Deck 11: The Endocrine System

Question 1

What is a main difference between the modes of action of peptide hormones and steroid hormones?

A) Peptide hormones bind to intracellular receptors, whereas steroid hormones bind to receptors on the cell surface.
B) Peptide hormones act as second messengers, whereas steroid hormones bind to receptors in the cytosol.
C) Peptide hormones bind to receptors on the cell surface, whereas steroid hormones act as second messengers.
D) Peptide hormones bind to receptors on the cell surface, whereas steroid hormones bind to intracellular receptors.
E) There are no differences; both act by binding to intracellular receptors.

Answer 1

D

Question 2

Which is NOT true about receptors for steroid hormones?

A) They may be proteins found in the nucleus.
B) They undergo allosteric modulation when they bind to the hormone.
C) They regulate gene transcription.
D) They may be found in the nucleus.
E) They are synthesized from cholesterol.

Answer 2

E

Question 3

Acting alone, epinephrine and thyroid hormone each stimulates release of only a small amount of fatty acids from adipose cells. In the presence of thyroid hormone, epinephrine causes a much more substantial release of fatty acids from the cells. What is the term describing the effect of thyroid hormone on epinephrine's actions?

A) antagonistic
B) agonistic
C) permissive
D) direct
E) paracrine

Answer 3

C

Question 4

A hormone may be

A) inactivated by its target cell.
B) activated by its target cell.
C) inactivated by nontarget cells.
D) excreted before it has a chance to act on a target cell.
E) All of the choices could be correct.

Question 5

Which is TRUE about hormone binding to the proteins found in plasma?

A) Steroid hormones do not bind to plasma proteins.
B) The binding proteins that transport hormones are hormones themselves.
C) The tighter that a hormone binds to a carrier protein in the plasma, the faster the body can usually get rid of that hormone.
D) Hydrophobic hormones like steroid and thyroid hormones need binding proteins because they are not very soluble in the blood plasma.
E) Only peptide-type hormones can bind to the carrier proteins found in the plasma.

Question 6

Which is most likely TRUE of an endocrine cell that contains an abundance of rough endoplasmic reticulum, a large Golgi apparatus, and secretory granules?

A) It secretes a peptide/protein hormone.
B) It secretes its product by diffusion through the lipid bilayer of the plasma membrane.
C) It secretes by endocytosis.
D) Its hormone product is synthesized from cholesterol.
E) It secretes a hormone with a hydrophobic structure.

Question 7

Peptide hormones are:

A) synthesized by the ribosomes of endocrine cells.
B) synthesized in the nucleus of endocrine cells.
C) synthesized out of the amino acid tryptophan.
D) the least prevalent type of hormone in the body.
E) manufactured cooperatively by the mitochondria and smooth endoplasmic reticulum.

Question 8

Which would most directly decrease the production of aldosterone?

A) going on a low-salt diet
B) ingesting extra dietary vitamin D
C) reducing dietary tyrosine
D) increasing dietary cholesterol
E) injecting a drug that blocks the production of angiotensin II

Question 9

Which of the following statements about oxytocin is TRUE?

A) Target cells of oxytocin have receptors for the hormone in their nucleus.
B) Oxytocin is synthesized in the hypothalamus.
C) Oxytocin is secreted by the anterior pituitary gland.
D) Oxytocin's main function is to increase the rate of respiration.
E) Oxytocin keeps uterine smooth muscle from contracting, so it prolongs pregnancy.

Question 10

Which does NOT apply to hormones?

A) They are chemical regulators that are conveyed from one organ to another via the bloodstream.
B) In some cases, the same chemical substances can also function as local regulators and/or neurotransmitters.
C) All hormones are derived from cholesterol.
D) They are secreted into the blood by ductless glands.
E) They are sometimes secreted by neural tissue.

Question 11

What is the definition of a prohormone?

A) Hormones that bind to endocrine glands and stimulate the secretion of a second hormone.
B) Hormones that bind to endocrine glands and inhibit the secretion of a second hormone.
C) A longer protein or peptide that is cleaved into shorter ones, at least one of which is a peptide or protein hormone.
D) Hormones that stimulate the expression of receptors for a second hormone, promoting their action.
E) Steroid hormones that are inactivated by having hydroxyl groups removed from their structure.

