Ch. 17- Final OpenStax Questions

13. How many hormones are produced by the posterior pituitary?

0

48. Explain why someone with a parathyroid gland tumor might develop kidney stones.

A parathyroid gland tumor can prompt hypersecretion of PTH. This can raise blood calcium levels so excessively that calcium deposits begin to accumulate throughout the body, including in the kidney tubules, where they are referred to as kidney stones.

9. A small molecule binds to a G protein, preventing its activation. What direct effect will this have on signaling that involves cAMP?

Adenylyl cyclase will not be activated.

42. Describe the mechanism of hormone response resulting from the binding of a hormone with an intracellular receptor.

An intracellular hormone receptor is located within the cell. A hydrophobic hormone diffuses through the cell membrane and binds to the intracellular hormone receptor, which may be in the cytosol or in the cell nucleus. This hormone-receptor complex binds to a segment of DNA. This initiates the transcription of a target gene, the end result of which is protein assembly and the hormonal response.

54. Compare and contrast the role of estrogens and progesterone.

Both estrogens and progesterone are steroid hormones produced by the ovaries that help regulate the menstrual cycle. Estrogens play an important role in the development of the female reproductive tract and secondary sex characteristics. They also help maintain pregnancy. Progesterone prepares the body for pregnancy and helps maintain pregnancy.

50. If innervation to the adrenal medulla were disrupted, what would be the physiological outcome?

Damage to the innervation of the adrenal medulla would prevent the adrenal glands from responding to the hypothalamus during the fight-or- flight response. Therefore, the response would be reduced.

39. Compare and contrast endocrine and exocrine glands.

Endocrine glands are ductless. They release their secretion into the surrounding fluid, from which it enters the bloodstream or lymph to travel to distant cells. Moreover, the secretions of endocrine glands are hormones. Exocrine glands release their secretions through a duct that delivers the secretion to the target location. Moreover, the secretions of exocrine glands are not hormones, but compounds that have an immediate physiologic function. For example, pancreatic juice contains enzymes that help digest food.

57. Why is foot care extremely important for people with diabetes mellitus?

Excessive blood glucose levels damage the blood vessels and nerves of the body's extremities, increasing the risk for injury, infection, and tissue death. Loss of sensation to the feet means that a diabetic patient will not be able to feel foot trauma, such as from ill-fitting shoes. Even minor injuries commonly lead to infection, which , can progress to tissue death without proper care, requiring amputation.

46. Define hyperthyroidism and explain why one of its symptoms is weight loss.

Hyperthyroidism is an abnormally elevated blood level of thyroid hormones due to an overproduction of T3 and T4. An individual with hyperthyroidism is likely to lose weight because one of the primary roles of thyroid hormones is to increase the body's basal metabolic rate, increasing the breakdown of nutrients and the production of ATP.

41. Compare and contrast the signaling events involved with the second messengers cAMP and IP3.

In both cAMP and IP3-calcium signaling, a hormone binds to a cell membrane hormone receptor that is coupled to a G protein. The G protein becomes activated when the hormone binds. In the case of cAMP signaling, the activated G protein activates adenylyl cyclase, which causes ATP to be converted to cAMP. This second messenger can then initiate other signaling events, such as a phosphorylation cascade. In the case of IP3-calcium signaling, the activated G protein activates phospholipase C, which cleaves a membrane phospholipid compound into DAG and IP3. IP3 causes the release of calcium, another second messenger, from intracellular stores. This causes further signaling events.

31. Which of the following statements about insulin is true?

Insulin facilitates the movement of intracellular glucose transporters to the cell membrane.

45. Explain why maternal iodine deficiency might lead to neurological impairment in the fetus.

Iodine deficiency in a pregnant woman would also deprive the fetus. Iodine is required for the synthesis of thyroid hormones, which contribute to fetal growth and development, including maturation of the nervous system. Insufficient amounts would impair these functions.

