22.3 Adrenal Hormones Flashcards
What is the function of the adrenal medulla?
- secrete epinephrine and norepinephrine
2. participate with the sympathetic response system
What type of hormones are secreted from the cortex of the adrenal gland directly in to the blood?
- mineralcorticoids
- glucocorticoids
- androgenic hormones
What layer are the cortisol and androgens secreted from?
- cortex, made of the zona fasciculata and zona reticularis
What area of the adrenal gland is the catecholamines secreted from?
- adrenal medulla
What is the rate limiting step for forming corticosteroids from cholesterol?
- cholesterol desmolase
What will increase the LDL receptors that will contribute to increasing the production of corticosteroids?
- Adrenocorticothyroid hormone, with angiotensin II increase conversion of cholesterol to pregnenolone
What is the main glucocorticoid?
cortisol, generally released in response to stress
WHat controls the release of cortisol?
adrenocortiotropic hormone from the anterior pituitary gland. This upregulates its own receptor and will increase the release of cAMP/
Where is cortisol secreted from?
zona fasciculata of the adrenal cortex.
When is cortisol highest in concentration and lowest in concentration?
- highest before waking
2. lowest in the evening
What group of hormones can dehydroepiandrosteron and androstenedione clumped into?
- androgenic hormones
18-carbon steroids have what type of activity?
- estrogenic activity
19-carbon steroids have what type of activity?
testosterone activity
Where are the androgenic hormones secreted from?
zona reticularis
What can lack of aldosterone lead to?
- death due to lack of mineralocorticoids and electrolyte imbalance
Why are mineralocorticoids important for survival?
- prevent increased levels of potassium, and loss of NaCl.
- this will prevent hypovolemic shock
- also prevents hyperkalemia and cardiac toxicity as secondary symptom/sign
What is the effect of excess aldosterone secretion?
- increased arterial pressure
- hypokalemia, muscle weakness
- increas potassium transport into cell bodies generating alkalosis, by exchanging H ion for K ion in intercalated cells.
What is the primary function of glucocorticoids?
- initiate gluconeogenesis.
2. increases lipolysis
What is secreted from the zona glomerulosa?
- mineralocorticoids, regulate BP and electrolyte balance
Corticosteroids are derivatives of what and attach to what?
- form from cholesterol and attach to coated pits
What must be present to convert cholesterol to corticosteroids?
- sholesterol desmolase (rate limiting step) which produces pregnenolone in the mitochondria
What can increase the activity of cholesterol desmolase?
ACTH, and angiotensin II. produce more pregnenolone
What effect will mineralocorticoids have on electrolytes?
- sodium reabsorption increased
- hyperkalemia increases aldosterone
- aldosterone increases potassium secretion by kidney
- aldosterone increase H ion secretion by kidney
What controls the secretion of mineralocorticoids?
- angiotensin II and potassium
What is the major glucocorticoid?
cortisol
What controls the release of glucocorticoids?
- Adrenocorticothyroid hormone, activate cAMP to increase stimulation of glucocorticoid secretion from the zona fasciculata
Which hormone oscillates with circadian rhythm. is high in the morning and low before bed?
cortisol
What is DHEA, dehydroepiandrosterone?
precursor that becomes testosterone in the testis
What must happen to precursors to form estrogen?
oxidation in the ovary which forms an 18-carbon steroid
Which steroids are precursors for testosterone?
19-carbon steroids
What can lack of aldosterone produce?
- hyperkalemia
- reduced ECF and blood volume
- hypovolemic shock
- rapid loss of sodium and chloride via urine
What can excess aldosterone produce?
- increase ECF and blood volume
- hypokalemia/ muscle fatigue
- transport K ion into the cells
- cause alkalosis. due to exchange for Na ions in renal system
What is the major overall effect of aldosterone?
- reabsorption of Na and secretion of K ions
What are the 6 steps to promote sodium reabsorption via aldosterone?
- aldosterone diffuse into tubular epithelial cells
- combine with mineralocorticoid receptor protein
- receptor-hormone complex fuse into nucleus
- RNA is transcribed into Na-K ATPase pumps
- spithelial sodium channels transcribed
What hormones can directly increase aldosterone secretions?
- increased K concentration
- increased angiotensin II
- ACTH required but independent of aldosterone secretion
What hormone has little to no effect on the rate of secretion of aldosterone
adrenocorticothyroid hormone
What is the main function of glucocorticoids?
stimulate gluconeogenesis, and can contribute to adrenal diabetes
How do glucocorticoids resist inflammation?
- prevent release of serotonin and histamine
- block anaphylactic response
- block IL-2 production
- reduce eosinophils/lymphocytes in blood
What is primary addison’s disease?
injury to adrenal cortex causing hypoadrenalism
What is secondary addison’s disease?
impaired function of the pituitary gland causes hypoadrenalism
What can a mineralocorticoid deficiency cause?
- hyponatremia, hypokalemia
- acidosis
- RBC increase
- reduced cardiac output
- metabolic acidosis
What can a glucocorticoid deficiency cause?
- hypoglycemia
- protein and fat reduction
- weight loss
- muscle weakness
- stress suscpetibility
What results in an uneven distribution of pigmentation across the skin?
melanin pigmentation abnormality from hypoadrenalism.Overproduced melanin stimulating hormone
What is cushing’s disease?
hyperadrenalism
What are causes of cushing’s disease?
- glucocorticoid
- pituitary gland adenoma
- hypothalamus abnormality
- adrenal cortex adenoma
- excess ACTH secretion
What are common characteristics of cushing’s syndrome?
- moon face
- acne/hirsutism
- increased BG
- HTN
- protein catabolism
