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Question 1
Correct
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Mast cells play a significant part in which of the following?
Your Answer: Allergic disease
Explanation:Mast cells play a central role in the response to allergen challenges. The activation of mast cells results in both an early and a delayed phase of inflammation. Mast cells have been implicated in both physiologic and pathogenic processes. Mast cells are important in defence against some bacteria and viruses and contribute to defence against parasites. They are key effector cells in both innate and acquired immunity and are capable of inducing and amplifying both types of responses. Specifically, mast cells are capable of detecting microbial products through surface pattern recognition receptors, and they are involved in the recruitment of other leukocytes, containment of bacterial infections, and tissue repair.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 2
Incorrect
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Which of the following is NOT a function of antibodies:
Your Answer: Stimulate degranulation of mast cells
Correct Answer: Act as antigen receptors on T lymphocytes
Explanation:Antibodies:
Neutralise toxins and prevent attachment of pathogens
Target, opsonise or agglutinate (clump together) antigens for phagocytosis
Activate the complement cascade (leading to lysis or opsonisation of the pathogen)
Act as antigen receptors on B lymphocytes
Activate antibody-dependent cell-mediated cytotoxicity by natural killer (NK) cells or T cytotoxic cells
Provide mucosal immunity (IgA-mediated)
Stimulate degranulation of mast cells (IgE and IgG mediated)
Provide passive immunity to the newborn (through transplacental passage of IgG and secretion of IgA in breast milk) -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 3
Incorrect
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Which of the following is NOT typically associated with eosinophilia:
Your Answer: Hodgkin lymphoma
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 4
Incorrect
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Eosinophils comprise what percentage of circulating white cells:
Your Answer: 0.2
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:
- Immune Responses
- Pathology
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Question 5
Incorrect
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C5 - C9 deficiency increases susceptibility to infection with which of the following:
Your Answer: Encapsulated bacteria
Correct Answer: Neisseria spp.
Explanation:If the complement sequence is completed, an active phospholipase (the membrane attack complex, MAC) is produced, which punches holes in the cell membrane and causes cell lysis. Because the MAC appears to be the sole means to destroy the Neisseria family of bacteria, C5 – C9 deficiency increases susceptibility to Neisseria infections.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 6
Incorrect
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Regarding basophils, which of the following statements is INCORRECT:
Your Answer: They are the largest type of granulocyte.
Correct Answer: They are the second most common type of granulocyte.
Explanation:Basophils are only occasionally seen in normal peripheral blood comprising < 1% of circulating white cells. However, they are the largest type of granulocyte. They have many dark cytoplasmic granules which overlie the nucleus and contain heparin and histamine. They have immunoglobulin E (IgE) attachment sites and their degranulation is associated with histamine release. Basophils are very similar in both appearance and function to mast cells.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 7
Correct
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Regarding cytotoxic T cells, which of the following statements is CORRECT:
Your Answer: They kill target cells by inducing cell apoptosis.
Explanation:CD8+ T-cells (Cytotoxic T cells)
Recognise antigen only in association with HLA Class I molecules (found on all nucleated cells; present endogenous antigens such as those found in cells infected by viruses or intracellular bacteria.)
Comprise about 25% of peripheral T-cells
Responsible for cytotoxic killing of target cells -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 8
Incorrect
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Which of the following is the most abundant immunoglobulin in plasma:
Your Answer: IgA
Correct Answer: IgG
Explanation:IgA is the major Ig in secretions, particularly from the gastrointestinal tract (but also in saliva, tears, sweat and breast milk).
IgE is important for mast cell degranulation in allergic and antiparasitic response. In the allergic response, the plasma cell produces IgE-antibodies, which, like antibodies of other immunoglobulin isotypes, are capable of binding a specific allergen via its Fab portion.
IgG is the most abundant in plasma (comprising 80% of normal serum immunoglobulin) and the main circulatory Ig for the secondary immune response. -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 9
Incorrect
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A 22-year-old man arrives at the emergency department with a sore throat, low-grade fever, and malaise. His partner has infectious mononucleosis, which was recently diagnosed. In this situation, which of the following cells is the most proliferative:
Your Answer: Monocytes
Correct Answer: Lymphocytes
Explanation:Histologic findings in EBV infectious mononucleosis: Oropharyngeal epithelium demonstrates an intense lymphoproliferative response in the cells of the oropharynx. The lymph nodes and spleen show lymphocytic infiltration primarily in the periphery of a lymph node.
Relative lymphocytosis (≥ 60%) plus atypical lymphocytosis (≥ 10%) are the characteristic findings of Epstein Barr virus (EBV) infectious mononucleosis. -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 10
Incorrect
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You are giving a presentation on the immune system as part of your peer-to-peer teaching sessions. Yu are currently discussing phagocytes. Macrophages are derived from which of the following cells:
Your Answer:
Correct Answer: Monocytes
Explanation:Monocytes spend only a short time in the marrow and, after circulating for 20-40 hours, leave the blood to enter the tissues where they become macrophages. Macrophages form the reticuloendothelial system in the liver, spleen and lymph nodes. The lifespan of macrophages may be as long as several months or even years. In tissues the macrophages become self-replicating without replenishment from the blood. They assume specific functions in different tissues e.g. dendritic cells which are involved in antigen presentation to T-cells. Macrophages may be activated by cytokines such as IFN-gamma, contact with complement or direct contact with the target cell through leucocyte adhesion molecules.
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This question is part of the following fields:
- Immune Responses
- Pathology
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SESSION STATS - PERFORMANCE PER SPECIALTY
