Hormones and the regulation of blood glucose concentration

Question 1

hormones are

Answer 1

• produced in the glands which secrete the hormone directly into the blood
• carried in the blood plasma target cells which have specific receptors in their cell surface membrane that are complementary to a specific hormone
• are effective in very low concentration but have widespread and long lasting effects

Question 2

what is the second messenger model

Answer 2

• used by 2 hormones involved in the regulation of blood glucose concentration namely adrenaline and glucagon

Question 3

mechanism involving adrenaline and glycogen

Answer 3

1. adrenaline binds to a trans membrane protein receptor within the cell surface membrane of a liver cell
2. the binding of adrenaline causes the protein to change shape on the inside of the membrane
3. this change of protein shape leads to the activation of adenyl cyclase. The activated adenyl cyclas converts ATP to cyclic AMP (cAMP)
4. the cAMP acts as the second messenger that binds to protein kineses enzyme changing its shape and activating it
5. the active protein kinase enzyme catalyses the conversion of glycogen to glucose which moves out of the liver cell by facilitated diffusion and into the blood , through channel proteins

Question 4

what is the pancreas

Answer 4

• large gland in the upper abdomen
• produces enzymes protease, amylase and lipase for digestion
• produces hormones insulin and glucagon for regulating blood glucose concentration

Question 5

what is the islets of Langerhans

Answer 5

• hormone producing cells
• includes alpha cells which are larger and produced glucagon
• beta cells which are smaller and produce insulin

Question 6

what is the liver

Answer 6

• located underneath the diaphragm
• made up of hepatocytes cells
• regulates blood glucose concentrations

Question 7

what are the 3 process associated with regulating blood sugar levels

Answer 7

• glycogenesis
• glycogenolysis
• gluconeogenesis

Question 8

what is glycogenesis

Answer 8

• the conversion of glucose into glycogen
• when blood glucose concentration is higher than normal the liver removes glucose from the blood and converts it into glycogen
• can store 100g of glycogen which is sufficient to a humans blood glucose concentration for 12 hours at rest

Question 9

what is glycogenolysis

Answer 9

• the breakdown of glycogen to glucose
• when blood glucose concentration is lower than normal the liver can covert stored glycogen back into glucose which diffuses into the blood to restore the normal blood glucose concentration

Question 10

what is gluconegenesis

Answer 10

• the production of glucose from sources other than carbohydrates
• the supply of glycogen is exhausted the liver can produce glucose from non carbohydrate sources such as glycerol and amino acids