce and secrete erythropoietin in response to hypoxia. On red blood cells, erythropoietin has two main effects:
– It encourages stem cells in the bone marrow to produce more red blood cells.
– It protects red blood cell progenitors and precursors from apoptosis by targeting them in the bone marrow.
As a result of the increased red cell mass, the oxygen-carrying capacity and oxygen delivery increase. -
This question is part of the following fields:
- Physiology
- Renal Physiology
-
-
Question 9
Correct
-
In adult basic life support, chest compressions should be performed at which of the following rates:
Your Answer: 100 - 120 per minute
Explanation:Chest compressions should be performed at a rate of 100 – 120 per minute.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 10
Incorrect
-
At rest, saliva is produced predominantly by which of the following:
Your Answer: Von Ebner's glands
Correct Answer: Submandibular gland
Explanation:At rest, most saliva is produced by the submandibular gland (65%). When stimulated by the autonomic nervous system, about 50% of saliva is produced by the parotid gland with only 30% produced by the submandibular gland.
-
This question is part of the following fields:
- Gastrointestinal
- Physiology
-
-
Question 11
Incorrect
-
The interquartile range (IQ) is often displayed using which of the following:
Your Answer: Forest plot
Correct Answer: Box and whisker plot
Explanation:A boxplot is a vertical or horizontal rectangle used to display the interquartile range, with the ends of the rectangle corresponding to the upper and lower quartiles of the data values. The box contains 50% of the data values. A line drawn through the rectangle corresponds to the median value. Whiskers, starting at the ends of the rectangle usually indicate the minimum and maximum values, therefore the entire box and whisker plot represents the range. Any outliers can be plotted independent of the box and whisker plot.
-
This question is part of the following fields:
- Evidence Based Medicine
- Statistics
-
-
Question 12
Incorrect
-
Which of the following best describes an intention to treat analysis:
Your Answer: Only patients who comply with treatment are included in the analysis.
Correct Answer: All patients are included in the analysis according to the group into which they were randomised even if they are withdrawn from the study.
Explanation:An intention to treat (ITT) analysis is one in which all patients are included in the analysis, classified according to the group into which they were randomised, even if they were withdrawn from the study and did not actually receive the treatment, did not comply with treatment or drop-out. Intention to treat analysis is a more reliable estimate of true treatment effectiveness by replicating what happens in the ‘real world’ (e.g. noncompliance and protocol violations commonly affect therapies).
-
This question is part of the following fields:
- Evidence Based Medicine
- Study Methodology
-
-
Question 13
Correct
-
A clinical audit cycle comprises of 5 steps. Each of these processes are listed below:
Which is the correct order that these should occur?
1. Observation of practice and collection of data
2. Identification of the problem
3. Implementation of change
4. Definition of criteria and setting of standards
5. Analysis of data and comparison of performance with the criteria and standardsYour Answer: 2,4,1,5,3
Explanation:An audit assesses if a certain aspect of health care is attaining a recognized standard. This lets care providers and patients know where their service is doing well, and where there could be improvements. The aim is to achieve quality improvement and improve outcomes for patients.
Audits are a quality improvement measure and one of the 7 pillars of clinical governance. It allows organizations to continually work toward improving quality of care by showing them where they are falling short, allows them to implement improvements, and reaudit or close the audit cycle to see if beneficial change has taken place.
Clinical audits are a cycle with several steps:
1. Identification of the problem
2. Definition of criteria and setting of standards
3. Observation of practice and collection of data
4. Analysis of data and comparison of performance with the criteria and standards
5. Implementation of change -
This question is part of the following fields:
- Evidence Based Medicine
-
-
Question 14
Incorrect
-
A 18 year old with known asthma presents himself to ED with acute breathlessness and wheeze for the past 20 minutes. On examination he is tachypneic and tachycardic. His oxygen saturations are 96% on air. What is the first line treatment for acute asthma:
Your Answer: Oxygen
Correct Answer: Salbutamol
Explanation:High-dose inhaled short-acting beta2-agonists are the first line treatment for acute asthma(salbutamol or terbutaline). Oxygen should only been given to hypoxaemic patients (to maintain oxygen saturations of 94 – 98%). A pressurised metered dose inhaler with spacer device is preferred in patients with moderate to severe asthma (4 puffs initially, followed by 2 puffs every 2 minutes according to response, up to 10 puffs, whole process repeated every 10 – 20 minutes if necessary). The oxygen-driven nebuliser route is recommended for patients with life-threatening features or poorly responsive severe asthma (salbutamol 5 mg at 15 – 30 minute intervals). Continuous nebulisation should be considered in patients with severe acute asthma that is poorly responsive to initial bolus dose (salbutamol at 5 – 10 mg/hour) The intravenous route should be reserved for those in whom inhaled therapy cannot be used reliably.
