Lecture 8- Starvations And Ketosis

Question 1

what is the fuel utilisation of the brain

Answer 1

almost exclusively glucose
but can also use ketone bodies

Question 2

what is the fuel utilisation of the liver

Answer 2

can store and create new glucose

can utilise most fuels

Question 3

what is the fuel store in the brain

Answer 3

none

Question 4

what is the fuel store of skeletal muscle when resting

Answer 4

glycogen

Question 5

what is the fuel store of skeletal muscle when exercising

Answer 5

none

Question 6

what is the fuel store of heart muscle during exercise

Answer 6

none

Question 7

what is the fuel store of adipose tissue

Answer 7

triacylglycerols

Question 8

what is the fuel store in liver

Answer 8

glycogen

Question 9

what is the preferred fuel of muscle at resting

Answer 9

fatty acids

Question 10

what are the preferred fuels of muscle during exercise

Answer 10

glucose

fatty acids

branch chain amino acids

Question 11

preferred fuel of the heart

Answer 11

fatty acids

Question 12

what are the fuels exported by skeletal muscle during exercise

Answer 12

lactate and alanine

Question 13

what are the fuels exported by adipose tissue

Answer 13

fatty acids

glycerol

Question 14

what are the fuel exported by the liver

Answer 14

Triaclyglycerols
Glucose
Ketone bodies

Question 15

during starvation what happens to ketone body production

Answer 15

large increase right from the beginning of starvation

Question 16

what happened to glucose levels during the Minnesota starvation experiment

Answer 16

Begins at a well fed state, then a slight drop initially which will activate the glucagon hormone

Then as time goes on glucose levels are maintained very stable

Question 17

what happened to urinary ammonia levels during the Minnesota starvation experiment

Answer 17

increases

Question 18

what happened to fatty acid levels during the Minnesota starvation experiment

Answer 18

Increase at the start and then slowly creeping up as the starving continues

Question 19

what happened to total urinary nitrogen levels during the Minnesota starvation experiment

Answer 19

decreases as the body needs to use body proteins for energy

Question 20

what is exogenous glucose

Answer 20

glucose from the diet

Question 21

during the first 4 hours of starvation what is the primary source of glucose for the body

Answer 21

exogenous glucose

Question 22

during hours 4-16 where is most of the glucose for the body coming from

Answer 22

glycogen

Question 23

after hour 16, what is the primary source of glucose in the body

Answer 23

gluconeogenesis - formation of new glucose

Question 24

during starvation what is a important ketone body that supplies the brain with fuel

Answer 24

B-hydroxy-butyrate

Question 25

why is total nitrogen excretion is decreased during starvation

Answer 25

Cause body is trying to spare proteins

Question 26

What happens to Urea and what happens to NH3

Answer 26

Urea decreases
NH3 increases

Question 27

Why less urea and more NH3

Answer 27

This is because putting urea out requires much more enrgy than ammonia

Question 28

how are ketones made in the liver in starvation

Answer 28

from catabolism of fat

Question 29

what are the inter-tissue relationships during starvation driven by

Answer 29

Driven by high glucagon to insulin ratio in response to low glucose

Question 30

what do cortisol and adrenaline do in the response to starvation and what are they related to

Answer 30

Related to stress + fight and flight response which will both help along with glucagon in the response to starvation

Question 31

what becomes the prominent hormone when starved

Answer 31

glucagon

Question 32

what is the regulation of fat metabolism in the liver by glucagon during starvation

Answer 32

glucagon inhibits the pathway so that fats can be used to produce ketone bodies instead of bing synthesised

Question 33

what enzyme is inhibited by glucagon in the fatty acid synthesis pathway during starvation and what does this do

Answer 33

acetyl CoA carboxylase

increases Acetyl CoA levels that can be used to make ketone bodies

stops the synthesis of fatty acids through inhibiting malonyl CoA, which promotes B oxidation in mitochondria

Question 34

what does acetyl CoA carboxylase do in fat metabolism

Answer 34

converts acetyl CoA to malonyl CoA

Question 35

why does glucagon inhibit the synthesis of fatty acid during starvation

Answer 35

you need fatty acid for fuel, they need to be going through the B oxidation pathway to make ATP

Question 36

what does malonyl CoA usually do in fatty acid synthesis if there are significant amounts of it around and when would we not want this to be happening

Answer 36

usually inhibits the fatty acids being transported into the mitochondria, which inhibits B oxidation (not what we want to be happening during starvation)

Question 37

does your ability to make ketone bodies depend on age and if so why

Answer 37

yes ketosis is enhanced in new borns because of their low carbohydrate diet and reduced ability to use gluconeogenesis

Question 38

when is your ability to make ketones also increased and why

Answer 38

pregnancy and lactation due to increased glucose requirements

Question 39

what do ketogenic diets produce

Answer 39

promote the use of body fat and ketones

Question 40

why do ketogenic diets reduce insulin secretion

Answer 40

due to low carbohydrates