Chapter 17: Endocrine system Flashcards
exocrine glands
ducts carry secretion to the body surface or other organ activity
endocrine glands
have no ducts, release hormones into tissue fluids, carried in the blood, produce hormones
hormone
chemical messenger secreted into bloodstream
target cells
have receptors for hormone
hypothalamus
i feel center, regulates functions such as water balance and sex drive
-many of its functions are carried out by the pituitary
-hormones inhibit and release
-these hormones target the anterior pituitary
posterior pituitary
no hormones are produced here, only stored for release
-the hormones stored here are ADH and oxytocin
-positive feedback loops
ADH
targets kidneys to increase water retention and reduce urine
oxytocin
involved in labor contractions and lactation
anterior pituitary
-targeted by hypothalamic hormones
-all hormones are tropins(regulate the hormone secretions of target organs)
-negative feedback
tropins
hormones that regulate the hormone secretions of target endocrine tissues
What controls the pituitary?
hypothalamus and cerebral cortex
anterior lobe control
releasing hormones and inhibiting hormones
growth hormone
-has the most widespread effects on the body
-induces liver to produce growth stimulants
pineal gland
-synchronizes physiological function w/in 24 hours circadian rhythms of daylight and darkness
-synthesizes melatonin
-undergoes involution
thymus
plays a role in endocrine, lymphatic, and immune
-goes through involution after puberty
thyroid
largest endocrine gland w/ high rate of blood flow
-secretes iodine
-
calcitonin
decreases blood calcium
-secreted by thyroid
parathyroid glands
secrete PTH and target tissues are bone, kidneys, and intestines
-the release of PTH increases blood calcium levels and promotes the synthesis of calcitriol
mineralcorticoids
aldosterone promotes sodium retention and potassium excretion(salt conserving hormone)
glucocorticoids
mainly cortisol
stimulates fat and protein catabolism
release of fatty acids and glucose into blood
sex steroids
androgen and estrogen
insulin
secreted after a meal
lowers blood sugar
glucagon
secreted when blood sugar levels fall
somatostatin
secreted after a meal and monitors the secretion of insulin and glucagon
-paracrine secretion
hyperglycemic hormones
raise blood sugar
epinephrine, norepinephrine, glucagon
hypoglycemic hormones
lowers blood sugar, insulin
diabetes mellitus
disruption of metabolism due to hyposecretion or inaction of insulin
symptoms include polyuria, polydipsia, polyphagia
type 1 diabetes
-lack of insulin
-treatment includes insulin injections
-autoantibodies attack and destroy pancreatic beta cells
type 2 diabetes
insulin resistance,
pathogenesis
cells can’t absorb glucose, must rely on fat and proteins for energy needs
fat catabolism
increases free fatty acids and ketones in the blood
ketonuria
promotes osmotic diuresis
ketoacidosis
occurs in ketones decrease blood’s pH
Which has a faster reaction time: nervous or endocrine?
nervous
What is more widespread: nervous or endocrine
endocrine
steroids
derived from cholesterol
secreted by gonads and adrenal cortex
estrogen, testosterone, cortisol
hydrophobic
peptides and glycoproteins
created from chains of amino acids
secreted by pituitary and hypothalamus
oxytocin, ADH
-hydrophilic
monoamines
derived from amino acids
secreted by adrenal medulla, pineal, thyroid
norepinephrine, melatonin
up regulation
number of receptors is increased, increases sensitivity
down regulation
reduces number of receptors, sensitive to hormones
synergistic effects
multiple hormones act together for greater effect
FSH and tesosterone
permissive effects
one hormone enhances the target organ’s response
estrogen prepares uterus for progesterone
