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Ch. 39-1 & 39-2: I. Endocrine System. FUNCTION : Transmit chemical messages to control growth, development & metabolism. Question Time!. The endocrine system transmits chemical messages to: Control growth Control metabolism Fight off antigens All of the above A & B. A. Hormones & Glands.
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Ch. 39-1 & 39-2: I. Endocrine System FUNCTION: Transmit chemical messages to control growth, development & metabolism
Question Time! The endocrine system transmits chemical messages to: • Control growth • Control metabolism • Fight off antigens • All of the above • A & B
A. Hormones & Glands Hormone = secreted chemical in blood stream or ducts that affects cells Ex: Human growth hormone (HGH), insulin Gland = organ that releases hormones into body
B. Compared to nervous system Message delivered throughout the body Body’s response is slower than nerve impulse
C. Two Gland Types: 1)EXOCRINE gland – secrete substance through ducts(Ex: sweat, tears) 2) ENDOCRINE gland – secretes hormones into bloodstream
Question Time! The exocrine gland secretes hormones into bloodstream and the endocrine gland secretes substances through ducts. True or False
D. Endocrine Glands: 1.Pituitary gland (in brain) • most important • regulates other glands 2. Thyroid (in neck) • makes thyroxine; regulates metabolism
3. Adrenal glands (above each kidney) • makes epinephrine(adrenaline) ; response to stress 4. Pancreas • makes insulin; regulates glucoselevels
Question Time! Which statement is not true? • Adrenal gland responds to stress • Thyroid regulates glucose levels • Pancreas makes insulin • Pituitary regulates other glands
E. Feedback Mechanism • adjusts to regulate hormone levels • maintains HOMEOSTASIS
Ex. Thyroid thyroxine Thyroid glandcontrolled by hypothalamus & pituitary gland Hypothalamus sense low levels of thyroxine in blood & sends a message to pituitary releases hormone
Signals the thyroid to produce & release thyroxine Thyroxine sent to cells to speed metabolism
Low Hormone Level Decrease Hormone Production Increase Hormone Production High Hormone Level