The Endocrine System

Control of the Body Section 35.3 Internal control of the body is directed by two systems: The Nervous System The Endocrine System

Systems that chemically coordinate the body: NERVOUS ENDOCRINE Stimuli-response Rapid response Short time Slow response Lasts long time Both=HOMEOSTASIS

The Endocrine System Section 35.3 Made up of endocrine glands Release chemicals (hormones) directly into the bloodstream - act as messengers in the body

Hormones Section 35.3 Chemicals secreted by endocrine glands Conveys information to cells in the body Bind to receptors of target cells

The Endocrine Glands Section 35.3 Located throughout the body Most are controlled by the pituitary gland Master endocrine gland

Pituitary: The Master Gland that controls other endocrine glands Bean-size, at base of skull Secretes 9 hormones that Regulate Many body functions

Hypothalamus Section 35.3 Portion of the brain Controls the pituitary gland Connected by nerves and blood vessels Sends messages to the pituitary gland Pituitary glands then releases its chemicals

Negative Feedback Control Section 35.3 Negative Feedback Control I.e. thermostat. Temperature drops Thermostat stimulates heater to increase output Temperature rises, thermostat stops stimulating the heater, so it shuts off. Cycle continues Most endocrine glands operate under negative feedback systems

Control of blood water levels Section 35.3 Control of blood water levels Lets say you are working out in the gym. Water level in your blood goes down. Hypothalamus stimulates the pituitary gland to release antidiuretic hormone (ADH). ADH reduces amount of water in urine by causing the absorption of water in the kidneys. If the body gets over-hydrated, hypothalamus stops stimulating the release of ADH

Control of blood glucose levels Section 35.3 Control of blood glucose levels When you eat, blood glucose levels rise. Pancreas releases insulin. Insulin causes liver and muscle cells to take in glucose. Lowers blood glucose levels. When levels go down, pancreas releases glucagon. Glucagon causes the release of glucose from the liver

I am STRESSED OUT!! Section 35.3 The Adrenal Gland is involved in preparing your body for stressful situations Located on top of the kidneys

The Adrenal Gland Section 35.3 Releases steroids Increases available glucose and raises blood pressure Secretes adrenaline and norepinephrine Increases heart rate, BP and rate of respiration

Thyroid and Parathyroid glands Section 35.3 Thyroid and Parathyroid glands Thyroid gland Regulates metabolism, growth and development Releases calcium Parathyroid gland causes kidney to absorb calcium and magnesium

Thymus The thymus is a specialized organ of the immune system. Section 35.3 Thymus The thymus is a specialized organ of the immune system. T cells attacks foreign substances

Section 35.3 Testes Testes are part of the reproductive system and part of the endocrine system Produce the male sex hormone testosterone and sperm