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Question 1
Correct
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The predominant site in the lymph node where B lymphocytes are found is:
Your Answer: Cortex
Explanation:The cortex of the lymph node consists of the lymphoid nodules and sinusoids and posses a germinal centre from which B cells proliferate. The cortex of the lymph node predominately consists of B cells.
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This question is part of the following fields:
- Immunology
- Physiology
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Question 2
Correct
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A 25-year-old female had a painful abdomen and several episodes of vomiting. She was severely dehydrated when she was brought to the hospital. Her ABG showed a pH 7.7, p(O2) 75 mmHg, p(CO2) 46 mmHg and bicarbonate 48 mmol/l. The most likely interpretation of this ABG report would be:
Your Answer: Metabolic alkalosis
Explanation:Metabolic alkalosis is a primary increase in bicarbonate (HCO3−) with or without compensatory increase in carbon dioxide partial pressure (Pco2); pH may be high or nearly normal. Metabolic alkalosis occurs as a consequence of a loss of H+ from the body or a gain in HCO3 -. In its pure form, it manifests as alkalemia (pH >7.40). As a compensatory mechanism, metabolic alkalosis leads to alveolar hypoventilation with a rise in arterial carbon dioxide tension p(CO2), which diminishes the change in pH that would otherwise occur. Normally, arterial p(CO2) increases by 0.5–0.7 mmHg for every 1 mmol/l increase in plasma bicarbonate concentration, a compensatory response that occurs very rapidly. If the change in p(CO2) is not within this range, then a mixed acid–base disturbance occurs. Likewise, if the increase in p(CO2) is less than the expected change, then a primary respiratory alkalosis is also present. However an elevated serum bicarbonate concentration can also occur due to a compensatory response to primary respiratory acidosis. A bicarbonate concentration greater than 35 mmol/l is almost always caused by metabolic alkalosis (as is the case in this clinical scenario). Calculation of the serum anion gap can also help to differentiate between primary metabolic alkalosis and the metabolic compensation for respiratory acidosis. The anion gap is frequently elevated to a modest degree in metabolic alkalosis because of the increase in the negative charge of albumin and the enhanced production of lactate. However, the only definitive way to diagnose metabolic alkalosis is by performing a simultaneous blood gases analysis, which reveals elevation of both pH and arterial p(CO2) and increased calculated bicarbonate.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 3
Incorrect
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Question 4
Correct
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Which of the following statements about neutrophils is TRUE:
Your Answer: Neutrophils are typically the first immune cell to arrive to a site of injury.
Explanation:Neutrophils are the most numerous peripheral blood leukocytes, accounting for 50-70 percent of all circulating white cells. Neutrophils have a compact nucleus with two to five lobes and a pale cytoplasm with an irregular shape containing numerous fine pink-blue or grey-blue granules. The granules are classified as primary, which emerges during the promyelocyte stage, and secondary, which develop at the myelocyte stage and predominate in the mature nucleus. The lifespan of neutrophils in the blood is only 6 – 10 hours. In response to tissue damage, cytokines and complement proteins, neutrophils migrate from the bloodstream to the site of insult within minutes, where they destroy pathogens by phagocytosis.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 5
Correct
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The histological exam of a tuberculous granuloma shows a periphery of multinuclear giant cells, with a central area of:
Your Answer: Caseous necrosis
Explanation:Granulomas with necrosis tend to have an infectious cause. The chronic infective lesion in this case typically presents with a central area of caseous (cheese-like) necrosis. Foam cells are the fat-laden M2 macrophages seen in atherosclerosis
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 6
Correct
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A 45 year old man who complains of chronic post prandial, burning epigastric pain undergoes a gastrointestinal endoscopy. There is no apparent mass or haemorrhage and a biopsy is taken from the lower oesophageal mucosa just above the gastro-oesophageal junction. The results reveal the presence of columnar cells interspersed with goblet cells. Which change best explains the above mentioned histology?
Your Answer: Metaplasia
Explanation:Metaplasia is the transformation of one type of epithelium into another as a means to better cope with external stress on that epithelium. In this case metaplasia occurs due to the inflammation resulting from gastro-oesophageal reflux disease. Dysplasia is disordered cellular growth. Hyperplasia is an increase in cell number but not cell type i.e. transformation. Carcinoma is characterized by cellular atypia. Ischaemia would result in necrosis with ulceration. Carcinoma insitu involves dysplastic atypical cells with the basement membrane intact and atrophy would mean a decrease in number of cells.
