Deck 17: The Endocrine System

Question 1

This chemical produced in the retina is important for the light-dark cycle of circadian rhythms:

A) melatonin
B) melanocortin
C) melanopsin
D) melanin
E) none of the above

Answer 1

melanopsin

Question 2

The posterior pituitary

A) secretes ADH.
B) stores anterior pituitary hormones.
C) stores ACTH and LH.
D) secretes vasopressin and oxytocin into the hypothalamo-hypophyseal portal system.
E) none of these answers.

Answer 2

secretes ADH.

Question 3

Which of the following has a direct anatomical connection to the hypothalamus?

A) adrenal gland
B) posterior lobe of the pituitary
C) thyroid gland
D) parathyroid gland
E) none of these answers.

Answer 3

posterior lobe of the pituitary

Question 4

Which structure(s) is/are neuroendocrine in nature?

A) anterior pituitary gland.
B) posterior pituitary gland.
C) hypothalamus
D) both (a) and (b) above.
E) both (b) and (c) above.

Question 5

This is the master biological clock:

A) anterior pituitary
B) posterior pituitary
C) thyroid hormone
D) arcuate nucleus
E) suprachiasmatic nucleus

Question 6

Melanocyte-stimulating hormones are

A) secreted by the intermediate lobe of the pituitary in some lower vertebrates.
B) known to cause skin darkening in certain lower vertebrates.
C) believed to be responsible for the tanning phenomenon in humans.
D) both (a) and (b) above.
E) all of these answers.

Question 7

Which secretes catecholamines?

A) posterior pituitary.
B) liver.
C) pancreas.
D) stomach.
E) adrenal medulla.

Question 8

Which of the following is a neurohormone?

A) vasopressin
B) thyroid hormone
C) growth hormone
D) cortisol
E) luteinizing hormone

Question 9

Melanocyte-stimulating hormones

A) are responsible for the deposition of melanin in the skin during the process of tanning.
B) are not present in significant amounts in adult humans.
C) are present in varying amounts in races of different skin color.
D) are important for color adaptations associated with camouflage in certain lower vertebrates.
E) are produced in the thyroid gland.

Question 10

This hormone is tied to circadian rhythms:

A) GH
B) melatonin
C) FSH
D) GnRH
E) SCN

Question 11

The anterior pituitary

A) is also known as the adenohypophysis.
B) is composed primarily of nervous tissue.
C) primarily secretes tropic hormones.
D) both (a) and (c) above.
E) all of these answers.

Question 12

Select the incorrect association.

A) adrenal medulla/vasopressin
B) anterior pituitary/adenohypophysis
C) epinephrine/catecholamine
D) insulin/polypeptide
E) posterior pituitary/neurohypophysis

Question 13

Which statement is true of the pituitary gland?

A) the two lobes are connected to one another by a direct neural connections
B) the posterior lobe produces and secretes two hormones
C) the two lobes arise from different embryological tissues
D) they anterior lobe is also called the neurohypohysis
E) none of the above

Question 14

Which of the following hormones is released from the hypothalamus and influences metabolism?

A) CRH
B) TSH
C) GnRH
D) LH
E) GH

Question 15

Which of the following is not a function of melatonin?

A) induces natural sleep
B) suppresses reproductive hormones
C) plays a role in breeding behavior
D) enhances immunity
E) all of the above are functions

Question 16

Endocrine controls:

A) occur quickly and last for short periods of time
B) are similar in onset and duration to CNS controls
C) require duration rather than speed
D) are targeted at precise organs
E) none of the above

Question 17

Which cells produce growth hormone?

A) somatotropes
B) thryrotropes
C) corticotropes
D) gonadotropes
E) lactotropes

Question 18

The posterior pituitary

A) is composed of nervous tissue.
B) stores anterior pituitary hormones, which are released into the blood upon hypothalamic stimulation.
C) synthesizes and secretes vasopressin and oxytocin.
D) both (a) and (c) above.
E) all of these answers.

Question 19

Melatonin is produced in which gland?

