endocrinology - exam 3 Flashcards
what do endocrine systems consist of
cells that secrete long-distance signaling molecules into the blood
what are the signaling molecules called
hormones
nervous system communication
short & voluntary
rapid response
endocrine communication
slow & involuntary
travels further but lasts longer
1st endocrinology experiment
remove testes on roosters –> not masculinized
remove & replace back into body cavity –> typical male
remove & transplant into body cavity –> typical male
1st experiment conclusion
must secrete something & must circulate whole body
testosterone from gonads
hormone
chemical messengers
released into bloodstream
act on distant target cells
glucose example
glucose is low
endocrine cell in pancreas releases GLUCAGON into bloodstream
acts on target cell = LIVER
response = glucose becomes available
endocrine system
consists of all hormone-secreting cells
access to entire body
some parts of endocrine system
hypothalamus & pituitary gland
thyroid gland
adrenal glands
what surrounds endocrine glands
blood vessels
why do hormones only affect certain cells
hormones bind to target cells
where are hormone receptors located
can be in the plasma membrane or inside the cell
synaptic signaling
neurotransmitters diffuse across synapses & trigger responses in target tissues
neurons, muscles, glands
endocrine signaling
secreted molecules diffuse into the bloodstream & trigger responses in target cells anywhere in the body
3 major classes of hormones
amines
peptides/proteins
steroids
peptide/protein/amine
water soluable
travel well through blood not lipids
where are water soluable hormones stored
vesicles
secreted through exocytosis
where do water soluble hormones bind
receptors in the plasma membrane
activate signal transduction pathways
rapid responses
water soluble hormone example
glucagon (peptide)
steroid
lipid soluble
travel well through lipids not blood
where are lipid soluble hormones stored
not stored
made on demand