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 7
Correct
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A 20-year-old woman had profuse watery diarrhoea for 2 days. She felt dizzy and weak, and thus decided to seek medical attention. At the emergency room her BP was 80/60 mmHg with a pulse of 118/min. What is the most appropriate intravenous treatment that should be given?
Your Answer: Isotonic saline
Explanation:Normal saline is typically the first fluid used when hypovolemia is severe enough to threaten the adequacy of blood circulation. It is isotonic and has long been believed to be the safest fluid to give quickly in large volumes.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 8
Incorrect
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A 34 year old opera singer undergoes a thyroidectomy. Post-operatively, it is discovered that he is only able to make a gargling noise. On examination, his voice sounds breathy. What is the best explanation for this symptom?
Your Answer: Bilateral inferior laryngeal nerve injury
Correct Answer: Unilateral inferior laryngeal nerve injury
Explanation:Unilateral vocal fold paralysis (UVFP) occurs from a dysfunction of the recurrent laryngeal (inferior laryngeal nerve) or vagus nerve innervating the larynx. It causes a characteristic breathy voice often accompanied by swallowing disability, a weak cough, and the sensation of shortness of breath. This is a common cause of neurogenic hoarseness. When this paralysis is properly evaluated and treated, normal speaking voice is typically restored. Specifically, thyroidectomy, carotid endarterectomy, anterior cervical spine surgery, thoracic, or mediastinal surgery most often result in a presentation of UVFP.
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This question is part of the following fields:
- Head & Neck
- Pathology
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Question 9
Incorrect
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Approximately what proportion of lymphocytes are B-cells:
Your Answer: 0.5
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.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 10
Incorrect
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Regarding T helper cells, which of the following statements is CORRECT:
Your Answer: They are CD8 receptor positive.
Correct Answer: They form the vast majority (about 75%) of the total circulating T-cell population.
Explanation:CD4+ T-cells (Helper T cells)Recognise antigen only in association with HLA class II molecules (found on antigen presenting cells (APCs) e.g. dendritic cells, B-cells; present exogenous antigens that have been phagocytosed/endocytosed into intracellular vesicles)Form most of the circulating T-cell population (about 75%)Secrete cytokines (e.g. IFN-gamma) which are required for recruitment and activation of other immune cells such as macrophages, T cytotoxic cells and NK cells and for the activation of and production of immunoglobulin from B-cells
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This question is part of the following fields:
- Immunology
- Pathology
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Question 11
Correct
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A 30 year old lawyer presented with a history of pleural effusions, pericarditis, arthralgia without joint deformity and episodes of myalgia for the past 12 months. Blood tests reveal a normocytic anaemia. Which of the following tests should be performed to investigate this condition further?
Your Answer: Antinuclear antibody test
Explanation:These non specific findings are suggestive of autoimmune disease. Antinuclear antibody (ANA) is the first test that should be performed when autoimmune diseases are suspected and later on more specific tests should be performed. This tests aids in the diagnosis of SLE, scleroderma, Sjogren’s syndrome, Raynaud’s disease, juvenile chronic arthritis, rheumatoid arthritis and antiphospholipid antibody syndrome etc. To confirm the disease a history, physical examination along with specific tests are required. CPK is more specific for acute conditions. ESR is a non specific test for inflammation.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 12
Correct
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A 42 year old man presents with end stage renal failure and is prepared to receive a kidney from his best friend. HLA testing showed that they are not a 100% match and he is given immunosuppressant therapy for this. Three months later when his renal function is assessed, he showed signs of deteriorating renal function, with decreased renal output, proteinuria of +++ and RBCs in the urine. He was given antilymphocyte globulins and his condition reversed. During the crisis period the patient is likely to be suffering from?
Your Answer: Acute rejection
Explanation:This patients is most likely experiencing an acute rejection. It is a cell mediated attack against the organ that has been transplanted. Antigens are either presented by blood borne cells with in the graft or antigen presenting cells in the body may be presenting class I and class II molecules that have been shed by the graft. Class I will activate CD8 and class II, CD4 cells, both of which will attack the graft. Chronic rejection is a slow process which occurs months to years after the transplant. The exact mechanism is not very well understood but it probably involves a combination of Type III and Type IV hypersensitivity directed against the foreign MHC molecules which look like self-MHC presenting a foreign antigen. Hyperacute Transplant Rejection occurs almost immediately and is often evident while you are still in surgery. It is caused by accidental ABO Blood type mismatching of the donor and recipient which almost never happens anymore. This means the host has preformed antibodies against the donated tissue.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 13
Incorrect
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A 28 years old women presents with a history of chronic cough with fever for the past 2 months. A chest x ray revealed a diffuse bilateral reticulonodular pattern. A transbronchial biopsy was performed and histological examination showed focal areas of inflammation with epithelioid macrophages, Langhans cells and lymphocytes. Which of the immune reaction is responsible for this?
