Coordination And Control: Temperature Control
14.5 Temperature Control
Organs And Structures Involved
- Skin → receptors, sweat glands, blood vessels, hairs, hair erector muscles, fatty tissue.
- Hypothalamus (brain) → detects blood temperature and coordinates response.
Insulation
- Fatty tissue under skin reduces heat loss.
- Hair/fur trap air for insulation.
Responses To High Temperature
- Sweating ↑ → evaporation removes heat.
- Vasodilation → arterioles widen, more blood to skin surface, more heat lost.
- Hairs lie flat → less air trapped, more heat lost.
Written And Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions And 11 World Records For Educate A Change O Level And IGCSE Biology Full Scale Course
Responses To Low Temperature
- Shivering → rapid muscle contractions generate heat.
- Vasoconstriction → arterioles narrow, less blood at skin surface, less heat lost.
- Hair erector muscles contract → hairs stand upright, trap insulating air layer.
Key Points
- Homeostasis keeps body temp ~37°C for enzyme function.
- Controlled by negative feedback via hypothalamus.
- Behavioural responses (e.g., seeking shade, wearing clothes) also help regulate.
Written And Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions And 11 World Records For Educate A Change O Level And IGCSE Biology Full Scale Course