A) anterior pituitary.
B) posterior pituitary.
C) pineal.
D) hypothalamus.
E) thyroid.

Question 20

Which of the following hormones secreted by the anterior pituitary is nontropic?

A) TSH
B) prolactin
C) LH
D) ACTH
E) FSH

Question 21

The hypothalamo-hypophyseal portal system

A) carries anterior pituitary hormones from the anterior pituitary gland to the hypothalamus to regulate the release of hypophysiotropic hormones.
B) diverts blood directly to the pituitary, completely bypassing the hypothalamus.
C) carries hypophysiotropic hormones from the hypothalamus to the anterior pituitary to regulate anterior pituitary hormone secretion.
D) carries the anterior pituitary hormones into the general systemic circulation.
E) connects the hypothalamus and posterior pituitary.

Question 22

Which statement regarding vasopressin in incorrect?

A) it is produced in the hypothalamus.
B) it stimulates uterine smooth muscle contraction.
C) it increases kidney reabsorption of water.
D) it is a potent arteriolar vasoconstrictor.
E) it is released when the osmolarity of the plasma increases.

Question 23

A portal system exists between the

A) adrenal cortex and adrenal medulla.
B) hypothalamus and anterior pituitary.
C) hypothalamus and posterior pituitary.
D) large intestine and small intestine.
E) large intestine and stomach.

Question 24

Which is not a characteristic of the hormone oxytocin?

A) it stimulate uterine contractions.
B) it promotes milk ejection from mammary gland ducts.
C) it influences bonding behavior between mother and baby.
D) it is a tropic hormone.
E) none of these answers.

Question 25

The growth hormone signals activity of the ____ of a long bone to influence its length.

A) articular cartilage.
B) endosteum.
C) epiphyseal plate.
D) medullary cavity.
E) periosteum.

Question 26

Chemical messengers like IGF-1 are released from the liver in response to

A) increased plasma growth hormone levels.
B) increased plasma somatostatin levels.
C) decreased plasma growth hormone levels.
D) decreased plasma somatostatin levels.
E) elevated levels of blood sugar.

Question 27

The hypothalamo-hypophyseal portal system

A) carries vasopressin and oxytocin from the hypothalamus to the posterior pituitary for storage.
B) carries hypophysiotropic hormones from the hypothalamus to the posterior pituitary to control the release of posterior pituitary hormones.
C) carries hypophysiotropic hormones from the hypothalamus to the anterior pituitary to control the release of anterior pituitary hormones.
D) carries vasopressin and oxytocin from the hypothalamus to the anterior pituitary to control the release of anterior pituitary hormones.
E) both (b) and (c) above.

Question 28

To exert its metabolic effects, GH

A) interacts with the liver to produce intermediary signaling compounds
B) interacts directly with target organs
C) acts indirectly by stimulating insulin-like growth factor
D) promotes hypertrophy and hyperplasia of soft tissue and bone
E) none of the above

Question 29

Growth hormone

A) directly stimulates bone growth.
B) exerts its effects on bones via somatomedin release.
C) promotes closure of the epiphyseal plate.
D) both (a) and (c) above.
E) both b) and (c) above.

Question 30

Excessive growth hormone secretion in an adult leads to

A) gigantism.
B) disproportionate growth resulting in thickened bones and coarse features.
C) no symptoms because growth is already complete.
D) acromegaly.
E) both (b) and (d) above.

Question 31

This large precursor molecule can be cleaved into ACTH, MSH and endorphins.

A) PSH
B) CRH
C) POMC
D) ACTHMSH
E) IGF-1

Question 32

In addition to GH, other hormones including the following are essential for normal growth:

A) insulin
B) thyroid hormone
C) androgens
D) estrogen
E) all of these answers.

Question 33

Which of the following statements concerning hypophysiotropic hormones is correct?

A) each hypophysiotropic hormone influences only one anterior pituitary hormone.
B) all hypophysiotropic hormones stimulate the release of anterior pituitary hormones.
C) hypophysiotropic hormones are also produced outside of the hypothalamus, where they serve different functions.
D) hypophysiotropic hormones are secreted into the general circulation.
E) none of these answers.

