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Question 1
Correct
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A 60-year-old patient had a sudden onset of palpitations and shortness of breath. He had a history of poorly controlled hypertension and ischemic heart disease. His ECG also shows atrial fibrillation. Based on the patient’s condition, which pharmacologic cardioversion would be best to use?
Your Answer: Amiodarone
Explanation:Chemical cardioversion, or pharmacologic cardioversion, is the treatment of abnormal heart rhythms using drugs.
Flecainide and propafenone are examples of drugs used as chemical cardioverters.
However, given the situation of the patient, these drugs are contraindicated for his ischaemic heart disease. Amiodarone is also an antiarrhythmic drug and is the best choice for this situation.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 2
Incorrect
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The following are all examples of type II hypersensitivity EXCEPT for:
Your Answer: Rheumatic heart disease
Correct Answer: Post-streptococcal glomerulonephritis
Explanation:Examples of type II reactions include:
Incompatible blood transfusions
Haemolytic disease of the newborn
Autoimmune haemolytic anaemias
Goodpasture’s syndrome
Rheumatic heart disease
Bullous pemphigoid -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 3
Incorrect
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A 29-year-old volunteer returns from a recent trip to the middle east with profuse watery diarrhoea. You make a diagnosis of cholera and organize a hospital admission for rehydration with intravenous fluids.
What is the mechanism of action of cholera toxin?
Your Answer: Inhibition of adenyl cyclase
Correct Answer: ADP-ribosylation of the G regulatory protein
Explanation:Cholera is caused by Vibrio cholerae, a motile, Gram-negative, curved bacillus. It is transmitted through water and food (especially seafood) and is primarily a disease seen in developing countries where there is poor sanitation and lack of safe water supplies.
The cholera toxin leads to stimulation of adenyl cyclase, ADP-ribosylation of the G regulatory protein, inactivation of GTPase leading to active outpouring of NaCl.
The cholera toxin consists of an A (the toxin) and B subunit. The B subunit attaches to the gut mucosa and presents the A subunit to the cell. The toxin stimulates adenyl cyclase by irreversible ADP-ribosylation of the GTP binding domain of adenyl cyclase leading to the opening of chloride channels resulting in an outpouring of NaCl and water into the lumen of the gut and causing secretory diarrhoea.
Incubation period is between 2 and 5 days, but can be as short as just a few hours.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 4
Incorrect
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If the afferent arteriole's diameter is smaller than the efferent arteriole's diameter in the glomerulus:
Your Answer:
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.
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This question is part of the following fields:
- Physiology
- Renal
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Question 5
Incorrect
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Which of the following clinical features is most suggestive of a lesion of the frontal lobe:
Your Answer:
Correct Answer: Conjugate eye deviation towards the side of the lesion
Explanation:Conjugate eye deviation towards the side of the lesion is seen in damage to the frontal eye field of the frontal lobe. Homonymous hemianopia is typically a result of damage to the occipital lobe (or of the optic radiation passing through the parietal and temporal lobes). Auditory agnosia may been seen in a lesion of the temporal lobe. Hemispatial neglect may be seen in a lesion of the parietal lobe. Receptive dysphasia is seen in damage to Wernicke’s area, in the temporal lobe.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 6
Incorrect
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An 8-year-old boy was brought to the emergency room with complaints of a rash and fever that have been present for the past 3 days. Upon history taking and observation, it was noted that the rash started behind the ears and then spread to the face and body. The presence of coryzal symptoms, dry cough, and conjunctivitis was also observed.
What is most likely the diagnosis of the case presented above?Your Answer:
Correct Answer: Measles
Explanation:The measles virus is an enveloped virus classified in the genus
Morbillivirus.
