thermoregulation

• what does a enzyme's opitmum temperature mean?

  the temperature at which they work best. The enzymes in the human body work best at 37 degrees.
• what 3 things happen when your body is too hot?

  1. erector muscles relax, so hairs lie flat.
  2. lots of sweat is produced in sweat glands in the dermis. It's released onto the surface of the skin through pores in the epidermis. When it evaporates it transfers energy from your skin to the environment.
  3. blood vessels close to the surface dilate (vasodilation) allowing more blood to flow near the surface, so it can transfer more energy into the surroundings.
• what 4 things happen when you're body is too cold?

  1. erector muscles contract. Hairs stand on end to trap an insulating layer of air near the surface of the skin, keeping you warm.
  2. very little sweat is produced.
  3. blood vessels near the surface of the skin constrict (vasoconstriction). Meaning less blood flows near the surface, so less energy transferred to the surroundings.
  4. you shiver (your muscles contract automatically), increasing rate of respiration, transferrig more energy to warm the body.
• what happens when the body goes above or below your enzyme's optimum temperature?

  below this temperature, enzyme activity slows down. above this temperature enzymes may start to denature so they can't work at all.
• what part of your body is basically a thermostat?

  the thermoregulatory centre in the hypothalamus
• what part of the body monitor the internal temperature as blood flows through the brain?

  receptors in the thermoregulatory centre of our brain.
• what do receptors on the surface of the skin do?

  monitor temperature at the surface of the body.
• what is vasodilation?

  blood vessels dilate to allow more blood to enter capillaries that pass close to the skin surface.
• what is vasoconstriction?

  blood vessels constrict to reduce blood flow in capillaries.
• why do we shiver when we're cold?

  When we are too cold, muscles start to contract automatically which makes us shiver. This process needs energy, which is generated through respiration. Respiration produces heat, which warms us up.
• why do we sweat when we're hot?

  sweat glands (in the middle layer of skin called dermis) release sweat, which covers the outer layer of skin (epidermis). Heat energy from the body is transferred to the water in this sweat and, when it has enough energy is evaporates. As it evaporates, it takes heat energy with it. This lowers average temperature of the body.
• why do our hair erector muscles contract when we are cold?

  This causes the hairs to stand up on end (which pull on the skin, giving you goosebumps). When all hairs are standing on end, they trap an insulating layer of air around the body.
• why do our blood vessels vasodilate when we're too hot?

  this allows more blood to enter and flow through capillaries close to the skin surface. The excess heat energy is transferred to the surroundings.
• why do our blood vessels vasoconstrict when we're too cold?

  this reduces the blood flowto the skin surface and heat energy is kept inside the body.
• what happens to muscular walls during vasoconstriction

  they contract
• what happens to muscular walls during vasodilation?

  they relax
• what is each hair on the body controlled by?

  a hair erector muscle in the dermis