HPA Flashcards
Corticotroph cells product and target organ
ACTH
adrenal glands
adipocytes
melanocytes
thyrotroph cells product and target organ
TSH
Thyroid gland
Gonadotroph cells product and target organ
LH, FSH
gonads
somatotroph cells products and target organ
all tissues
liver
lactotrophs prodcut and target organ
PRL
mammary gland
growth hormone
stimulates growth of skeletal epiphyseal plates and body to synthesize protein.
Precursor of GH is
Growth hormone releasing hormone (GHRH) from the hypothalamus.
what increases levels of GH?
energy deficient states like starvation, protein deficiency, hypoglycemia, low free fatty acid levels
indirect anabolic effect of GH
Acts on the liver to cause Insulin Growth Factor
Direct catabolic effect of GH
Hyperglycemia and lipolysis.
Fxns. of GH
Carbohydrate metabolism
Fat Metabolism
Protein metabolism
GH defficiency
dwarfism
acromegaly
Adrenocorticotropic hormone stimulates
adrenal cortex and secretion of glucocorticoids
Cortisol is a
glucocorticoid
ACTH is secreted from the anterior pituitary in response to
corticotrophin-releasing hormone (CRH) from the hypothalamus
CRH or corticotropin is released in response to
stress
CRH is inhibited by
glucocorticoids, part of a negative feedback loop
ACTH acts on
steriodogenic tissue of the adrenal glands affecting carbohydrate and mineral metabolism
Each adrenal gland is separated in 2 parts
adrenal cortex - outer
adrenal medulla - inner
adrenal cortex secretes
corticosteroids
corticosteroids are
lipid based steroid hormones
corticosteroids are divided in 2 categories
mineralcorticoids
glucocorticoids
name a mineralcorticoid
aldosterone
name a glucocorticoid
cortisol
what does the adrenal medulla secrete ?
epinephrine and nor-epinephrine
fxn. of mineralcorticoids
Na+, K+ and water homeostasis in blood and extracellular fluid
fxn. of glucocorticoids
Glucose homeostasis and many other function
cortisol
helps body deal with stressful situations
Regulates or supports a variety of important cardiovascular, metabolic, immunologic, and homeostatic functions, including water balance
what happens to people that have adrenal insufficiency?
stress causes hypotension shock and death
treatment for adrenal insufficiency
glucocorticoids supplementation
Keeps blood glucose levels high enough to support brain’s activity
Forces other body cells to switch to fats and amino acids as energy sources
breaks down protein
Redirects circulating lymphocytes to lymphoid and peripheral tissues
cortisol
adrenal cortex charateristics
mainly glandular tissue
site of corticosteroid synthesis
t/f Large quantities of cortisol can depress the immune system and cause an inflammatory response
true
Hormonal stimulation of glucocorticoids is mediated via the
HPA axis (hypothalamic/pituitary/adrenal axis)
Stress response steps
hypothalamus sends CRH to adenohypophysis
adenohypophysis secretes ACTH
ACTH is carried through blood stream to adrenal cortex and stimulates glucocorticoid secretion
t/f the SNS can also stimulate glucocorticoid secretion
true
fxn. of dehydroepiandrosterone DHEA
secreted by adrenal cortex
converted in peropheral tissues to testosterone and estrogen
unclear function related to stress
site of corticosteroid synthesis
adrenal cortex
steroid hormones are not
stored in cells
synthesis = secretion
