Regulating Blood Glucose

Question 1

Pancreas

Answer 1

Exocrine and endocrine functions

Question 2

Exocrine functions

Answer 2

Secretes digestive enzymes into the pancreatic duct which leads to the small intestine

Question 3

Endocrine functions

Answer 3

In the pancreas there are patches of tissues called the Islets of Langerhans

Contain alpha and beta cells

Alpha cells secrete GLUCAGON

Beta cells secrete INSULIN

Question 4

Glycogenesis

Answer 4

Synthesis of glycogen from glucose molecules

Triggered by insulin after an increase in blood glucose concentration

Removes glucose from the blood — decreasing blood glucose concentration

Question 5

Glycogenolysis

Answer 5

Breakdown of glycogen into glucose

Triggered by glucagon after a decrease in blood glucose concentration

Activates enzymes in the liver that breakdown glycogen

Releases more glucose into the blood to increase blood glucose conc within the normal range

Question 6

Gluconeogenesis

Answer 6

Synthesis of glucose from fats and amino acids

Triggered by glucagon by activating enzymes within the liver

Glucose molecules enter blood increasing blood glucose conc

Question 7

Hypoglycaemia

Answer 7

What happens when blood glucose is too low for too long

Inadequate supply of glucose to tissues

Can lead to seizures, unconsciousness and death

Question 8

Hyperglycaemia

Answer 8

What happens when glucose levels are too high for long periods of time

Organ damage and cell dehydration

Question 9

If blood glucose rises too high…

Answer 9

Detected by beta cells in Islets of Langerhans

Secrete insulin into blood and travel to target cells - liver and muscle (mainly)

Binds to receptor in membrane of target cells and activates the enzyme on the inside of the membrane attached to the receptor

Causes vesicle made of membrane with GLUT4 embedded to move and fuse with the membrane

Protein changes allow glucose to enter the cell

Glucose converted into glycogen (GYLYCOGENESIS) or used in respiration etc.

Question 10

If blood glucose drops too low…

Answer 10

Detected by alpha cells of Islets of Langerhans

Secretes glucagon into blood and travels to target cells - hepatocytes (liver)

Glucagon or adrenaline attaches to receptor in membrane of hepatocytes

Stimulates a protein in the membrane that activates adenylate cyclase inside each cell

Converts ATP into cyclic AMP (cAMP) which activates protein kinase A which intern activates a cascade that causes GLYCOGENOLYSIS