Ch. 10: Endocrine Function Flashcards
(102 cards)
how do hormones influence processes?
by binding to receptors on the surface or within their target cells. only small amounts of these potent substances are required to make a significant impact at the cellular and organism levels
what are hormones classified or described based on?
their action, source, or chemical structure
when the end product of a biochemical process inhibits it’s own production - the hormone is released only when its levels decline, and production stops when its levels rise
negative feedback loop
rare and occurs when one hormone product stimulates the production of more
positive feedback loop
what is the difference between tropic and nontropic hormones?
tropic hormones- regulate endocrine glands to produce other hormones
nontropic hormones - directly stimulate cellular metabolism and other activities
what happens once the hormone has acted upon the target cell?
the liver metabolizes and the kidneys excrete it to prevent an accumulative effect
“master gland”, located at the base of the brain, regulated by the hypothalamus
pituitary gland
basal portion of the diencephalon which regulates the pituitary gland. connects the nervous and endocrine systems. contains receptors that monitor hormone, nutrient, and ion levels
hypothalamus
what is the difference between the anterior and posterior pituitary with how they are regulated?
the anterior pituitary is regulated by hormones released by the hypothalamus. the brain controls the posterior pituitary gland by neurohormones in this region
what are the endocrine functions of the pancreas carried out by?
the islest of langerhan
which cells secrete glucagon and which secrete insulin?
alpha cells secrete glucagon and beta cells secrete insulin. these are in the islets of langerhan
what hormones are secreted by the anterior pituitary gland?
thyroid-stimulating hormone, adrenocorticotropin, prolactin, growth hormone, gonadotropins
what hormones are secreted by the posterior pituitary gland?
antidiuretic hormone and oxytocin
released when serum glucose levels fall and stimulates the breakdown of glycogen to glucose which raises serum glucose levels
glucagon
released when serum glucose levels increase. stimulates cellular uptake of glucose, which in turn decreases serum glucose levels
insulin
hormones are produced within the follicles of the thyroid. what are these hormones?
thyroxin or T4, triiodothyronine or T3, and thyrocalcitonin or calcitonin.
two hormones together that regulate cellular metabolism as well as growth and development
T3 and T4 together
how does the hypothalamus influence the thyroid gland?
it stimulates the pituitary gland to release thyroid-stimulating hormone, using a negative feedback loop. TSH drives the thyroid to produce T3 and T4
what does the thyroid require in order to synthesize T3 and T4
iodine
this, along with parathyroid hormone, regulates serum calcium levels
calcitonin
how does calcitonin regulate serum calcium levels?
inhibits osteoclast activity and stimulates osteoblast activity.
when is calcitonin secreted?
when serum calcium levels are high
usually four of theses, on the posterior surface of the thyroid gland
parathyroid glands
works in the opposite way of calcitonin to regulate serum calcium levels. secreted when calcium levels drop
parathyroid hormones (PTH)