ch 46

21) Which of the following best describes the neuroendocrine-to-endocrine pathway of hormone action?

A) A structure within the nervous system produces and release a hormone that regulate the activity of an endocrine gland.

58) The regulation of blood sugar levels and our stress responses are controlled in part by a negative feedback loop involving cortisol, adrenocorticotropic hormone (ACTH), and corticotropin-releasing hormone (CRH). What would likely be the result during times of stress if cortisol receptors in the hypothalamus were nonfunctional?

A) Blood sugar levels would rise to dangerous levels.

30) What property of steroid hormones allows them to cross the phospholipid bilayer?

A) Steroid hormones are lipid soluble and easily cross the phospholipid bilayer.

32) Hormone X activates the cAMP second messenger system in its target cells. The greatest response by a cell would come from ________.

A) applying a molecule of hormone X to the extracellular fluid surrounding the cell

23) When adenylyl cyclase is activated ________.

A) cAMP is synthesized

40) The steroid hormone that coordinates molting in arthropods is ________.

A) ecdysone

53) A tumor that decreases the production of adrenocorticotropic hormone (ACTH) would lead to a decrease in plasma levels of ________.

A) glucocorticoid hormones

9) Oxytocin and antidiuretic hormone (ADH) are synthesized in the ________.

A) hypothalamus

57) Predict the immediate effects of a drug that increases adrenocorticotropic hormone (ACTH) synthesis.

A) increase in glucocorticoid production

20) For hormones that homeostatically regulate cellular functions, ________.

A) negative feedback typically regulates hormone secretion

15) Which hormone is correctly paired with its action?

A) oxytocin—stimulates uterine contractions during childbirth

10) Which of the following is an endocrine gland?

A) parathyroid glands

29) The signal cascade activated by epinephrine leads to ________.

A) the amplification of the epinephrine signal, increasing the release of glucose

2) In experiments where researchers suspect that a hormone may be responsible for a certain physiological effect, they may cut the neurons leading to the organ where the effect being studied occurs. What is the purpose of cutting these neurons?

A) to make sure that the effect is not occurring through actions in the nervous system

44) Tadpoles must undergo a major metamorphosis to become frogs. This change includes reabsorption of the tail, growth of limbs, calcification of the skeleton, increase in rhodopsin in the eye, development of lungs, change in hemoglobin structure, and reformation of the gut from the long gut of an herbivore to the short gut of a carnivore. Amazingly, all of these changes are induced by triiodothyronine. What is the most likely explanation for such a wide array of effects of thyroxine?

B) Different tissues have triiodothyronine receptors that activate different signal transduction pathways.

33) Estradiol is an example of ________.

B) an estrogen

1) Chemical signals that act on the same cells that secrete them are called ________.

B) autocrine signals

25) Which of the following is NOT a chemical class of hormones?

B) complex carbohydrates

39) In response to stress, the adrenal gland promotes the synthesis of glucose from non-carbohydrate substrates via the action of the steroid hormone ________.

B) cortisol

22) The hormone that stimulates the production of red blood cells and the organ where this hormone is synthesized are ________.

B) erythropoietin and kidney, respectively

12) Analysis of a blood sample from a fasting individual who had not eaten for 24 hours would be expected to reveal high levels of ________.

B) glucagon

14) An example of two hormones that have opposite effects in maintaining homeostasis is ________.

B) insulin and glucagon in glucose metabolism

37) The effects of the hormone ecdysone on development in insects depend on the levels of which hormone?

B) juvenile hormone

56) Removing which of the following glands would have the most wide-reaching effect on bodily functions of an adult human?

B) pituitary gland

8) In a lactating mammal, the two hormones that promote milk synthesis and milk release, respectively, are ________.

B) prolactin and oxytocin

59) The release of hormones by the posterior pituitary is the result of what process?

C) Neurosecretory cells of the hypothalamus directly release hormones into blood vessels within the posterior pituitary.

50) Oxytocin helps initiate labor in mammals. During labor and delivery, the contraction of uterine muscles increases the release of oxytocin. This is an example of ________.

C) a hormone that is involved in a positive feedback loop

54) During a stressful interval, ________.

C) adrenocorticotropic hormone (ACTH) stimulates the adrenal cortex, and neurons of the sympathetic nervous system stimulate the adrenal medulla

5) Most animal hormones ________.

C) are carried to target cells in the blood or hemolymph

35) Which of the following is characteristic of a steroid hormone action?

