Hormonal coordination in humans 5.3

Question 1

Give the name of the body’s coordination system which involves hormones

Answer 1

The endocrine system

Question 2

What is a hormone?

Answer 2

A hormone is a chemical messenger secreted by a gland. It travels in the blood to a target organ, where it causes a response

Question 3

What type of organ secretes hormones?

Answer 3

Glands

Question 4

Which gland controls many other glands in the body?

Answer 4

The pituitary gland

Question 5

Why is the pituitary gland considered a ‘master gland’?

Answer 5

It secretes a wide range of hormones, some of which may stimulate other endocrine glands

Question 6

What is the role of the pituitary gland in the endocrine system?

Answer 6

• Secretes human growth hormone - controls human growth
• Stimulates the thyroid gland
• Stimulates ovulation and the production of oestrogen in the ovaries
• Stimulates the production of sperm and testosterone in the testes

Question 7

What is the role of the thyroid gland in the endocrine system?

Answer 7

Secretes the hormone thyroxine - controls the metabolism, heart rate and body temperature

Question 8

What is the role of the pancreas in the endocrine system?

Answer 8

Secretes the hormone insulin - controls the bloods glucose levels

Question 9

What is the role of the adrenal gland in the endocrine system?

Answer 9

Secretes adrenaline - controls the body’s ‘fight or flight’ response

Question 10

What is the role of the ovaries in the endocrine system?

Answer 10

Secrete oestrogen, which coordinates the menstrual cycle and the development of female secondary sexual characteristics

Question 11

What is the role of the testes in the endocrine system?

Answer 11

Secrete testosterone, which coordinates the production of sperm and the development of male secondary sexual characteristics

Question 12

Which organ monitors and controls blood glucose concentration

Answer 12

The pancreas

Question 13

How does the pancreas respond when blood glucose levels are too high?

Answer 13

The pancreas secretes the hormone insulin. Insulin binds to receptors on the liver and muscles, causing excess glucose to be converted into glycogen and stored

Question 14

How does the pancreas respond when blood glucose levels are too low?

Answer 14

The pancreas secretes the hormone glucagon. Glucagon binds to liver cells, causing glycogen to be converted into glucose and released into the blood

Question 15

How is blood glucose concentration controlled using a negative feedback loop?

Answer 15

• When the blood glucose concentration rises or falls below the optimum, a hormone is secreted by the pancreas
• The action of either hormone (insulin or glucagon) helps bring back the concentration to the correct level

Question 16

What is Type 1 diabetes?

Answer 16

Type 1 diabetes is an autoimmune disorder in which the pancreas does not produce sufficient insulin to control the blood glucose concentration. As a result, blood glucose levels are often very high, leading to excessive urination, tiredness and weight loss

Question 17

How can Type 1 diabetes be treated?

Answer 17

• Insulin injections before meals - allows glucose to be converted into glycogen
• Limiting carbohydrate intake
• Attempts using pancreas and pancreatic cell transplants: investigation into genetic engineering of pancreatic cells

Question 18

What is Type 2 diabetes?

Answer 18

Type 2 diabetes is a disorder in which the body’s cells stop responding to insulin, leading to an uncontrolled blood glucose concentration. Its onset is linked with increasing age and obesity

Question 19

How can Type 2 diabetes be treated?

Answer 19

• Following a carefully controlled diet
• Doing regular exercise
• Losing weight
• Use of drugs which increase insulin production and effectiveness

Question 20

What is osmosis?

Answer 20

Osmosis is the movement of water from a dilute solution to a concentrated solution through a partially permeable membrane

Question 21

In what ways is water lost from the body?

Answer 21

• During exhalation via the lungs
• Sweating
• Urine (some reabsorbed in the kidney)

Question 22

In what way are ions lost from the body?

Answer 22

• Sweating

- Urine (some reabsorbed in the kidney)