Your Answer: Type II hypersensitivity
Correct Answer: Type IV hypersensitivity
Explanation:A reactivated tuberculosis with granuloma formation is characteristic of type IV reaction. It is also called a delayed type of hypersensitivity reaction and takes around 2-8 days to deliver. It is a cell mediated response with the involvement of CD8 and CD4 cells and the release of IL-1 from macrophages that further activate these CD cells.Granulomatous reactions are mostly cell-mediated. Type I reactions are allergic and anaphylactic reactions and type II are complement-mediated immune reactions.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 14
Incorrect
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Eosinophils comprise what percentage of circulating white cells:
Your Answer: 0.05
Correct Answer: 1 - 3%
Explanation:Eosinophils comprise 1 – 3% of circulating white cells. Eosinophils are similar to neutrophils, except that the cytoplasmic granules are coarser and more deeply red staining, and there are rarely more than three nuclear lobes. They are less motile, but longer lived. They enter inflammatory exudates and have a special role in allergic responses, defence against parasites and removal of fibrin formed during inflammation. Thus they play a role in local immunity and tissue repair.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 15
Correct
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A biopsy taken from the respiratory passage of a 37 year old male, chronic smoker will mostly likely show which cellular adaptation?
Your Answer: Stratified squamous metaplasia
Explanation:Metaplasia is a change in the cell type caused in part due to an extrinsic stress on the organ. It involves a change in the surface epithelium from one cell type to the another, most commonly squamous to columnar. This is a reversible process, and removal of the stress should theoretically reverse the surface epithelium back to normal morphology. Respiratory tract metaplasia is a classic example, in which the normal pseudostratified columnar epithelium is replaced by stratified squamous epithelium to better cope with the stress. Under continuous stress metaplasia can progress to dysplasia which is a disordered growth of cells eventually leading to the development of carcinoma.
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 16
Correct
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A 30 year old welder presents to his family doctor with symptoms of chronic ear discharge and a left-sided facial nerve palsy. On examination, he has foul smelling fluid draining from his left ear and a complete left-sided facial nerve palsy. What is the most likely cause?
Your Answer: Cholesteatoma
Explanation:A cholesteatoma consists of squamous epithelium that is trapped within the skull base and that can erode and destroy important structures within the temporal bone. They often become infected and can result in chronically draining ears. Treatment almost always consists of surgical removal. The majority (98%) of people with cholesteatoma have ear discharge or conductive hearing loss or both in the affected ear.Other more common conditions (e.g. otitis externa) may also present with these symptoms, but cholesteatoma is much more serious and should not be overlooked. If a patient presents to a doctor with ear discharge and hearing loss, the doctor should consider cholesteatoma until the disease is definitely excluded.Other less common symptoms (all less than 15%) of cholesteatoma may include pain, balance disruption, tinnitus, earache, headaches and bleeding from the ear. There can also be facial nerve weakness. Balance symptoms in the presence of a cholesteatoma raise the possibility that the cholesteatoma is eroding the balance organs in the inner ear.
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This question is part of the following fields:
- Head & Neck
- Pathology
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Question 17
Incorrect
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A 5 year old boy is taken to the doctor by his father. He has had an earache for the past day and he is constantly pulling and touching his ear. His father noticed a foul smelling discharge leaking from his ear after which the earache resolved. Which of the following is the most likely cause?
Your Answer: Otitis externa
Correct Answer: Acute otitis media
Explanation:Acute otitis media (AOM) is a painful type of ear infection. It occurs when the area behind the eardrum, the middle ear, becomes inflamed and infected.The following behaviours in children often mean they have AOM:- fits of fussiness and intense crying (in infants)- clutching the ear while wincing in pain (in toddlers)- complaining about a pain in the ear (in older children).Perforation of the tympanic membrane is not unusual as the process advances, most frequently in posterior or inferior quadrants. Before or instead of a single perforation, an opaque serum like exudate is sometimes seen oozing through the entire tympanic membrane.With perforation and in the absence of a coexistent viral infection, the patient generally experiences rapid relief of pain and fever. The discharge initially is purulent, though it may be thin and watery or bloody; pulsation of the otorrhea is common. Otorrhea from acute perforation normally lasts 1-2 days before spontaneous healing occurs. Otorrhea may persist if the perforation is accompanied by mucosal swelling or polypoid changes, which can act as a ball valve.
