lecture 5: feedback loops and the regulation of glucose Flashcards
(19 cards)
why is it important to control blood glucose levels
it is the main source of energy for the brain. Unlike skeletal muscles and the liver, the brain does not have glycogen stores. it can use fatty acids and ketones but very poorly.
what are the principles of feedback loops
- stimulus enters the body
- the change gets detected, in most cases thi is a receptor. with glucose we are talking about alpha and beta cells .
- the change relative to the set point triggers a response
what body functions provide a sink for glucose. out of this which is the largest
muscles, liver, fat and brain, muscle provides the biggest sink
what are the two transporters that move glucose in the membranes
SGLT and GLUT
what and where can you find SGLT transporters
SGLT transporters transport glucose AND Sodium. they are found in the small intestine and the kidney. they play a role in movement of glucose but not its control. it takes the glucose from the small intestine to the blood and the glucose from the urine in the nephron back to the body.
what are SGLT inhibitors and why are they important
they block glucose and can aid in type 2 diabetes-because type 2 diabetes struggles from increased glucose. this means instead of glucose going back into your body, it gets peed out instead.
what are the types of GLUT transporters and where can you find them
the GLUT 4 transporters can be found in muscles and fat while GLUT 2 can be found in liver.
why is it important to have mechanisms to regulate glucose and how do we do this.
during satiation state, the glucose will just continue to go up and during fasting state, the glucose will continue to go down (Sleeping). the glucose gets stored in the tissues and is release by the pancreas
what happens when glucose enters the muscles and then go out of the muscles
glucose will enter the muscles and be turned into glycogen b the pyruvate. during fasting and exercise, the glycogen is used as lactate.
how does fasting lead to the breakdown of muscles
fasting means that the muscle is not getting and energy (glucose). muscles will breakdown to form amino acids to be used as an energy source.
what happens when glucose enters and leave fat cells.
glucose enters the fat cells and turns into triglycerides by fatty acids and glycerol 3 phosphate. it then comes out as fatty acids and glycerol.
what happens when glucose enters and leaves the liver
glucose enters the liver through glycogenesis. glucagon from your pancreas will signal the liver to generate stored glycogen to make glucose. it can also, lactic acid, glycerol and fatty acids to make glucose or ketones
how is glucose regulated in muscle cells
its present in little vesicles inside the muscle cells. the insulin released from the pancreas will cause the vesicles to fuse with the cell membranes and that inserts the GLUT transporter into the membrane. they get attached and removed all then time- the insulin just makes this process quicker. This increases the amount of glucose that can get in the cell.
where are the GLUT 4 transporters located
they are located in the vesicles inside the cells. it works as soon as its in the membrane.
how is glucose regulated in fat cells
it works the same as muscle cells. the GLUT 4 is attached to the vesicles in the membrane which when activated by insulin, connects to the membrane allowing the glucose to be released more.
how does insulin work in liver
glucose will go in through GLUT 2 and converted to glycogen and accelerated by insulin naturally.
what does glucagon do
glucagon is an important hormone for when the blood glucose levels go too low. it targets stores of glycogen, turns them into glucose and deposits them back to the blood.
why is the GLUT 2 transporter always in the liver
this is important to make sure that generated glucose in the cell can also go out.
what is the main role of glucagon
its on the liver to ormolu glycogen breakdown and create glucose to be released back in the blood.
