endocrine system

what two systems coordinate body functions together?

the nervous system and the endocrine system

what do neurons release in the nervous system?

neurotransmitters

what does the endocrine system release?

horomones

what are target cells?

cells that have specific receptors that hormones bind to.

what are two types of glands in the body?

exocrine glands and endocrine glands

what do exocrine glands do?

they secrete their products into ducts

what do endocrine glands do?

they secrete hormones into the blood or surrounding fluid

name the major endocrine glands

pituitary, thyroid, parathyroid, adrenal, and pineal glands

what organs outside the endocrine system also secrete hormones?

thymus, pancreas, ovaries, testes, kidneys, stomach, liver, small intestine, skin, heart, adipose tissue, and placenta

why do hormones only affect certain cells?

only target cells have the correct protein receptors

what is down-regulation?

when cells lose receptors due to high hormone concentration, decreasing sensitivity

what is up-regulation?

when cells gain receptors due to low hormone concentration, increasing sensitivity

what are circulating hormones?

hormones that travel through the bloodstream to targets

what are local hormones?

hormones that act locally instead of traveling through the blood.

what are paracrines?

local hormones that act on nearby cells

what are autocrines?

hormones that act on the same cell that secreted them

what are the two main types of hormones?

lipid-soluble hormones and water-soluble hormones

what are some examples of lipid-soluble hormones?

steroid hormones, thyroid hormones, and nitric oxide

what are some examples of water-soluble hormones?

amine hormones, peptide hormones, protein hormones, and eicosanoids

how do water-soluble hormones travel in blood?

freely in plasma

how do lipid-soluble hormones travel in blood?

bound to transport proteins

when are hormones secreted?

in short bursts when needed?

what regulates hormone secretion?

nervous system signals, chemical changes in blood, and other hormones

what type of feedback regulates most hormones?

negative feedback

what type of feedback regulates a few hormones?

positive feedback

which two structures control most endocrine glands?

the hypothalamus and pituitary gland

what structure connects the hypothalamus and pituitary gland?

the infundibulum

what percentage of the pituitary gland is the anterior lobe?

about 75%

how many hormones does the anterior pituitary secrete?

seven

what does the posterior pituitary do?

stores and releases hormones made by the hypothalamus

what system carries hormones from the hypothalamus to the pituitary?

the hypophyseal portal system

what hormone do thyrotrophs release?

thyroid stimulating hormone

what hormone do corticotrophs release?

ACTH and MSH

what hormone do somatotrophs release?

human growth hormone

what hormone to lactotrophs release?

prolactin

what hormones do gonadotrophs release?

follicle-stimulating hormone and luteinizing hormone

what does TSH stimulate?

production of thyroid hormones

what hormone controls TSH release?

thyrotropin-releasing hormone

what does ACTH stimulate?

production of cortisol and glucocorticoids in the adrenal cortex

what hormone stimulates ACTH release?

corticotropin-releasing hormone

what is the most abundant anterior pituitary hormone?

human growth hormone

what do growth hormones stimulate?

insulin-like growth factors

what do IGFs do?

cell growth, muscle and bone growth, fat breakdown, and glycogen breakdown

what does prolactin do in females?

beings and maintains milk production

what inhibits prolactin release?

dopamine

what does LH do in females?

triggers ovulation, forms corpus luteum, stimulates estrogen and progesterone

what does LH do in males?

stimulates testosterone secretion

what does FSH do in females?

stimulates ovarian follicle development and estrogen secretion

what does FSH do in males?

stimulates sperm production

which two hormones does the posterior pituitary release?

oxytocin and antidiuretic hormone

what triggers oxytocin release?

cervix stretching and infant suckling

what does oxytocin do?

stimulates uterine contractions and milk let-down

what is the function of ADH?

decreases urine output

what controls ADH release?

blood osmotic pressure detected by hypothalamus osmoreceptors

what happens to ADH when blood volume increases?

ADH secretion decreases

What happens to ADH when blood volume decreases?

ADH secretion increases.