Question 12

Which of the following statements about hormone synthesis is NOT correct?

A) Progesterone can be a precursor of cortisol.
B) Progesterone is a precursor of mineralocorticoid and glucocorticoid hormones.
C) Pregnenolone is a precursor for all steroid hormones.
D) Tryptophan is a precursor for thyroid hormones.
E) Peptide hormones are polymers of amino acids.

Question 13

Which of the following statements is NOT true of the endocrine system?

A) It is one of two major regulatory systems of the body.
B) It is composed of glands that secrete chemical messengers into the blood.
C) It is an important regulator of homeostatic mechanisms.
D) It influences and is influenced by the nervous system.
E) Most of its components are anatomically connected, like most other systems of the body.

Question 14

Which is a characteristic of hydrophobic hormones?

A) They mostly bind to receptor proteins in the surface membrane of target cells.
B) They are generally polar molecules.
C) They usually have very rapid effects on target cells.
D) Their mechanism of action generally involves altering protein synthesis.
E) They are highly soluble in blood plasma.

Question 15

Which accurately describes the median eminence of the hypothalamus?

A) It is the site of synthesis of adrenocorticotropic hormone (ACTH).
B) It is a site where neurohormones are release into blood vessels.
C) It is the site where vasopressin is released into blood vessels.
D) It is the stalk connecting the hypothalamus to the posterior pituitary.
E) It is the main site where thyroid-stimulating hormone first enters the bloodstream.

Question 16

Which is TRUE regarding the structure and synthesis of hormones?

A) Steroid hormones are synthesized from cholesterol.
B) Thyroid hormones are catecholamines.
C) The hormones of the adrenal cortex have the same structure as the neurotransmitters of adrenergic neurons.
D) Most peptide hormones require binding proteins for transport in the blood.
E) Vasopressin is synthesized in the posterior pituitary.

Question 17

Which is most likely a characteristic of cells that secrete steroid hormones?

A) They store large amounts of hormone.
B) They are characterized by abundant smooth endoplasmic reticulum and few secretory granules.
C) They contain large numbers of secretory granules.
D) They are found in the anterior pituitary gland.
E) They are found in the medulla of the adrenal gland.

Question 18

What term describes hormones that influence the secretion of other hormones?

A) mineralocorticoids
B) trophic
C) tropic
D) allosteric
E) teratogen

Question 19

How is the concentration of a hormone in plasma determined?

A) only by its rate of secretion
B) by the number of its target cells in the body
C) only by its rate of synthesis
D) by its secretion and clearance rates, and whether or not it binds to carriers and/or other plasma proteins
E) only by the rate of its degradation by the liver and kidneys

Question 20

Which is NOT an endocrine function performed by the liver?

A) secreting insulin-like growth factor 1
B) clearing hormones from plasma
C) secreting angiotensinogen
D) producing plasma proteins that bind hormones
E) secreting insulin

Question 21

What term describes hormones secreted by the hypothalamus that regulate the secretion of hormones from the anterior pituitary gland?

A) growth factors
B) paracrine factors
C) hypophysiotropic hormones
D) metabotrobic-releasing factors
E) cerebrovitalistic hormones

Question 22

Which is a result of consuming a diet deficient in iodine?

A) low plasma concentration of thyroid hormones due to reduced secretion of thyroid-stimulating hormone (TSH) by the pituitary gland
B) low plasma concentration of thyroid hormones and an enlarged thyroid gland
C) high plasma concentration of thyroid-stimulating hormone (TSH) due to a deficiency of thyrotropin-releasing hormone (TRH)
D) high plasma concentration of thyroid hormones due to increased secretion of TSH by the pituitary gland
E) low plasma concentration of thyroid hormones and atrophy of the thyroid gland due to reduced concentrations of thyroid-stimulating hormone (TSH)

Question 23

If the pituitary gland is removed from a human subject, which of the following is likely to occur?

