Homeostasis; Thermoregulation A2/A level Biology
- Created by: evaabarry
- Created on: 01-03-22 18:05
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- Homeostasis: Thermoregulation
- Receptors that detect changes in core temperature= THERMORECEPTORS
- Found ; Hypothalamus in the brain
- Thermoreceptors in skin detect changes in external environment
- When receptors detect temperature rise
- 1.) Impulses sent along motor neurones to arterioles in skin , causing muscle in their walls to relax. - causes arterioles to widen (vasolidation) allowing more blood to flow to capillaries at skin surface. - Allows more heat to be lost from blood to environment
- 2.) Impulses sent along motor neurones to sweat glands in skin, causing more secretion of sweat. - Water in sweat evaporates, taking heat from skin, therefore cooling the body
- If receptors detect temperature fall
- 1.) Impulses sent along motor neurones to arterioles in skin , causing arterioles to become narrower (Vasoconstriction) , allowing less blood flow to capillaries at skin surface. - Allows heat loss from blood to environment
- 2.) Impulses sent along sensory neurones to skeletal muscles , causing contraction and relaxing rapidly (shivering) , generating heat thats transferred to body
- 3.) In non human mammals ; erector muscles stimulated to contract, raising hairs on end and trapping a layer of air between hairs on skin. -Air is good insulator, reduces heat loss from body
- This control mechanism is a good example of negative feedback
- Receptors that detect changes in core temperature= THERMORECEPTORS
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