49

23) Which of the following best describes the neuroendocrine-to-endocrine pathway of hormone action? A) A neural organ that produces hormones regulates another gland through the release of hormones into the circulation that travel to the affected gland. B) A neural organ that produces hormones releases its hormones directly into another gland that it regulates. C) A gland releases hormones directly into a neural structure, thus regulating neural functions. D) A gland exhibits negative feedback on the nervous system by releasing hormones into neural tissue both directly and indirectly through the circulation .

A) A neural organ that produces hormones regulates another gland through the release of hormones into the circulation that travel to the affected gland.

51) 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. B) Blood sugar levels would be unaffected. C) ACTH production would cease. D) CRH production would cease. E) Cortisol production would cease.

A) Blood sugar levels would rise to dangerous levels.

22) What property of steroid hormones allows them to cross the phospholipid bilayer? A) Steroid hormones are lipid soluble and easily cross the phospholipid bilayer. B) Steroid hormones can act in very small concentrations and very few molecules of steroids need to cross the lipid bilayer. C) Steroid hormones act on cells close to where they were produced and very few molecules are required to travel such a short distance to cross the lipid bilayer. D) Steroid hormones act on the same cells in which they are produced and, therefore, are within the cell they are acting upon.

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

55) 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 B) injecting a molecule of hormone X into the cytoplasm of the cell C) applying a molecule of cAMP to the extracellular fluid surrounding the cell D) injecting a molecule of cAMP into the cytoplasm of the cell E) injecting a molecule of activated, cAMP-dependent protein kinase into the cytoplasm of the cell

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

63) When adenylyl cyclase is activated ________. A) cAMP is created B) cAMP is destroyed C) G proteins bind to cAMP D) steroid hormones pass through the lipid bilayer

A) cAMP is created

31) The steroid hormone that coordinates molting in arthropods is _____. A) ecdysteroid B) glucagon C) thyroxine D) oxytocin E) growth hormone

A) ecdysteroid

11) Oxytocin and antidiuretic hormone (ADH) are synthesized in the _____. A) hypothalamus B) adenohypophysis C) anterior pituitary D) adrenal cortex E) posterior pituitary

A) hypothalamus

50) Predict the effects of a drug that increases adrenocorticotropic hormone (ACTH) synthesis. A) increase in glucocorticoid production B) increase in release of corticotropin-releasing hormone (CRH) C) decrease in cortisol release D) decrease in release of corticotropin-releasing hormone (CRH)

A) increase in glucocorticoid production

35) You have three strains of mice: A, B, and C. You experimentally manipulate each strain and find that all three show increased secretion of molecule X. Now you perform a parabiosis experiment with the three combinations of these mice: AB, AC, and BC. You perform the same experimental manipulation as above on one mouse of each pair without directly affecting the other mouse and look for effects on the other mouse. You find no detectable effect on the unmanipulated partner in any of the combinations. What is the logical conclusion based on these results? The effect on molecule X ____. A) is not mediated by hormones B) is not mediated by nerves C) was just an artifact of the first experiment D) is controlled by higher integrative centers of the brain

A) is not mediated by hormones

57) For hormones that homeostatically regulate cellular functions, _____. A) negative feedback typically regulates hormone secretion B) the circulating level of a hormone is held constant through a series of positive feedback loops C) both lipid-soluble hormones and water-soluble hormones bind to intracellular protein receptors D) endocrine organs release their contents into the bloodstream via specialized ducts E) it is impossible to also have neural regulation of that system

A) negative feedback typically regulates hormone secretion

17) Which hormone is correctly paired with its action? A) oxytocin — stimulates uterine contractions during childbirth B) thyroxine — affects biological rhythms, seasonal reproduction C) insulin — stimulates glycogen breakdown in the liver D) adrenocorticotropic hormone (ACTH) — stimulates metabolic processes E) melatonin — stimulates the release of glucocorticoids by the adrenal cortex

A) oxytocin — stimulates uterine contractions during childbirth

12) The endocrine glands include the _____. A) parathyroid glands B) salivary glands C) sweat glands D) sebaceous glands E) gallbladder

A) parathyroid glands

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 B) to make sure that the organ being affected cannot function unless the researchers stimulate it with an external electrical probe C) to impair the normal functions of the organ so that the hormonal effect can be more easily studied D) to numb the organ so that it can be probed without inducing pain in the lab animal

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

33) When a person drinks alcohol, the rate of urination increases. This suggests that antidiuretic hormone (ADH) may be affected by alcohol consumption in some way. Which of the following best accounts for the increase in urination? A) Alcohol stimulates the release of ADH. B) Alcohol inhibits the release of ADH. C) Alcohol inhibits the binding of ADH to receptors in the nephron. D) Alcohol could inhibit ADH release or the binding of ADH to receptors in the nephron.