-
This question is part of the following fields:
- Pharmacology
- Respiratory
-
-
Question 15
Incorrect
-
Which of the following statements regarding forest plots is true? Select ONE answer only.
Which of the following statements regarding forest plots is true? Select ONE answer only.Your Answer: The area of the squares is inversely proportional to the number of events in each study
Correct Answer: Larger studies are associated with smaller horizontal lines
Explanation:Forest plots are graphical displays designed to illustrate the relative strength of treatment effects in multiple individual studies addressing the same question.
-
This question is part of the following fields:
- Evidence Based Medicine
-
-
Question 16
Incorrect
-
A 19-year-old woman presents with dysuria and vaginal discharge. A swab was taken for culture. Culture results showed the presence of Neisseria gonorrhoeae infection. Treatment of azithromycin and doxycycline was started.
Which of the following statements is considered correct regarding Neisseria gonorrhoeae?Your Answer: An effective vaccine is available
Correct Answer: Throat swabs can be used for diagnosis
Explanation:Neisseria gonorrhoeae is a Gram-negative diplococcus that causes gonorrhoea. Gonorrhoea is an acute pyogenic infection of nonciliated columnar and transitional epithelium; infection can be established at any site where these cells are found. Gonococcal infections are primarily acquired by sexual contact and occur primarily in the urethra, endocervix, anal canal, pharynx, and conjunctiva.
In men, acute urethritis, usually resulting in purulent discharge and dysuria (painful urination), is the most common manifestation. The endocervix is the most common site of infection in women. Symptoms of infection, when present, include dysuria, cervical discharge, and lower abdominal pain. Some cases in women may be asymptomatic leading to complications such as pelvic inflammatory disease. Blood-borne dissemination occurs in less than 1% of all infections, resulting in purulent arthritis and rarely septicaemia. Fever and a rash on the extremities can also be present. Other conditions associated with N. gonorrhoeae include anorectal and oropharyngeal infections. Infections in these sites are more common in men who have sex with men but can also occur in women.
Pharyngitis is the chief complaint in symptomatic oropharyngeal infections, whereas discharge, rectal pain, or bloody stools may be seen in rectal gonorrhoea. Approximately 30% to 60% of women with genital gonorrhoea have concurrent rectal infection. Newborns can acquire ophthalmia neonatorum, a gonococcal eye infection, during vaginal delivery through an infected birth canal.
Specimens collected for the recovery of N. gonorrhoeae may come from genital sources or from other sites, such as the rectum, pharynx, and joint
fluid. According to the 2010 STD Treatment guidelines, cephalosporins (e.g., ceftriaxone, cefixime) are currently recommended treatments. -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 17
Incorrect
-
In adults in the United Kingdom, which of the following pathogens is the most likely cause of viral infectious gastroenteritis:
Your Answer: Rhinovirus
Correct Answer: Norovirus
Explanation:Norovirus is the most common viral cause of epidemic gastroenteritis worldwide; it is also a common cause of endemic diarrhoea in community settings. In the United Kingdom, norovirus has become the most common cause of gastroenteritis in adults and children since the introduction of rotavirus vaccination.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 18
Correct
-
Which of these cell types in the stomach releases pepsinogen?
Your Answer: Chief cells
Explanation:The gastric chief cells in the stomach wall releases pepsinogen. Pepsinogen is a proenzyme. It mixes with hydrochloric acid in the stomach and is converted to pepsin. Pepsin breaks down proteins into peptides aiding protein digestion.
-
This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
-
-
Question 19
Incorrect
-
A young female was diagnosed with a urinary tract infection and was sent home with medications. However, after 48 hours of discharge, she returned to the hospital because there had been no relief from her symptoms. The urine sensitivity test report is still unavailable. Fresh blood tests were sent, and her estimated GFR is calculated to be >60 ml/minute.
She was prescribed nitrofurantoin 100 mg modified-release orally twice a day for two days.
