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Coordination and Regulation

Coordination and Regulation. The endocrine system. Definition of Homeostasis. homeo = same; stasis = standing Homeostasis is the term we use to describe the constant state of the internal environment. Homeostasis is a state of balance in the body.

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Coordination and Regulation

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  1. Coordination and Regulation The endocrine system

  2. Definition of Homeostasis • homeo = same; stasis = standing • Homeostasis is the term we use to describe the constant state of the internal environment. • Homeostasis is a state of balance in the body. • The processes and activities that help to maintain homeostasis are referred to as homeostatic mechanisms.

  3. Set point

  4. Homeostasis • You are exposed to ever changing environmental conditions. For example, you may walk out of an air conditioned room into the hot summer sun. • However the cells in your body work best when their surroundings are kept constant. Your body has many mechanisms that keep the cells surroundings constant even though your external environment is changing. This is homeostasis. • Homeostasis is very important because when it fails you become ill and may die.  

  5. Stimulus Sensor Linkage system Effector Reponse Maintaining Homeostasis • Biochemical processes are vital to life and occur efficiently only within a limited temperature range and at a specific pH. • The body must have good internal communication, using the endocrine and nervous systems, to maintain homeostasis.

  6. Negative Feedback • Negative feedbackOccurs when feedback (from sensory organ to CNS) results in a reversal of the direction of change. • Negative feedback tends to stabilisea system, correcting deviations from the set point.

  7. The endocrine system

  8. The endocrine system • Made up of endocrine glands that release chemical messengers called HORMONES right into the bloodstream. • Allow for the maintenance of the internal environment in the body, or internal homeostasis.

  9. Functions of Endocrine Glands • The endocrine glands include the hypothalamus, pituitary, thyroid, parathyroid, adrenal, thymus, and pancreas.

  10. Functions of Endocrine Glands The pituitary gland communicates with the hypothalamus to control many body activities.

  11. What Are Hormones? • Hormones are chemical substances created by the body that control numerous body functions. They actually act as "messengers" to coordinate functions of various body parts. Most hormones are proteins consisting of amino acid chains. Functions controlled by hormones include: • activities of entire organs • growth and development • Reproduction • sexual characteristics • usage and storage of energy • levels of fluid, salt and sugar in the blood

  12. Endocrine Glands are found throughout the body Hypothalamus and Pituitary are in the brain Parathyroids are in the neck and sit on the Thyroid Adrenals sit on the kidneys Pancreas is in the abdomen Testes are in the scrotum and Ovaries are in the hip area

  13. Negative Feedback Through negative feedback, when the amount of a particular hormone in the blood reaches a certain level, the endocrine system sends signals that stop the release of that hormone.

  14. An example...

  15. Controlling Glucose levels • Your cells also need an exact level of glucose in the blood. • Excess glucose gets turned into glycogen in the liver • This is regulated by 2 hormones (chemicals) from the pancreas called: Insulin Glucagon

  16. Glycogen If there is too much glucose in the blood, Insulin converts some of it to glycogen Insulin Glucose in the blood

  17. Glycogen If there is not enough glucose in the blood, Glucagon converts some glycogen into glucose. Glucagon Glucose in the blood

  18. Diabetes • Some people do not produce enough insulin. • When they eat food, the glucose levels in their blood cannot be reduced. • This condition is known as DIABETES. • Diabetics sometimes have to inject insulin into their blood. They have to be careful of their diet.

  19. Glucose levels rise after a meal. Insulin is produced and glucose levels fall to normal again. Glucose Concentration Normal Time Meal eaten

  20. Glucose levels rise after a meal. Glucose Concentration Diabetic Insulin is not produced so glucose levels stay high Time Meal eaten

  21. The glucose in the blood increases. Glycogen Insulin But there is no insulin to convert it into glycogen. Glucose concentration rises to dangerous levels. Glucose in the blood

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