Homeostasis

Question 1

What is homeostasis

Answer 1

Maintenance of a near constant internal environment

Question 2

What is the process of homeostasis?

Answer 2

1. Stimulus
   - Change in a controlled condition
2. Receptor
   - Detects a stimulus in the internal body eg. Change in temperature
   - Sends nerve impulses to CC or EFFECTOR
3. Control Center (Optional)
   - Determines how body responds
   - In nerve impulses or hormones
4. Effector
   - Produces responses to lead to change in stimulus

Action restores parameter back to set norm by negative feedback

Question 3

What is the homeostatic process of thermoregulation?

Answer 3

• Thermoreceptors in the skin detect changes to skin temperature (stimulus) -> send nerve impulses to the hypothalamus
• The hypothalamus acts as a control centre, activating mechanisms that promote heat loss or gain (action)
• The hypothalamus sends nerve impulses to the relevant body parts (effectors)
• This allows temperature to return to set norm and reverses the stimulus

Question 4

What actions happen with rise of skin temperature?

Answer 4

1. Vasodilation of skin arterioles, more blood flow through capillaries -> more heat lost by radiation convection and conduction
2. Sweat glands become more active -> increased sweat production -> More water in sweat evaporates from surface of skin -> more heat loss
3. Decreased metabolic rate -> reduced the amount of heat released within body

Question 5

What actions happen to increase body temperature

Answer 5

1. Vasoconstriction of skin arterioles, less blood to flow through capillaries -> reduces heat lost by radiation convection and conduction
2. Sweat glands become less active -> decreased production of sweat -> less water in sweat evaporates from surface of skin -> less heat loss
3. Increased metabolic rate -> increase the amount of heat released within body
4. If needed, shivering reflex contraction of the body muscles occurs -> contractions of muscles increases amount of heat released