Hypothalamic-pituitary-adrenal Axis

Question 1

What is the HPA axis mainly concerned with

Answer 1

Production of steroid hormones from adrenal cortex

Question 2

Of the HPA axis, what does the hypothalamus release

Answer 2

CRH

Question 3

Of the HPA axis, what doesthe anterior pituitary release?

Answer 3

ACTH

Question 4

In the HPA, what does the adrenal cortex release

Answer 4

ACTH from anterior pituitary stimulates the release of cortisol and aldosterone from the adrenal cortex

Question 5

What kind of feedback is there in the HPA axis

Answer 5

Both short and long loop

• ACTH inhibits CRH release
• cortisol levels inhibit ACTH and cortisol levels

Question 6

Cortisol during time of fasting

Answer 6

• is a stress hormone in times of fasting
• maintains blood glucose levels
• increases protein catabolism
• increases FA utilization
• reduces inflammation and suppresses the immune system

Question 7

A secondary hypercortisolism would present with

Answer 7

Low levels of CRH

Question 8

Where do the adrenal glands sit

Answer 8

On top of the kidneys

Question 9

What are the two main divions of the adrenal glands

Answer 9

Medulla and cortex

Question 10

What does the adrenal medulla do

Answer 10

Makes epinephrine and norepinephrine

Question 11

What are the divisions of the adrenal cortex

Answer 11

• zona glomerulosa
• zona fasciculate
• zona reticularis

Question 12

What part of the adrenal cortex makes aldosterone

Answer 12

Zone glomerulosa

Question 13

What part of the adrenal cortex makes cortisol and androgens

Answer 13

Both the zona fasciculate and the zona reticularis

Question 14

What parts of the adrenal cortex are important for the HPA axis

Answer 14

Zona fasciculate and zona reticularis

Question 15

What is the outermost layer of the adrenal cortex

Answer 15

Zona glomerululosa

Question 16

What are medullary hormones made from

Answer 16

Tyrosine

Question 17

What are Adrian cortex hormones derivatives of

Answer 17

Cholesterol

Question 18

Synthesis of hormones in the adrenal cortex

Answer 18

• cortex contains the enzymes to make all necessary hormones
• stimulated by ACTH
• disruption can lead to excess production of others

Question 19

What happens when there is a disruption of the pathway of one of the adrenal hormones?

Answer 19

Results in excess production of other hormones

Question 20

21B hydroxylase deficiency

Answer 20

• loss of aldosterone and cortisol production

- overproduction of androgens (causes masculinization)

Question 21

What do low levels of cortisol and aldosterone do to ACTH levels

Answer 21

Increases them

Question 22

In a male with an ACTH deficiency, which of the following hormones would be affected the most

Answer 22

Aldosterone

Question 23

Regulation of glucocorticoids (cortisol) and adrenal androgens

Answer 23

• normally pulsatile
• controlled by circadian rhythm
• normally no exogenous control

Question 24

When do levels of adrenal hormones rise?

Answer 24

Right before waking and peak after

• this prepares the body to wake up and move prior to a meal
• raises blood glucose and mobilizes other energy stores

Question 25

What is difficult for a persons to do that has hypocortisol

Answer 25

Get out of bed

Question 26

What is a powerful stimulus for cortisol

Answer 26

Stress | -can cause weigh can and illness

Question 27

ACTH stimulators factors

Answer 27

- decreased blood cortisol levels !! - sleep-wake transition - stress; hypoglycemia; surgery; trauma - psychiatric disturbances - ADH - alpha adrenergic agonists - B adrenergic antagonists - serotonin

Question 28

ACTH inhibitory factors

Answer 28

- increased blood cortisol levels - opioids - somatostatin

Question 29

What are mineralocroticoids (aldosterone) controlled by

Answer 29

RAAS | Blood potassium levels (need ANgII to make it)

Question 30

Mechanisms of mineralocroticoids (aldosterone)

Answer 30

- retain water and sodium | - secrete potassium and H

Question 31

Cortisol and blood glucose

Answer 31

Maintainence of blood glucose levels

Question 32

Mechanism of actions of cortisol and blood glucose levels

Answer 32

Stimulates gluconeogenesis by liver - liver produces glucose from other sources like fat, protein - causes muscle breakdown to provide Amina acids to liver

Question 33

Other than gluconeogensis, what else does cortisol do

Answer 33

It is antiinflammatory and immunosuppressant - inhibits production of inflammatory molecules - inhibits proliferation of lymphocytes - inhibits platelet activation

Question 34

Which of the following would be true of someone with loss of both cortical hormones (aldosterone and cortisol)

Answer 34

Low blood volume and low blood glucose

Question 35

What are the main pathologies of the adrenal gland

Answer 35

- Addison's disease - Cushing disease - conn syndrome - congenital adrenal hyperplasia (21B hydroxylase deficiency and 17a hydroylase deficiency)

Question 36

Addison's disease

Answer 36

Primary hypocorticolism | -adrenal gland does not make enough cortisol

Question 37

Symptoms of Addison's disease

Answer 37

- hypoglycemia and weight loss - muscle weakness - hypotension, hyperkalemia - metabolic acidosis - hyperpigmentation

Question 38

Hyperpigmentation due to Addison's disease

Answer 38

- ACTH and MSH come from same protein - MSH causes activation of melanocytes and skin darkening - bronze skin and dark gums

Question 39

What is the difference between Cushing's syndrome and Cushing's disease

Answer 39

Cushing's syndrome is a primary hypercortisolism Cushing's disease is a secondary hypercortisolism

Question 40

Cushing's syndrome

Answer 40

Primary hypercortisolism | -adrenal cortex makes too much cortisol

Question 41

Cushing's disease

Answer 41

Secondary hypercortisolism | -anterior pituitary makes too much ACTH

Question 42

What are the symptoms of Cushing's

Answer 42

- hyperglycemia, weight gain - central obesity, moon face, buffalo hump - muscle wasting - hypertension - striae (huge stretch marks) - virilization in females (masculinization)

Question 43

What is the virilization in Cushing's from

Answer 43

Due to overflow into androgen production, more so in secondary

Question 44

Will someone with Cushing's have high aldosterone

Answer 44

Not really. If there is a reason to need aldosterone they may have a larger than normal amount of it released, but overall not too much floating around

Question 45

Conn syndrome

Answer 45

Aldosterone secreting tumor | -primary hyperaldosteronism

Question 46

Symptoms of conn syndrome

Answer 46

Hypertension Hypokalemia Alkalosis

Question 47

Dysfunction in one of the enzymes required for adrenal function

Answer 47

Congenital adrenal hyperplasia | -hyperplasia and hypertrophy compensate

Question 48

21B hydroxylase deficiency

Answer 48

- congenital adrenal hyperplasia - loss of both cortisol and aldosterone - virilization in both sexes

Question 49

17a hydroxylase deficiency

Answer 49

- congenital adrenal hyperplasia - loss of cortisol and adrenal androgens - over production of aldosterone

Question 50

Which congenital adrenal hyperplasia results in the loss of cortisol and aldosterone

Answer 50

21B hydroxylase deficncy

Question 51

Which congenital adrenal hyperplasia results in the loss of cortisol and adrenal androgens

Answer 51

17a hydrozylase deficiency

Question 52

Which is more severe, 21B H deficiency or 17a H deficiency

Answer 52

21B hydroxylase deficiency

Question 53

How would you differentiate between Cushing's syndrome and Cushing's disease

Answer 53

ACTH levels