A night-shift worker experiences extreme difficulty falling asleep due to being exposed to bright lights during both night and day.
The unusual pattern of light exposure is disturbing which controls the release of the hormone:
Metabolic rate; thyroxine.
Limbic system; thymosin.
Circulatory system; dopamine.
Circadian rhythm; melatonin.
The Correct Answer is D
Circadian rhythm is the term for the biological clock that regulates the sleep-wake cycle and other physiological processes in the body.
Melatonin is a hormone that is produced by the pineal gland in the brain in response to darkness.
It helps with the timing of the circadian rhythm and promotes sleep.
Choice A is wrong because metabolic rate is not affected by light exposure, and thyroxine is a hormone that regulates metabolism, not sleep.
Choice B is wrong because the limbic system is a part of the brain that is involved in emotions, memory, and motivation, not sleep.
Thymosin is a hormone that stimulates the development of T cells, which are part of the immune system.
Choice C is wrong because the circulatory system is the system of blood vessels and organs that transport blood throughout the body, not a part of the brain that controls sleep.
Dopamine is a neurotransmitter that is involved in reward, motivation, and movement, not sleep.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
T lymphocytes, also known as T cells, are a type of white blood cell that is an essential part of the immune system.
T cells are one of two primary types of lymphocytes — B cells being the second type — that determine the specificity of immune response to antigens (foreign substances) in the body.
T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell surface.
T cells originate in the bone marrow and mature in the thymus.
After migration to the thymus, the precursor cells mature into several distinct types of T cells.
One of these types is the CD8+ T cell, also known as cytotoxic T cell, which is responsible for cell-mediated immunity.
Cell-mediated immunity is the type of immunity that involves the direct killing of infected cells and cancer cells by cytotoxic T cells.
Choice A is wrong because humoral immunity is the type of immunity that involves the production of antibodies by B cells and plasma cells.
Antibodies are proteins that bind to specific antigens and mark them for destruction by other immune cells.
Choice C is wrong because programming macrophages is not a function of T lymphocytes.
Macrophages are a type of phagocytic cell that can engulf and digest pathogens and cellular debris.
Macrophages can be activated by cytokines, which are chemical messengers secreted by helper T cells and other immune cells.
Choice D is wrong because producing antibodies is not a function of T lymphocytes.
As mentioned above, antibodies are produced by B cells and plasma cells, which are another type of lymphocyte.
Correct Answer is C
Explanation
A newborn is protected against certain digestive and respiratory infections by IgA received via the mother’s milk.
IgA is the main antibody found in breast milk, and it coats and seals the baby’s respiratory and intestinal tract to prevent germs from entering the body and bloodstream.
Choice A is wrong because the blood does not contain IgA, which is the main antibody that protects mucosal membranes.
Choice B is wrong because the placenta does not transfer IgA to the fetus, but only some other antibodies such as IgG.
Choice D is wrong because the intestine does not produce IgA in newborns, as they are born with low levels of IgA.
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