Out of the following, which antibiotic is most appropriate to be prescribed to this patient?Your Answer: Amoxicillin
Correct Answer: Fosfomycin
Explanation:The NICE guidelines for women with lower UTIs who are not pregnant are:
1. Consider prescribing a different antibiotic if symptoms do not improve within 48 hours or worsen at any time
2. If the urine culture and susceptibility test results are available, review the choice of antibiotic according to the results and change the antibiotic accordingly if symptoms are not improving or bacteria is resistant to the prescribed antibioticThe first choice of antibiotics for non-pregnant women aged 16 years and over is:
1. Nitrofurantoin
100 mg modified-release PO BD for 3 days – if eGFR >45 ml/minute
2. Trimethoprim
200 mg PO BD for three daysThe second-choice (no improvement in lower UTI symptoms on first-choice for at least 48 hours, or when first-choice is not suitable) are:
1. Nitrofurantoin
100 mg modified-release PO BD for three days – if eGFR >45 ml/minute
2. Pivmecillinam
400 mg PO initial dose, then 200 mg PO TDS for three days
3. Fosfomycin 3 g single sachet dose -
This question is part of the following fields:
- Infections
- Pharmacology
-
-
Question 20
Incorrect
-
You are reviewing a patient in the Emergency Department brought in by the ambulance team from a burning building. After examination, you decide to intubate the patient due to laryngeal oedema. The induction agent you are planning to use is propofol.
Which one of the following statements about this medicine is TRUE?Your Answer: It is thought to work by inhibiting GABA and glycine
Correct Answer: It decreases cardiac output by approximately 20%
Explanation:Propofol is a short-acting anaesthetic that is thought to work by potentiating GABA and glycine. It induces anterograde amnesia and anaesthetic effects and is used to induce anaesthesia, outpatient surgeries and preoperative sedation. The dose for induction of anaesthesia is 1.5-2.5mg/kg. The dose for maintenance of anaesthesia is 4-12 mg/kg/hour. Following intravenous injection, propofol acts within 30 seconds and its duration of action is 5-10 minutes.
Propofol produces a 15-25% decrease in blood pressure and systemic vascular resistance without a compensatory increase in heart rate. It is negatively inotropic and decreases cardiac output by approximately 20%.
The main side effects of propofol are:
Pain on injection (in up to 30%)
Hypotension
Transient apnoea
Hyperventilation
Coughing and hiccough
Headache
Thrombosis and phlebitis -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
-
-
Question 21
Incorrect
-
The correct statement regarding the parasympathetic nervous system is which of the following?
Your Answer: Parasympathetic ganglia lie in chains beside the vertebral column.
Correct Answer: Parasympathetic preganglionic neurones run in cranial nerves III, VII, IX and X.
Explanation:The electron transfer system is responsible for most of the energy produced during respiration. The is a system of hydrogen carriers located in the inner mitochondrial membrane. Hydrogen is transferred to the electron transfer system via the NADH2 molecules produced during glycolysis and the Krebs cycle. As a result, a H+ion gradient is generated across the inner membrane which drives ATP synthase. The final hydrogen acceptor is oxygen and the H+ions and O2 combine to form water.
-
This question is part of the following fields:
- Basic Cellular
- Physiology
-
-
Question 22
Correct
-
Hepatitis A is transmitted by which of the following routes:
Your Answer: Faecal-oral route
Explanation:Hepatitis A transmission is by the faecal-oral route; the virus is excreted in bile and shed in the faeces of infected people.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 23
Incorrect
-
Where:
Capillary hydrostatic pressure is (P c)Hydrostatic pressure in the interstices is (P I )
Plasma oncotic pressure is (Ï€ p)Interstitial oncotic pressure is (Ï€ i)
Which of the following formulas best represents fluid flow at the capillary bed?
Your Answer: Volume / min = (P c - P i ) - (π i - π p )
Correct Answer: Volume / min = (P c - P i ) - (π p - π i )
Explanation:Starling’s equation for fluid filtration describes fluid flow at the capillary bed.
Filtration forces (capillary hydrostatic pressure and interstitial oncotic pressure) stimulate fluid movement out of the capillary, while resorption forces promote fluid movement into the capillary (interstitial hydrostatic pressure and plasma oncotic pressure). Although the forces fluctuate along the length of the capillary bed, overall filtration is achieved.At the capillary bed, there is fluid movement.
The reflection coefficient (σ), the surface area accessible (S), and the hydraulic conductance of the wall (Lp) are frequently used to account for the endothelium’s semi-permeability, yielding:
Volume / min = LpS [(Pc- Pi) –  σ(Ï€p– Ï€i)]
Volume /min = (Pc-Pi) – (Ï€p–πi) describes the fluid circulation at the capillaries.
Where:
Pc= capillary hydrostatic pressure
Pi= interstitial hydrostatic pressure
Ï€p= plasma oncotic pressure
Ï€i= interstitial oncotic pressure -
This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
-
-
Question 24
Incorrect
-
A 22-year-old student presents with a painful, red and itchy right eye. On examination, there is mild erythema of palpebral conjunctiva, and follicles are visible on eversion of the eyelid. Lid oedema is evident, and you can also see a few petechial subconjunctival haemorrhages. The eye appears watery, and there is no purulent discharge. He has recently recovered from a mild upper respiratory tract infection.
