The Adrenal Glands

Question 1

location

Answer 1

just above the kidneys

Question 2

Adrenal gland anatomy

Answer 2

central medulla, outer cortex, completely unconnected

Question 3

Outer cortex

Answer 3

produces three major classes of steroid hormones synthesized from cholesterol
Glucocorticoids
mineralocorticoids
androgens

Question 4

Three concentric zones of the cortex

Answer 4

Differ in the major steroid hormones they secrete
Zona glomerulosa - aldosterone
Zona fasciculata - cortisol
Zona reticularis - adrenal androgens

Question 5

Adrenal medulla produces

Answer 5

catecholamine hormones

Question 6

Cells of the medulla are derived from

Answer 6

nervous system

is an extension of the nervous system

Question 7

Principal cell type of the medulla

Answer 7

Chromaffin cell

Question 8

Cortisol

Answer 8

the major glucocorticoid
production controlled from the pituitary via ACTH secretion
increases gluconeogenesis
has anti-inflammatory properties
acts on renal tubules to increase sodium reabsorption and excretion of potassium
21 carbons

Question 9

Aldosterone

Answer 9

the major mineralocorticoid
controlled by the renin-angiotensin system
acts on renal tubules to increase sodium reabsorption and excretion of potassium
21 carbons

Question 10

Adrenal androgens

Answer 10

production controlled by pituitary ATCH
mimic the effects of testosterone on secondary sexual characteristics
females: constitute the major androgens produced
most common: DHEA, a precursor for gonadal hormones
lab testing: DHEA-S level (sulfated form)
19 carbons

Question 11

Renin

Answer 11

converts angiotensinogen to angiotensin I

secreted by the juxtaglomerular kidney cells in response to a decrease in blood pressure

Question 12

angiotensin converting enzyme (ACE)

Answer 12

convers angiotensin I to angiotensin II

Question 13

angiotensin II causes

Answer 13

vasoconstriction, increase in blood pressure, more blood passes through the kidneys
causes increase in aldosterone production –> more sodium reabsorption –> more blood volume –> more potassium excretion

Question 14

ACE inhibitors

Answer 14

work the renin-angiotensin system to regulate blood pressure

Question 15

Cushing’s (Hypercortisolism) syndrome

Answer 15

a disease of the adrenal cortex

causes: adrenal tumor, adrenal hyperplasia, ectopic production of ACTH by a non-pituitary tumor, exogenous glucocorticoids
signs: loss of diurnal variation

Question 16

Cushing’s disease

Answer 16

a type of Cushing’s syndrome where the cause is overproduction of ACTH by a pituitary adenoma

Question 17

Laboratory diagnosis of Cushing’s

Answer 17

serum cortisol: + reagents allowing coritsol to release from its binding proteins –> total cortisol
urine gives an indication of the amount of free cortisol
saliva: free cortisol, only collected at midnight
24 hour urine cortisol: give dexamethasone suppression test and measure serum. Normal: suppression of ACTH, cortisol will decrease through negative feedback. Cushing’s: cortisol is not suppressed

Question 18

Hyperaldosteronism - primary

Answer 18

Conn’s syndrome
tumor in adrenal cortex producing aldosterone
results in high plasma sodium, low plasma potassium, high plasma and urine aldosterone, low plasma renin

Question 19

Secondary hyperaldosteronism

Answer 19

Renin-secreting tumor of the kidney

Results in high plasma sodium, low plasma potassium,high plasma and urine aldosterone, high plasma renin

Question 20

Adrenal insufficiency (Addison’s disease)

Answer 20

major cause: autoimmune
result: low cortisol and aldosterone, high ACTH
low sodium and high potassium in blood
ACTH is a small polypeptide (39 aas) that fragments from a large molecule that also makes melanocyte stimulating hormone –> dark complexion

Question 21

Congenital adrenal hyperplasia (CAH)

Answer 21

inherited enzyme defects in the adrenocortical steroid synthesis pathway
defect at the 21-hydroxylase enzyme
excess pituitary ACTH production, impaired cortisol and aldosterone synthesis
negative feedback is lost
uncontrolled stimulation of adrenal cortex tissue and excess synthesis of all steroids
high levels of adrenal androgens

Question 22

Diagnosis of CAH

Answer 22

measure 17-OH progesterone, the substrate for 21-hydroxylsae

Question 23

The Adrenal Medulla

Answer 23

central portion of the adrenal gland
comes from ectodermal/neural crest
secretes catecholamines

Question 24

catecholamines

Answer 24

cause changes that are normally associated w/ fight or flight when bound to adrenergic receptors on target cells

Question 25

Fight or flight response

Answer 25

constriction of many blood vessels
increased heart rate
hyperglycemia
increased oxygen consumption
dilation of pupils
slowed digestion

Question 26

Phoechromocytoma

Answer 26

catecholamine produdcing tumor
90% of these are in the adrenal medulla
diagnosis: measure catecholamines in urine or plasma
also: measure urinary VMA and HVA