Measles is highly contagious and spreads by aerosol. Initial replication takes place in the mucosal cells of the respiratory tract; measles virus then replicates in the local lymph nodes and spreads systemically. The virus circulates in the T and B cells and monocytes, until eventually the lungs, gut, bile duct, bladder, skin, and lymphatic organs are involved. After an incubation period of 7 to 10 days, there is an abrupt onset, with symptoms of sneezing, runny nose and cough, red eyes, and rapidly rising fever. About 2 to 3 days later, a maculopapular rash appears on the head and trunk. Koplik spots, lesions on the oral mucosa consisting of irregular red spots, with a bluish white speck in the centre, generally appear 2 to 3 days before the rash and are diagnostic.Measles is easily diagnosed clinically, so few requests for laboratory identification are made. The virus is fragile and must be handled carefully. The specimens of choice are from the nasopharynx and urine, but the virus can only be recovered from these sources in the early stages of infection. The virus grows on PMK cells, causing the formation of distinctive spindle-shaped or multinucleated cells.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 7
Incorrect
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A patient presents with a history of renal problems, generalised weakness and palpitations. Her serum potassium levels are measured and come back at 6.2 mmol/L. An ECG is performed, and it shows some changes that are consistent with hyperkalaemia.
Which of the following ECG changes is usually the earliest sign of hyperkalaemia? Select ONE answer only.Your Answer:
Correct Answer: Peaked T waves
Explanation:Hyperkalaemia causes a rapid reduction in resting membrane potential leading to increased cardiac depolarisation and muscle excitability. This in turn results in ECG changes which can rapidly progress to ventricular fibrillation or asystole. Very distinctive ECG changes that progressively change as the K+level increases:
K+>5.5 mmol/l – peaked T waves (usually earliest sign of hyperkalaemia), repolarisation abnormalities
K+>6.5 mmol/l – P waves widen and flatten, PR segment lengthens, P waves eventually disappear
K+>7.0 mmol/l – Prolonged QRS interval and bizarre QRS morphology, conduction blocks (bundle branch blocks, fascicular blocks), sinus bradycardia or slow AF, development of a sine wave appearance (a pre-terminal rhythm)
K+>9.0 mmol/l – Cardiac arrest due to asystole, VF or PEA with a bizarre, wide complex rhythm. -
This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 8
Incorrect
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A patient presents with a rash for a dermatological examination. A flat circumscribed area of discoloured skin measuring 0.7 cm in diameter is seen on examination.
What is the best description of this rash that you have found on examination?
Your Answer:
Correct Answer: Macule
Explanation:A macule is a flat, well circumscribed area of discoloured skin less than 1 cm in diameter with no changes in the thickness or texture of the skin.
A vesicle is a visible collection of clear fluid measuring less than 0.5 cm in diameter.
A papule is a solid, well circumscribed, skin elevation measuring less than 0.5 cm in diameter.
A nodule is a solid, well circumscribed, raised area that lies in or under the skin and measures greater than 0.5 cm in diameter. They are usually painless.
A plaque is a palpable skin lesion that is elevated and measures >1cm in diameter.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 9
Incorrect
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A 35 year old man presents with a deep laceration to the proximal part of the forearm. On further assessment, the patient is unable to flex the metacarpophalangeal joints and interphalangeal joints of the index, middle finger and the thumb.
The ring and little fingers are intact but there is weakness at the proximal interphalangeal joint.
There is also loss of sensation over the lateral palm and the palmar surface of the lateral three and a half fingers.
Which of these nerve(s) has most likely been affected?
Your Answer:
Correct Answer: Median nerve
Explanation:A median nerve injury affecting the extrinsic and intrinsic muscles of the hand will present with:
Loss of sensation to the lateral palm and the lateral three and a half fingers.
Weakness of flexion at the metacarpophalangeal joints of the index and middle finger. This is because of paralysis of the lateral two lumbricals.
Weakness of flexion of the proximal interphalangeal joints of all four fingers due to paralysis of the flexor digitorum superficialis
Weakness of flexion at the distal interphalangeal joints of the index and middle finger following paralysis of the lateral half of the flexor digitorum profundus.