Question 34

Hypophysiotropic hormones from the hypothalamus

A) control the release of oxytocin and vasopressin from the posterior pituitary.
B) travel via neuron axons from the hypothalamus to the anterior pituitary.
C) are carried in the hypothalamo-hypophyseal portal system.
D) are released upon positive-feedback stimulation via the anterior pituitary tropic hormones.
E) always act to stimulate the release of anterior pituitary hormones.

Question 35

Growth hormone

A) closes the epiphyseal plate of long bones.
B) promotes hypertrophy and hyperplasia.
C) secretion is stimulated by an increased blood glucose level.
D) is the only factor responsible for governing the growth of an individual.
E) all of these answers.

Question 36

GH deficiency:

A) is always caused by pituitary problems
B) results in dwarfism in a child
C) results in acromegaly in a child
D) result in gigantism
E) is the primary cause of Lardon dwarfism

Question 37

Hormone secretion from the anterior pituitary gland is controlled

A) by hypophysiotropic hormones from the hypothalamus.
B) directly by neural innervation of anterior pituitary cells.
C) by negative-feedback action of target-tissue hormones.
D) both (a) and (c) above.
E) all of these answers.

Question 38

Which one of the following hormones signals the kidneys to control water balance?

A) vasopressin
B) ACTH
C) TRH
D) somatostatin
E) prolactin-inhibiting hormone

Question 39

Which of the following hormones is regulated by the anterior pituitary?

A) parathyroid hormone
B) cortisol
C) aldosterone
D) insulin
E) TRH

Question 40

LH stimulates the

A) cells that destroy the cells of Leydig.
B) enlargement of the follicles.
C) development of the hypothalamus.
D) formation of the corpus luteum.
E) water balance in the kidney.

Question 41

Thyroid hormones

A) regulate basal metabolic rate.
B) released from the thyroid gland immediately after synthesis.
C) contain chromium and zinc as structural cofactors.
D) are tropic.
E) none of these answers.

Question 42

The endocrine gland that secretes hormones containing iodine is the

A) adrenal cortex.
B) adrenal medulla.
C) pancreas
D) thyroid.
E) thymus.

Question 43

Thyroxine (T4)

A) is formed by coupling one MIT and one DIT within the colloid.
B) is produced by the C cells of the thyroid gland.
C) exerts a calorigenic effect.
D) inhibits thyroid-stimulating immunoglobulin in negative-feedback fashion.
E) is more potent than tri-iodothyronine.

Question 44

Which of the following statements concerning the synthesis and storage of thyroid hormones is incorrect?

A) the "iodine pump" of the follicular cells is important for thyroid hormone production.
B) thyroid hormones are formed within a much larger molecule called thyroglobulin.
C) thyroid-hormone synthesis is greatly stimulated by the presence of TSH.
D) a one- to two-hour supply of thyroid hormone is stored within the colloid in the lumen of the follicle.
E) the coupling of two DIT molecules yields thyroxine.

Question 45

About 90% of the secretory product released from the thyroid gland is in the form of

A) T3
B) T4
C) MIT
D) DIT
E) TSH

Question 46

TSH

A) is stimulated by thyrotropin-releasing hormone (TRH).
B) is inhibited by T3 and T4.
C) increases the rate of thyroid hormone secretion.
D) promotes hypertrophy and hyperplasia of thyroid cells.
E) all of these answers.

Question 47

Which of the following factors does not increase growth hormone secretion?

A) deep sleep
B) exercise
C) low blood amino acid level
D) stress
E) low blood glucose level

Question 48

Growth hormone exerts its effects on growth

A) by stimulating production of somatomedins.
B) by directly invoking gene activity.
C) by elevating blood glucose levels.
D) by increasing fat metabolism.
E) by increasing thyroid hormone levels.

Question 49

What happens to most of the secreted T4?

