Question 1

Which hormone is highly bound to carrier proteins in the bloodstream?
A) Thyroid hormones
B) Insulin
C) Glucagon
D) Parathyroid hormone

Accepted Answer

Thyroid hormones are carried in the circulation bound to thyroid-binding proteins.Insulin is an important stimulator of growth hormone.Glucagon is not bound to carrier proteins in the bloodstream.Parathyroid hormones are not bound to carrier proteins in the bloodstream.

Question 2

Up-regulation of target cell receptors results in
A) decreased target cell sensitivity to hormone.
B) reduced production of hormone.
C) increased target cell responsiveness to hormone.
D) an increased hormone half-life.

Accepted Answer

Up-regulation would make the cell more sensitive to the hormone,and hormone-dependent cellular activity could occur at normal or nearly normal levels despite a lower than normal hormone concentration.Down-regulation would result in decreased target cell sensitivity.A reduction in hormone production does not occur with up-regulation.Up-regulation of target cell receptors does not result in an increased hormone half-life.

Question 3

Which hormone is regulated by releasing and inhibiting factors from the hypothalamus?
A) Oxytocin
B) Vasopressin
C) Adrenocorticotropic hormone (ACTH)
D) Aldosterone

Accepted Answer

ACTH is produced in the anterior pituitary gland in response to hypothalamic corticotrophin-releasing hormone.Oxytocin is a hormone of the posterior pituitary gland.Vasopressin is antidiuretic hormone which is released by nerve terminals in the posterior pituitary gland.Aldosterone is a steroid hormone produced by the adrenal cortex.

Question 4

An example of a secondary endocrine disorder is
A) pituitary hyposecretion of TSH.
B) adrenal insufficiency following adrenalectomy.
C) congenital adrenal hyperplasia.
D) pheochromocytoma.

Accepted Answer

Secondary endocrine disorder occurs when secretion of a tropic hormone such as TSH or ACTH is inadequate to cause the target gland to secrete adequate amounts of hormone.Primary hyposecretion occurs when an endocrine gland,such as the thyroid or adrenal cortex,releases an inadequate amount of hormone to meet physiologic needs.Congenital adrenal hyperplasia is an example of a hypersecretion disorder.Pheochromocytoma is not a secondary endocrine disorder.

Question 5

An increase in serum osmolality would be expected to ________ secretion.
A) increase vasopressin
B) decrease vasopressin
C) decrease ADH
D) decrease aldosterone

Accepted Answer

An increase in serum osmolality stimulates the release of vasopressin,also referred to as antidiuretic hormone.Tubular epithelial cells allow free diffusion of water from the tubular fluid into the cell.The enhanced reabsorption conserves water in the body,creates concentrated urine,and reduces serum osmolality.ADH secretion is stimulated by baroreceptors in response to hypovolemia.When body fluids become too concentrated,ADH is released.Aldosterone is not decreased in response to serum osmolality.

Question 6

A primary endocrine disorder occurs when
A) the pituitary gland oversecretes hormones.
B) the pituitary gland undersecretes hormones.
C) exogenous hormones suppress endogenous production.
D) the target gland is unresponsive to pituitary regulation.

Accepted Answer

Primary endocrine disorder is because of dysfunction of the target glands.Hypersecretion disorders can be primary or secondary.Abnormal tropic signals from the pituitary gland are known as secondary disorder.Hyposecretion occurs when an endocrine gland is unable to release adequate amounts of hormone to meet physiologic needs.Hyporesponsiveness of the target tissues will cause the same response as that of hyposecretion.

Question 7

Most endocrine hormones are water-soluble and exert their effects on target cells by
A) binding to nuclear receptors.
B) generating second messengers.
C) binding to intracellular receptors.
D) stimulating action potentials.

Accepted Answer

Water-soluble hormones are unable to cross the plasma membrane to enter cells and must bind to receptors located on the surface of target cell membranes.Hormones exert their actions by binding to target cell receptor proteins.Water-soluble hormones bind to receptors on the surface of the target cell membranes.Endocrine hormones do not stimulate action potentials on target cells.

Question 8

The endocrine system closely resembles the ________ system because many of their actions are coordinated at the level of the hypothalamus.
A) nervous
B) immune
C) integumentary
D) lymphatic

Accepted Answer

The nervous and endocrine systems are closely integrated,and many of their actions are coordinated at the level of the hypothalamus.Endocrine systems are suited for regulating complex functions.The integumentary system does not resemble the endocrine system.The endocrine system and the lymphatic system do not resemble each other in actions.

Question 9

The release of prolactin is normally inhibited by
A) dopamine.
B) acetylcholine.
C) somatostatin.
D) somatomedin.

Accepted Answer

The prolactin-inhibiting factor is dopamine produced in the hypothalamus.Acetylcholine does not inhibit the release of prolactin.Prolactin is not inhibited by somatostatin.Somatomedin is not a prolactin-inhibiting factor.

Question 10

An example of a lipid-soluble hormone is
A) catecholamine.
B) thyroid hormone.
C) peptide hormone.
D) pituitary hormone.

Accepted Answer

Thyroid hormones are lipid-soluble.Catecholamines and peptide hormones are water-soluble.Peptide hormones are released from the pituitary gland.

Question 11

_________ is the hormone which causes uterine and milk duct contractions.
A) Vasopressin
B) Prolactin
C) Oxytocin
D) Antidiuretic

Accepted Answer

Oxytocin is released during sexual activity,childbirth,and breast feeding and causes uterine and milk duct contractions.Vasopressin is an antidiuretic hormone that responds to hypovolemia and low arterial blood pressure.Prolactin is known for its effects on breast tissue development and lactation and its ability to suppress reproductive function in men and women.Antidiuretic hormone is released in response to altered serum osmolality and hypotension and causes water retention by increasing water reabsorption by the renal collecting duct.