60. Distinguish between the effects of menopause and andropause on fertility.

Menopause occurs as the result of a progressive decline in the function of the ovaries, resulting in low estrogen and progesterone levels. Ovulation ceases, and postmenopausal woman can no longer conceive a child. In contrast, andropause is a much more gradual and subtle decline in testosterone levels and functioning. A man typically maintains fertility until very old age, although the quantity, quality, and motility of the sperm he produces may be reduced.

55. Describe the role of placental secretion of relaxin in preparation for childbirth.

Relaxin produced by the placenta is thought to soften and widen the pubic symphysis. This increases the size of the pelvic outlet, the birth canal through which the fetus passes during vaginal childbirth.

52. Seasonal affective disorder (SAD) is a mood disorder characterized by, among other symptoms, increased appetite, sluggishness, and increased sleepiness. It occurs most commonly during the winter months, especially in regions with long winter nights. Propose a role for melatonin in SAD and a possible non-drug therapy.

SAD is thought to occur in part because low levels and duration of sunlight allow excessive and prolonged secretion of melatonin. Light therapy—daytime exposure to very bright lighting—is one common therapy.

12. Which of the following is an anterior pituitary hormone?

TSH

16. The secretion of thyroid hormones is controlled by ________.

TSH from the anterior pituitary

43. Compare and contrast the anatomical relationship of the anterior and posterior lobes of the pituitary gland to the hypothalamus.

The anterior lobe of the pituitary gland is connected to the hypothalamus by vasculature, which allows regulating hormones from the hypothalamus to travel to the anterior pituitary. In contrast, the posterior lobe is connected to the hypothalamus by a bridge of nerve axons called the hypothalamic-hypophyseal tract, along which the hypothalamus sends hormones produced by hypothalamic nerve cell bodies to the posterior pituitary for storage and release into the circulation.

56. What would be the physiological consequence of a disease that destroyed the beta cells of the pancreas?

The beta cells produce the hormone insulin, which is important in the regulation of blood glucose levels. All insulin-dependent cells of the body require insulin in order to take up glucose from the bloodstream. Destruction of the beta cells would result in an inability to produce and secrete insulin, leading to abnormally high blood glucose levels and the disease called type 1 diabetes mellitus.

38. Describe several main differences in the communication methods used by the endocrine system and the nervous system.

The endocrine system uses chemical signals called hormones to convey information from one part of the body to a distant part of the body. Hormones are released from the endocrine cell into the extracellular environment but then travel in the bloodstream to target tissues. This communication and response can take seconds to days. In contrast, neurons transmit electrical signals along their axons. At the axon terminal, the electrical signal prompts the release of a chemical signal called a neurotransmitter that carries the message across the synaptic cleft to elicit a response in the neighboring cell. This method of communication is nearly instantaneous, of very brief duration, and is highly specific.

44. Name the target tissues for prolactin.

The mammary glands are the target issues for prolactin.

49. What are the three regions of the adrenal cortex and what hormones do they produce?

The outer region is the zona glomerulosa, which produces mineralocorticoids such as aldosterone; the next region is the zona fasciculata, which produces glucocorticoids such as cortisol; the inner region is the zona reticularis, which produces androgens.

58. Summarize the role of GI tract hormones following a meal.

The presence of food in the GI tract stimulates the release of hormones that aid in digestion. For example, gastrin is secreted in response to stomach distention and causes the release of hydrochloric acid in the stomach. Secretin is secreted when acidic chyme enters the small intestine, and stimulates the release of pancreatic bicarbonate. In the presence of fat and protein in the duodenum, CCK stimulates the release of pancreatic digestive enzymes and bile from the gallbladder. Other GI tract hormones aid in glucose metabolism and other functions.