Weakness of thumb flexion, abduction and opposition due to paralysis of the flexor pollicis longus and thenar muscles -
This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 10
Incorrect
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A 72-year-old man presents with chest pain that is characteristic of angina. You administer a dose of glyceryl trinitrate (GTN), which rapidly resolved his symptoms. Unfortunately, he also develops an unpleasant side effect.
Which of the following side effects is he most likely to have developed? Select ONE answer only.Your Answer:
Correct Answer: Headache
Explanation:Nitrates are used in the treatment of angina pectoris and the prevention of myocardial ischaemia. Commonly used examples of nitrates are glyceryl trinitrate and isosorbide dinitrate. Unwanted effects, however, are common and can limit therapy, particularly when angina is severe or when patients are unusually sensitive to the effects of nitrates.
The following are common or very common side effects of nitrates
Arrhythmias
Asthenia
Cerebral ischaemia
Dizziness
Drowsiness
Flushing
Headache
Hypotension
Nausea and vomiting
Diarrhoea, syncope and cyanosis can occur, but these are rare side effects. Dry eyes, bradycardia and metabolic acidosis have not been reported. -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 11
Incorrect
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The weight distribution in a group of patients included in a study was normal. The patients averaged 80 kg in weight. 5 kg was determined to be the standard deviation. Which of the following statements most accurately describes this group of patients:
Your Answer:
Correct Answer: 68% of the patients will weigh between 75 and 85 kg.
Explanation:We can estimate the range of values that would be anticipated to include particular proportions of observations if we know the mean and standard deviation of a collection of normally distributed data: 68.2 percent of the sample results fall within a one SD range above and below the mean (+/- 1 SD), implying that 68 percent of the patients will weigh between 75 and 85 kg. Because +/- 2 SD encompasses 95.4 percent of the data, around 95 percent of the patients will weigh between 70 and 90 kg. +/- 3 SD encompasses 99.7% of the values, implying that nearly all of the patients will weigh between 65 and 95 kg.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 12
Incorrect
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What is the primary route of transmission of Norovirus?
Your Answer:
Correct Answer: Oral-faecal route
Explanation:Norovirus is spread primarily by faecal-oral contact, but it can also be spread through contact with an infected person, ingestion of contaminated food or water, or contact with contaminated surfaces or items.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 13
Incorrect
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The Frank-Starling curve is shifted downhill in heart failure due to which of the following?
Your Answer:
Correct Answer: Decrease in contractility
Explanation:The Frank–Starling mechanism states that the left ventricle can increase its force of contraction and hence stroke volume in response to increases in venous return and thus preload.
Changes in afterload or inotropy cause the Frank–Starling curve to rise or fall. In heart failure, the Frank–Starling curve is shifted downward (flattened), requiring higher venous return and filling pressure to enhance contractility and stroke volume.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 14
Incorrect
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How does dipyridamole mediate its antiplatelet effect:
Your Answer:
Correct Answer: It is a phosphodiesterase inhibitor.
Explanation:Dipyridamole inhibits both the reuptake of adenosine and phosphodiesterase, preventing the degradation of cAMP and thus blocking the platelet aggregation response to ADP.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 15
Incorrect
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A 1-year-old male is brought to the paediatrician by his mother due to swelling of the right knee after a minor fall. On examination, the right knee is swollen, fluctuant and tender. Ultrasound-guided aspiration reveals a massive hemarthrosis. Family history shows that his older brother also has a bleeding disorder.
Which one of the following conditions does the patient most likely have?Your Answer:
Correct Answer: Haemophilia A
Explanation:A diagnosis of Haemophilia is supported in this patient by the family history and the presence of hemarthrosis-both characteristics of Haemophilia. Haemophilia A is caused by Factor VIII deficiency, leading to impaired coagulation. This disease typically presents after six months when the child starts crawling.
Von Willebrand disease presents with nosebleeds and hematomas. Idiopathic thrombocytopenic purpura presents with bruises that resemble a rash.
