Ketone Bodies and Ketosis Flashcards
where are ketone bodies produced?
in the liver
what are the 3 ketone bodies?
- acetoacetate
- B-hydroxybutyrate
- acetone
why are ketone bodies produced? describe how structure aids
as a glucose substitute for the brain; they are small molecules that can readily pass through the blood brain barrier
when ketone bodies are high, what does this mean about blood glucose levels?
blood glucose is low
what can acetoacetate and B-hydroxybutyrate be used for?
used for energy by extrahepatic tissue
what can acetone be used for?
nothing; it is a waste product
where does ketogenesis occur?
in the mitochondria
what are the products of ketogenesis? can they be interconverted?
B-hydroxybutyrate and acetoacetate, which can be interconverted
how is acetone produced? can it be interconverted?
spontaneously forms from acetoacetate; cannot be interconverted. once you have acetome you’re stuck with acetone
once ketone bodies are produced in the liver, where do they go and what happens there?
they leave the liver, enter the bloodstream, and enter extrahepatic tissues like the muscles and the brain for ketone body oxidation
where in muscle and brain cells does ketone body oxidation occur?
mitochondria
when other energy sources are not available, what serves as a readily available energy source for extraheptaic tissues?
ketone bodies
what is ketosis?
the culmination of three body states (ketonemia, ketonuria, and ketoacidosis) as body fat is mobilized at excessive rates
what is ketonemia?
accumulation of ketone bodies in the blood (increase in concetration)
what is ketonuria?
excretion of ketone bodies in urine as the body tries to get rid of the ketone bodies
what is ketoacidosis?
a drop in blood pH
how can you usually diagnose ketosis?
by smelling acetone on the breath
how do you treat ketosis?
with readily available carbohydrates to increase blood glucose which causes insulin secretion and inhibits hormone senstitive lipase to stop mobilization of fat
in what animals is ketosis seen?
in all animals but most commonly in dairy cattle
why is ketosis so often seen in dairy cattle?
it is very hard to meet their energy requirement (not enough room in tract bc of highly fibrous feed) and it takes so much energy to produce as much milk as they have been bred for that a negative energy balance is often induced during lactation that leads to body fat mobilization and ketosis
what is one way to prevent ketosis in dairy cattle?
control body condition. if not extra fat to mobilize, there are no precursors for ketone bodies so will only see drop in milk production instead of ketosis (prevent from getting too fat)
where does cholsterol synthesis occur?
in all nucleated cells in the cytosol
what organs are major sites of cholesterol synthesis?
liver and intestine
how does the body obtain cholesterol? (2)
- present in diet
2. synthesized by body