Question 12

Cortisol is produced in the zona ________ of the adrenal cortex.
A) glomerulosa
B) reticularis
C) fasciculata
D) medulla

Accepted Answer

The middle zona fasciculata produces the glucocorticoid,cortisol,in response to stimulation of ACTH from the pituitary gland.The outer zona glomerulosa produces the mineralocorticoid,aldosterone,in response to stimulation by AII.The inner zona reticularis is adjacent to the adrenal medulla and produces the androgen,DHEAS.The inner zone is adjacent to the adrenal medulla.

Question 13

Growth hormone has several effects on the body,including
A) decreasing plasma glucose level.
B) increasing lean body mass.
C) enhancing deposition of fat.
D) depressing immune function.

Accepted Answer

Growth hormone binds to receptors on muscle tissue to increase muscle mass.Growth hormone slows carbohydrate utilization and does not depress immune function.Growth hormone binds to receptors on adipose tissue and decreases fat mass by inducting lipolysis.

Question 14

What suppresses the normal secretion of growth hormone?
A) Hypoglycemia
B) Somatostatin
C) Somatomedin
D) Amino acids

Accepted Answer

GHRH binds to receptors on pituitary somatotropes and stimulates release of growth hormone (GH),whereas somatostatin inhibits GH release.Hypoglycemia stimulates the release of growth hormone.Somatomedin is an anabolic hormone that increases the growth of bone and cartilage tissues.A rise in amino acids in the blood stimulates the release of growth hormone,as do starvation and exercise.

Question 15

The tightness of the hormone-receptor bond is known as
A) specificity.
B) affinity.
C) half-life.
D) set-point.

Accepted Answer

Affinity describes the degree of "tightness" of the hormone-receptor bond,or the inclination of the hormone to remain bound to the receptor.Specificity refers to the molecular "fit" of a hormone within a receptor binding pocket.Half-life describes the duration of hormone activity in the circulation.The negative feedback loop is a mechanism for maintaining hormone activity within a normal range or set-point of normal activity.

Question 16

Thyroid hormones are derived from
A) peptides.
B) tyrosine amino acids.
C) globulin.
D) catecholamines.

Accepted Answer

Thyroid hormones (T₃ and T₄)are derived from tyrosine amino acids to which iodine has been attached.The majority of endocrine hormones are peptides and are easily transported through the circulation.Thyroid hormones require globulins to convey them through the circulation.The catecholamine hormones are dopamine,epinephrine,and norepinephrine.

Question 17

It is true that lipid-soluble hormones are
A) transported in a free state in the bloodstream.
B) bound to receptors on the plasma membranes of target cells.
C) diffused through cell membranes to activate intracellular receptors.
D) activated by second-messenger cascades within the target cell.

Accepted Answer

Once formed,lipid-soluble hormones simply diffuse through the plasma membrane and into the circulation.Lipid-soluble hormones are diffused through the plasma membrane for release into the circulation.Lipid-soluble hormones are not bound to receptors for release to target cells.Second-messenger cascades are not required for activation of lipid-soluble hormones.

Question 18

Growth hormone stimulates the liver to release
A) ketones.
B) insulin.
C) bile.
D) IGF-1.

Accepted Answer

A major target for growth hormone is the liver,where IGF-1 is released.This is an anabolic hormone that increases the growth of bone and cartilage tissues of the body.Growth hormone is an amino acid protein that is similar to prolactin.Ketones are not released in response to growth hormone.Insulin is an important co-stimulator of growth factor.Bile is not produced in response to growth hormone.

Question 19

In primary thyroid hormone deficiency,the TSH levels are
A) high.
B) low.
C) undetectable.
D) constantly fluctuating.

Accepted Answer

In primary hypothyroidism,serum thyroid hormone would be low,but TSH levels high,because the anterior pituitary gland would not receive negative feedback from thyroid hormone.The serum thyroid hormone level,not the TSH level,is low in primary thyroid hormone deficiency.TSH levels are detectable at a high level in primary thyroid hormone deficiency.High TSH levels,not constantly fluctuating levels,are synonymous with primary thyroid hormone deficiency.

Question 20

The most common mechanism regulating hormone production and secretion is
A) positive feedback.
B) negative feedback.
C) positive reinforcement.
D) negative reinforcement.

Accepted Answer

The most common mechanism regulating hormone production and secretion is negative feedback control.In negative feedback control,some aspect of the secreted hormone is sensed and regulates further secretion.Positive reinforcement is not related to hormone production.Hormone production is not associated with negative reinforcement.

Quiz 39: Endocrine Physiology and Mechanisms of Hypothalamic-Pituitary Regulation

Which hormone is highly bound to carrier proteins in the bloodstream?

Up-regulation of target cell receptors results in

Which hormone is regulated by releasing and inhibiting factors from the hypothalamus?

An example of a secondary endocrine disorder is

An increase in serum osmolality would be expected to ________ secretion.

A primary endocrine disorder occurs when

Most endocrine hormones are water-soluble and exert their effects on target cells by

The endocrine system closely resembles the ________ system because many of their actions are coordinated at the level of the hypothalamus.

The release of prolactin is normally inhibited by

An example of a lipid-soluble hormone is

_________ is the hormone which causes uterine and milk duct contractions.

Cortisol is produced in the zona ________ of the adrenal cortex.

Growth hormone has several effects on the body,including

What suppresses the normal secretion of growth hormone?

The tightness of the hormone-receptor bond is known as

Thyroid hormones are derived from

It is true that lipid-soluble hormones are

Growth hormone stimulates the liver to release

In primary thyroid hormone deficiency,the TSH levels are

The most common mechanism regulating hormone production and secretion is