14.1 Hormonal Communication

Question 1

What is an endocrine gland?

Answer 1

An endocrine gland is a group of cells which are specialised to secrete hormones.
Has no ducts

Question 2

What are hormones?

Answer 2

Hormones are chemical messengers which travel around the body in the blood stream.

Question 3

Which hormones does the pituitary gland produce?

Answer 3

• Growth hormone
• Anti-diuretic hormone
• Gonadotrophins

Question 4

What is the role of the growth hormone?

Answer 4

controls growth of bones and muscles

Question 5

What is the role of the anti-diuretic hormone?

Answer 5

The anti-diuretic hormone increases reabsorption of water in the kidneys.

Question 6

What is the role of gonadotrophins?

Answer 6

Gonadotrophins control the development of ovaries and testes

Question 7

What hormone does the thyroid gland produce and what is it responsible for?

Answer 7

Thyroxine.

• Controls rate of metabolism
• Controls rate that glucose is used up in respiration
• Promotes growth.

Question 8

What hormone does the adrenal gland produce and what is it responsible for?

Answer 8

Adrenaline.

• Increases heart and breathing rate
• Raises blood sugar level

Question 9

What hormone does the testes produce and what is it responsible for?

Answer 9

Testosterone.

- Controls sperm production and secondary sexual characteristic.

Question 10

What hormone does the pineal gland produce and what is it responsible for?

Answer 10

Melatonin.

- Affects reproductive development and daily cycles.

Question 11

What hormone does the thymus produce and what is it responsible for?

Answer 11

Thymosin.

- Promotes production and maturation of white blood cells.

Question 12

What hormone does the pancreas produce and what is it responsible for?

Answer 12

Insulin: Converts excess glucose into glycogen in the liver.
Glucagon: Converts glycogen back to glucose in the liver.

Question 13

What hormone does the ovary produce and what is it responsible for ?

Answer 13

• Oestrogen: Controls ovulation and secondary sexual characteristics
• Progesterone: Prepares uterus lining for receiving an embryo

Question 14

How are hormones transported to target cells?

Answer 14

1) The hormones diffuse out of the blood and bind to specific receptors for that hormone, found on the membranes or in the cytoplasm of target cells.
2) Once bound to their receptors the hormones stimulate the target cells to produce a response.

Question 15

What are steroid hormones?

Answer 15

• Steroid hormones are lipid-soluble.
• They pass through the lipid component of the cell membrane and bind to steroid hormone receptors to form a hormone-receptor complex.

Question 16

Give an example of steroid hormones.

Answer 16

Oestrogen

Question 17

What are non-steroid/peptide hormones?

Answer 17

• Non-steroid hormones are hydrophilic so cannot pass directly through the cell membrane,
• Instead they bind to specific receptors on the cell surface membrane of the target cell.
• This triggers a cascade reaction mediated by chemicals called secondary messengers/cAMP

Question 18

Give examples of non-steroid hormones

Answer 18

Adrenaline

Question 19

What are the two parts of the adrenal gland?

Answer 19

1) The adrenal cortex

2) The adrenal medulla

Question 20

What are three main types of hormones produced by the adrenal cortex?

Answer 20

1) Glucocorticoids
2) Mineralocorticoids
3) Androgens

Question 21

What main hormone is produced from glucocorticoids and what is it responsible for?

Answer 21

Cortisol.

• regulates metabolism of proteins and glucose
• regulates blood pressure and cardiovascular function in response to stress.

Question 22

What other hormone is produced from glucocorticoids and what is responsible for?

Answer 22

Corticosterone.

- This works with cortisol to regulate immune response and suppress inflammatory reactions.

Question 23

What main hormone is produced from mineralocorticoids and what is it responsible for?

Answer 23

Aldosterone.
- Helps control blood pressure by maintaining blood pressure between salt and water concentration in the blood and bodily fluids.

Question 24

What hormones do androgens produce?

Answer 24

Small amounts of male and female sex hormones.

Question 25

When are the hormones of the adrenal medulla released?

Answer 25

Hormones of the adrenal medulla are released when the sympathetic nervous system is stimulated, and when the body is stressed.

Question 26

What hormones are secreted by the adrenal medulla?

Answer 26

• Adrenaline

- Noradrenaline

Question 27

What is the role of adrenaline?

Answer 27

• Adrenaline increases the heart rate sending blood quickly to muscles and brain.
• Rapidly raises blood glucose concentration levels by converting glycogen to glucose in the liver.

Question 28

What is the role of noradrenaline?

Answer 28

This hormone works with adrenaline in response to stress, producing effects such as:

• Increased heart rate
• Widening of pupils
• Widening of air passages in the lungs
• Narrowing of blood vessels in non-essential organs.