endocrine physiology Flashcards
What are the classes of hormones
- peptides: largest group
- amines: catecholamines; thyroid hormones
- steriod
- others
What are factors that influence hormones
-rate of hormone secretion
-rate of metabolism or excretion
-quantity of transport proteins
-changes in plasma volume
down-regulation and up regulation of receptors
-the receptors that hormones bind to will be up-regulated if the hormone is used a lot or down regulated if it is not used
what are the general actions of hormones
-alter DNA activity to modify protein synthesis
-use “second messengers” to activate special proteins
change membrane transport mechanics
What does the posterior pituitary gland release
ADH and oxytocin
Role of ADH
-controls water balance by causing water retention
-osmoreceptors send info based on extracellular osmorlarity top the para-ventricular nucleus and supra-optic nucleus
-changes in blood volume are also detected by baroreceptors
role of Oxytocin
stimulates uterine contactions, milk ejection and maternal behavior
thyroid gland
-releases calcitonin, Thyroxine (t4) and triiodothyronine (T3)
-thryoid homrone receptors are all through the body
-increases metabolic rate
-increase hepatic glucose production through gluconeogenesis
what type of hormones are made in the medulla of the adrenal gland
- catecholamines: epinephrine and norepinephrine
- peptides: somatostatin and substance P
What is made in the Zona reticularis layer of the cortex of the adrenal gland
Androgens: estrogen and testosterone
What is made in the zona fasciculata of the adrenal cortex of the adrenal gland
glucocorticoids: cortisole and cortisone
What is made in the zona glomerulosa of the adrenalcortex of the adrenal gland
mineralocorticoids: aldosterone and corticosterone
What are catecholamines and describe
-released by adrenal medulla but controlled by preganglionic sympathetic neurons
-epinephrine: major endocrine product
-norepinephrine: major sympathetic neurotransmiter
What reactions do catecholamines cause in the cell
-depends on the receptor type
-Aphla1 = increase in intracellular Ca in cells
-alpha2 = suppress cAMP response
-Alpha 1,2,and 3 = increase cAMP
short term response of caetcholamines
-increased cardiac output, bronchodilation, and elevation of blood glucose
Aldosterone functions
-maintains normal extracellular volume
-stimulates Na reabsorption and K excretion
Pancrease: what hormones does it secret and from what cells
- alpha cells: secrete glucogon
- beta cells: secrete insulin, proinsulin and C peptide
-gamma cells: secrete somatostatin
what does insulin do, what does it effect and what stimulates its release
-increases after meals and reduces glucose, amino acids, fatty acids and ketones
-effects the liver, skeletal muscle and adipose tissue
-release stimulated by rising blood glucose levels and plasma concentration of arginine, leucine, or lysine amino acids
what does glucogon do, what does it effect and what stimulates its release
-increase glucose and ketone production by the liver
-targets the liver
-stimulated by hypoglycemia and inhibited by hyperglycemia and by eating a protein rich meal
Explain the initial rapid phase of insulin release
-when plsma glucose increases; depletes cells of insulin; beigins in 1 minute and lasts about 10 minutes