A) The adrenal gland will hypertrophy to increase cortisol production.
B) The adrenal gland will atrophy and plasma cortisol levels will be reduced.
C) The hypothalamus will secrete less CRH.
D) The subject will remain euthyroid.
E) There will be increased negative feedback on growth hormone by insulin-like growth factor 1 (IGF-1).

Question 24

A patient goes to her doctor, complaining of fatigue, weight gain, and intolerance to cold. She also has a noticeable goiter in her neck. Which of the following is a most likely diagnosis and cause?

A) She has hypothyroidism, possibly due to destruction of thyrotrope cells of her anterior pituitary gland.
B) She has hyperthyroidism, possibly due to Graves' disease.
C) She has hypothyroidism, possibly due to low iodine in her diet.
D) She has hyperthyroidism, possibly due to a hypersecreting tumor of the anterior pituitary gland.

Question 25

Which is an accurate description of the posterior pituitary and its functions?

A) It is glandular tissue and secretes vasopressin and prolactin.
B) It is neural tissue and is stimulated to secrete oxytocin and vasopressin by hypophysiotropic hormones.
C) It is neural tissue, and vesicles containing oxytocin and vasopressin are transported to axon terminals there.
D) It is glandular tissue and releases oxytocin and somatostatin when action potentials arrive along axons from the hypothalamus.
E) It is neural tissue that secretes hypophysiotropic hormones that control the secretion of the anterior pituitary hormones.

Question 26

Which is part of the endocrine reponse to stress?

A) increased secretion of corticotropin from the anterior pituitary
B) increased secretion of corticotropin from the hypothalamus
C) increased secretion of adrenocorticotropic hormone (ACTH) from the hypothalamus
D) negative feedback to the adrenal cortex by adrenocorticotropic hormone (ACTH)
E) decreased secretion of corticotropin-releasing hormone (CRH) by the hypothalamus

Question 27

Which is a function of the gonadotropic hormones?

A) stimulating the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
B) inhibiting the release of growth hormone
C) inhibiting the release of prolactin
D) inducing the secretion of steroid hormones by the gonads in both males and females
E) stimulating the release of gonadotropin-releasing hormone (GnRH)

Question 28

A chemical precursor for cortisol is ________, which is made from ________. Cortisol is secreted by ________ when stimulated by ________ from the anterior pituitary.

A) androstenedione, progesterone, adrenal cortex, corticotropin-releasing hormone (CRH)
B) progesterone, cholesterol, adrenal medulla, adrenocorticotropic hormone (ACTH)
C) testosterone, cholesterol, adrenal medulla, adrenocorticotropic hormone (ACTH)
D) progesterone, cholesterol, adrenal cortex, adrenocorticotropic hormone (ACTH)
E) estradiol, cholesterol, adrenal medulla, corticotropin-releasing hormone (CRH)

Question 29

Which of the following statements about hormone actions is correct?

A) Growth hormone is a tropic hormone for insulin-like growth factor 1.
B) Inhibition of prolactin release by dopamine is an example of short-loop negative feedback.
C) Somatostatin stimulates growth hormone secretion.
D) ACTH inhibits cortisol secretion.
E) Gonadotropin-releasing hormone (GnRH) stimulates growth hormone secretion.

Question 30

Which of the following statements about hormones is correct?

A) Anterior pituitary hormones are synthesized in the hypothalamus.
B) All hormones secreted by the anterior and posterior pituitary glands are peptides.
C) IGF-1 stimulates growth by increasing growth hormone secretion through positive feedback.
D) All of the hypophysiotropic hormones are peptides.
E) Only steroid hormones can regulate the secretion of steroid hormones.

Question 31

Which would be the effect of a blood clot that blocked the vessels of the hypothalamo-pituitary portal system in the infundibulum between the hypothalamus and the anterior pituitary gland?

