endocrine system Flashcards
2 types of hormones
peptide hormones: modified amino acids, small peptides, or proteins
cells will have more rough ER
secreted by secretory granules via exocytosis
steroid hormones: lipid based (cholesterol derived)
cells will have more smooth ER
secreted by diffusion
types of endocrine glands
- pure endocrine: only endocrine cells
- organs containing endocrine cells (but also function in another system)
- organs containing some endocrine cells
list the pure endocrine glands (5)
- pituitary
- pineal
- thyroid
- parathyroid
- adrenal glands
list the organs containing endocrine cells (4)
- hypothalamus
- pancreas
- thymus
- gonads
list the organs containing some endocrine glands (5)
- heart
- kidneys
- digestive tract
- placenta
- skin
2 basic divisions of the pituitary gland
- anterior (adenohypophysis)
2. posterior (neurohypophysis)
major divisions of the adenohypophysis (and what cells they contain)
- pars distalis (corticotropic, thyrotropic, somatropic, prolactin, gonadotropic, ehromophobes)
- pars intermedia (corticotropic releasing more MSH than ACTH)
- pars tuberalis (gonadotropic, thyrotropic)
major divisions of neurohypophysis
- pars nervosa
2. infundibulum
corticotropic cells release
ACTH - stimulates adrenal cortex to release corticosteroids in long term stress response
MSH - target is CNS for appetite suppression
thyrotropic cells release
TSH - targets follicular cells of thyroid to release T3 and T4
gonadotropic cells release
FSH - ovaries and testes to release testosterone, estrogen, and for follicle maturation, sperm production
LH - ovaries and testes to produce sex hormones and trigger ovulation
somatotropic cells release
GH - to most places in the body causes protein synthesis, somatic growth, metabolizes fats, increase blood glucose
neurohypohysis secretes
- oxytocin to uterus and breast for labor and milk production
- ADH - to kidneys to resorb more water and avoid fluid loss
what is the largest pure endocrine gland
thyroid (located in the neck)
thyroid hormones
T3 and T4 (produced by follicular cells, main function is to increase basal metabolic rate)
calcitonin
produced by parafollicular cells - function is to lower blood calcium level when it is too high
a. osteoclasts to slow release Ca from bones
b. increase Ca excretion by kidneys
thyroglobin
is the thyroid hormone precursor which is converted when TSH stimulates follicular cells
where is the parathyroid gland located
on the posterior surface of the thyroid
what does parathyroid secrete
PTH - increases blood calcium level when it is too low
a. osteoclasts to increase release of Ca from bones
b. decrease Ca excretion in kidneys
2 main divisions of the adrenal gland
- adrenal cortex
2. adrenal medulla
what hormones does the adrenal medulla secrete and what is the function
adrenal medulla - catecholamines
(epinephrine, norepinephrine)
function: short term stress response
increase heart rate, increase BP, dilate bronchioles, liver release glucose, BMR increase, less blood to digestive system and urine output
what hormones does the adrenal cortex secrete and what is the function
adrenal cortex - corticosteroids
where is the pineal gland located
the roof of the diencephalon in the brain
what hormone does the pineal gland secrete and what is the function
pinealocytes in the pineal gland secrete melatonin which responds to lack of light visual input from the retina to increase sleepiness
where is the pancreas located
posterior abdominal wall
4 types of pancreatic cells
- alpha cells
- beta cells
- delta cells
- pp cells
alpha cells release
glucagon which increases blood glucose
beta cells release
insulin which decreases blood glucose
delta cells release
somatostatin which may inhibit alpha and beta cells
pp cells release
secrete pancreatic polypeptide which may inhibit exocrine activity
where is the thymus located
in the lower neck and anterior thorax just posterior to the sternum
what hormone does the thymus release
thymopoietin and thymosin which trigger the maturation of T-lymphocytes
testes secrete
testosterone - sperm formation, maintains reproductive organs, secondary sex characteristics
ovaries secrete
- estrogen - maintains reproductive organs and secondary sex characteristics
- progesterone - prepares uterus for pregnancy
heart hormone
ANP (atrial natriuretic peptide) which decreases blood volume and BP
GI tract
enteroendocrine cell secreting hormones
placenta hormone
human chorionic gonadotropin - used to test for pregnancy
kidneys hormone
erythropoietin - signals bone marrow to increase red blood cell production
skin hormone
convert modified cholesterol molecules to vitamin D (needed for calcium metabolism)
