Feedback and Factors


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Feedback and Factors

  1. 1. Homeostasis and the body
  2. 2. What is Homeostasis? <ul><li>Body cells work best if they have the correct </li></ul><ul><ul><li>Temperature </li></ul></ul><ul><ul><li>Water levels </li></ul></ul><ul><ul><li>Glucose concentration </li></ul></ul><ul><li>Your body has mechanisms to keep the cells in a constant environment. </li></ul>
  3. 3. What is Homeostasis? <ul><li>The maintenance of a constant environment in the body is called Homeostasis. </li></ul><ul><li>(It’s all about BALANCE!) </li></ul>
  4. 4. What does the body balance? <ul><li>The body is always striving to maintain HOMEOSTASIS, which means balance or equilibrium between these two factors: </li></ul><ul><li>External Environment Internal Environment </li></ul><ul><li>*temperature/weather *sweat/shiver </li></ul><ul><li>*allergies *sneezing/swelling </li></ul><ul><li>*work/stress *faster heart rate/ </li></ul><ul><li>higher blood pressure </li></ul>
  5. 5. How does the body keep balanced? <ul><li>In order to control homeostasis, your body uses a process called feedback. </li></ul><ul><li>The body surveys the internal conditions and responds to external conditions to keep it in a constant state of balance. </li></ul><ul><ul><li>Any changes that vary from the body’s normal condition result in a response. </li></ul></ul>It works much like a thermostat in a house!
  6. 6. Feedback: Temperature <ul><li>Human beings have a body temperature of about </li></ul><ul><li>37 º C. If you are in a hot environment, then you </li></ul><ul><li>begin to sweat and your skin becomes red. </li></ul><ul><ul><li>External: Hot environment </li></ul></ul><ul><ul><li>Internal: Blood vessels dilate and glands produce sweat </li></ul></ul><ul><ul><li>Feedback: Sensors tell the blood vessels to relax and glands to produce sweat. </li></ul></ul>
  7. 7. Feedback: Glucose levels <ul><li>Your cells also need an exact level of glucose in the blood. </li></ul><ul><li>Excess glucose gets turned into glycogen in the liver. </li></ul><ul><li>This is regulated by 2 hormones (chemicals) from the pancreas called: </li></ul><ul><li>Insulin </li></ul><ul><li>Glucagon </li></ul>
  8. 8. If there is too much glucose in the blood, Insulin converts some of it to glycogen Glycogen Insulin Glucose in the blood
  9. 9. If there is not enough glucose in the blood, Glucagon converts some glycogen into glucose. Glycogen Glucagon Glucose in the blood
  10. 10. Diabetes <ul><li>Some people do not produce enough insulin. </li></ul><ul><li>When they eat food, the glucose levels in their blood cannot be reduced. </li></ul><ul><li>This condition is known as DIABETES. </li></ul><ul><li>Diabetics sometimes have to inject insulin into their blood. They have to be careful of their diet. </li></ul>
  11. 11. Time Glucose Concentration Meal eaten Insulin is produced and glucose levels fall to normal again. Glucose levels rise after a meal. Normal
  12. 12. Diabetic’s Response After Eating Time Glucose Concentration Meal eaten Insulin is not produced so glucose levels stay high Glucose levels rise after a meal. Diabetic
  13. 13. External Factors <ul><li>Organisms are affected by different external (outside) factors: </li></ul><ul><ul><li>Abiotic (non-living, physical) factors </li></ul></ul><ul><ul><ul><li>Examples: temperature, amount of water, etc. </li></ul></ul></ul><ul><ul><li>Biotic (living) factors </li></ul></ul><ul><ul><ul><li>Examples: disease, predation, etc. </li></ul></ul></ul><ul><li>What are some other biotic and abiotic factors that affect organisms? </li></ul>