March 5, 2009 Sample midterm questions on the endocrine system. Correct answers are highlighted in bold. 18. The effective plasma concentration of a hormone is normally regulated by appropriate adjustments in the hormone’s a. rate of synthesis. b. extent of binding to plasma proteins. c. rate of metabolic inactivation. d. rate of secretion. e. rate of binding with target-cell receptors. 19. Too little activity of a particular hormone can arise from a. an abnormality within the endocrine gland that produces this hormone. b. a deficiency in production of this hormone's tropic hormone. c. an inborn lack of target-cell receptors for this hormone. d. Both (a) and (c) above. e. All of these answers. 20. Hypophysiotropic hormones from the hypothalamus a. control the release of oxytocin and vasopressin from the posterior pituitary. b. travel via neuronal axons from the hypothalamus to the anterior pituitary. c. are carried to the anterior pituitary via a local portal system (blood vessel). d. are released upon positive-feedback stimulation via the anterior pituitary tropic hormones. e. always act to stimulate the release of anterior pituitary hormones. 21. Select the correct statement(s) a. peptide hormones are lipophilic. b. steroid hormones are lipophilic. c. lipophilic hormones can not be delivered orally (ingested). d. Both (b) and (c) above. e. Both (a) and (c) above. 22. Growth hormone a. promotes closure of the epiphyseal plate of long bones. b. promotes hypertrophy and hyperplasia, especially during childhood. c. insufficiency in adulthood causes acromegaly. d. is the only factor responsible for governing the growth of an individual. e. Both (a) and (b) above. 23. DHEA is a weak androgen (masculinizing hormone) made in the adrenal gland. Hypersecretion of this hormone in childhood causes adrenogenital syndrome. Which statement is correct? a. the fundamental cause of adrenogenital syndrome is a defect in the cortisol biosynthetic pathway. b. cortisol and DHEA are derived from different initial precursors. c. Excess DHEA effectively promotes excess gonadotropin (FSH, LH) secretion from the H-P axis. d. Both (a) and (c) above. e. All of these answers.24. When animals including humans are chronically deprived of all light/dark cues they a. cease to exhibit a circadian rhythm. b. go into “free run,” that is, reveal the period of their endogenous generator. c. continue to exhibit photoentrainment due to specialized receptors located in the eye. d. Both (a) and (b) above. e. Both (b) and (c) above. 25. You are a neuroendocrine research scientist and just invented a new technique for use in mice. With this technique, it is possible to selectively kill off only those 1 in 100 retinal ganglion cells that express melanopsin. As a result these cells and their connections to the brain disappear. All other cell types in the retina, including photoreceptors and regular retinal ganglion cells, and their normal connections to brain, survive. Based on what you now know about photoentrainment, what would you predict as the acute consequence of this experimental treatment? a. mice would lose much of their visual perception. b. mice would go into free run. c. mice would become diurnal instead of nocturnal. d. mice would show partially impaired yet partially spared photoentrainment e. All of these answers. 26. A new vegetable is discovered. It is delicious to eat and many people add it to their regular diet. But the public is not aware the vegetable contains a powerful chemical that readily absorbs into the bloodstream. There, even small amounts of this chemical effectively destroy all thyroid hormone. What will happen to the adventuresome eaters of the vegetable? a. they’ll develop Graves disease. b. their blood will contain higher than normal levels of TSH. c. they won’t develop goiters. d. their overall basal metabolic rate will increase. e. Both (b) and (d) above. 27. A student experiencing psychological and emotional stress a. will secrete CRH at higher levels. b. will secrete ACTH at higher levels. c. will secrete cortisol at higher levels. d. may experience a greater risk of infections due to immune system suppression. e. All of these answers. 28. Blood glucose levels a. decrease in response to gluconeogenic activity. b. must be maintained at or above a sufficient concentration because the brain needs a constant supply of glucose. c. increase in response to insulin secretion. d. decrease in response to glucagon secretion. e. Both (b) and (d) above. 29. Which of the following characterizes Type II but not Type I diabetes mellitus? a. hyperglycemia b. lack of insulin c. polyuria and polydipsia d. can usually be successfully managed by dietary control and weight reduction without the necessity of insulin injections30. Calcium balance a. involves the immediate adjustments required to maintain a constant free Ca2+ concentration on a minute-to-minute basis. b. involves slowly responding adjustments required to maintain a constant total amount of Ca2+ in the body. c. is maintained by the actions of parathyroid hormone and vitamin D. d. Both (a) and (c) above. e. Both (b) and (c)