Jackson Lectures 3

Question 1

The adrenal medulla is a modified

Answer 1

sympathetic ganglion. Recall that the SNS includes preganglionic neurons that arise from the thoracic and lumbar regions of the spinal cord.

Question 2

In the case of the adrenal medulla, the gland is the

Answer 2

ganglion and there are no postsynaptic neurons with axons. Instead, the postganglionic cells, or chromaffin cells, release epinephrine (80%) and norepinephrine (20%) into the blood. NE stronger of the two.

Question 3

NE is —- than E

Answer 3

stronger

Question 4

adrenal medulla contains significant amounts of the enzyme

Answer 4

phenyl-N-methyltransferase which converts NE to E.

Question 5

E and NE from the adrenal medulla have effects similar to those of

Answer 5

SNS innervation of target organs, although β-adrenergic receptors have a greater affinity for E, and α-adrenergic receptors have a greater affinity for NE, so the responses to neural (NE) and endocrine (NE and E) stimulation can vary (see Table 6.11).

Question 6

In summary, the adrenal medulla enhances the

Answer 6

sympathetic response by releasing hormones that can reach additional targets without using neural circuits. And because the endocrine signal is blood-borne, the responses may last longer.

Question 7

The adrenal cortex is divided into three structurally and functionally different zones:

Answer 7

zona glomerulosa – outermost

zona fasciculata – middle

zona reticularis – innermost, adjacent to the medulla

Question 8

zona glomerulosa –

Answer 8

outermost

Question 9

zona fasciculata –

Answer 9

middle

Question 10

zona reticularis –

Answer 10

innermost, adjacent to the medulla

Question 11

Steroid synthesis and secretion are stimulated by

Answer 11

ACTH, with the exception that aldosterone is regulated more strongly by other signals discussed below.

Question 12

Aldosterone is a

Answer 12

mineralocorticoid produced by cells in the zona glomerulosa;

Question 13

the cells in the zona glomerulosa that produce aldosterone contain

Answer 13

high levels of aldosterone synthase, and are deficient in the enzymes that convert corticosterone to cortisol or androgens.

Question 14

The principle action of aldosterone is to stimulate

Answer 14

Na+ and H2O retention by the kidney in order to maintain blood volume and blood pressure.

Question 15

The mechanisms by which aldosterone helps reabsorb Na+ and H2O in the kidney results in an increase in

Answer 15

urinary excretion of K+ and H+.

Question 16

. The effect of aldosterone include: more —– in apical membrane

Answer 16

more Na+ channels in apical membrane

Question 17

. The effect of aldosterone include: more —— in basolateral membrane

Answer 17

more Na+-K+ ATPase in basolateral membrane –

Question 18

. The effect of aldosterone include: increased

Answer 18

increased synthesis of mitochondrial enzymes used in oxidative phosphorylation (electron transport system) –

Question 19

. The effect of aldosterone include: increased

Answer 19

increased synthesis of mitochondrial enzymes used in oxidative phosphorylation (electron transport system) –

Question 20

The secretion of aldosterone is regulated by multiple factors (ACTH has a minor/negligible effect).
• stimulated by an increase in

Answer 20

plasma angiotensin II – angiotensin II is a hormone produced in response to renin, a hormone released by the kidney in response to a decrease in Na+ or blood pressure.

Question 21

Aldosterone secretion is • stimulated by an increase in plasma

Answer 21

K+ -

Question 22

Aldosterone secretion is • • stimulated by a decrease in

Answer 22

plasma pH or increase in plamsa H+ -

Question 23

Aldosterone secretion is • • stimulated by a drop in

Answer 23

systemic blood pressure –

Question 24

Aldosterone secretion is • • inhibited by increased

Answer 24

Na+ intake –

Question 25

Glucocorticoids, cortisol and corticosterone, are secreted by the cells of the

Answer 25

zona fasciculata. In humans, cortisol is the physiologically important hormone.

Question 26

The major effects of glucocorticoids or cortisol are to increase

Answer 26

metabolic fuel availability and use in tissues.

Question 27

glucocorticoids or cortisol : increases —— in liver

Answer 27

• ↑ gluconeogenesis in liver -

Question 28

glucocorticoids or cortisol: • ↑ proteolysis in

Answer 28

muscle –

lots of AA used in liver*

Question 29

glucocorticoids or cortisol increases

Answer 29

• ↑ lipolysis –

Question 30

glucocorticoids or cortisol: • ↓ glucose uptake in

Answer 30

muscle and fat – inhibits gluc transport

Question 31

glucocorticoids or cortisol: • ↓

Answer 31

immune and inflammatory responses- inhibits cytokine production.

Question 32

glucocorticoids or cortisol: • ↓ growth and reproductive function via combo of

Answer 32

upstream inhibition and central effects.

Question 33

glucocorticoids or cortisol: • permissive action on ——– to reg BP

Answer 33

β-adrenergic receptors in vascular smooth muscle to regulate blood pressure. Increases receptor expression*

Question 34

Synthesis and secretion of glucocorticoids is stimulated by

Answer 34

ACTH.

Question 35

Cortisol has a

Answer 35

negative feedback action on both CRH and ACTH.

Question 36

Sex steroids (mostly androgens) are secreted by the

Answer 36

zona reticularis;

Question 37

the two major androgens are

Answer 37

dehydroepiandrosterone (DHEA) and androstenedione.

Question 38

DHEA is a precursor of

Answer 38

other sex steroids (see steroid biosynthetic pathway figure) so it can serve as a circulating reservoir for conversion in peripheral tissues containing steroidogenic enzymes.

Question 39

DHEA has relatively

Answer 39

weak androgenic action

Question 40

DHEA: peripheral concentrations reflect overall activity of the

Answer 40

adrenal cortex

Question 41

androstenedione is synthesized by enzymatic conversion of

Answer 41

DHEA

Question 42

Androstenedione is a

Answer 42

stronger androgen that DHEA

Question 43

Androstenedione provides a non-gonadal source of

Answer 43

testosterone and estradiol

Question 44

DHEA is an important source of

Answer 44

reproductive steroids prior to puberty and in postmenopausal women

Question 45

Adrenal sex steroids are important regulators of

Answer 45

mood and libido, hair growth, erythropoiesis, and acne.

Question 46

Synthesis and secretion of adrenal androgens is stimulated by

Answer 46

ACTH (not GnRH or LH….just because adrenal androgens are sex steroids doesn’t mean they are regulated by gonadotropin releasing hormone/GnRH or gonadotropins!)

Question 47

A stress response is a response of the

Answer 47

stress axis (hypothalamus – anterior pituitary – adrenal cortex) to a stressor that stimulates hypothalamic CRH neurons and inputs to the SNS.

Question 48

SNS activation →

Answer 48

specific organ responses and increased circulating epinephrine.

rapid response involving smooth muscle stimulation and inhibition

widespread effects of epinephrine

Question 49

activation of the stress axis →

Answer 49

increased secretion of cortisol → increases availability of metabolic fuel and other functions

Question 50

activation of stress axis: this is a

Answer 50

delayed response

Question 51

cortisol inhibits the actions of insulin, leading to fulfilling three goals:

Answer 51

• maintain bp (insure delivery of o2 and glucose),
• mobilize and increase metabolic fuel availability,
• inhibit nonessential functions (decrease motility in gut, urinary and repro systems).

Question 52

In the short term, the stress response is

Answer 52

good, and it is shut off by removal of the stressor and negative feedback actions of cortisol on CRH and ACTH.