B) Alcohol inhibits the release of ADH.

37) 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 thyroxine. What is the most likely explanation for such a wide array of effects of thyroxine? A) There are many different forms of thyroxine, each specific to a different tissue. B) Different tissues have thyroxine receptors that activate different signal transduction pathways. C) Some tissues have membrane receptors for thyroxine, while other tissues have thyroxine receptors within the nucleus. D) Different releasing hormones release thyroxine to different tissues.

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

52) Patients diagnosed with hypercortisolism may have tumors that secrete _____. A) growth hormone B) adrenocorticotropic hormone (ACTH) C) estrogen D) leptin

B) adrenocorticotropic hormone (ACTH)

58) Estradiol is an example of _____. A) an androgen B) an estrogen C) a progestin D) a catecholamine E) a glucocorticoid

B) an estrogen

30) In response to stress, the adrenal gland promotes the synthesis of glucose from non-carbohydrate substrates via the action of the steroid hormone _____. A) glucagon B) cortisol C) epinephrine D) thyroxine E) adrenocorticotropic hormone (ACTH)

B) cortisol

24) The hormone that stimulates the production of red blood cells, and the organ where this hormone is synthesized, are _____. A) growth hormone and pancreas, respectively B) erythropoietin and kidney, respectively C) cortisol and adrenal gland, respectively D) epinephrine and adrenal gland, respectively E) acetylcholine and bone marrow, respectively

B) erythropoietin and kidney, respectively

14) Analysis of a blood sample from a fasting individual who had not eaten for twenty-four hours would be expected to reveal high levels of _____. A) insulin B) glucagon C) secretin D) gastrin E) glucose

B) glucagon

16) An example of antagonistic hormones controlling homeostasis is _____. A) thyroxine and parathyroid hormone in calcium balance B) insulin and glucagon in glucose metabolism C) progestins and estrogens in sexual differentiation D) epinephrine and norepinephrine in fight-or-flight responses E) oxytocin and prolactin in milk production

B) insulin and glucagon in glucose metabolism

28) To prevent insect pests from maturing into reproducing adults, pest controllers use synthetic chemicals that bind to the receptor of _____. A) ecdysteroid B) juvenile hormone C) oxytocin D) brain hormone E) prothoracic hormone

B) juvenile hormone

8) The reason that the steroid hormone aldosterone affects only a small number of cells in the body is that _____. A) only its target cells get exposed to aldosterone B) only its target cells contain aldosterone receptors C) it is unable to enter nontarget cells D) nontarget cells destroy aldosterone before it can produce any effect E) nontarget cells convert aldosterone to a hormone to which they do respond

B) only its target cells contain aldosterone receptors

1) External chemical signals that coordinate potential reproductive partners are called _____. A) hormones B) pheromones C) paracrine signals D) cytokines E) gametes

B) pheromones

49) Removing which of the following glands would have the most wide-reaching effect on bodily functions of an adult human? A) adrenal glands B) pituitary gland C) thyroid gland D) ovaries (in female) or testes (in male)

B) pituitary gland

10) In a lactating mammal, the two hormones that promote milk synthesis and milk release, respectively, are _____. A) prolactin and calcitonin B) prolactin and oxytocin C) follicle-stimulating hormone and luteinizing hormone D) luteinizing hormone and oxytocin E) prolactin and luteinizing hormone

B) prolactin and oxytocin

43) During mammalian labor and delivery, the contraction of uterine muscles is enhanced by oxytocin. This is an example of _____. A) a negative feedback system B) a hormone that acts in an antagonistic way with another hormone C) a hormone that is involved in a positive feedback loop D) signal transduction immediately changing gene expression in its target cells E) the key role of the anterior pituitary gland in regulating uterine contraction

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

54) Different body cells can respond differently to the same peptide hormones because _____. A) different target cells have different sets of genes B) each cell converts that hormone to a different metabolite C) a target cell's response is determined by the components of its signal transduction pathways D) the circulatory system regulates responses to hormones by routing the hormones to specific targets E) the hormone is chemically altered in different ways as it travels through the circulatory system

C) a target cell's response is determined by the components of its signal transduction pathways

