24 - Adrenal Glands

Question 1

where is the adrenal gland located
What type of organ

Answer 1

superior to kidney
a retroperitoneal organ

Question 2

What are the three layers of the adrenal cortex
What do the layers do

Answer 2

secrete lipophilic steroid hormones that are essential for life

1) zona glomerulosa
2) zona fasciculata
3) zona reticularis

Question 3

What is the zona glomerulosa
What controls

Answer 3

produces aldosterone (mineralcorticoid)
- alters Na+ and K+ balance
- helps adjust Bp and Bv

controlled by the renin-angiotensin-aldosterone (RAA) pathway/system

Question 4

What is the aldosterone release stimulated by

Answer 4

dehydration
Na+ deficiency
hemorrhage
elevated K+

Question 5

Describe the negative feedback system of aldosterone

Answer 5

1) stimulus
2) decrease in BV –> decrease in BP
3) Juxtaglomerular cells of kidneys
4) increased renin (enzyme)
5) angiotensin from liver
6) lungs convert angiotensin 1 to angiotensin 2
7) increased aldosterone in adrenal cortex
8) kidneys
- increased Na+ and water reabsoprtion and increased secretion of K+ and H+ into urine
9) increased BV
10) BP increases until it returns to normal (neg feedback)
11) vasoconstriction of arterioles

Question 6

What is the zona fasciculata
What does it do

Answer 6

secretes glucocorticoids - stress hormones
- cortisol, cortisone, corticosterone

1) promote protein breakdown
2) promote lipolysis
3) promote glucose formation
4) promote resistance to stress
5) exert anti-inflammatory and immunosuppressive effects

Question 7

How is glucocorticoid secretion regulated

Answer 7

negative feedback system

1) CRH stimulates release of corticotropin (ACTH)
2) ACTH stimulates secretion of cortisol by the adrenal cortex
3) elevated cortisol levels inhibit release of ACTH by the ant pituitary and CRH from the hypothalamus

Question 8

What is the zona reticularis

Answer 8

secretes androgens
- primary androgen secreted is dehydroepiandrosterone (DHEA)
- androgens promote axillary and pubic hair growth and contribute to “growth spurts” during puberty

Question 9

How does adrenal androgen differ in males and females

Answer 9

Males: adrenal androgen secretion is much less than testicular androgen secretion

Females: adrenal androgens contribute to libido (sex drive) and some are converted to estrogens by other tissues
- during menopause: all estrogens are derived from adrenal androgens

Question 10

How is androgen secretion regulated

Answer 10

regulated by ACTH
no negative feedback on hypothalamus

1) Stimulus
2) CRH stimualtes release of corticotropin (ACTH)
3) ACTH stimulates secretion of androgens by the adrenal cortex
4) Androgens (DHEA)
5) tissue effect

Question 11

What does the adrenal medulla represent

Answer 11

a modified sympathetic ganglion

Question 12

How do the chromaffin cells release hormones
How are they regulated

Answer 12

lack axons –> release directly into the blood
regulated by neural input (splanchnic nerves) –> hormones released quickly

Question 13

What are the types of stress

Answer 13

eustress
distress

Question 14

What are the three phases of stress

Answer 14

alarm (f or f response)
- activation of sympathetic nervous system

resistance
- release of adrenal cortical hormones, growth hormone and thyroid hormone

exhaustion
- consequence of stress hormones that deplete body resources leading to msucle wasting, immunosuppression, gastric ulcers

Question 15

What is the main cause of disease of the adrenal gland

Answer 15

excess or insufficient levels of cortisol

Question 16

What is cushing’s syndrome
What are the causes

Answer 16

disorder caused by excessive levels of glucocorticoids (cortisol)

source of glucocorticoids may be
- endogenous (ACTH- secreting tumor, adrenal adenoma)
- exogenous (glucocorticoid administration)

Question 17

What are the signs and symptoms of cushings

Answer 17

muscle wasting, atrophy (Catabolism)
moon face or buffalo hump (fat redistribution)
weight gain - central obesity, hyperlipidemia striae
hypertension
hyperglycemia
osteoporosis
susceptibility to infection
poor wound healing

Question 18

What is adrenocortical insufficiency (addision’s)
what are the causes

Answer 18

disorder caused by insufficient secretion of glucocorticoids (cortisol) and mineralocorticoids (aldosterone)

autoimmune disorder
- destruction of the adrenal cortex or antagonism of the ACTH-receptors by autoantibodies
primary disease
- adrenal atrophy
secondary disease
- insufficient CRH or ACTH
withdrawl syndrome

Question 19

What are the signs and symptoms of Addison’s

Answer 19

weight loss
hypoglycemia
weakness
decreased serum na
dehydration
hypotension
increased serum K+
cardiac arrhythmias

Question 20

What is congenital adrenal hyperplasia (CAH)
what are the causes

Answer 20

rare, recessive, autosomal disorder (males and females equally)

due to an enzyme deficiency – cannot produce cortisol or aldosterone
pituitary homrones kick in, resulting in excess androgen production

Question 21

What are the signs and symptoms of CAH

Answer 21

males:
- premature development of male characteristics
- early appearance of pubic and armpit hair
- severe illness within days of birth due to loss of salt (hyponatremia, hyperkalemia)

females
- virilization may occur
- hirsutism, clitoral enlargement, deepened voice, amenorrhea, breast atrophy, acne

Question 22

What is the treatment for CAH

Answer 22

exogenous glucocoritcoid
salt replacement therapy