A) it is phagocytized by target tissues.
B) it is converted into T3 after being peripherally stripped of one of its I atoms.
C) it is the major biologically active form of thyroid hormone at the cellular level.
D) it is split to form two DIT molecules, which are excreted in the urine.
E) it is permitted to exert its full biological effect as a result of epinephrine's permissive actions.

Question 50

Which biochemical event does not take place within during thyroid hormone synthesis?

A) one monoiodotyrosine molecule combines with one diiodotyrosine molecule to form one triiodothyronine molecule.
B) two iodine molecules combine with one tyrosine molecule to form one diiodotyrosine molecule.
C) two diiodotyrosine molecules combine to form one molecule of thyroxine.
D) four iodine molecules combine with one tyrosine molecule to form one tetraiodothyronine molecule.
E) all of these answers.

Question 51

Dwarfism may be the result of a deficiency of

A) growth-hormone releasing hormone.
B) GH.
C) somatomedins.
D) both GH and somatomedins are correct.
E) all of these answers.

Question 52

Which hormone below targets osteoclasts when blood calcium levels are too low, thus, causing an increase in the concentration of calcium in the blood

A) aldosterone.
B) thyroid hormone.
C) cortisol.
D) parathyroid hormone.
E) calcitonin.

Question 53

The "iodine pump" refers to the

A) mechanism whereby target cells extract iodine-containing thyroid hormone from the blood.
B) active transport mechanism that concentrates iodine in the thyroid.
C) mechanism whereby T3 and T4 are released from thyroglobulin and pumped into the circulation.
D) protein binding process whereby T3 and T4 are pumped throughout the body bound to plasma proteins.
E) mechanism whereby ingested iodine is absorbed by the small intestine.

Question 54

With regards to thyroid hormone secretion

A) the anterior pituitary controls daily regulation while the hypothalamus controls long term patterns of secretion.
B) TSH causes TRH to be secreted which in tern stimulates T3 and T4 release.
C) thyroid hormone negatively feedback to the hypothalamus.
D) control is primarily neural.
E) all of these answers.

Question 55

During thyroid hormone secretion,

A) the follicular cells phagocytize a piece of colloid.
B) T4 and T3 are split off of thyroglobulin by lysosomal enzymes within the follicular cell and subsequently diffuse out of the cell into the blood.
C) T4 and T3 are secreted by exocytosis of the colloid that has been internalized by the follicular cells.
D) both (a) and (b) above.
E) both (a) and (c) above.

Question 56

Which of the following are masculinizing hormones produced from the adrenal gland?

A) growth hormone
B) androgens
C) thyroid hormone
D) cortisol
E) insulin

Question 57

Which of the following is not an effect of thyroid hormone?

A) increased metabolic rate.
B) increased tissue responsiveness to catecholamines.
C) increased absorption of iodine from the digestive tract into the blood.
D) normal growth.
E) normal development of the nervous system.

Question 58

Thyroid hormones

A) are derivatives of an amino acid.
B) are produced from tyrosine.
C) are stored on thyroglobulin within the follicular colloid.
D) both (a) and (c) above.
E) all of these answers.

Question 59

Osteoblasts

A) secrete the organic matrix components of bone.
B) become osteocytes once they become entrapped in the bone that they form.
C) dissolve bone.
D) form cartilage.
E) both (a) and (b) above.

Question 60

Hormones produced by the thyroid include

A) calcitonin.
B) thyroxine.
C) triiodothyronine.
D) both (a) and (b) above.
E) all of these answers.

Question 61

Mineralocorticoids

A) stimulate gluconeogenesis.
B) stimulate protein degradation.
C) act at the kidneys to promote sodium retention and enhance potassium elimination.
D) contribute to the pubertal growth spurt.
E) are important in maintaining proper plasma calcium levels.

Question 62

The actions of glucocorticoids include

A) increased gluconeogenesis and glycogenolysis.
B) increased fat mobilization.
C) increased breakdown of muscle proteins.
D) anti-inflammatory and immunosuppressive effects at pharmacological levels.
E) all of these answers.