46) A disease that destroys the adrenal cortex should lead to an increase in the plasma levels of _____. A) glucocorticoid hormones B) epinephrine C) adrenocorticotropic hormone (ACTH) D) glucose E) acetylcholine

C) adrenocorticotropic hormone (ACTH)

47) During a stressful interval, _____. A) thyroid-stimulating hormaon (TSH) stimulates the adrenal cortex and medulla to secrete acetylcholine B) the alpha cells of islets secrete insulin and simultaneously the beta cells of the islets secrete glucagon C) adrenocorticotropic hormone (ACTH) stimulates the adrenal cortex, and neurons of the sympathetic nervous system stimulate the adrenal medulla D) the posterior pituitary gland secretes more growth hormones E) the calcium levels in the blood are increased due to actions of two antagonistic hormones, epinephrine and norepinephrine

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

5) Most animal hormones _____. A) are produced by endocrine glands B) are lipid-soluble molecules C) are carried to target cells in the blood or hemolymph D) are protein molecules E) elicit the same biological response from all of their target cells

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

45) Portal blood vessels connect two capillary beds found in the _____. A) hypothalamus and thalamus B) anterior pituitary and posterior pituitary C) hypothalamus and anterior pituitary D) posterior pituitary and thyroid gland E) anterior pituitary and adrenal gland

C) hypothalamus and anterior pituitary

36) Glucocorticoids do which of the following? A) promote the immune response B) promote the release of fatty acids C) increase blood glucose levels D) increase insulin production

C) increase blood glucose levels

25) After drinking alcoholic beverages, increased urine excretion is the result of _____. A) increased aldosterone production B) increased blood pressure C) inhibited secretion of antidiuretic hormone (ADH) D) increased reabsorption of water in the proximal tubule E) the osmoregulator cells of the brain increasing their activity

C) inhibited secretion of antidiuretic hormone (ADH)

60) Which of the following is characteristic of a steroid hormone action? A) protein phosphorylation B) cell-surface receptor binding C) internal receptor binding D) second messenger activation

C) internal receptor binding

38) Prolactin stimulates mammary gland growth and development in mammals and regulates salt and water balance in freshwater fish Many scientists think that this wide range of functions indicates that prolactin _____. A) is a nonspecific hormone B) has a unique mechanism for eliciting its effects C) is an evolutionarily conserved hormone D) is derived from two separate sources E) interacts with many different receptor molecules

C) is an evolutionarily conserved hormone

53) Estrogen is a(n) _____. A) peptide hormone B) amine derivative C) lipid-soluble hormone D) iodinated protein hormone made by the thyroid gland E) gaseous neurotransmitter

C) lipid-soluble hormone

44) The interrelationships between the endocrine and the nervous systems are especially apparent in a _____. A) neuron in the spinal cord B) steroid-producing cell in the adrenal cortex C) neurosecretory cell in the hypothalamus D) brain cell in the cerebral cortex E) cell in the pancreas that produces digestive enzymes

C) neurosecretory cell in the hypothalamus

59) 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. A) only I and III B) only II and IV C) only I, II, and III D) only II and III E) I, II, III, and IV

C) only I, II, and III

62) Which of the following hormones does NOT act using a second messenger system? A) glucagon B) leptin C) testosterone D) growth hormone

C) testosterone

34) 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? A) testosterone and estrogen B) estrogen and progesterone C) testosterone and Müllerian inhibitory substance D) estradiol and estrogen E) testosterone and estradiol

C) testosterone and Müllerian inhibitory substance

56) When a steroid hormone and a peptide hormone exert similar effects on a population of target cells, then _____. A) the steroid and peptide hormones must use the same biochemical mechanisms B) the steroid and peptide hormones must bind to the same receptor protein C) the steroid hormones affect the synthesis of effector proteins, whereas peptide hormones activate effector proteins already present in the cell D) the steroid hormones affect the activity of certain proteins within the cell, whereas peptide hormones directly affect the processing of mRNA E) the steroid hormones affect only the release of proteins from the target cell, whereas peptide hormones affect only the synthesis of proteins that remain in the target cell

C) the steroid hormones affect the synthesis of effector proteins, whereas peptide hormones activate effector proteins already present in the cell

18) Steroid and peptide hormones typically have in common _____. A) the building blocks from which they are synthesized B) their solubility in cell membranes C) their requirement for travel through the bloodstream D) the location of their receptors E) their reliance on signal transduction in the cell

C) their requirement for travel through the bloodstream

61) Which of the following is true during a typical cAMP-type signal transduction event? A) The second messenger is the last part of the system to be activated. B) The hormone activates the second messenger by directly binding to it. C) The second messenger amplifies the hormonal response by attracting more hormones to the cell being affected. D) Adenylyl cyclase is activated after the hormone binds to the cell and before phosphorylation of proteins occurs.

