homeostasis

homeostasis

Is maintaining a stable internal enviroment
1. Conditions in your body need to be kept stable, for cells to fuction properly
Osmoergulation
1. Regulating water conent, need a balance between the water you gain and loose
  1. Gain- drink, food,respiration. Loose- pee,sweat,breath out.
Thermoregulation
1. regulating body temperature, getting rid of excess body heat when youre hot,but retain when the enviroment is cold
Blood glucose
1. regulating a steady level of glucose
Thermoregulation
1. all enzymes work best at 37
2. when receptors detect you're too hot
  1. Erector muscles relax, so hairs lie flat
    1. lots of sweat (water+salt) is produced. when sweat evaporates it transferes heat from your skin into the enviroment cooling you down.
      1. blood vessels close to the surface of the skin dilate(widen).
3. When receptors dectect you're too cold
  1. Erector muscles contract. Hairs stand up to trap an instulating layer of air which helps keep us warm.
    1. very little sweat produced
      1. Blood vessels near the surface of the skin constrict. so less blood near the surface, so less heat is transferred to the surroundings
Hypothalamus
1. part of the brain, with receptors that are sensitive to blood temperature in the brain
  1. also recieves impulses from receptors in the skin that provides info about skin temperature.
2. body temp is regulated by this
3. when the hypothalamus detects a change, it causes a response in the dermis
there are two ways that signals can be sent around the body, nerves or sloooow hormones
1. Hormoones are chemical messengers which travel in the blood to activate target cells
  1. hormones are chemicals produced in glads called endocrine glands, travels in the blood and affect particular cells in particular places
    1. the affected cells are called target cells, they have the right receptors to respond to that hormone, an organ with target cells is a target organ
      1. they travell at the speed of blood
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Glucose is needed by cells for respiration. It is important that the concentration of glucose in the blood is maintained at a constant level.
1. How glucose is regulated
  1. Too high glucose level-insulin secreted into the blood, liver converts glucose into glycogen, then glucose lever increases
  2. Too low glucose level- insulin not secreted into the blood, liver does not turn glucose into glycogen, glucose level goes up
Type 1 diabeties - lack of insulin ( the pancreas produces little or no insulin
1. can be controlled in two ways..
  1. Avoiding foods rich in carbohydrates, i.e sugars which make glucose levels rise rapidly
  2. injecting insulin into the blood at meal times, into subcutaneous fat
    1. This will make the liver remove glucose,
    2. insulin is converted into glycogen in the liver, too stop the glucose levels getting too high
2. The amount of insulin that needs to be injected depends on..
  1. persons diet, healthy diet reduces the amount of insulin
  2. Regular exercise
Type 2 diabetes- resistant to insulin
1. Can be controlled by eating a healthy diet, physical activity + weight loss if needed.
  1. obese people have an increased risk of developing type 2 diabetes. (bmi) of over 30. BMI= body mass index divided by height.

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	Created by Alesha Oconnor almost 11 years ago