Endocrine System Flashcards
What are the peptide hormones
All hormones made by the hypothalamus: GnRH, CRH, GHRH, ADH, oxytocin
All hormones made by the anterior pituitary: TSH, ACTH, LH, FSH, prolactin, GH
Glucagon and Insulin
Calcitonin and parathyroid hormone
What are the steroid hormones
All hormones made by the adrenal cortex: glucocorticoids, mineralcorticoids, androgenic steroids
All hormones made by the reproductive organs: progesterone, testosterone, estrogen
What are the amino acid derived hormones?
All hormones made by the adrenal medulla: epinephrine, norepinephrine
Triiodothyronine (T3) and thyroxine (T4)
G protein
Also known as guanine nucleotide-binding protein
A category of proteins that activate other things
Consists of three subunits: alpha, beta and gamma
How is G protein activated and what does the activated G protein do?
Becomes activated once a GTP molecule replaces the GDP molecule that was bound to the G protein, and the beta and gamma subunits dissociate from the alpha subunit
The G protein in the activated GPCR will then activate some effector, which leads to some message being sent
G protein couples receptors (GPCRs)
Cell surface receptors that initiate a secondary messenger response after binding to a peptide hormone (ligand) extracellularly
Once G protein is activated and dissociated into its subunits due to conformational changes, the subunits can then act upon intracellular second messages to propagate a signal
What are the second messengers
cAMP, IP3, DAG, Ca2+
What does the IP3/DAG pathway regulate?
Intracellular calcium levels
IP3 binds to calcium channels on the ER which triggers the activation and opening of calcium channels, releasing calcium ions into the cytosol
What is the adrenal cortex stimulated by?
ACTH from the anterior pituitary in response to stress –> releases glucocorticoids via second messenger cAMP
The adrenal cortex stimulates the secretion of which hormones?
Steroid hormones called corticosteroids which include glucocorticoids, mineralocorticoids and androgenic steroids
What is the adrenal medulla controlled by?
Directly controlled by the sympathetic nervous system
The adrenal medulla stimulates the secretion of what hormones?
Amino acid derived hormones called catecholamines which include adrenaline and noradrenaline
Catecholamines
Amino-acid derived hormones which include epinephrine (adrenaline) and norepinephrine (noradrenaline)
Secreted by the adrenal medulla
“Flight or fight” hormones secreted when facing acute stress
What kind of cells can catecholamines act on?
Any cell with complementary adrenergic receptors
What occurs when catecholamines are released?
Increase heart rate and quickly break down glucose into ATP to energize the body