47. Describe the role of negative feedback in the function of the parathyroid gland.

The production and secretion of PTH is regulated by a negative feedback loop. Low blood calcium levels initiate the production and secretion of PTH. PTH increases bone resorption, calcium absorption from the intestines, and calcium reabsorption by the kidneys. As a result, blood calcium levels begin to rise. This, in turn, inhibits the further production and secretion of PTH.

53. Retinitis pigmentosa (RP) is a disease that causes deterioration of the retinas of the eyes. Describe the impact RP would have on melatonin levels.

The retina is important for melatonin production because it senses light. Bright light inhibits the production of melatonin, whereas low light levels promote the production of melatonin. Therefore, deterioration of the retinas would most likely disturb the sleep-wake pattern because melatonin production would be elevated.

51. Compare and contrast the short-term and long-term stress response.

The short-term stress response involves the hormones epinephrine and norepinephrine, which work to increase the oxygen supply to organs important for extreme muscular action such as the brain, lungs, and muscles. In the long-term stress response, the hormone cortisol is involved in catabolism of glycogen stores, proteins, and triglycerides, glucose and ketone synthesis, and downregulation of the immune system.

59. Compare and contrast the thymus gland in infancy and adulthood.

The thymus gland is important for the development and maturation of T cells. During infancy and early childhood, the thymus gland is large and very active, as the immune system is still developing. During adulthood, the thymus gland atrophies because the immune system is already developed.

40. True or false: Neurotransmitters are a special class of paracrines. Explain your answer.

True. Neurotransmitters can be classified as paracrines because, upon their release from a neuron's axon terminals, they travel across a microscopically small cleft to exert their effect on a nearby neuron or muscle cell.

23. Cushing's disease is a disorder caused by ________.

abnormally high levels of cortisol

18. Iodide ions cross from the bloodstream into follicle cells via ________.

active transport

15. Which of the following statements about the thyroid gland is true?

all of the above

14. Which of the following hormones contributes to the regulation of the body's fluid and electrolyte balance?

antidiuretic hormone

32. The walls of the atria produce which hormone?

atrial natriuretic peptide

34. Athletes may take synthetic EPO to boost their ________.

blood oxygen levels

22. What secretory cell type is found in the adrenal medulla?

chromaffin cells

37. In the elderly, decreased thyroid function causes ________.

decreased basal metabolic rate

35. Hormones produced by the thymus play a role in the ________.

development of T cells

26. The production of melatonin is inhibited by ________.

exposure to bright light

20. Which of the following can result from hyperparathyroidism?

fractures

30. If an autoimmune disorder targets the alpha cells, production of which hormone would be directly affected?

glucagon

33. The end result of the RAAS is to ________.

increase blood pressure

28. The production of FSH by the anterior pituitary is reduced by which hormone?

inhibin

21. The adrenal glands are attached superiorly to which organ?

kidneys

11. The hypothalamus is functionally and anatomically connected to the posterior pituitary lobe by a bridge of ________.

nerve axons

10. A student is in a car accident, and although not hurt, immediately experiences pupil dilation, increased heart rate, and rapid breathing. What type of endocrine system stimulus did the student receive?

neural

36. The anterior pituitary gland develops from which embryonic germ layer?

oral ectoderm

7. Chemical signaling that affects neighboring cells is called ________.

paracrine

25. What cells secrete melatonin?

pinealocytes

29. The function of the placental hormone human placental lactogen (hPL) is to ________.

prepare the breasts for lactation

24. Which of the following responses s not part of the fight-or-flight response?

reduced mental activity

6. Endocrine glands ________.

secrete chemical messengers that travel in the bloodstream

27. The gonads produce what class of hormones?

steroid hormones

19. When blood calcium levels are low, PTH stimulates ________.

the activity of osteoclasts

17. The development of a goiter indicates that ________.

there is an excessive accumulation of colloid in the thyroid follicles

8. A newly developed pesticide has been observed to bind to an intracellular hormone receptor. If ingested, residue from this pesticide could disrupt levels of ________.

thyroid hormone