Question 63

Which of the following is a byproduct of neonatal hypothyroidism?

A) elevated BMR
B) elevated body temperature
C) Grave's disease
D) cretinism
E) type I diabetes mellitus

Question 64

Aldosterone

A) enhances the ability of the kidneys to eliminate excess K⁺.
B) directly promotes H₂O conservation by the kidneys.
C) secretion is encourages by angiotensin II.
D) is nonsteroidal.
E) is produced ion the adrenal medulla.

Question 65

Which syndrome is associated with excess mineralcorticoid secretion?

A) Cushing's
B) Lordon's
C) Conn's
D) Addison's
E) both (c) and (d)

Question 66

The precursor to testosterone is

A) aldosterone.
B) cortisol.
C) dehydroepiandrosterone.
D) estradiol.
E) testosterone.

Question 67

Diurnal variation in secretion

A) occurs with glucocorticoids.
B) is related to the sleep-awake cycle.
C) occurs as a result of stress.
D) both (a) and (b) above.
E) all of these answers.

Question 68

Aldosterone

A) causes conservation of sodium.
B) facilitates lipolysis.
C) promotes gluconeogenesis.
D) is regulated by ACTH.
E) is secreted by the adrenal medulla.

Question 69

In this condition, all layers of the adrenal show insufficiency:

A) Cushing's
B) Lordon's
C) Conn's
D) Addison's
E) both (c) and (d)

Question 70

Which of the following statements concerning adrenocortical hormones is incorrect?

A) the glucocorticoids are examples.
B) some are steroids.
C) they are all controlled primarily by TSH.
D) they are secreted from the outer layer of the adrenal gland.
E) aldosterone is a mineralocorticoid.

Question 71

The most abundant and physiologically important adrenal sex hormone is

A) aldosterone.
B) cortisol.
C) dehydroepiandrosterone.
D) estradiol.
E) testosterone.

Question 72

Which of the following hormones exhibits a marked diurnal variation in secretion?

A) aldosterone.
B) cortisol.
C) thyroid hormone.
D) epinephrine.
E) calcitonin.

Question 73

Which of the following is not characteristic of hypothyroidism?

A) depressed MR
B) depressed body temperature
C) exopthalmos
D) cretinism
E) myxedema

Question 74

Insulin

A) promotes the insertion of additional glucose transporters in the plasma membranes of insulin-dependent cells.
B) stimulates glycogenesis and inhibits glycogenolysis.
C) secretion is increased in response to a fall in blood glucose concentration.
D) two of these answers.
E) all of these answers.

Question 75

Which of the following would not decrease thyroid hormone production?

A) a decrease in TSH production.
B) an iodine deficient diet.
C) an increase in TRH production.
D) inhibition of the iodine pump.
E) removal of the pituitary.

Question 76

Glucocorticoids cause all of the following except

A) carbohydrate conservation.
B) protein degradation.
C) increased metabolic rate.
D) mobilization of fats for energy.
E) anti-inflammatory and immunosuppressive effects at pharmacological levels.

Question 77

The zona glomerulosa of the adrenal cortex secretes

A) aldosterone.
B) cortisol.
C) androgens and estrogens.
D) both (b) and (c) above.
E) all of these answers.

Question 78

Glucocorticoids cause all of the following except

A) carbohydrate conservation.
B) protein degradation.
C) increased metabolic rate.
D) mobilization of fats for energy.
E) anti-inflammatory and immunosuppressive effects at pharmacological levels.

Question 79

The major factor that promotes increased secretion of cortisol from the adrenal cortex is

A) low Na+ concentration in the extracellular fluid.
B) stress.
C) angiotensin II.
D) increased blood amino acid concentration.
E) increased blood glucose concentration.

Question 80

Adrenocorticotropic hormone

A) is a tropic hormone secreted by the adrenal cortex.
B) stimulates the production of androgens by the testes.
C) is controlled in part by CRH from the hypothalamus.
D) both (a) and (c) above.
E) all of these answers.