Principles of hormonal control

Question 1

What is the endocrine system?

Answer 1

The endocrine system is composed of glands that secrete chemicals called hormones directly into the blood stream. The blood carries hormones to a target hormone to a target organ where it produces an effect.

Question 2

What is a hormone?

Answer 2

Is a molecule made in one part of the body and then transported to another part of the organism where it has an effect.

Question 3

Where are hormones made in the endocrine system?

Answer 3

They are made in the endocrine glands and are secreted directly into the blood stream.

Question 4

How does the target organ detect the hormones?

Answer 4

The target organ has receptors on the cell membranes that pick up the hormone molecules, triggering a response in the cell.

Question 5

What are some rapid response hormones in the endocrine system?

Answer 5

Insulin which controls the blood glucose levels, and adrenaline, which prepares the body for flight or fight.

Question 6

What are some slow acting hormones?

Answer 6

Growth hormones and sex hormones.

Question 7

What hormones does the pituitary gland secrete and the roles those hormones plays in the endocrine system?

Answer 7

1. ADH: affects the amount of urine produced by the kidney.
2. Growth hormone: controls the rate of growth in children
3. TSH: Stimulates the thyroid gland to make thyroxine, a hormone that helps control the rate of metabolism.
4. FSH:
   a) In females, stimulates ovaries to make oestrogen and to produce and release eggs.
   b) In males, stimulates the testes to make sperm and the male sex hormone testosterone.

Question 8

What hormone does the thyroid gland produce and what role does it play in the endocrine system?

Answer 8

Thyroxine: Controls the metabolic rate of the body.

Question 9

What hormone does the pancreas secrete and what role does it play in the endocrine system?

Answer 9

Insulin: controls the level of glucose in the blood.

Question 10

What hormone does the adrenal gland secrete and what role does it play in the endocrine system?

Answer 10

Adrenaline: prepares the body for fight or flight response.

Question 11

What hormones does the ovaries produce and what role does it play in the endocrine system?

Answer 11

Oestrogen: controls the development of the female secondary sexual characteristics and is involved in the menstrual cycle.

Question 12

What hormone does the testes produce and what role does it play in the endocrine system?

Answer 12

Testosterone: Controls the development of the male secondary sexual characteristics and is involved in the production of sperm.