midterm physio deck 4 Flashcards
insulin dependent tissue
muscles and adipose
protein sparing effect of ketones
as ketone production rises, they are used increasingly by the CNS as a fuel –> spares breakdown of muscle in survival situations
glycogen vs fat as storage efficiency
glycogen is inefficient since each gram requires 1-2 g of intracellular watervsfat that is a water free environment
islet cells and their roles
alpha - glucagon secretingbeta - insulin secretingdelta - somatostatin (SRIF) secreting
what cells secrete glucagon?
alpha cells of islet pancreas
SRIF (somatostatin) actions
all actions of somatostatin are INHIBITORYinhibits TSH and GH in pituitaryinhibits insulin and glucagon release in pancreatic islet cells
insulin circulates _____what enzyme breaks it down?
free in plasmaglutathione transhydrogenase (breaks all three disulfide bonds)
does insulin cross placenta?
no
insulin receptor is what type?
tyrosine kinase that autophosphorylates
do insulin receptors use cAMP?
no, it is not a messenger for insulin stimulationtyrosine kinase does notcAMP actually goes down
malonyl coA and insulin
insulin enhances malonyl coa production in hepatocytesmalonyl coa then inhibits the transport of free FA into mitochondria so ketoacids arent made; allows FA biosynthesishigh malonyl coa = low ketogensis
glucagon receptor
Gs protein linked to adenylate cyclase
is there a backup for insulin?
NO
is there a backup for glucagon?
yes4 other catabolic hormones = norepi, epi, cortisol, and GHall correct for hypoglycemiaglucagon and catecholamines are short termcortisol and GH are longer term adaptation
obesity results in what kinds of state?basis for what?
chronic, low grade systemic inflammationbasis for t2 diabetes insulin resistance–elevated levels of pro-inflammatory cytokines act to down regulate insulin receptors
what triggers pro-inflammatory cytokines in obesity?
adipocytes accumulatelipid stores increase in sizeincreased distance oxygen must diffuse cells become hypoxic and upregulate cytokine expressionattracts monocytes and activated into macrophagesleads to systemic proinflammatory state with generalized insulin resistance