regulating body temp

• label:

  A) erector muscle

  B) sweat gland

  C) hair

  D) hair follicle

  E) sweat pore

  F) sweat duct

  G) blood vessel

  
• conditions that prevent effective sweating?

  humidity (sauna, rainforest, etc) & swimming pool
• how does sweat get removed from your skin?

  evaporation of the water on skin (sweat) into water vapour due to heat from skin
• how is sweat used when too hot?

  more sweat produced by sweat glands -> sweat travels up sweat ducts, out of sweat pores onto surface of skin -> heat from skin causes water in sweat to evaporate -> cooling you down
• sweat when too cold?

  less sweat produced and it is not released at sweat pore
• blood vessels when too hot?

  vasodilation - blood vessels become wider, increasing blood flow to surface of skin -> allows more heat to be lost from blood by RADIATION
• blood vessels when too cold?

  vasoconstriction - DIAMETER of blood vessels become narrower -> less blood flows to surface of skin -> less heat RADIATED away from skin
• vasodilation = blood vessels become wider to increase blood flow to surface of skin so more heat is lost by radiation
• vasoconstriction = diameter of blood vessels become narrower so less blood flows to surface of skin so less heat is lost from blood by radiation
• hairs when too hot?

  erector muscles relax -> hairs lie flat -> less insulating air is trapped -> more heat lost
• hairs when too cold?

  erector muscles contract -> hairs pulled up -> more insulating air trapped -> less heat lost
• how does shivering help when too cold?

  generates heat from muscles contracting and relaxing rapidly
• explain how increasing blood flow to the skin helps cool the body down

  allows more heat to be lost from blood by radiation, cooling body down as blood is warm
• explain how vasoconstriction and vasodilation work by negative feedback to maintain body's normal temp

  too cold: electrical impulses sent to blood vessels -> diameter of blood vessels narrow (vasoconstriction) -> reduces blood flow to surface of skin -> less heat lost by radiation

  too hot: electrical impulse -> vasodilation (diameter widens) -> increases blood flow to surface of skin -> increases heat loss as blood is warm

  both examples of how negative feedback helps to maintain a constant internal environment (homeostasis) in the body