Glucose-6-phosphate dehydrogenase (G6PD) deficiency presents with haemolytic anaemia induced by specific drugs or foods.
Factor V Leiden mutation causes blood clotting rather than bleeding.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 16
Incorrect
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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:
Correct 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
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Question 17
Incorrect
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A 72-year-old man has a past medical history of diverticular disease. He now presents in the clinic with crampy abdominal pain. The nurse at the triage suggests prescribing hyoscine butyl bromide to help relieve the abdominal pain. However, you do not agree with this medication, as you can see on his chart that the patient has several other comorbidities.
Out of the following, what is NOT a contraindication to using hyoscine butyl bromide?Your Answer:
Correct Answer: Prostatic hyperplasia
Explanation:Hyoscine butylbromide is an antispasmodic drug that blocks muscarinic receptors and reduces intestinal motility. It is used for gastrointestinal and genitourinary smooth muscle spasms and symptomatic relief of IBS.
It has the following contraindications:
1. Closed-angle glaucoma
2. Gastrointestinal obstruction
3. Intestinal atony
4. Paralytic ileus
5. Toxic megacolon
6. Severe ulcerative colitis
7. Significant bladder outflow obstruction
8. Urinary retention
9. Myasthenia gravisUse cautiously in the following conditions:
1. Acute myocardial infarction (in adults)
2. Arrhythmias (may be worsened)
3. Autonomic neuropathy
4. Hypertension
5. Cardiac insufficiency (due to association with tachycardia)
6. Congestive cardiac failure (maybe worsened)
7. Cardiac surgery (due to association with tachycardia)
8. Gastro-oesophageal reflux disease
9. Ulcerative colitis
10. Prostatic hyperplasia
11. Use in children (increased risk of side effects) -
This question is part of the following fields:
- Gastrointestinal Pharmacology
- Pharmacology
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Question 18
Incorrect
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A 67-year-old man with chronic breathlessness is sent for a lung function test.
Which statement concerning lung function testing is true?Your Answer:
Correct Answer: In restrictive lung disease, the FEV 1 /FVC ratio is usually >0.7
Explanation:In restrictive lung disease, the FEV1/FVC ratio is usually >0.7%.
In obstructive lung disease, FEV1 is reduced to <80% of normal and FVC is usually reduced. The FEV1/FVC ratio is reduced to <0.7. Airflow obstruction is defined in the NICE guidelines as:
Mild airflow obstruction = an FEV 1 of >80% in the presence of symptoms
Moderate airflow obstruction = FEV 1 of 50-79%
Severe airflow obstruction = FEV 1 of 30-49%
Very severe airflow obstruction = FEV1<30%. Spirometry is a poor predictor of quality of life in COPD. However, it can be used as part of the assessment of severity of COPD. -
This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 19
Incorrect
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An injury to the brachial plexus can cause Erb's palsy. The following is expected to happen to a patient suffering from this condition, except for which one:
Your Answer:
Correct Answer: Weakness of medial rotation of the arm
Explanation:Erb’s palsy can be caused by a traumatic force downward on the upper arm and shoulder that damages the upper root of the brachial plexus.
The patient will lose shoulder abduction (deltoid, supraspinatus), shoulder external rotation (infraspinatus), and elbow flexion as a result of this condition (biceps, brachialis).
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 20
Incorrect
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Hepatitis A is transmitted by which of the following routes:
Your Answer:
Correct 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.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 21
Incorrect
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A paediatric patient comes to the emergency room with complaints of right lower quadrant pain. The attending physician is considering appendicitis. Inside the operating room, the surgeon asks the medical student to locate the McBurney's point prior to the first incision.
Which of the following is the surface anatomy of the McBurney's point?Your Answer:
Correct Answer: One-third of the distance from the anterior superior iliac spine to the umbilicus
Explanation:Inflammation of the appendix is a significant public health problem with a lifetime incidence of 8.6% in men and 6.7% in women, with the highest incidence occurring in the second and third decade of life. While the rate of appendectomy in developed countries has decreased over the last several decades, it remains one of the most frequent emergent abdominal operations. Appendicitis can often result in anorexia, nausea, vomiting, and fever.
