Endocrine System
Endocrine Glands
The Hypothalamus and Pituitary Gland's Role
General Info
anterior pituitary
thyroid gland
ovaries
parathyroid glands
adrenal cortex
adrenal medulla
pancreas
thymus gland
hypothalamus - release of ant. pit. hormones OR inhibits hormone secretion from ant. pit.
post. pit - part of brain that STORES hormones
terms
hormone - chemical messenger that travels through the bloodstream
true or "pure" endocrine glands- anterior pituitary, pineal, thyroid, parathyroid, adrenal glands (adrenal cortex and adrenal medulla)
endocrine tissue/cells- found in GI tract, placenta, kidneys, skin, pancreas, thymus, gonads, hypothalamus, heart
target cells- hormone influences only specific tissues cells, called target cells. if a cell has a receptor, it is a target cell
difference btwn endocrine and exocrine cells
exocrine have DUCTS
insulin - lowers blood sugar levels
glucagon - raises blood sugar levels
testes
estrogen
progesterone
testosterone
differences btwn how the nervous system and the endocrine system control body function
thyroid stimulating hormone (TSH) - stimulates thyroid to produce hormone
adrenocorticotropic hormone (ACTH) - stimulate, outer part of adrenal gland
growth hormone (GH) - stimulates growth of all cells and growth at epiphyseal plates *not only found in adolescents but also in adulthood for maintenance
overall function of the endocrine system: control, coordinate, and regulate body functions
messenger molecule: called a hormone, NS = neurotransmitter
site of messenger action: target cell, which can be near or far, NS = from axon terminal to synapse (binds with target)
types of target cells: various cells, target cells are throughout the body, NS = all 3 types of muscle cells, glands
time to onset of action: seconds/hours/days, NS = milliseconds
duration of action: hours/days, NS = milliseconds
endocrine manufacture product and "throw it out the window"
glands in linings of digestive, respiratory, reproductive, urinary
gonadotropins - stimulate testes/ovaries - ex: FSH and LH
prolactin (PRL) - stimulates synthesis of milk in breast tissue
thyroid hormone - increase rate of metabolism (conversion of nutrients to energy, O2 needed)
calcitonin - active only in children, decreases activity of OSTEOCLASTS (b/c kids are forming new bones)
parathyroid hormone - increase blood calcium levels when it falls too low, targets: bones, kidneys, GI tract for increased absorption
produces corticosteroids
zona glomerulosa
zona fasciculata
zona reticularis
outer zone - secretes mineralocorticoids = make kidneys reabsorb (keep) water and sodium
secretes glucocorticoids = keeps blood glucose levels normal, helps us deal with short and long term stress
secretes glucocorticoids and adrogen (in other tissues becomes testosterone and estrogen)
functions with the sympathetic nervous system, epinephrine and norepinephrine
Islet cells - endocrine function
alpha cells - glucagon
beta cells - insulin
has both endocrine AND exocrine function
also wears a hat in the immune system
site where WBC's (T lymphocytes) arise from precursor cells, our text says this transformation "seems to be stimulated by thymic hormones"
thymic hormones cause T lymphocytes to become immunocompetent, responding to invaders
hypothalamus - synthesizes 2 hormones that are stored in axon terminals in the posterior pituitary gland
oxytocin - stimulates contraction of uterus
vasopressin - antidiuretic hormone - kidneys will preserve water