Homeostatsis

Question 1

Homeostasis

Answer 1

The maintenance of relatively stable conditions within the internal environment

Question 2

Steps in a feedback loop

Answer 2

Receptor
Control centre
Effector

Question 3

Receptor

Answer 3

Detects changes (produced by a stimulus) in the controlled condition and sends a signal to the control centre

Question 4

Control centre

Answer 4

Set the range of values that controlled condition should be maintained. It receives inputs from the receptor, evaluates these inputs and sends signals to effectors if required

Question 5

Effector

Answer 5

The structure receives outputs from the control centre and subsequently produces a response that acts to change the controlled condition

Question 6

Negative feedback loop

Answer 6

Tends to decrease change or revert to before the stimulus occur

Question 7

Example of Negative feedback loop

Answer 7

Body temp
Skin receptor detects increase in temp and sends to control centre
Regions in the brain receive the receptors signals evaluates and sends impulses to the effector
Blood vessels dilate to increase blood flow to the skin and sweat glands increase secretions to allow heat loss to the environment

Question 8

Positive Feedback loop

Answer 8

Produces a response from the effectors to further change the controlled condition

Question 9

Examples of positive feedback loop

Answer 9

Blood clotting
Damage to the cells in blood vessel wall releases chemicals that begin the process of blood clotting
As clotting continues each step releases chemicals that further accelerate the process
The escalating process finishes with the formation of a blood clot with patches the vessel wall and stops the bleeding