101: Lec 11

What part of the pancreas secretes hormones?

Islets of Langerhan

In a fed state, what are the levels of glucose, insulin, and glucagon?

BGL are high, causing a spike in insulin and a drop in glucagon

Why does glucagon drop exactly when insulin increases?

The secretion of insulin suppresses glucagon

How many amino acids is glucagon and what cells secrete it?

29 amino acids long, alpha cells in pancreas

How does glucagon raise BGL?

How many amino acids is insulin and what cells secrete it?

51 amino acids long, and beta cells in pancreas

How does insulin lower BGL?

What are the other effects of insulin?

Where does insulin mainly promote glycogen storage?

Liver and skeletal muscle

Describe the whole process of insulin release

When BGL are high, GLUT2 on pancreatic beta cells allows glucose into the cell. This glucose undergoes glycolysis to make lots of ATP. The ATP binds to a potassium channel, causing Ca2+ to enter the cell and cause depolarization. This pushes insulin-filled vesicles out.

What do 80% of diabetics die from?

Heart failure

Type I diabetes

Type II diabetes

What cells in the pancreas produce proteases and in what form are these proteases?

Acinar cells, inactive form in the pancreas

What chains make up insulin upon release and then when mature?

Glucagon has chains A,B,C and insulin only has A,B because C gets chopped off

What is the function of the C chain after it is chopped off premature insulin?

Regulates iron in the kidneys

Is insulin a growth factor?

Yes

What does arginine do?

Stimulate insulin secretion

Describe the process of insulin promoting glucose uptake

Insulin binds to receptors on cells, which causes a signaling cascade that pushes glucose transporters to the surface of the cell. Then glucose can enter

How does diabetes affect the kidneys?

Causes nephropathy. This makes kidneys not filter properly and be bumpy

How does diabetes affect the eyes?

Causes retinopathy where the back of the eyes start to deteriorate