Presentation on theme: "The endocrine system. hhomeo = same; stasis = standing HHomeostasis is the term we use to describe the constant state of the internal environment."— Presentation transcript:
hhomeo = same; stasis = standing HHomeostasis is the term we use to describe the constant state of the internal environment. HHomeostasis is a state of balance in the body. TThe processes and activities that help to maintain homeostasis are referred to as homeostatic mechanisms.
YYou are exposed to ever changing environmental conditions. For example, you may walk out of an air conditioned room into the hot summer sun. HHowever 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.
BBiochemical processes are vital to life and occur efficiently only within a limited temperature range and at a specific pH. TThe body must have good internal communication, using the endocrine and nervous systems, to maintain homeostasis. Linkage system Effector Reponse Sensor Stimulus
NNegative feedback Occurs when feedback (from sensory organ to CNS) results in a reversal of the direction of change. NNegative feedback tends to stabilise a system, correcting deviations from the set point.
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.
The endocrine glands include the hypothalamus, pituitary, thyroid, parathyroid, adrenal, thymus, and pancreas.
The pituitary gland communicates with the hypothalamus to control many body activities.
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
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
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.
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
If there is too much glucose in the blood, Insulin converts some of it to glycogen Glycogen Insulin Glucose in the blood
If there is not enough glucose in the blood, Glucagon converts some glycogen into glucose. Glycogen Glucagon Glucose in the blood
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.
Time Glucose Concentration Meal eaten Insulin is produced and glucose levels fall to normal again. Glucose levels rise after a meal. Normal
Time Glucose Concentration Meal eaten Insulin is not produced so glucose levels stay high Glucose levels rise after a meal. Diabetic
The glucose in the blood increases. Glycogen Insulin Glucose in the blood But there is no insulin to convert it into glycogen. Glucose concentration rises to dangerous levels.