A) secretion of adrenocorticotropic hormone (ACTH) would decrease and the adrenal cortex would atrophy
B) secretion of gonadotropins will decrease and the gonads will hypertrophy
C) secretion of corticotropin-releasing hormone (CRH) would decrease
D) secretion of prolactin would decrease
E) secretion of follicle-stimulating hormone (FSH) would increase

Question 32

Which stimulates the secretion of growth hormone?

A) waking from sleep
B) exercise
C) increased levels of IGF-I in blood
D) high plasma glucose
E) increased somatostatin secretion

Question 33

Deficiency of iodine in the diet results in _____________ caused by ________________.

A) a goiter; increased production of thyroid-stimulating hormone (TSH) and increased thyroid hormone levels
B) atrophy of the thyroid gland; loss of negative feedback by thyroid hormones and increased thyroid-stimulating hormone (TSH) levels
C) a goiter; loss of negative feedback by thyroid hormones and increased thyroid-stimulating hormone (TSH) levels
D) atrophy of the thyroid gland; decreased sensitivity of receptors for thyroid-stimulating hormone (TSH)
E) atrophy of the anterior pituitary gland; loss of negative feedback by thyroid hormones

Question 34

Which of these could be a cause of hypertrophy of the adrenal cortex?

A) autoimmune destruction of receptors for adrenocorticotropic hormone (ACTH)
B) autoimmune destruction of hypothalamic cells that secrete corticotropin-releasing hormone
C) injection of an excess of cortisol
D) destruction of the anterior pituitary by a stroke
E) excessively rapid clearance of cortisol from the circulation

Question 35

Which is an example of long-loop negative feedback?

A) stimulation of dopamine release by prolactin
B) inhibition of growth hormone-releasing hormone (GHRH) release by growth hormone (GH)
C) inhibition of growth hormone-releasing hormone (GHRH) release by insulin-like growth factor-1
D) inhibition of corticotropin-releasing hormone by adrenocorticotropic hormone (ACTH)
E) stimulation of thyroid-stimulating hormone (TSH) release by thyrotropin-releasing hormone (TRH)

Question 36

Short-loop negative feedback occurs when hormones from the ______________ inhibit hormone secretion by the ______________.

A) hypothalamus; anterior pituitary
B) adrenal cortex; hypothalamus
C) anterior pituitary; hypothalamus
D) adrenal cortex; anterior pituitary
E) anterior pituitary; adrenal cortex

Question 37

If the adrenal glands were removed from a patient, his plasma cortisol levels would ________, secretion of CRH by the __________________ would __________________, and secretion of ACTH by the ______________ would _____________.

A) increase; hypothalamus; decrease; anterior pituitary gland; decrease
B) decrease; hypothalamus; increase; adenohypophysis; increase
C) decrease; anterior pituitary gland; increase; hypothalamus; increase
D) increase; hypothalamus; increase; adenohypophysis; increase
E) decrease; adenohypophysis; increase; anterior pituitary gland; increase

Question 38

Which of these describes secondary hypersecretion of hormone X?

A) A growing tumor secretes hormone Y, which stimulates the gland that secretes hormone X.
B) Cells of a growing tumor manufacture hormone X in unregulated fashion.
C) Negative feedback from a tumor that hypersecretes hormone Z inhibits the gland that secretes hormone X.
D) Hormone X is secreted by a growing tumor that is in the anterior pituitary gland.
E) Hormone X is secreted in unregulated fashion by a tumor growing in a tissue that does not normally secrete hormone X.

Question 39

Which are hormones secreted by the posterior pituitary?

A) vasopressin and dopamine
B) corticotropin and dopamine
C) oxytocin and prolactin
D) vasopressin and corticotropin
E) antidiuretic hormone (ADH) and oxytocin

Question 40

Which of the following hormones is NOT secreted by the anterior pituitary gland?

A) somatotropin
B) prolactin
C) corticotropin
D) erythropoietin
E) thyroid-stimulating hormone (TSH)

Question 41

Which of the hormones listed below has the most profound direct effect to stimulate the increased resorption of bone when plasma Ca²⁺ levels decrease?

A) thyroxine
B) parathyroid hormone
C) calcitonin
D) cortisol
E) insulin

Question 42

Which is most likely a result of hypersecretion of growth hormone?

