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ENDOCRINE SYSTEM . Series of glands that produce hormones to help maintain homeostasis . Hormones: Chemical regulators that affect other parts of the body. Insulin Growth Hormone Gastrin. Hormones. Some glands produce one hormone, some produce many kinds and even other chemicals.
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ENDOCRINE SYSTEM • Series of glands that produce hormones to help maintain homeostasis. • Hormones: Chemical regulators that affect other parts of the body. • Insulin • