body temperature

• Thermoregulation


  The control of our internal body temperature
• We need to regulate our temperature to allow our cells to function properly
• Homeostasis


  The process of maintaining a stable internal environment
• Our body temperature needs to be kept around 37 degrees Celsius
• 37 degrees Celsius is the perfect temperature for our enzymes to function
• Thermoregulatory sensor


  A part of the hypothalamus within our brain that acts as a thermostat for our body
• Thermoregulatory sensor


  • Receives information about temperature changes from receptors in the body
  • Determines if we are too hot or too cold
  • Sends signals to warm us up or cool us down
• Warming up


  1. Conserve heat

  2. Generate more heat
• Conserving heat


  • Constrict blood vessels near skin surface (vasoconstriction)
  • Contract erector muscles to trap insulating air
• Generating more heat


  • Shiver (muscle contraction requires energy and produces heat)
• Cooling down


  1. Lose heat

  2. Evaporate sweat
• Losing heat


  • Relax erector muscles
  • Expand blood vessels (vasodilation) to allow more heat transfer
• Blood glucose concentration


  The amount of sugar in our bloodstream
• Evaporating sweat


  • Sweat is a mixture of water and salts released onto skin surface
  • Evaporation of sweat takes heat energy from the body
• We need a decent amount of sugar in our blood so that our cells have a constant supply of glucose for respiration
• If the blood glucose concentration gets too high it can start to damage our tissues
• What happens when we eat a big meal with lots of carbohydrates

  1. Carbohydrates broken down in intestines into glucose

  2. Glucose absorbed into bloodstream

  3. Blood glucose concentration increases
• Pancreas


  An organ that sits just behind the stomach
• How insulin regulates high blood glucose

  1. Pancreas detects high glucose

  2. Releases insulin into bloodstream

  3. Insulin binds to cells

  4. Cells take up glucose

  5. Glucose stored as glycogen
• Glycogen


  A long-term storage form of glucose
• How glucagon regulates low blood glucose

  1. Pancreas detects low glucose

  2. Releases glucagon into bloodstream

  3. Glucagon binds to liver cells

  4. Liver breaks down glycogen into glucose

  5. Glucose released into blood
• Insulin and glucagon


  Create a negative feedback loop to maintain normal blood glucose levels
• Our blood glucose concentration constantly changes or fluctuates rather than being a flat line