endocrine introduction Flashcards
functions of the endocrine system
- stimulation of growth and development
- coordination of the reproductive system
- maintenance of internal environment
- adaptation to emergency demands of body
all hormones use what feedback systems
positive OR negative
all hormones ONLY affect what cells
target
hormones are either used by target cells OR are what
deactivated or excreted by kidneys or liver
the ___ is both a endocrine and exocrine gland
pancreas
pancreatic cells
islets of langerhans
endocrine cells of the pancreas
- alpha (glucagon)
- beta (insulin)
exocrine cells of the pancreas
- delta (somatostatin and gastrin)
- F cells (pancreatic enzymes)
(GI functions)
functions of insulin
- facilitates glucose uptake into the cells of the body
- facilitates cellular uptake of K+, phosphate, Mg++
- synthesizes (makes) proteins, lipids, nucleic acid
what are the two hormones secreted by the thyroid gland
thyroid hormone, calcitonin
thyroid hormone (TH) is a ____ feedback process
negative
if TH is low what happens to TSH and vice versa
is TH is low TSH increases and if TH is high TSH decreases
TH is 90% T4 (____ form) and 10% T3 (_____ form)
T4 = inactive form and T3 = active form
TH drives mechanisms of what cells
ALL body cells
(growth, heat regulation, oxygen consumption)
_____ is needed for production of TH
iodine
____ decreases serum Ca++
calcitonin
what hormone is made by the parathyroid glands
parathyroid hormone (PTH)
what does PTH increase and what does it decrease
increases serum calcium and decreases serum phosphate
PTH is an ANTAGONIST of _____
calcitonin
PTH needs ______
vitamin D
_____ is the OUTER adrenal gland
adrenal cortex
_____ is the core of the adrenal gland
adrenal medulla
what does the adrenal cortex secrete
cortisol and aldosterone (steroids)
what is the secretion of cortisol and aldosterone by the adrenal cortex stimulated by
adrenocorticotropic hormone (ACTH)
the adrenal medulla is connected/controlled by what
autonomic nervous system
what type of cells are found in the adrenal medulla
chromaffin cells (pheochromocytes)
chromaffin cells release what
catecholamines (for the flight or fight response)
(epinephrine and norepinephrine)
cortisol is a _____ hormone
glucocorticoid hormone
(cortisol is the most potent and naturally occuring steroid)
when is cortisol released
in periods of stress (increases blood glucose)
aldosterone is a _____ hormone
mineralocorticoid hormone
what is aldosterone regulated by
the renin-angiotensin system
(retention of Na+ retention (fluid) and loss of K+ (cardiac) and H+ (pH imbalance))
steroids are what (have what properties)
anti-inflammatory, growth-suppression, immunosuppression
what do decreased levels of steroids lead to
dehydration, anorexia, anemia, low sugar, low sodium, high calcium, high potassium (Addison’s disease)
what do increased steroid levels lead to
moon facies, fluid retention, increased fat distribution, hirsutism, decreased immunity, high sodium, high sugar, low calcium, low potassium (Cushing’s disease)
what two systems regulate metabolic activities
endocrine and nervous
- neuro: fast acting but short lasting
- endocrine: slow response but long lasting
what hormones act as antagonists
- calcitonin and PTH
- insulin and glucagon
describe two of the negative feedback systems of the endocrine system
- if TH is high TSH would drop until TH is WNL
- if glucose is low then the body releases glucose and cortisol until glucose is normal
give an example of a positive feedback system
childbirth (contractions) - continue until baby is delivered
an increase in receptors on the target cells is called what
up-regulation
a decrease in receptors on the target cell is called what
down-regulation
hormones travel to target cells via _____
the bloodstream
(target cells have hormone-specific receptors; steroid vs non-steroid hormones)
