Which of the following is not an example of a negative homeostatic mechanism in the human body?
Increasing heart rate and force of contraction when blood pressure falls.
Secreting insulin after a meal to return blood sugar concentration to normal.
Retention of fluid leads to retention of more fluid.
Shivering when body temperature falls below normal.
The Correct Answer is C
This is because it is an example of a positive feedback loop, which amplifies the change and moves the system away from its normal state.
A negative feedback loop is a mechanism that reverses a deviation from the set point and maintains homeostasis.
Choice A is wrong because increasing heart rate and force of contraction when blood pressure falls is a negative feedback loop that restores blood pressure to normal.
Choice B is wrong because secreting insulin after a meal to return blood sugar concentration toward normal is a negative feedback loop that regulates glucose levels.
Choice D is wrong because shivering when body temperature falls below normal is a negative feedback loop that increases heat production and raises body temperature.
Normal ranges for blood pressure are 90/60 mmHg to 120/80 mmHg, for blood glucose, are 70 mg/dL to 140 mg/dL, and for body temperature are 36.5°C to 37.5°C or 97.7°F to 99.5°F.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Red blood cells do not contain a large nucleus; in fact, they do not contain a nucleus at all when they are mature.
This is an adaptation that allows them to carry more hemoglobin, the protein that binds oxygen, and to squeeze through narrow capillaries.
Choice B is wrong because it contradicts the fact that red blood cells are enucleated (lacking a nucleus) in humans and most mammals.
Some vertebrates, such as birds and fish, have nucleated red blood cells, but they are not thick near the center and thin around the rim of the cell.
Correct Answer is B
Explanation
Monocytes are a type of agranulocytes, which are white blood cells that lack visible granules in their cytoplasm.
Agranulocytes also include lymphocytes, which are involved in adaptive immunity.
Choice A is wrong because basophils are a type of granulocytes, which are white blood cells that have granules in their cytoplasm.
Granulocytes also include neutrophils and eosinophils, which are involved in innate immunity.
Choice C is wrong because neutrophils are also a type of granulocyte.
Neutrophils are the most abundant white blood cells and are responsible for phagocytizing bacteria and fungi.
Choice D is wrong because eosinophils are also a type of granulocytes. Eosinophils are involved in allergic reactions and parasitic infections.
Normal ranges for white blood cells vary depending on age, gender, and health status, but generally, they are between 4,000 and 11,000 cells per microliter of blood.
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