Changes In The Environment

Question 1

Two types of response

Answer 1

• chemical

- nervous

Question 2

How does the nervous system work?

Answer 2

The nervous system allows the body to respond to stimuli in the internal and external environment and is coordinated by the brain and/or spinal cord

Question 3

What does the endocrine system (chemical response) do?

Answer 3

The endocrine system allows the body to respond to stimuli in the external and internal environment and is coordinated by glands throughout the body

Question 4

What is homeostasis?

Answer 4

It is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal or external changes

Question 5

Examples of homeostasis

Answer 5

• body water content

- body temperature

Question 6

What does a coordinated response require?

Answer 6

A stimulus, receptor and effector

Question 7

Stimulus

Answer 7

Detects change in the environment

Question 8

Receptor

Answer 8

Receives message and detects stimuli

Question 9

Effector

Answer 9

Where messages from control center is directed to for initiating effect - brings about responses to restore optimum conditions

Question 10

Role of skin (hot)

Answer 10

When we are hot:

• erector muscles relax to cool the skin
• sweat is secreted by the sweat glands
• blood flow in capillaries increases because blood vessels close to the skin get wider - this is vasodilation
• more blood can flow near the surface, so it can transfer more energy to the surface

Question 11

Role of skin(cold)

Answer 11

When we are cold:

• erector muscles contract and pull hairs upwards
• erect hairs trap a layer of air around the skin which acts as an insulator
• blood flow in capillaries slow down because blood vessels close to the skin get narrower - this is vasoconstriction