C) cytosolic hormone receptor binding

45) Xenoestrogens are an example of what group of chemicals described by Rachel Carson in her book Silent Spring?

C) endocrine disruptors

43) Glucocorticoids do which of the following?

C) increase blood glucose levels

24) After drinking alcoholic beverages, increased urine excretion is the result of ________.

C) inhibited secretion of antidiuretic hormone (ADH)

31) Estrogen is a(n) ________.

C) lipid-soluble hormone

51) The interrelationships between the endocrine and the nervous systems are especially apparent in a ________.

C) neurosecretory cell in the hypothalamus

34) Which of the following are examples of amplification of a hormone signal? I. Epinephrine initiates an enzyme cascade. II. Steroids bind hormone-response elements in the cell and initiate transcription of many genes. III. A quantity of 0.09 mg of growth hormone leads to a 10,000-mg weight gain in a cow. IV. Different cell types have different receptors capable of binding the same hormone.

C) only I, II, and III

41) In human embryonic development, which of the following pairs of hormones are released by the developing testes and result in development of the male reproductive tract and inhibition of the female reproductive tract?

C) testosterone and Müllerian inhibitory substance

16) Steroid and peptide hormones typically have in common ________.

C) their requirement for travel through the bloodstream

36) Which of the following is TRUE during a typical cAMP-type signal transduction event?

D) Adenylyl cyclase is activated after the hormone binds to the cell and before phosphorylation of proteins occurs.

19) Polypeptides can have which of the following types of effects? I. autocrine II. paracrine III. endocrine

D) I, II, and III

6) Testosterone is an example of a chemical signal that affects the very cells that synthesize it, the neighboring cells in the testis, along with distant cells outside the gonads. Thus, testosterone is an example of ________. I. an autocrine signal II. a paracrine signal III. an endocrine signal

D) I, II, and III

46) Which of the following is an example of negative feedback?

D) When the level of glucose in the blood increases, the pancreas produces and releases the hormone insulin. Insulin acts to decrease blood glucose. As blood glucose decreases, the rate of production and release of insulin decreases.

28) Epinephrine activates ________ leading to ________.

D) a cAMP signal cascade; increased blood glucose

49) Antidiuretic hormone (ADH) functions at the cellular level by ________.

D) activating aquaporin molecules of collecting duct cells

38) Fight-or-flight reactions include activation of the ________.

D) adrenal medulla, leading to increased secretion of epinephrine

47) A physician finds that a 9-year-old male patient is entering puberty much earlier than is usual. Such a condition is most likely the result of a tumor in the ________.

D) anterior pituitary, directly producing elevated levels of gonadotropin-stimulating hormone

18) Which hormone is produced from cholesterol?

D) cortisol

48) Hormones secreted by the posterior pituitary gland are made in the ________.

D) hypothalamus

55) The increased contraction of the human uterus during labor and delivery is at least partially due to the actions of ________.

D) oxytocin

4) Which of these glands has both exocrine and endocrine function?

D) pancreas

26) The receptor for the steroid hormone estradiol is found ________.

D) primarily within the nucleus

52) Neurons in the hypothalamus regulate the activity of secretory cells in the anterior pituitary gland by ________.

D) secreting releasing hormones into special blood vessels that connect the hypothalamus to the pituitary

7) A cell with membrane-bound proteins that selectively bind a specific hormone is called the ________ for that hormone

D) target cell

42) During puberty, the development of sex-specific traits results from a surge of ________ in boys and ________ and girls.

D) testosterone; estradiol

11) Which of the following has both endocrine and exocrine activity?

D) the pancreas

17) If a biochemist discovers a new molecule, which of the following pieces of data would allow her to draw the conclusion that the molecule is a steroid hormone? I. The molecule is lipid soluble. II. The molecule is derived from a series of steps beginning with cholesterol. III. The molecule acts at a target tissue some distance from where it is produced. IV. The molecule uses a carrier protein when in an aqueous solution such as blood.

E) I, II, III, and IV

27) If a person loses a large amount of water in a short period of time, he or she may die from dehydration. Antidiuretic hormone (ADH) can help reduce water loss through its interaction with its target cells in the ________.

E) kidney

13) Which of the following statements is (are) correct? I. Hormones often regulate homeostasis through antagonistic functions. II. Hormones of the same chemical class usually have the same function. III. Hormones are secreted by specialized cells usually located in exocrine glands. IV. Hormones are often regulated through feedback loops.

E) only I and IV

3) What is the only type of chemical signal that diffuses locally and affects nearby cells?

E) paracrine signals