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This question is part of the following fields:
- Head & Neck
- Pathology
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Question 18
Incorrect
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A 19-year-old female presents to the oncology clinic after noticing a painless neck lump. On examination, she is noted to have bilateral thyroid masses and multicentric nodules near the base of the thyroid. Her corrected calcium level is 2.18 mg/dL. Which of the following is the most likely diagnosis?
Your Answer: Follicular thyroid carcinoma
Correct Answer: Medullary carcinoma of the thyroid associated with multiple endocrine neoplasia
Explanation:Based on the aforementioned findings in this case, the most likely diagnosis is medullary carcinoma of the thyroid associated with multiple endocrine neoplasia (MEN). Medullary thyroid cancer is a tumour of the parafollicular cells (C cells) of the thyroid and is neural crest in origin. It may be familial and occur as part of the MEN 2A disease spectrum. Less than 10% of thyroid cancers are of this type with patients typically presenting as children or young adults. Diarrhoea occurs in 30% of the cases. In association with MEN syndromes, medullary thyroid cancers are always bilateral and multicentric. Spread may either be lymphatic or haematogenous, and as these tumours are not derived primarily from thyroid cells, they are not responsive to radioiodine. Toxic nodular goitre is very rare. In sporadic medullary carcinoma of the thyroid, patients typically present with a unilateral solitary nodule and it tends to spread early to the lymph nodes in neck.
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This question is part of the following fields:
- Head & Neck
- Pathology
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Question 19
Correct
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A 47 -year-old male was admitted due to a bleeding peptic ulcer. On his 3rd hospital day, he developed a cardiac arrhythmia. His serum potassium was markedly elevated. What is the most likely cause of hyperkalaemia in this patient?
Your Answer: Multiple blood transfusions
Explanation:Patients with gastrointestinal bleeding often require blood transfusion. Among the various side effects of blood transfusions, is the increase of potassium levels. The use of stored blood for transfusions is followed by an increase of serum potassium levels. Potassium level increases are more pronounced in patients who receive blood stored for more than 12 d. Furthermore, the lysis and destruction of red blood cells, especially in the transfusion of older PRBCs, can further increase potassium levels. Excessive use of a PPi has been associated with hyperkaelemia however would be less likely in this acute setting.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 20
Correct
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A 15 year old girl presented to the emergency with a history of chronic cough, fever and weight loss. Her chest X-ray showed multiple nodules 1-4 cm in size and some of them with cavitation especially in the upper lobe. A sputum sample was positive for acid fast bacilli. Which of the following cells played a part in the development of the lung lesions?
Your Answer: Macrophage
Explanation:The characteristic cells in granulomatous inflammation are giant cells, formed from merging macrophages and epithelioid cells elongated with granular eosinophilic cytoplasm. Granulomatous reactions are seen in patients with tuberculosis. A tuberculous/caseating granuloma is characterised by a zone of central necrosis lined with giant multinucleated giant cells (Langhans cells) and surrounded by epithelioid cells, lymphocytes and fibroblasts. The caseous zone is present due to the damaged and dead giant cells and epithelioid cells. Mast cells are only few in number and fibroblasts lay down collagen. Basophils are not present. The giant cell made up of macrophages are the most abundant cells in this inflammatory process.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 21
Correct
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A 36 year old opera singer is admitted for a right thyroid lobectomy. Post operatively, he is unable to sing high notes. Which muscle is likely to demonstrate impaired function?
Your Answer: Cricothyroid
Explanation:Thyroidectomy has been reported as the most frequent cause of external branch of superior laryngeal nerve (EBSLN) injury. Diagnosis of EBSLN injury may be difficult because the symptoms are nonspecific in many cases. However, advanced diagnostic techniques have revealed the incidence to be relatively high, ranging from 5 to 28%. Paralysis of the EBSLN causes difficulty with high pitch phonation and decreased pitch range secondary to failure of cricothyroid muscle stimulation and lack of tension in the vocal cord. This symptom may be extremely serious for professional voice users. EBSLN injury can also cause vocal fatigue, hoarseness, breathy sounding voice, and vocal nodules.