Which of these is the most likely causative organism?
Your Answer:
Correct Answer: Adenovirus
Explanation:The most frequent cause of red eye is conjunctivitis. It is caused by inflammation of the conjunctiva which can be infective or allergic and accounts for about 35% of all eye problems presenting to general practice.
Viral conjunctivitis is commonly caused by adenoviruses and it is the most common infectious conjunctivitis.
The common bacterial causes of conjunctivitis are Haemophilus influenzae, Streptococcus pneumoniae, and Staphylococcus aureus.
The clinical features of infective conjunctivitis include:
Acute onset of conjunctival erythema
Feeling ‘grittiness’, ‘foreign body’ or ‘burning’ sensation in the eye.
Watering and discharge which may cause transient blurring of visionFeatures of viral conjunctivitis include: watery and non-purulent eye discharge, lid oedema, follicles present on eyelid eversion, petechial subconjunctival haemorrhages and pseudomembranes may be seen on the tarsal conjunctival surfaces.
This patients features are consistent with a viral aetiology, and the most likely causative organism is adenovirus,
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 25
Incorrect
-
A 58-year-old man with a long history of depression presents with a deliberate overdose of verapamil tablets, which he is prescribed for a heart condition.
What is verapamil's mechanism of action?Your Answer:
Correct Answer: L-type calcium channel blockade
Explanation:Overdosing on calcium-channel blockers should always be taken seriously and regarded as potentially fatal. Verapamil and diltiazem are the two most lethal calcium channel blockers in overdose. These work by binding the alpha-1 subunit of L-type calcium channels, preventing calcium from entering the cell. In cardiac myocytes, vascular smooth muscle cells, and islet beta-cells, these channels play an important role.
The standard ABC approach should be used to resuscitate all patients as needed. If life-threatening toxicity is expected, intubation and ventilation should be considered early on. If hypotension and shock are developing, early invasive blood pressure monitoring is recommended.
The primary goal of specific treatments is to support the cardiovascular system. These are some of them:
1. Fluid resuscitation: Give up to 20 mL of crystalloid per kilogramme of body weight.
2. Calcium supplementation
This can be a good way to raise blood pressure and heart rate temporarily.
via central venous access: 10% calcium gluconate 60 mL IV (0.6-1.0 mL/kg in children) or 10% calcium chloride 20 mL IV (0.2 mL/kg in children)
Boluses can be given up to three times in a row.
To keep serum calcium >2.0 mEq/L, consider a calcium infusion.3. Atropine: 0.6 mg every 2 minutes up to 1.8 mg is an option, but it is often ineffective.
4. HIET (high-dose insulin-euglycemic therapy):
The role of HIET in the step-by-step management of cardiovascular toxicity has changed.5. Vasoactive infusions:
This was once thought to be a last-ditch measure, but it is now widely recommended that it be used sooner rather than later.
Insulin with a short half-life 50 mL of 50 percent glucose IV bolus plus 1 U/kg bolus (unless marked hyperglycaemia present)
Short-acting insulin/dextrose infusions should be continued.
Glucose should be checked every 20 minutes for the first hour, then hourly after that.
Regularly check potassium levels and replace if they fall below 2.5 mmol/L.
Titrate catecholamines to effect (inotropy and chronotropy); options include dopamine, adrenaline, and/or noradrenaline infusions.6. Sodium bicarbonate: Use 50-100 mEq sodium bicarbonate (0.5-1.0 mEq/kg in children) in cases where a severe metabolic acidosis develops.
7. Cardiac pacing: It can be difficult to achieve electrical capture, and it may not improve overall perfusion.
Bypass AV blockade with ventricular pacing, which is usually done at a rate of less than 60 beats per minute.8. Intralipid transport
Calcium channel blockers are lipid-soluble agents, so they should be used in refractory cases. -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
-
-
Question 26
Incorrect
-
Pancreatic acinar digestive enzyme secretion is mainly stimulated by which of the following hormones:
Your Answer:
Correct Answer: Cholecystokinin
Explanation:Exocrine pancreatic secretion is controlled by:
Parasympathetic stimulation which enhances secretion of both the enzyme and aqueous components
Sympathetic stimulation which inhibits pancreatic secretion
Secretin which stimulates secretion of the alkaline-rich fluid from ductal cells
Cholecystokinin which stimulates secretion of the enzyme-rich fluid from acinar cells
Somatostatin which inhibits secretion from both acinar and ductal cells
Gastrin which stimulates pancreatic acinar cells to secrete digestive enzymes -
This question is part of the following fields:
- Gastrointestinal
- Physiology
-
-
Question 27
Incorrect
-
A possible diagnosis of Cushing's illness is being investigated in an overweight patient with resistant hypertension. A CRH (corticotropin-releasing hormone) test is scheduled.
