2.77b Thermoregulation 2

understand that homeostasis is the maintenance of a constant internal environment and that body water content and body temperature are both examples of homeostasis

Negative feedback loop - A method of control / maintaining constant conditions

Body temperature
Receptor: Hypothalamus
Hypothalamus responds to stimulus (body temperature / temperature of blood)
Co-ordinator - Compares the body temp. to the constant (37/38˚c)
Effector - Skin
Response - an increase or decrease of the body temperature
Response feeds back to the receptor

Source: www.click4biology.info

Source: www.click4biology.info

1. Features of the skin for temperature control
- Sweat glands
- Capillary network
Allows blood to move closer or further away from the surface of the skin

Source: www.wikimedia.org

2. Temperature regulation point / Time graph
- Body temp. increases => Cooling (sweating)
- Increased blood flow
- Vasodilation (blood vessels widen)
- More blood flow to the surface
- Increases exchange of heat to the outside of the body (sweat / radiation)
- Hairs flat
- Body temp. decreases => Heating
- Shivering
- Vasoconstriction (blood vessels constrict)
- Decreases heat exchange to the outside
- Raised hairs
- Efficiency of regulation varies with the amount of deviation from the x-axis

Source: www.click4biology.info