Lesson 1: Homeostasis

Question 1

Give the definition of homeostasis.

Answer 1

• Homeostasis is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes.

Question 2

Why is it important that the conditions in the body are constant?

Answer 2

• Enzymes and cells don’t work well if conditions around them are constantly changing.

Question 3

What does homeostasis include the control of?

Answer 3

• Blood glucose concentration
• Body temperature
• Water levels.

Question 4

Which systems in the body are involved in homeostasis?

Answer 4

• Automatic control systems.
• These may include nervous responses or chemical responses (ie. hormones.)

Question 5

What three parts do all automatic control systems include?

Answer 5

1.) Receptor cells
2.) Coordination centres
3.) Effectors.

Question 6

What do receptor cells do?

Answer 6

• They detect stimuli (changes in the environment.)

Question 7

**Give 1 internal stimulus and 1 **external **stimulus

Answer 7

• Internal: change in blood glucose concentration.
• External: Temperature of skin (ie. touching something hot.)

Question 8

Give 3 examples of coordination centres in the body.

Answer 8

1.) Brain
2.) Spinal Chord
3.) Pancreas

Question 9

What do coordination centres do?

Answer 9

• Coordination centres receive and process information from receptors. Send instruction to effectors (to bring about a response.)

Question 10

What can effectors be?

Answer 10

• Muscles or glands.

Question 11

What does an effector do?

Answer 11

• An effector brings about a response to restore optimum levels in the body.