Thermoregulation

• What ways does the body use to maintain a constant body temperature?

  insulation, vasodilatation, vasoconstriction, sweating, skin receptors, shivering, thermoregulatory centre

  
• Insulation: provided by fatty tissue retains heat. Hairs become erect to trap warm air by contracting erector muscles and vice versa.

  
• Vasodilatation: when it is hot, arterioles, which supply blood to the skin-surface capillaries, dilate (become wider) to allow more blood near to skin surface to increase heat loss (face redder)

  
• Vasoconstriction: when it is cold, arterioles, which supply blood to the skin-surface capillaries, constrict (become smaller) to allow less blood near to skin surface to decrease heat loss

  
• Sweating: the water evaporates giving a cooling effect

  
• Skin receptors: sense heat and sensory neurons send impulses to the hypothalamus

  
• Shivering: muscular activity generates heat

  
• Thermoregulatory centre: in the hypothalamus, it controls the use of corrective mechanisms (e.g. sweating and shivering).