Which of the following statements about corticotropin-releasing hormone is correct?Your Answer:
Correct Answer: It is produced by cells within the paraventricular nucleus of the hypothalamus
Explanation:Corticotropin-releasing hormone (CRH) is a neurotransmitter and peptide hormone. It is generated by cells in the hypothalamic paraventricular nucleus (PVN) and released into the hypothalamo-hypophyseal portal system at the median eminence through neurosecretory terminals of these neurons. Stress causes the release of CRH.
The CRH is carried to the anterior pituitary through the hypothalamo-hypophyseal portal system, where it activates corticotrophs to release adrenocorticotropic hormone (ACTH). Cortisol, glucocorticoids, mineralocorticoids, and DHEA are all produced in response to ACTH.
Excessive CRH production causes the size and quantity of corticotrophs in the anterior pituitary to expand, which can lead to the creation of a corticotrope tumour that generates too much ACTH.
-
This question is part of the following fields:
- Endocrine Physiology
- Physiology
-
-
Question 28
Incorrect
-
Cardiac myocytes contract by excitation-contraction coupling, very much like skeletal myocytes. On the other hand, calcium-induced calcium release (CICR) is a mechanism that is unique to Cardiac myocytes. The influx of calcium ions (Ca 2+) into the cell causes a 'calcium spark,' which causes more ions to be released into the cytoplasm.
In CICR, which membrane protein in the sarcoplasmic reticulum is involved?Your Answer:
Correct Answer: Ryanodine receptor
Explanation:Cardiac myocytes contract by excitation-contraction coupling, just like skeletal myocytes. Heart myocytes, on the other hand, utilise a calcium-induced calcium release mechanism that is unique to cardiac muscle (CICR). The influx of calcium ions (Ca2+) into the cell causes a ‘calcium spark,’ which causes more ions to be released into the cytoplasm.
An influx of sodium ions induces an initial depolarisation, much as it does in skeletal muscle; however, in cardiac muscle, the inflow of Ca2+ sustains the depolarisation, allowing it to remain longer. Due to potassium ion (K+) inflow, CICR causes a plateau phase in which the cells remain depolarized for a short time before repolarizing. Skeletal muscle, on the other hand, repolarizes almost instantly.
The release of Ca2+ from the sarcoplasmic reticulum is required for calcium-induced calcium release (CICR). This is mostly accomplished by ryanodine receptors (RyR) on the sarcoplasmic reticulum membrane; Ca2+ binds to RyR, causing additional Ca2+ to be released.
-
This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
-
-
Question 29
Incorrect
-
Regarding flucloxacillin, which of the following statements is CORRECT:
Your Answer:
Correct Answer: It is resistant to bacterial beta-lactamases.
Explanation:Flucloxacillin is unique in that it is beta-lactamase stable and it can be used in infections caused by beta-lactamase producing staphylococci e.g. S. aureus. It is acid-stable and can therefore be given by mouth as well as by injection. It is used first line for treatment of widespread impetigo infection, cellulitis, mastitis, osteomyelitis, septic arthritis, severe erysipelas, severe/spreading otitis externa and infective endocarditis caused by staphylococci. The most common adverse effects of flucloxacillin include nausea, vomiting, skin rash, and diarrhoea. Cholestatic jaundice and hepatitis may occur very rarely, up to two months after treatment with flucloxacillin has been stopped. Administration for more than 2 weeks and increasing age are risk factors. First line treatment of animal and human bites is co-amoxiclav.
-
This question is part of the following fields:
- Infections
- Pharmacology
-
-
Question 30
Incorrect
-
A 67-year-old man complains of chest pain and goes to the emergency room. He takes several medications, including amiodarone.
Which of the following is amiodarone mechanism of action?Your Answer:
Correct Answer: Blocks Na + and K + channels and beta-adrenoreceptors in the heart
Explanation:Amiodarone is an anti-arrhythmic medication that can be used to treat both ventricular and atrial arrhythmias. It’s a class III anti-arrhythmic that works by blocking a variety of channels, including Na+ and K+ channels, as well as beta-adrenoreceptors. As a result, it slows conduction through the SA and AV nodes and prolongs phase 3 of the cardiac action potential (slowing repolarisation).
-
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
-
SESSION STATS - PERFORMANCE PER SPECIALTY
