Endocrine system Flashcards
(29 cards)
how do endocrine glands secrete
directly into bloodstream, no ducts (e.g., insulin, glucagon)
how do exocrine glands secrete
onto epithelial surfaces via ducts (e.g., sweat, mucous, digestive enzymes)
what are the main functions of the endocrine system
regulates growth, reproduction, sleep, stress response, homeostasis, circulation, RBC production
what is a hormone
a blood-borne chemical messenger acting on specific targets at low concentrations via receptors
where are hormone receptors located
cell membrane, cytoplasm, and nucleus
water-soluble hormone characteristics
cannot cross cell membrane; use second messengers e.g., insulin, PTH, adrenaline
Fat-soluble hormone characteristics
cross cell membrane; direct effects inside cell; e.g., cortisol, aldosterone, sex hormones, vitamin D, thyroid hormones
what are the mechanisms of hormone action
modify enzyme activity, control transport (channels), regulate gene expression (protein production)
what controls anterior pituitary release
Hypothalamic releasing and inhibiting hormones via capillary beds
does the anterior pituitary produce its own hormones
yes
what hormones are released by the posterior pituitary
oxytocin and ADH
where are there hormones made
hypothalamus
what does oxytocin do
uterine contractions and milk release
what does ADH do
water reabsorption in kidneys, regulates blood osmolarity
what hormones does the thyroid produce
T3, T4, and calcitonin
what is needed for thyroid hormone production
Iodine
Functions of thyroid hormones
increased metabolic rate, heat production, protein synthesis, sympathetic activity, growth and development
what does calcitonin do
lowers blood calcium
where are adrenal glands located
on top of the kidneys
what are the two adrenal regions
cortex (outer), medulla (inner)
what hormones are secreted by the adrenal medulla
adrenaline and noradrenaline
metabolic effects
glycogenolysis (glucose release), lipolysis (fat breakdown)
cardiovascular affects in the adrenal medulla
increases cardiac output, vasodilation in skeletal/coronary vessels, bronchodilation, vasoconstriction to non-essentials
why do cells need glucose
to produce ATP for biological functions
