B1 Staying in Balance mindmap

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  • Created by: Spanish
  • Created on: 30-04-16 13:23
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  • Staying in balance
    • Homeostasis
      • Keeping a constant internal environment
      • Homeostasis involves balancing bodily inputs and outputs
      • Automatic control systems keep the levels of temperature, water and carbon dioxide steady.
        • This makes sure that all cells can work at their optimum level
      • Negative feedback controls are used in homeostasis
        • Negative feedback systems act to cancel out a change such as a decreasing temperature level
    • Temperature Control
      • The body temperature of 37 degrees Celsius is linked to the optimum temperature for many enzymes
        • A high temperature can cause; heat stroke, dehydration
      • To avoid overheating sweating increases heat transfer from the body to the environment
        • The evaporation of sweat requires body heat to change the liquid sweat into water vapor
      • A low temperature can cause hypothermia which can be fatal if not treated
      • Blood temperature is monitored by the hypothalamus gland in the brain. Reaction to temperature extremes are controlled by the nervous and hormonal systems, which trigger vasoconstriction or vasodilation
        • Vasoconstriction is the constriction (narrowing) of small blood vessels in the skin. This causes less blood flow and less heat transfer
          • Vasodilation is the dilation (widening) os small blood vessels in the skin. This causes more blood flow near the skin surface resulting in more heat trasnfer
    • Control of blood sugar levels
      • A hormone called insulin controls blood sugar levels.
      • Hormone action is slower than nervous reactions as the hormones travel in the blood.
      • Type 1 diabetes is cause by the pancreas not producing any insulin, so must be treated by doses of insulin
        • Type 2 diabetes, which is caused either by the body producing too little insulin or the body not reacting to it, can be controlled by diet
          • Insulin converts excess glucose in the blood into glycogen, which is stored in the liver. This regulates the blood sugar level
            • Insulin dosage in type 1 diabetes needs to vary according to the person's diet and activity. Strenuous exercise needs more glucose to be present in the blood, so a lower insulin dose is required


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