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ENDOCRINE SYSTEM pp 1031-1042 . Warm-up 4/15: Describe the function of the Endocrine System. What tissues/ organs are part of the endocrine system? . FUNCTION. Controls body function with chemical messengers Hormones: chemical messengers Glands: secrete chemicals/hormones . HORMONES.
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ENDOCRINE SYSTEMpp 1031-1042 Warm-up 4/15: Describe the function of the Endocrine System. What tissues/ organs are part of the endocrine system?
FUNCTION • Controls body function with chemical messengers • Hormones: chemical messengers • Glands: secrete chemicals/hormones
HORMONES • Amino acid-based hormones: first messenger binds to cell surface receptor causing second messenger inside the cell to initiate cell activity
Steroid hormones: diffuse through cell membrane to bind to a protein which starts transcription
GLANDS • exocrine: secrete nonhormonal chemicals through ducts (sweat, saliva, mucous, digestive, etc) • endocrine: secrete hormones into the bloodstream a. gonads: sex hormones b. thyroid: metabolism c. adrenal gland: adrenaline d. pituitary: hormones that affect other glands and growth hormones e. pancreas: insulin and glucagons to regulate sugar f. thymus: stimulates formation of T-cells
FEEDBACK MECHANISMS • Homeostasis: stable internal environment • Last step of the series controls the first
NEGATIVE FEEDBACK • A secondary substance inhibits production of the initial stimulating substance A = Insulin B = glucagon (sugar)
Holding breath, CO2 levels rise, O2 /CO2 level returns to normal Control system forces exhale, inhale Negative feedback loops are necessary for homeostasis. Negative Feedback Loop
POSITIVE FEEDBACK • A secondary substance stimulates production of the initial stimulating substance
HW • Worksheet: Nervous and Sense Organs (Due Tuesday) • Trifold Vocab: homeostasis, neuron, gland, hormone, positive feedback loop, negative feedback loop, synapse, neurotransmitter (Due Wednesday)