endocrine 1 - intro Flashcards
what is an endocrine gland
gland that lacks ducts
what is an exocrine gland
gland that has a duct system
which organ is just endocrine
thyroid
which organ is just exocrine
salivary
which organ is endocrine and exocrine
pancreas
how do endocrine signals spread and where
hormone sent into blood, effects far target
how do neuroendocrine signals spread and where
neurotransmitters released by diffusion, effects are local
how do paracrine signals spread to where
target cells are very close
how do autocrine signals spread to where
released in interstitial space but it is self-acting
are endocrine or nervous system communication quicker
NERVOUS
are endocrine or nervous system communication more target specific
endocrine has many target cells, nervous is more target specific
what are 3 ways that you could regulate hormones
in production, transport and receptors
are protein hormones water or lipid soluble
water
are steroid hormones water or lipid soluble
lipid
are thyroid hormones water or lipid soluble
lipid
are catecholamines hormones water or lipid soluble
water
are eicosanoids hormones water or lipid soluble
lipid
when/how are protein hormones stored
after synthesis
when/how are steroid hormones stored
not stored but made on demand
which is the most important precursor for steroid hormones
cholesterol
what are the two types of receptors
cell surface receptors and intracellular receptors
which type of hormones go to cell surface receptors
protein and catecholamines
which type of hormones go to intracellular receptors
steroids and thyroid
are G-protein linked receptors cell surface or intracellular
surface
are catalytic receptors cell surface or intracellular
surface
what 4 things happen after G proteins
2nd messenger
protein kinase
protein phosphorylation
response of target cells
what is the pathway of adenylate cyclase (G protein)
cAMP to PKA which causes protein phosphorylation
what is the pathway of phospholipase C (G protein)
DAG–> PKC then protein phosphorylation
AND also IP3 to Ca2+
what happens in the Ca2+ pathway (G protein)
Ca binds to calmodulin then Ca2+/Calmodulin dep. Kinase which causes protein phosphorylation
what are the two types of catalytic receptors
receptor with intrinsic tyrosine kinase and also one that recruits tyrosine kinase
what is the mechanism of intrinsic tyrosine kinase
receptor phosphorylates the hormone once it binds, response of target cells
what is the mechanism of recruiting tyrosine kinase
the hormone binds, receptor causes recruitment of a tyrosine kinase, phosphorylates, response of target cells
what does protein kinase do
phosphorylate protein
what does protein phosphatase do
remove phosphate group from protein
is a phosphorylated or non phosphorylated protein active
they can both be active or unactive (more common that phosphorylated means active and inactive is non phosphorylated)
where are the 3 locations of intracellular receptors
cytoplasm, nucleus or bound to DNA in nucleus
what are the common effects of all intracellular receptors
they end up in nucleus and act as transcription factors
what are examples of intracellular receptors in the cytoplasm
steroid hormones of adrenal cortex
what are examples of intracellular receptors in the nucleus
sex steroids
what are examples of intracellular receptors in the DNA in nucleus
thyroid hormones
what does the ability of a cell to respond to a hormone depend on
the presence of receptors for that hormone on/ in the target cell
what is up regulation
increase in the number of receptors for a hormone
what is down regulation
decrease in the number of receptors for a hormone
what could cause up regulation
low hormone levels
what could cause down regulation
high hormone levels
what is permissive actions of hormones
when hormone A must be present for the full action of hormone B to occur
what is a connection between permissive actions of hormones and upregulation
hormone A may upregulate the receptors for hormone B on a target cell
what are two examples of hormones that do permissive action
thyroid and epinephrine (the two together have much higher effects than either alone)
what does negative feedback do to response
dampen
what does positive feedback do to response
amplify
what kind of feedback system is PTH and Ca2+
negative
when is PTH secreted
when there is low Ca+
when is PTH inhibited
when there is high Ca+
what kind of feedback system is oxytocin secretion and cervical stretch
positive
what is a tropic hormone
a hormone that controls the secretion of another hormone
what is a trophic hormone
a hormone that increases secretion of hormone and stimulates growth of the gland
whats a trophic effect
when a hormone stimulates growth of a gland
what is hypo-secretion
secretion of too little hormone
what is hypersecretion
secretion of too much hormone
what is hypo-responsiveness
reduced responsiveness of target cells
what can cause hypo-responsiveness
abnormal receptors, defective cell signalling, defective enzyme function in target cell
what is Laron dwarfism caused by
when receptors on the cell do not respond to growth hormone
what is hyper-responsiveness
increased responsiveness of target cells
what is signal transduction?
signal is transmitted through a cell as a series of molecular events, most commonly protein phosphorylation catalyzed by protein kinases, which ultimately results in a cellular response
