Hormonal Communication

Question 1

What is thermoregulation?

Answer 1

the control of body temperature

Question 2

What is osmoregulation?

Answer 2

the control of the water potential of body fluids

Question 3

What is a hormone?

Answer 3

a chemical messenger produced by an endocrine gland and carried by the blood

Question 4

Where are the adrenal glands located?

Answer 4

above each kidney

Question 5

What are the two main areas in the structure of the adrenal glands?

Answer 5

a central medulla and an outer cortex

Question 6

What type of hormone is released from the adrenal cortex?

Answer 6

steroid hormones

Question 7

What are the three categories of steroid hormones?

Answer 7

• glucocorticoid
• mineralocorticoid
• androgen

Question 8

What is glycogenesis?

Answer 8

production of glycogen from glucose

Question 9

What is gluconeogenesis?

Answer 9

production of glucose from non-carbohydrate sources so liver can make glucose from lipids and amino acids

Question 10

What is glycogenolysis?

Answer 10

process in which glycogen stored in the liver and muscle cells is broken down into glucose which is released into the bloodstream and increases blood glucose concentration

Question 11

What is glucagon?

Answer 11

a hormone released to increase blood glucose concentration and is produced by alpha cells in islets of Langerhans in pancreas

Question 12

What is glycogen?

Answer 12

a branched polysaccharide formed from alpha glucose molecules. A chemical energy store in animal cells.

Question 13

What is glucose?

Answer 13

a monosaccharide with the chemical formula C6H12O6. One of the main products of photosynthesis in plants

Question 14

What are the steps in the control of insulin secretion?

Answer 14

1, At normal blood glucose concentration levels, potassium channels in the plasma membrane of beta cells are open and potassium ions diffuse out of the cell. The inside of the cell is at a potential of -70mV with respect to the outside of the cell.
2, When blood glucose concentration rises, glucose enters the cell by a glucose transporter.
3, The glucose is metabolised inside the mitochondria, resulting in the production of ATP.
4, The ATP binds to potassium channels and causes them to close. They are known as ATP-sensitive potassium channels.
5, As potassium ions can no longer diffuse out of the cell, the potential difference reduces to around -30mV and depolarisation occurs.
6, Depolarisation causes the voltage-gated calcium channels to open.
7, Calcium ions enter the cell and cause secretory vesicles to release the insulin they contain by exocytosis.