Control of Blood Glucose Concentration (WIP)

Question 1

What does the pancreas do?

Answer 1

Regulate blood glucose through the production of insulin and glucagon.

Question 2

Why do we need a maintain a supply of glucose?

Answer 2

Cells require glucose for respiration to release energy for cellular processes. Glucose moves from the blood into cells via diffusion and so we must maintain a concentration gradient.

Question 3

What cells produce insulin + glucagon and where are they found?

Answer 3

Alpha cells produce the hormone glucagon. Beta cells produce the hormone insulin. Alpha and beta cells are found in the islets of Langerhans in the pancreas.

Question 4

Describe the mechanism of action for insulin / how insulin is produced.

Answer 4

Beta cells act as receptors and detect a rise in blood glucose + release insulin. Insulin stimulates the uptake of glucose by most respiring cells (mainly liver + muscle). In some cells this is done by opening up glycoprotein receptors on cell surface which bind with insulin.

Question 5

How does insulin increase the permeability of the liver to glucose?

Answer 5

Insulin binds to receptors on the surface of the target liver cells. This causes a conformational change to the tertiary structure of the channel proteins to allow more facilitated diffusion of glucose into the cells. It also causes the release of an intracellular signalling molecule which triggers the release of channel protein-containing vesicles which fuse with the cell membrane (exocytosis).