After an infection, many dead and fragmented bacterial cells must be filtered from the body.
Which of the following cells will clear out the cell debris?
Lymphocytes.
Cytokines.
Mast cells.
Macrophages.
The Correct Answer is D
Macrophages are the main cells that clear out the cell debris by phagocytosis, a process that involves recognition, engulfment, and degradation of the disposable particles.
Macrophages are professional phagocytes that can be found in various tissues and organs, where they perform efferocytosis, the removal of dead and dying cells.
Choice A is wrong because lymphocytes are not phagocytes, but rather immune cells that mediate adaptive immunity by producing antibodies or killing infected cells.
Choice B is wrong because cytokines are not cells, but rather soluble molecules that regulate inflammation and immunity by acting as signals between cells.
Choice C is wrong because mast cells are not primarily involved in clearing cell debris, but rather in allergic reactions and innate immunity by releasing histamine and other mediators.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
As a result of the allergen-antibody reaction, mast cells release histamine.
This is because when mast cells are exposed to an allergen that binds to IgE antibodies attached to their FcɛRI receptors, they release histamine and other inflammatory mediators.
Histamine causes vasodilation, increased capillary permeability, mucus secretion, and smooth muscle contraction, which result in allergic symptoms such as itching, swelling, sneezing, and wheezing.
Mast cells do release histamine in response to allergen-antibody reactions. Some additional sentences are:
Normal ranges of histamine levels vary depending on the tissue and the method of measurement, but they are usually low in healthy individuals and elevated in allergic conditions.
Histamine can be degraded by enzymes such as diamine oxidase and histamine N- methyltransferase, or inhibited by drugs such as antihistamines.
Correct Answer is D
Explanation
Paracrine secretions are chemical signals that affect only nearby cells.
They are released by the sending cell and diffuse through the extracellular space to the target cell, which has a specific receptor for the signal.
Paracrine signaling is a form of local signaling that occurs in multicellular organisms.
Choice A is wrong because autocrine secretions are chemical signals that act on the same cell that produced them.
Autocrine signaling is also a form of local signaling, but it involves cell signaling itself.
Choice B is wrong because endocrine secretions are chemical signals that are secreted into the blood and act at long distances.
Endocrine signaling is a form of long-range signaling that involves ductless glands that secrete hormones.
Choice C is wrong because exocrine secretions are non-hormonal substances that are secreted into ducts to the external environment.
Exocrine signaling is not a form of cell-cell communication, but rather a way of releasing substances such as sweat, saliva, or digestive enzymes.
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