Regulation and Integration of Metabolism Flashcards
the ___ system controls the body’s organ systems
nervous system
describe top-down oversight/control that the nervous system has over the body’s organ system
- nervous system has direct or indirect control over the entire body’s organ system
- it is metabolically demanding
what type of control is the autonomic nervous system?
direct control
what are the two pathways for nervous system control of organ function, and what controls these pathways?
- autonomic nervous system
- neuroendocrine system
- controlled by the hypothalamus
the hypothalamus provides ___ organ system control
descending
describe the 2 pathways of control that the hypothalamus provides
- direct
- autonomic
- innervation of pre-ganglionic neurons
- indirect
- hormonal
- release of pituitary and adrenal cortex hormones
describe the 3 parts of the autonomic nervous system
- sympathetic nervous system
- fight or flight
- response to stressful or harmful stimuli
- ACh used in pre-ganglionic signals
- parasympathetic nervous system
- rest and digest
- replenishment of the body’s resources
- enteric nervous system
- digestive system function
- movement of food through the gut
“direct innervation of organ systems to unconsciously coordinate their function” describes what nervous system?
autonomic nervous system
what 2 receptors feed back to the nucleus of the solitary tract in autonomic control of cardiac function, and what do they detect?
- chemoreceptors detect blood O2/CO2 composition
- baroreceptors detect blood pressure
describe sympathetic vs parasympathetic autonomic control of cardiac function
- sympathetic
- NE
- increases heart rate and vasoconstriction
- parasympathetic
- cholinergic
- decreases heart rate and vasodilation
what are the effects of increased vs decreased blood pressure in relation to sympathetic/parasympathetic cardiac function?
- increased BP inhibits tonic sympathetic activity and activates vagal parasympathetic activity
- decreased BP activates vagal sympathetic activity and inhibits parasympathetic activity
describe the enteric nervous system
- governs gastrointestinal function
- mesh-like neuronal network surrounding the gut
- roughly 100 million neurons
- sympathetic and parasympathetic oversight
- can function independently of the CNS
what are the main organs involved in the neuroendocrine system?
- thyroid
- parathyroid
- adipose tissue
- adrenals
- pancreas
- ovaries/testes
what are the 3 key players of the HPA axis?
- hypothalamus
- pituitary
- adrenal glands
part of the neuroendocrine system
the neuroendocrine system responds to what?
- responds to peripheral sensory information and higher brain centers
the neuroendocrine system is initiated by what?
the release of hormones and signals from the hypothalamus
T or F:
the neuroendocrine system provides diffuse, system wide endocrine signaling
true
describe the HPA axis
hypothalamus - pituitary - adrenal axis regulates hormone release
realize that cortisol is changing the metabolism of its targets
describe the major HPA axis hormones and their targets
what type of hormone is insulin and glucagon?
- peptide hormone
- proteolytic processing of prohormone
- plasma membrane receptors; second messengers
what type of hormone is epinephrine?
- catecholamine
- from tyrosine
- plasma membrane receptors; second messengers
what are eicosanoids?
- hormones formed from arachidonate
- plasma membrane recetpors; second messengers
- ex. PGE1
- blocked by NSAIDs
what are the major organs that influence metabolism?
- brain
- cardiac muscle
- lymphatic system
- adipose tissue
- skeletal muscle
- small intestine
- portal vein
- liver
- pancreas
describe how the brain influences metabolism
- transports ions to maintain membrane potential
- integrates inputs from body and surroundings
- sends signals to other organs
describe how cardiac muscle influences metabolism
- uses ATP generated aerobically to pump blood
describe how the lymphatic system influences metabolism
- carries lipids from intestine to liver
describe how adipose tissue influences metabolism
- synthesizes, stores, and mobilizes triacylglycerols
describe how skeletal muscle influences metabolism
uses ATP generated aerobically or anaerobically to do mechanical work
describe how the small intestine influences metabolism
- absorbs nutrients from the diet
- moves them into blood or lymphatic system
describe how the portal vein influences metabolism
carries nutrients from intestine to liver
describe how the liver influences metabolism
- processes fats, CHOs, and proteins from the diet
- synthesizes and distributes lipids, ketone bodies, and glucose for other tissues
- converts excess nitrogen to urea
describe how the pancreas influences metabolism
secretes insulin and glucagon in response to changes in blood glucose concentration
describe carbohydrate liver metabolism
- remember, pyruvate can be obtained from the cori cycle
describe the roles of the liver, pancreas, and gallbladder in the regulation of CHO, AA, and lipid metabolism
- liver
- blood sugar
- CHO storage (glycogen) and regulation
- AA content
- lipid formation and mobilization
- first pass metabolism
- pancreas
- insulin release during high blood sugar
- glucagon release during low blood sugar
- large intestine pH buffering
- protease release
- gallbladder
- bile salts release to degrade lipids
describe amino acid liver metabolism
describe the glucose-alanine cycle
alanine transports amine groups to the liver
describe fatty acid liver metabolism
describe how hormone signaling controls feeding
don’t need to know the specifics, just the main pathways and what they do
describe how blood glucose levels directly regulate insulin release
glucagon is constitutively released at ___ glucose levels
low
insulin and somatostatin inhibit ___ release
glucagon
reduced ___ incites glucagon release and inhibits insulin release
glucose
describe glucagon’s role in response to low blood glucose
describe somatostatin’s role in response to high blood glucose
describe how insulin drives glucose uptake, glycogen storage, and lipid synthesis
describe how glucagon drives glucose release, and amino acid and fatty acid breakdown
describe fuel sources during starvation
what are the normal available metabolic fuels?
- triacylglycerols (adipose tissue)
- proteins (mainly muscle)
- glycogen (muscle, liver)
- circulating fuels (glucose, fatty acids, triacylglycerols)
describe the relationship between grehlin, plasma glucose, and insulin in relation to eating a meal
describe what happens in the liver during starvation
end up having to break down musculature in order to get glucose to the brain
