The function of angiotensin II is to
decrease the production of aldosterone
decrease water absorption
decrease arterial blood pressure
constrict arterioles and increase blood pressure
increase the production of ADH
The Correct Answer is D
A. decrease the production of aldosterone: Angiotensin 2 serves as the primary secretagogue for the zona glomerulosa of the adrenal cortex. It directly stimulates the synthesis and release of aldosterone to enhance sodium retention. Increasing aldosterone is a vital step in the homeostatic response to low blood pressure.
B. decrease water absorption: This effector molecule promotes water retention by stimulating thirst centers in the hypothalamus and increasing the release of antidiuretic hormone. It also enhances sodium reabsorption in the proximal tubule, which creates an osmotic gradient for water. These actions collectively increase total body water volume.
C. decrease arterial blood pressure: Angiotensin 2 is one of the most potent endogenous vasoconstrictors known in human physiology. Its primary systemic effect is to increase peripheral resistance and venous return to elevate blood pressure. Decreasing pressure would contradict the corrective goals of the renin-angiotensin-aldosterone system.
D. constrict arterioles and increase blood pressure: By binding to AT1 receptors on vascular smooth muscle, angiotensin 2 induces rapid systemic vasoconstriction. This increases systemic vascular resistance and immediately raises arterial blood pressure to maintain organ perfusion. It specifically targets the efferent arterioles to maintain glomerular filtration during hypotension.
E. increase the production of ADH: While angiotensin 2 does stimulate the posterior pituitary to release antidiuretic hormone, choice D is the most direct and comprehensive description of its primary cardiovascular function. ADH works synergistically with angiotensin 2 to restore blood volume and pressure. Both are essential for long-term hemodynamic stability.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
A. not develop secondary sex characteristics: Secondary sex characteristics, such as muscle growth and hair distribution, are driven by testosterone produced by interstitial cells. Since LH levels are normal, these cells will still be stimulated to produce adequate testosterone. The boy would likely appear physically mature in terms of external male characteristics.
B. have impaired function of interstitial cells: Interstitial endocrine cells are specifically regulated by luteinizing hormone, which the question states is functioning normally. These cells will continue to synthesize testosterone regardless of the FSH deficiency. Their endocrine function remains intact because their primary tropic hormone is still present in the circulation.
C. be impotent (unable to have an erection): Erection is a neurovascular reflex mediated by the parasympathetic nervous system and is not directly dependent on FSH. While low testosterone can decrease libido, LH is present to maintain testosterone levels. Therefore, the physiological mechanism for erection should remain functional in this mature male.
D. be unable to produce viable sperm: Follicle-stimulating hormone is strictly required to stimulate the sustentacular cells to facilitate the final stages of sperm maturation. Without FSH, the process of spermatogenesis cannot be completed effectively, leading to infertility. The individual would produce few or no functional spermatozoa despite normal hormonal levels.
Correct Answer is C
Explanation
A. estrogen: Estrogen is the primary hormone responsible for female secondary sex characteristics, such as breast development and pelvic widening. While males produce small amounts of estrogen through the aromatization of testosterone, it does not drive the development of male traits. Excessive estrogen in males can lead to feminization.
B. progesterone: This hormone is primarily involved in the female menstrual cycle and the maintenance of pregnancy. It prepares the endometrium for implantation and supports the secretory phase of the uterine cycle. It plays no significant role in the development of male secondary sex characteristics or male reproductive maturation.
C. testosterone: Secreted by the interstitial endocrine cells of the testes, testosterone is the primary androgen responsible for male maturation. It drives the growth of facial and body hair, the deepening of the voice through laryngeal enlargement, and the increase in muscle mass. It is also essential for the initiation of spermatogenesis.
D. growth hormone: While growth hormone is essential for overall somatic growth and bone elongation during puberty, it does not specifically determine sexual characteristics. It works synergistically with sex steroids but lacks the specific androgenic effects required for the development of male-specific traits. Its action is generalized across most body tissues.
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