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This question is part of the following fields:
- Head & Neck
- Pathology
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Question 22
Correct
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Type 2 hypersensitivity is mediated by:
Your Answer: IgG, IgM & complement
Explanation:In type II hypersensitivity the antibodies, IgG and IgM bind to antigens to form complexes that activate the classical pathway of complement to eliminate cells presenting foreign antigens.
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This question is part of the following fields:
- Immunology
- Physiology
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Question 23
Incorrect
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By the third day of wound healing, which sort of inflammatory cell has predominated:
Your Answer: Lymphocytes
Correct Answer: Macrophages
Explanation:The inflammatory phase of healing is sometimes called the lag phase because wound strength does not begin to return immediately. The inflammatory phase is completed within three days except in the presence of infection or other factors associated with impaired wound healing. Mononuclear leukocytes accumulate and are transformed into macrophages. The maturation of blood-derived monocytes into macrophages is heralded by several events, including secretion of vimentin, which is a structural filament protein involved in wound healing.
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 24
Correct
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What is the primary function of collagen in wound healing?
Your Answer: Strength and support
Explanation:Key elements of the maturation stage include collagen cross-linking, collagen remodelling, wound contraction, and repigmentation. The tensile strength of the wound is directly proportional to the amount of collagen present. Numerous types of collagen have been identified; types I and III predominate in the skin and aponeurotic layers. Initially, a triple helix (tropocollagen) is formed by three protein chains; two are identical alpha-1 protein chains, and the third is an alpha-2 protein.
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 25
Incorrect
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Neutrophils are attracted to an infected area by:
Your Answer: Cytokines
Correct Answer: Chemokines
Explanation:The major role of chemokines is to act as a chemoattractant to guide the migration of cells like neutrophils to the site of infection.
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This question is part of the following fields:
- Immunology
- Physiology
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Question 26
Correct
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A 33 year old woman presents with a history of recurrent infections and abscesses in the neck. Examination reveals a midline defect with an overlying scab which moves upwards on tongue protrusion. Which of the following is the most likely diagnosis?
Your Answer: Thyroglossal cyst
Explanation:Congenital neck masses are developmental anomalies typically seen in infants or children. Common conditions include thyroglossal duct cysts, branchial cleft cysts, and cystic hygromas. These malformations present as painless neck masses, which can cause dysphagia, respiratory distress, and neck pain due to compression of surrounding structures. The location of the mass depends on the embryological structure the cysts arise from. Diagnosis is made based on clinical findings and imaging results (ultrasound, CT, MRI), which also help in surgical planning. Treatment consists of complete surgical resection to prevent recurrence and complications such as infection or abscess formation. The thyroglossal cyst is present from birth and usually detected during early childhood. It presents as a painless, firm midline neck mass, usually near the hyoid bone, which elevates with swallowing and tongue protrusion. May cause dysphagia or neck/throat pain if the cyst enlarges.
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This question is part of the following fields:
- Head & Neck
- Pathology
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Question 27
Correct
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Which of the following is NOT one of the cardinal features of acute inflammation:
Your Answer: Discharge
Explanation:Classic signs: Rubor (redness) Calor (heat) Dolour (pain) Tumour (swelling) Functio laesa (loss of function) These classic signs are produced by a rapid vascular response and cellular events. The main function of these events is to bring elements of the immune system to the site of injury and prevent further tissue damage.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 28
Incorrect
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The following are all examples of type IV hypersensitivity EXCEPT for:
Your Answer: Contact dermatitis
Correct Answer: Extrinsic allergic alveolitis
Explanation:Examples of type IV reactions includes: Contact dermatitis Hashimoto’s thyroiditis Primary biliary cholangitis Tuberculin skin test (Mantoux test) Chronic transplant rejection Granulomatous inflammation (e.g. sarcoidosis, Crohn’s disease)
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This question is part of the following fields:
- Immunology
- Pathology
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Question 29
Incorrect
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Cell mediating innate immunity include:
Your Answer: T lymphocytes
Correct Answer: Natural killer cells
Explanation:Antigen receptors recognize the shape of the antigen. They identify specific epitopes and are found on T cells.
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This question is part of the following fields:
- Immunology
- Physiology
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Question 30
Incorrect
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Where does control of self-reactive T cells (self-tolerance) initially occur?
Your Answer: Spleen
Correct Answer: Thymus
Explanation:The thymus provides an inductive environment for development of T cells from hematopoietic progenitor cells. In addition, thymic stromal cells allow for the selection of a functional and self-tolerant T cell repertoire. Therefore, one of the most important roles of the thymus is the induction of central tolerance.
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This question is part of the following fields:
- Immunology
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