McBurney’s point, which is found one-third of the distance between the anterior superior iliac spine and the umbilicus, is often the point of maximal tenderness in a patient with an anatomically normal appendix. A McBurney’s incision is chiefly used for cecostomy and appendectomy. It gives a limited exposure only, and should any doubt arise about the diagnosis, an infraumbilical right paramedian incision should be used instead.
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This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
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Question 22
Incorrect
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For which of the following is micelle formation necessary to facilitate intestinal absorption?
Your Answer:
Correct Answer: Vitamin D
Explanation:The arrangement of micelles is such that hydrophobic lipid molecules lie in the centre, surrounded by hydrophilic bile acids that are arranged in the outer region. This arrangement allows the entry of micelles into the aqueous layers surrounding the microvilli. As a result, the products of fat digestion (fatty acids and monoglycerides), cholesterol and fat-soluble vitamins (such as vitamin D) can then diffuse passively into the enterocytes. The bile salts are left within the lumen of the gut where they are reabsorbed from the ileum or excreted in faeces.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 23
Incorrect
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After a work-related accident, a 33-year old male is taken to the emergency room with difficulty in adduction and flexion of his left arm at the glenohumeral joint. The attending physician is suspects involvement of the coracobrachialis muscle.
The nerve injured in the case above is?Your Answer:
Correct Answer: The musculocutaneous nerve
Explanation:The coracobrachialis muscle is innervated by the musculocutaneous nerve (C5-C7) a branch of the lateral cord of the brachial plexus.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 24
Incorrect
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While on morning rounds in the medical ward, the attending physician asks a medical student about the differences between transudates and exudates and their causes. The student explains that a transudate is an excess fluid that leaks out of an intravascular compartment due to an imbalance between oncotic and hydrostatic pressures.
Which ONE of the following conditions will he mention as the cause of a transudate?Your Answer:
Correct Answer: Meig’s syndrome
Explanation:Transudative effusions are caused due to systemic causes leading to increased hydrostatic pressure or decreased oncotic pressure. These include:
1) Meig’s Syndrome (Ovarian tumour causing ascites and pleural effusion)
2) Congestive heart failure
3) Nephrotic Syndrome
4) Myxoedema
5) Cirrhosis
6) SarcoidosisAn exudate is caused by local inflammation and results from increased vascular permeability. Causes include:
1) Rheumatoid arthritis
2) Pneumonia leading to empyema
3) Malignancies
4) Pericarditis -
This question is part of the following fields:
- General Pathology
- Pathology
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Question 25
Incorrect
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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:
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.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 26
Incorrect
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Which of the following is NOT a common side effect of adenosine:
Your Answer:
Correct Answer: Yellow vision
Explanation:Common side effects of adenosine include:
Apprehension
Dizziness, flushing, headache, nausea, dyspnoea
Angina (discontinue)
AV block, sinus pause and arrhythmia (discontinue if asystole or severe bradycardia occur) -
This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 27
Incorrect
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This anatomic part lies at the heart of the tooth.
