Endo physiology review Flashcards
functional anatomy of the pituitary gland
The artery goes into the median eminence, along with input from the hypothalamus
Hormones of the anterior pituitary
Glyco protein Family:
1. TSH (thyroid stimulating hormone)- goes to thyroid and stimulates synthesis and secretion of thyroid hormones
FSH- goes to ovary and stimulates growth of follicles and estrogen secretion. goes to the testis and acts on sertoli cells to promote maturation of sperm
LH- goes to ovary and stimulates ovulation of ripe follicle and formation of corpus lutem, stimulates estrogen and progesterone synthesis by corpus luteum, stimulates intersitial cells of leydig to synthesize and secrete testosterone
GH: promotes growth in stature and mass, stimulates production of somatomedin, stimulates protein synthesis, usually inhibits glucose utilization and promotes fat utilization
Prolactin: mammary glands promotes milk secretion
ACTH: adrenal cortex, promotes synthesis and secretion of adrenal cortical hormones
Hypothalamic hormones that control the anterior pituitary (hypophysiotropic)
CRH: stimulates ACTCH production (and LPH and endorphin)
GnRH: gonadotropin releasing hormone–> stimulates secretion of FSH and LH
SRIF/somatostatin: inhibits secretion of GH
Prolactin stimulating factor- stimulates prolactin secretion
Prolactin inhibiting factor- dopamine- inhibits prolactin secretion
TRH: thyrotropin releasing hormone- stimulates secretion of TSH and prolactin
control of prolactin release
Suckling stimulus and pregnancy inhibit hypothalamus
Hypothalamus usually releases dopamine which inhibits lactotroph–> prolactin
Growth hormone effects
Human growth hormone–>
Adipose Tissue: decreased glucose uptake, increased lypolysis, decreased adiposity
Liver: increased gluconeogenesis, increased IGF1
Muscle: decreased glucose uptake, increased amino acid uptake, increase in protein synthesis, increased lean body mass
IGF1:
bone, heart and lung: increased protein synthesis, increased DNA and RNA expression, increased cell size/number, increased organ size, increased organ function
Chondrocytes: increased amino acid uptake, increased protein synthesis, increased DNA and RNA expression, Increased collagen, increased chondroitin sulfate, increased cell size and number, increased linear growth
regulation of Growth hormone secretion
Stimulation: amino acids (acute), starvation (chronic), hypoglycemia, exercise, stage 3/4 sleep, gonadal steroids and thytoid hormone
Inhibition: glucose (negative feedback), GH (short loop feedback), IGF 1 (negative feedback), cortisol
congenital adrenal hyperplasia
CRH–> ACTH–> Pregnenolone–> androgens and cortisol–/CRH and ACTh
Primary adrenal insufficiency (addison’s disease) when the adrenal gland isnt working/ not responding to ACTH
Secondary adrenal insufficiency The pituitary isnt working so no ACTH is there to stimulate cortisol
Calcium receptor on pth hormone secreting cells
On parathyroid cell there is a calcium receptor that when stimulated (from high serum calcium) inhibits the release of parathyroid hormone, but when inactivated PTH is released to act on bone, kidney and intestine
Vitamin D pathway
UV light activates provitamin D in the skin (7 dehydrocholesterol) in skin–> cholecalciferol and ergrocalviferol from diet go to the liver (25 OH vit D)–> kidney
increased calcium 24 hydroxylase, 24 25 OH2 vit D (inactive form), PTH activates 1a-hydroxylase
1, 25 OH2 D (active form)–> bone resorption and formation, Ca absorption from the gut, Ca reabsorption in kidney, decreased PTH synthesis
Serum 25 OHD- index of vitamin D stores, intake/absorption - not altered by changes in 1 hydroxylase activity
Serum 1 25 OH 2 D index of renal 1 hydroxylase activity (biologic activity)
Phosphorous is always carried with calcium so PTH will tell the kidney to pee it out
Thyroid hormone
from tyrosine- T 3 more potetnm T4 less potent
The Thyroid follicle
NIS: Iodine is taken up with Na
Pendrin: Cl is put back into the thyroid, and I2 is spit in the colloid
Thyroglobulin: spits out Tg
In the colloid, Ioination of Tg, and coupling
TG with MIT, DIT, T3, RT3, T4 is pinocytosed, Colloid droplet is proteased into MIT and DIT, T3 and T4, Secreted
Thyroid hormone increases sympathetic adrenergics
