15.1 - The principles of homeostasis

Question 1

Homeostasis

Answer 1

Maintenance of a stable equilibrium in the conditions inside the body

Question 2

Receptors

Answer 2

Detect stimuli (change in the environment)

Question 3

Effectors

Answer 3

Muscles or glands that react to a stimulus to bring about a change in response to a stimulus

Question 4

Negative feedback systems

Answer 4

Small change in one direction is detected by sensory receptors
Effectors work to reverse the change and restore conditions to base level
Negative feedback work to reverse the initial stimulus

Question 5

Positive feedback systems

Answer 5

Change in the internal environment is detected by sensory receptors
Effectors are stimulated to reinforce that change and increase the response

Question 6

Positive feedback with blood vessel damage

Answer 6

When a blood vessel is damaged, platelets attach to the damaged region - release factors that initiate clotting and attract more platelets
Platelets add to the positive feedback cycle and continue until clot is formed

Question 7

Positive feedback in childbirth

Answer 7

Head of baby presses against cervix - stimulating oxytocin production
Oxytocin stimulates uterus contractions
Baby’s head is pushed harder against the cervix and triggers release of more oxytocin
This continues until the baby is born