Lecture 26 Flashcards
(46 cards)
What does the brain do when it is under starvation?
It can adapt because it has no significant fuel store and can use ketone bodies.
What does the brain do with energy?
It stores little energy as glycogen and relies on circulating glucose for fuel. It uses it to drive the ion pump that maintain membrane potentials.
What type of fuel does muscle use?
glucose, fatty acids, and ketone bodies
What type of energy does resting muscle use?
fatty acids from blood
What type of fuel does muscle exertion use?
glucose from muscle glycogen an then fatty acids
What is true about muscles?
It stores 3/4 of body’s glycogen and the remaining in the liver
What are the primary substrates of the heart metabolism to generate ATP?
fatty acids, ketone bodies, glucose, and lactate
How does metabolism of the heart differ from skeletal muscle?
Work output is more constant, the heart is a completely aerobic tissue, and the heart has few energy reserves as creatibe phosphate
What function does adipose tissue serve?
heat insulation, mechanical cushion, and source of energy
What are adipocytes designed for?
Continuous breakdown and synthesis of TGs via activation of hormone-sensitive lipases
What is the role of the liver?
Synthesize fuel for use by other organs such as fatty acids, glucose from lover glycogen stores via gluconeogenesis, glycerol from adipose tissue or aa, ketone bodies synthesis
What is the role of the liver and blood glucose?
It regulates blood glucose levels via the liver-specific enzyme, hexokinase IV (glucokinase), and the transport protein, the glucose transporter (GLUT2 – carries out facilitated diffusion of glucose
What is glucokinase?
A kinase found in the liver. It does not have a high affinity for glucose. Only saturated for 50-100mM. Only active for a lot of glucose.
What is hexokinase?
A kinase found anywhere but the liver. It has a high affinity for glucose. Saturated for all concentrations. Active at all times
How is hexokinase regulated?
Negative feedback by glucose 6-P
What happens where there is a lot of glucose?
Glucokinase is activated and hexokinase to be inhibited and glycogen can be synthesized for storage
What is the role of glucokinase?
produce glucose 6-P for glycogen synthesis
What glycolysis does blood use?
It uses anaerobic glycolysis for all energy needs because there is no mito.
What is the physiological action(or role) of insulin?
it lowers blood glucose levels
What is the physiological action(role) of glucagon?
increases the blood glucose level
What is the physiological action(role) of epinephrine?
It increases blood glucose level during fight or flight
What is the role of insulin
It is secreted by the pancreas and has endocrine and exocrine properties. The pancreas are also secreted by beta cells
What do beta cells do?
sense blood glucose levels by taking up and catabolizing glucose.
What does insulin do during eating?
It indicates fed state and uptake of fuel into muscle and adipose, storage of fuels, and biosynthesis of macromolecules