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

21) Polypeptides can have which of the following types of effects? I) autocrine II) paracrine III) endocrine A) only I and III B) only II and III C) only I and II D) I, II, and III

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 A) only I and II B) only II and III C) only I and III D) I, II, and III

D) I, II, and III

39) Which of the following is an example of negative feedback? A) During birthing contractions, oxytocin (a hormone) is released and acts to stimulate further contractions. B) When a baby is nursing, suckling leads to the production of more milk and a subsequent increase in the secretion of prolactin (a hormone that stimulates lactation). C) After a blood vessel is damaged, signals are released by the damaged tissues that activate platelets in the blood. These activated platelets release chemicals that activate more platelets. 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 as blood glucose decreases.

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 as blood glucose decreases.

32) Epinephrine is an example of _____. A) an androgen B) an estrogen C) a progestin D) a catecholamine E) a glucocorticoid

D) a catecholamine

29) Fight-or-flight reactions include activation of the _____. A) parathyroid glands, leading to increased metabolic rate B) thyroid gland, leading to an increase in the blood calcium concentration C) anterior pituitary gland, leading to cessation of gonadal function D) adrenal medulla, leading to increased secretion of epinephrine E) pancreas, leading to a reduction in the blood sugar concentration

D) adrenal medulla, leading to increased secretion of epinephrine

40) A physician finds that a nine-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 _____. A) hypothalamus, producing elevated levels of testosterone B) anterior pituitary, producing elevated levels of testosterone C) testes, producing elevated levels of estrogen D) anterior pituitary, producing elevated levels of gonadotropin-stimulating hormone

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

26) Antidiuretic hormone (ADH) functions at the cellular level by _____. A) stimulating the reabsorption of glucose through channel proteins B) triggering the synthesis of an enzyme that makes the phospholipid bilayer more permeable to water C) causing membranes to include more phospholipids that have unsaturated fatty acids D) causing an increase in the number of aquaporin molecules of collecting duct cells E) decreasing the speed at which filtrate flows through the nephron, leading to increased reabsorption of water

D) causing an increase in the number of aquaporin molecules of collecting duct cells

41) Hormones secreted by the posterior pituitary gland are made in the _____. A) cerebrum B) cerebellum C) thalamus D) hypothalamus E) medulla oblongata

D) hypothalamus

48) The increased contraction of the human uterus during labor and delivery is at least partially due to the actions of _____. A) ecdysteroid B) glucagon C) thyroxine D) oxytocin E) growth hormone

D) oxytocin

4) Which of these glands is located within the abdominal cavity? A) thyroid B) pituitary C) parathyroid D) pancreas

D) pancreas

9) Which of the following substances is released outside of the body in its normal route of action? A) paracrine signal B) neurotransmitter C) prostaglandin D) pheromone E) growth factor

D) pheromone

3) What is the only type of chemical signal that does not alter the physiology of the animal producing that signal? A) neural B) paracrine C) neuroendocrine D) pheromones

D) pheromones

7) A cell with membrane-bound proteins that selectively bind a specific hormone is called that hormone's _____. A) secretory cell B) plasma cell C) endocrine cell D) target cell E) regulatory cell

D) target cell

20) Which of the following are similar in structure to cholesterol? A) leptin and serotonin B) luteinizing hormone and insulin C) melanocyte-stimulating hormone and vasopressin D) testosterone, estradiol, and cortisol E) oxytocin and vasopressin

D) testosterone, estradiol, and cortisol

13) Which of the following has both endocrine and exocrine activity? A) the pituitary gland B) parathyroid glands C) salivary glands D) the pancreas E) adrenal glands

D) the pancreas

19) 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. A) only I and III B) only II and IV C) only I, III, and IV D) only II and III E) I, II, III, and IV

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 _____. A) anterior pituitary B) posterior pituitary C) adrenal gland D) bladder E) kidney

E) kidney

15) Which of the following statements 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. A) only I and II B) only II and III C) only I and III D) only III and IV E) only I and IV

E) only I and IV

42) Hormones that promote homeostasis _____. A) are not found as members of antagonistic signaling mechanisms B) travel to target cells without passage in the plasma C) utilize receptors that bind any hormone D) initiate signal transduction in the target cell without binding to receptors E) usually operate as part of a negative feedback system

E) usually operate as part of a negative feedback system