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 B
Explanation
Kidney disease can cause hypertension by activating the renin-angiotensin mechanism.
This mechanism involves the release of renin from the kidneys, which stimulates the production of angiotensin II, a hormone that constricts blood vessels and increases blood pressure.
Choice A is wrong because kidney disease does not directly signal the brain stem to increase blood pressure.
The brain stem regulates blood pressure through the autonomic nervous system, which responds to various stimuli such as stress, pain, or emotions.
Choice C is wrong because kidney disease does not increase the release (excretion) of sodium and water.
On the contrary, kidney disease can impair the ability of the kidneys to filter out excess sodium and water, which can lead to fluid retention and increased blood pressure.
Choice D is wrong because kidney disease does not stimulate the secretion of ANP.
ANP stands for atrial natriuretic peptide, a hormone that is secreted by the heart when it senses high blood pressure.
ANP causes the kidneys to excrete more sodium and water, which lowers blood pressure.
Correct Answer is A
Explanation
This is the correct sequence of parts through which blood moves from the vena cava to the lungs.
Choice B is wrong because it reverses the order of the right atrium and right ventricle. Blood flows from the right atrium to the right ventricle, not the other way around.
Choice C is wrong because it switches the positions of the tricuspid valve and the pulmonary valve.
Blood flows from the right atrium through the tricuspid valve to the right ventricle, and then through the pulmonary valve to the pulmonary artery.
Choice D is wrong because it also switches the positions of the tricuspid valve and the pulmonary valve, and reverses the order of the right atrium and right ventricle.
Blood flows from the right atrium through the tricuspid valve to the right ventricle, and then through the pulmonary valve to the pulmonary artery.
The normal range of blood pressure in the vena cava is about 0 to 5 mmHg, while in the pulmonary artery, it is about 15 to 25 mmHg.
The normal range of oxygen saturation in the vena cava is about 60% to 80%, while in the pulmonary vein, it is about 95% to 100%.
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