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 C
Explanation
Uterine contractions during childbirth illustrate a positive feedback mechanism.
A positive feedback mechanism is a process in which the end products of an action cause more of that action to occur in a feedback loop.
This amplifies the original action.
For example, when a woman goes into labor, the pressure of the baby’s head on the cervix stimulates nerve impulses that travel to the brain and trigger the release of oxytocin, a hormone that causes the uterus to contract.
The contractions increase the pressure on the cervix, which stimulates more nerve impulses, more oxytocin, and more contractions.
This cycle continues until the baby is delivered.
Choice A is wrong because body temperature control is an example of a negative feedback mechanism, which is when the end results of an action inhibit that action from continuing to occur.
For example, when the body temperature rises above normal, the skin sweats, and blood vessels dilate to release heat.
This lowers the body temperature back to normal and stops sweating and dilation.
Choice B is wrong because control of blood sugar is also an example of a negative feedback mechanism.
For example, when the blood sugar level rises after a meal, the pancreas secretes insulin, a hormone that helps cells take up glucose from the blood.
This lowers the blood sugar level back to normal and stops the insulin secretion.
Choice D is wrong because maintaining blood pressure is another example of a negative feedback mechanism.
For example, when the blood pressure drops due to blood loss or dehydration, the heart beats faster and stronger, and the blood vessels constrict to increase the blood pressure.
This restores the blood pressure back to normal and stops the heart rate and vessel constriction.
Correct Answer is A
Explanation
A monocyte is a type of white blood cell that is markedly larger than a red blood cell and has a large kidney-shaped nucleus.
Monocytes are involved in defending the body against infectious diseases and foreign materials.
Choice B is wrong because a basophil is a type of granular white blood cell that has a lobed nucleus and stains purple with basic dyes.
Basophils are involved in allergic reactions and inflammation.
Choice C is wrong because a neutrophil is a type of granular white blood cell that has a multilobed nucleus and stains pale pink with neutral dyes.
Neutrophils are involved in phagocytosis and killing bacteria.
Choice D is wrong because an eosinophil is a type of granular white blood cell that has a bilobed nucleus and stains red-orange with acidic dyes.
Eosinophils are involved in combating parasitic infections and allergic responses. The normal ranges of different types of blood cells are:
Red blood cells: 4.5 to 5.9 million per microliter (mcL) for males, 4.1 to 5.1 million per mcL for females
White blood cells: 4,000 to 11,000 per mcL for both males and females
Platelets: 150,000 to 450,000 per mcL for both males and females
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