Hormones & the regulation of blood glucose concentration

Question 1

What are hormones?

Answer 1

• chemical messengers
• secreted form glands into the blood
• carried by the blood plasma to target cells
• widespread, long lasting effects

Question 2

What is the second messenger model?

Answer 2

• hormones activate chemical pathways in calls by binding to receptors on the cells to create a second messenger chemical to be produced in cells by activating an enzyme in the cell by changing its tertiary structure
• for example adrenaline causes ATP to produce cAMP which activates an enzyme which converts glycogen to glucose

Question 3

What is the role of the pancreas in regulating blood glucose?

Answer 3

-it produces enzymes for digestion and the hormones insulin and glycogen from the islets of Langerhans

Question 4

What are the cells of the islets of Langerhans?

Answer 4

• alpha cells = larger, produce glucagon when there is a low concentration of glucose as glucagon converts glucose to glycogen and forms glucose from glycogen
• beta cells = smaller, produce insulin when the blood glucose level is high as it opens chemical pathways for glucose to be stored as glycogen and fat, it also increases the respiratory rate

Question 5

Which sources do blood glucose come from?

Answer 5

• hydrolysis of food
• glycogenolysis
• gluconeogenesis

Question 6

What is blood glucose?

Answer 6

• normally 90mg
• eating increases blood glucose
• exercise decreases blood glucose

Question 7

What does adrenaline do?

Answer 7

• produces glucose for the fight or flight response
• produces by adrenal glands above the kidneys
• breaks down glycogen
• synthesises glycogen

Question 8

What is the feedback mechanism?

Answer 8

• glucagon increases glucose levels

- insulin decreases glucose levels which prevents it ever getting too high or too low

Question 9

What are the three important processes associated with regulating blood sugar which take place in the liver?

Answer 9

• glycogenesis: the conversion of glucose into glycogen when glucose concentration is high
• glycogenolysis: breakdown of glycogen to glucose when glucose concentration is low
• gluconeogenesis: glucose is produced from glycerol and amino acids when there is no glycogen