Adrenal Glands

Question 1

Where are the adrenal glands?

Answer 1

one on top of each kidney

Question 2

Each adrenal gland is structurally and functionally…

Answer 2

two endocrine glands in one:

• inner adrenal medulla
• outer adrenal cortex

Question 3

What is the inner adrenal medulla made up of?

Answer 3

catecholamine-secreting nervous tissue, and acts as part of sympathetic nervous system

Question 4

What does the outer adrenal cortex consist of?

Answer 4

steroid-secreting tissues

Question 5

What forms the bulk (80%) of the adrenal gland?

Answer 5

outer adrenal cortex

Question 6

What are the ‘cells’ of the adrenal medulla?

Answer 6

highly modified sympathetic postganglionic neuron

Question 7

What do the cells of the adrenal medulla produce?

Answer 7

catecholamines

Question 8

What are the two types of catecholamines?

Answer 8

• epinephrine (E) or adrenaline

- norepinephrine (NE) or noradrenaline

Question 9

Where is epinephrine and norepinephrine stored?

Answer 9

in granules similar to neurotransmitter storage vesicles

Question 10

When are large amounts of catecholamines released?

Answer 10

activation of sympathetic nervous system in response to stress (including exercise) or fight-or-flight response

Question 11

When large amounts of catecholamines are released, how much is epinephrine, and how much is norepinephrine?

Answer 11

80% of it is E

20% of it is NE

Question 12

How are cells of the adrenal cortex arranged?

Answer 12

into three zones:

• zona glomerulosa
• zona fasciculata
• zona reticularis

Question 13

What does each zone of the adrenal cortex do?

Answer 13

produces several corticosteroids

Question 14

What is zona glomerulosa, and what does it produce?

Answer 14

outer-most layer of cells that produces mineralocorticoids

Question 15

What is zona fasciculata, and what does it produce?

Answer 15

middle zone composed of cells that secrete glucocorticoids (metabolic hormones)

Question 16

What is zona reticularis, and what does it produce?

Answer 16

innermost (directly adjacent to adrenal medulla) layer that produces small amounts of adrenal sex steroid

Question 17

Adrenal Cortex

What do mineralocorticoids do?

Answer 17

regulate Na+ and K+ balance and blood pressure homeostasis

Question 18

Adrenal Cortex

What is aldosterone?

Answer 18

most potent mineralocorticoid in humans, and accounts for 95%+ of production

Question 19

Adrenal Cortex

What is aldosterone release induced by?

Answer 19

elevated blood K+ and activation of renin-angiotensin system (RAS)

Question 20

Adrenal Cortex

What is aldosterone’s primary target organs? What does it do there?

Answer 20

distal and collecting tubules of kidney, where it stimulates reabsorption of Na+ ions from urine back to bloodstream, while promoting elimination of K+

Question 21

Mineralocorticoids – Diagram

Answer 21

–

Question 22

Adrenal Cortex

What do glucocorticoids do?

Answer 22

exert a wide range of actions in multiple target tissues

Question 23

Adrenal Cortex

What is one type of mineralocorticoid?

Answer 23

aldosterone

Question 24

Adrenal Cortex

What is one type of glucocorticoid?

Answer 24

cortisol

Question 25

Adrenal Cortex What is cortisol?

Answer 25

most important glucocorticoid in humans

Question 26

Adrenal Cortex What are cortisol's target tissues?

Answer 26

liver, fat, muscle, intestines, CNS

Question 27

Adrenal Cortex What can cortisol regulate, and how?

Answer 27

plasma glucose levels by activating gluconeogenesis in liver

Question 28

Adrenal Cortex When does cortisol's blood levels increase? What happens

Answer 28

increase significantly during stress – results in breakdown of adipose tissue and release of fatty acids, which can be used by many tissues as source of energy, "saving” glucose for the brain (“glucose sparing”)

Question 29

Adrenal Cortex What type of effects does chronic excess of cortisol have?

Answer 29

significant anti-inflammatory and anti-immune effects

Question 30

Adrenal Cortex What are glucocorticoid drugs used for?

Answer 30

to control symptoms of inflammatory disorders (ie. rheumatoid arthritis or allergic responses)

Question 31

Adrenal Cortex What are the metabolic effects of cortisol?

Answer 31

- increase hepatic gluconeogenesis - increase lipolysis → increase fatty acids in blood (alternative fuel for most tissues) - both effects – glucose sparing for brain (which is critical during prolonged stress)

Question 32

Adrenal Cortex What is cortisol secretion regulated by?

Answer 32

hypothalamic-pituitary-adrenocortical axis

Question 33

Adrenal Cortex Hypothalamic-Pituitary-Adrenocortical Axis – Diagram

Answer 33

–

Question 34

What is Addison's disease?

Answer 34

uncommon disorder that occurs due to low cortisol, and often aldosterone, production