Ketone Bodies and Ketosis

Question 1

where are ketone bodies produced?

Answer 1

in the liver

Question 2

what are the 3 ketone bodies?

Answer 2

1. acetoacetate
2. B-hydroxybutyrate
3. acetone

Question 3

why are ketone bodies produced? describe how structure aids

Answer 3

as a glucose substitute for the brain; they are small molecules that can readily pass through the blood brain barrier

Question 4

when ketone bodies are high, what does this mean about blood glucose levels?

Answer 4

blood glucose is low

Question 5

what can acetoacetate and B-hydroxybutyrate be used for?

Answer 5

used for energy by extrahepatic tissue

Question 6

what can acetone be used for?

Answer 6

nothing; it is a waste product

Question 7

where does ketogenesis occur?

Answer 7

in the mitochondria

Question 8

what are the products of ketogenesis? can they be interconverted?

Answer 8

B-hydroxybutyrate and acetoacetate, which can be interconverted

Question 9

how is acetone produced? can it be interconverted?

Answer 9

spontaneously forms from acetoacetate; cannot be interconverted. once you have acetome you’re stuck with acetone

Question 10

once ketone bodies are produced in the liver, where do they go and what happens there?

Answer 10

they leave the liver, enter the bloodstream, and enter extrahepatic tissues like the muscles and the brain for ketone body oxidation

Question 11

where in muscle and brain cells does ketone body oxidation occur?

Answer 11

mitochondria

Question 12

when other energy sources are not available, what serves as a readily available energy source for extraheptaic tissues?

Answer 12

ketone bodies

Question 13

what is ketosis?

Answer 13

the culmination of three body states (ketonemia, ketonuria, and ketoacidosis) as body fat is mobilized at excessive rates

Question 14

what is ketonemia?

Answer 14

accumulation of ketone bodies in the blood (increase in concetration)

Question 15

what is ketonuria?

Answer 15

excretion of ketone bodies in urine as the body tries to get rid of the ketone bodies

Question 16

what is ketoacidosis?

Answer 16

a drop in blood pH

Question 17

how can you usually diagnose ketosis?

Answer 17

by smelling acetone on the breath

Question 18

how do you treat ketosis?

Answer 18

with readily available carbohydrates to increase blood glucose which causes insulin secretion and inhibits hormone senstitive lipase to stop mobilization of fat

Question 19

in what animals is ketosis seen?

Answer 19

in all animals but most commonly in dairy cattle

Question 20

why is ketosis so often seen in dairy cattle?

Answer 20

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

Question 21

what is one way to prevent ketosis in dairy cattle?

Answer 21

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)

Question 22

where does cholsterol synthesis occur?

Answer 22

in all nucleated cells in the cytosol

Question 23

what organs are major sites of cholesterol synthesis?

Answer 23

liver and intestine

Question 24

how does the body obtain cholesterol? (2)

Answer 24

1. present in diet

2. synthesized by body

Question 25

what is cholesterol used for in the liver?

Answer 25

lipoproteins come from cholesterol

Question 26

what is cholesterol used for in the intestine?

Answer 26

cholesterol is a precursor to bile