low body temp

• changes blood flow so?

  less blood flows near skin surface
• what causes shivering?

  muscles contract and relax rapidly so energy from respiration warms you up
• what causes goosebumps?

  when body hairs are raisede by erector muscles in skin
• what happens when body hairs stand upright?

  traps air next to skin causing insulation
• function of hair muscles?

  contracts when cold to pull hairs upright trapping an insulating layer of air
• vasoconstriction?

  blood vessels are constricted so less blood flows near surface capilaries so less heat energy lost to surroundings