A) acromegaly
B) dwarfism
C) decreased plasma concentration of IGF-I
D) decreased secretion of somatostatin
E) increased secretion of growth hormone-releasing hormone (GHRH)

Question 43

Which of the following is NOT stimulated by cortisol during stress?

A) gluconeogenesis
B) protein catabolism
C) glucose uptake into muscle cells
D) triglyceride catabolism in adipose cells
E) decreased sensitivity to insulin

Question 44

Which is a result of elevated thyroid hormone levels?

A) an increase in triglyceride storage
B) increased Na⁺/K⁺ ATPase activity
C) decreased body temperature
D) mental lethargy

Question 45

What is the major hormone responsible for mediating the body's general response to stress?

A) thyroid hormone
B) growth hormone
C) testosterone
D) aldosterone
E) cortisol

Question 46

Which of the following is an action of the sympathetic nervous system during stress?

A) It increases the ability to respond to situations where physical activity is required.
B) It increases blood flow to the skeletal muscles and viscera.
C) It inhibits blood clotting.
D) It decreases ventilation of the lungs to save oxygen.
E) It increases glycogen synthesis in the liver.

Question 47

At what time in the lifespan is growth hormone secretion rate highest?

A) in utero
B) during childhood
C) during adolescence
D) during adulthood
E) during senescence

Question 48

Which is NOT an effect of parathyroid hormone?

A) increases the bone-degrading activity of osteoclasts
B) decreases reabsorption of calcium by the kidneys
C) promotes vitamin D synthesis, leading to increased intestinal absorption of calcium
D) increases plasma [Ca²⁺]
E) decreases reabsorption of phosphate by the kidneys

Question 49

Which would result from a vitamin D deficiency?

A) hypercalcemia
B) an increase in bone mass
C) an increase in parathyroid hormone levels
D) increased intestinal absorption of calcium

Question 50

What would be the effect of a thyroid deficiency beginning in infancy?

A) Gigantism would occur.
B) Acromegaly would occur.
C) Growth rate would be faster than normal.
D) Growth rate would be slower than normal.
E) Body temperature would be above normal.

Question 51

Which of the following is NOT true of pituitary growth hormone?

A) It directly promotes protein anabolism in many cells.
B) It causes differentiation of precursor cells that then respond to IGF-I by proliferating.
C) Hypersecretion of growth hormone in adults leads to acromegaly.
D) It is absent or deficient in pituitary dwarfs.
E) It is necessary for fetal growth.

Question 52

Which of the following is TRUE regarding pituitary growth hormone (GH)?

A) The liver produces a factor that mediates the metabolic actions of GH.
B) GH stimulates insulin-like growth factor-1 (IGF-1) production by the liver and by many other cells.
C) GH increases the sensitivity of tissues to the action of insulin.
D) GH exerts negative feedback on its own production by inhibiting the hypothalamic secretion of somatostatin.
E) IGF-1 stimulates the secretion of GH by anterior pituitary gland cells.

Question 53

Which statement best describes the manner in which growth hormone stimulates cell proliferation?

A) It directly stimulates cell division in most tissues.
B) It stimulates the release of insulin-like growth factor I (IGF-1) from the liver and other target tissues of growth hormone.
C) It stimulates metabolism.
D) It stimulates the release of eicosanoids from lymphoid tissues.
E) It stimulates sleep.

Question 54

A deficiency in dietary iodine can cause:

A) congenital hypothyroidism (cretinism).
B) a slowing of mental functions.
C) a low metabolic rate.
D) a goiter.
E) All of the choices are correct.

Question 55

A patient appears in a clinic complaining of irritability and chronic sweatiness. He also has a lump in his neck near his larynx. Blood tests show he has low levels of thyroid-stimulating hormone (TSH) in his plasma. Which of the following is the most likely diagnosis?

A) primary hypothyroidism
B) an iodine-insufficient diet
C) secondary hypothyroidism
D) hyposecretion of TRH
E) Graves' disease

Question 56

Which of the following hormones is NOT usually secreted at higher levels in response to stress?

