1: Principles of Endocrinology- Henry Flashcards
goal of the endocrine system
to coordinate and integrate cellular activity within the whole body by regulating cellular and organ function throughout life and maintaining homeostasis
5 functions of endocrine system
- regulate sodium and water balance
- regulate calcium and phosphate balance
- regulate energy balance
- coordinate stress response
- regulate reproduction, development, growth and senescence
3 different types of hormones and their water solubility
peptides (more water soluble)
amino acids
steroids (less water soluble)
endocrine v. paracrine v. autocrine v. intracrine
- into blood stream
- into interstitial space
- to the same cell
- within the same cell
greater prtn binding = _______ half-life
increased
briefly describe the formation and release of peptide hormones
- synthesized as pre-prohormones
- post-translational processing (cleavage, glycosylation)
- vesicle storage
- calcium dependent release
how do peptide hormones travel in the blood?
hydrophilic, so they circulate freely
this gives a short half-life as well
where are receptors for peptide hormones generally found?
cell surface - the hydrophilic peptide hormones can’t cross the cell membrane
from what are all steroid hormones derived?
cholesterol
how do steroid hormones travel in the blood?
lipophilic, so they circulate in a bound form
where in general are steroid hormone receptors found?
intracellular receptors- steroid hormones are lipophilic and can cross plasma membranes
name the catecholamines
NE
Epi
DA
what are the catecholamines and thyroid hormones derived from?
tyrosine
characteristics of catecholamines
hydrophilic, so they circulate freely and bind to cell surface receptors
unique characteristics of thyroid hormone
hydrophilic but circulates bound and binds to intracellular receptors (needs transporter to get through membrane)
what hormones use g-prtn receptors?
catecholamines and TSH, LH, and ADH
what hormones use receptor protein tyrosine kinases?
insulin and growth hormone
what hormones use intracellular receptors?
thyroid hormone and steroid hormones
how is the thyroid hormone receptor different?
the receptor is already in the nucleus, repressing the gene transcription without thyroid hormone bound
usually receptor and hormone bind in the cytoplasm and then enter the nucleus to affect gene transcription
the release of hormones is ______ and _______
pulsatile and periodic
monitor hormone excretion over 24 hrs, better than 1 time plasma reading
what does tropic mean?
hormone that regulates the release of another hormone
hypothalamus –> hypothalamus feedback loop
ultra-short loop
anterior pituitary —> hypothalamus feedback loop
short loop
target organ –> hypothalamus feedback loop
long loop
what would the presence of a non-competitive inhibitor cause? competitive?
non-comp = decreased responsiveness
comp = decreased sensitivity
shift to a right in the dose response curve…
decreased sensitivity
decreased maximal response…
decreased responsiveness
target hormone level low and pituitary hormone level high
failure of target organ
target hormone level low and pituitary hormone level low
pituitary failure
target hormone level high and pituitary hormone level high
autonomous secretion of pituitary hormone or resistance to target hormone action
target hormone level high and pituitary hormone level low
autonomous secretion by target endocrine organ
if you measure \_\_\_\_\_\_\_\_, a. glucose b. calcium c. estradiol ... you should also measure \_\_\_\_\_\_\_\_.
a. insulin
b. PTH
c. LH
elevation of glucose and insulin indicates…
resistance
oral glucose to test insulin release is an example of …
stimulation test
dexamethasone to test negative feedback on ACTH release from pituitary is an example of….
suppression test