Your Answer:
Correct Answer: The pulp cavity
Explanation:Within the central portion of the tooth lies the dental pulp. The pulp chamber provides mechanical support and functions as a barrier from external stimuli and the oral microbiome. The dental pulp is a unique tissue that is richly innervated and has an extensive microvascular network. Maintaining its vitality increases both the mechanical resistance of the tooth and the long-term survival. The junctional epithelium forms a band around the tooth at the base of the gingival sulcus, sealing off the periodontal tissues from the oral cavity.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 28
Incorrect
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Which of the following is NOT typically associated with eosinophilia:
Your Answer:
Correct Answer: Whooping cough
Explanation:An eosinophil leucocytosis is defined as an increase in blood eosinophils above 0.4 x 109/L.It is most frequently due to:
Allergic diseases (e.g. bronchial asthma, hay fever, atopic dermatitis, urticaria)
Parasites (e.g. hookworm, ascariasis, tapeworm, schistosomiasis)
Skin diseases (e.g. psoriasis, pemphigus, urticaria, angioedema)
Drug sensitivity -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 29
Incorrect
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How is measles primarily transmitted:
Your Answer:
Correct Answer: Respiratory droplet route
Explanation:Measles belongs to the paramyxoviridae group of viruses. The incubation period is 7-18 days (average 10) and it is spread by airborne or droplet transmission. The classical presentation is of a high fever with coryzal symptoms and photophobia with conjunctivitis often being present. The rash that is associated is a widespread erythematous maculopapular rash. Koplik spots are pathognomonic for measles, and are the presence of white lesions on the buccal mucosa.
Differential diagnoses would include:
Rubella
Roseola infantum (exanthem subitom)
Scarlet fever
Kawasaki disease
Erythema infectiosum (5thdisease)
Enterovirus
Infectious mononucleosis
Diagnosis can be confirmed by the following means:
Salivary swab for measles specific IgM
Serum sample for measles specific IgM
Salivary swab for RNA detection
Possible complications include:
Otitis media
Febrile convulsions
Pneumonia
Bronchiectasis
Diarrhoea
Meningitis
Encephalitis
Immunosuppression
Subacute sclerosing panencephalitis
Death -
This question is part of the following fields:
- Microbiology
- Pathogens
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Question 30
Incorrect
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Capillaries are designed with a small diffusion distance for nutrition and gaseous exchange with the tissues they serve. Capillaries come in a variety of shapes and sizes, each with its own function in transcapillary exchange.
Which of the following types of capillaries is the least permeable in the human body?
Your Answer:
Correct Answer: Continuous capillaries
Explanation:Capillaries are designed with a small diffusion distance for nutrition and gaseous exchange with the tissues they serve. Because oxygen and carbon dioxide are both highly soluble in lipids (lipophilic), they can easily diffuse along a concentration gradient across the endothelial lipid bilayer membrane. In contrast, glucose, electrolytes, and other polar, charged molecules are lipid-insoluble (hydrophilic). These chemicals are unable to pass through the lipid bilayer membrane directly and must instead travel through gaps between endothelial cells.
Capillaries are divided into three types: continuous, fenestrated, and sinusoidal. Each of these capillary types contains different sized gaps between the endothelial cells that operate as a filter, limiting which molecules and structures can pass through.The permeability of capillaries is affected by the wall continuity, which varies depending on the capillary type.
Skeletal muscle, myocardium, skin, lungs, and connective tissue all have continuous capillaries. These capillaries are the least permeable. They have a basement membrane and a continuous layer of endothelium. The presence of intercellular spaces allows water and hydrophilic molecules to pass across. Tight connections between the cells and the glycocalyx inhibit passage via these gaps, making diffusion 1000-10,000 times slower than for lipophilic compounds. The diffusion of molecules larger than 10,000 Da, such as plasma proteins, is likewise prevented by this narrow pore system. These big substances can pass through the capillary wall, but only very slowly, because endothelial cells have enormous holes.The kidneys, gut, and exocrine and endocrine glands all have fenestrated capillaries. These are specialized capillaries that allow fluid to be filtered quickly. Water, nutrients, and hormones can pass via windows or fenestrae in their endothelium, which are connected by a thin porous membrane. They are ten times more permeable than continuous capillaries due to the presence of these fenestrae. Fenestrated capillaries have a healthy basement membrane.
The spleen, liver, and bone marrow all have sinusoidal capillaries, also known as discontinuous capillaries. Their endothelium has huge gaps of >100 nm, and their basement membrane is inadequate. They are highly permeable as a result, allowing red blood cells to travel freely. -
This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