A) aldosterone
B) gonadotropins
C) vasopressin
D) antidiuretic hormone (ADH)
E) beta-endorphin

Question 57

Which is a hormonal response to a stressful situation?

A) Negative feedback from cortisol increases secretion of adrenocorticotropic hormone (ACTH).
B) Secretion of aldosterone by the adrenal gland is decreased.
C) Negative feedback from cortisol increases the secretion of corticotropin-releasing hormone (CRH).
D) Plasma levels of adrenocorticotropic hormone (ACTH) decrease.
E) Plasma levels of cortisol increase.

Question 58

In what form is the body's largest pool of calcium?

A) embedded in collagen in many types of connective tissue
B) blood, dissolved within the plasma
C) skeletal muscle, stored in terminal cisternae
D) bones, in the form of hydroxyapatites
E) liver, inside the endoplasmic reticulum

Question 59

Which is a result of an absence of thyroid hormones during fetal development?

A) acromegaly
B) Cushing's syndrome
C) congenital hypothyroidism (cretinism)
D) Graves' disease
E) Addison's disease

Question 60

Which is true about the growth of long bones?

A) Osteoblasts dissolve bone tissue when bones remodel in response to sex hormones.
B) Osteoclasts are responsible for depositing new bone tissue at the epiphyseal growth plate before puberty.
C) Before adolescence, bones are completely made up of cartilage; after puberty they ossify and harden.
D) Growth in length occurs at a single epiphyseal growth plate in the center of the shaft of long bones.
E) Growth in length occurs at two epiphyseal growth plates near the ends of long bones.

Question 61

Binding of hydrophilic hormones to their receptors often results in the formation of one or more second messengers that lead to alterations of the cell's activity.

Question 62

Thyroid hormones exert a permissive effect on the actions of epinephrine.

Question 63

Which correctly lists a function of estrogens in females and testosterone in males?

A) They prevent the pubertal growth spurt.
B) They are responsible for epiphyseal plate closure.
C) They stimulate the secretion of gonadotropin-releasing hormone (GnRH).
D) They stimulate the secretion of luteinizing hormone (LH).
E) They stimulate the reabsorption of bone.

Question 64

The adrenal cortex secretes androgens.

Question 65

In cases where the plasma concentration of an ion or nutrient affects the secretion rate of a hormone, the affected hormone is usually a regulator of the homeostasis of that ion or nutrient.

Question 66

Stimuli for the secretion of hormones include changes in plasma concentrations of ions, nutrients, and other hormones.

Question 67

The mechanism of action of lipid-soluble hormones is generally via the stimulation or inhibition of specific DNA-dependent protein synthesis.

Question 68

Ovaries synthesize as much androgen as they do estrogen.

Question 69

A precursor of cortisol is cholesterol.

Question 70

In general, the metabolism and excretion rates of steroid hormones are higher than those of peptide hormones.

Question 71

Steroid hormones are stored in the cells that synthesize them until a stimulus is received that provokes their secretion.

Question 72

Most amine and peptide hormones circulate in the plasma as free hormones, whereas steroid hormones are mostly bound to circulating binding proteins.

Question 73

The adrenal cortex is part of the autonomic nervous system.

Question 74

The concentration of a hormone in the blood can affect the number of receptors for that hormone on or in a target cell.

Question 75

Both thyroxine and thyroid-stimulating hormone (TSH) are amine hormones.

Question 76

Hormones of the posterior lobe of the pituitary are synthesized in neuronal cell bodies of the hypothalamus and transported to the pituitary by axonal transport.

Question 77

The receptors for estradiol, T₃, and vasopressin are all located in the nuclei of target cells.

Question 78

An endocrine cell that contains an abundance of rough endoplasmic reticulum, a large Golgi apparatus, and many secretory granules is likely to secrete a peptide hormone.

Question 79

Unlike neurons, endocrine cells generally do not act as integrators of various kinds of positive or negative inputs.

Question 80

In general, steroid hormones bind to receptors on cell membranes, whereas peptide hormones bind to receptors inside of cells.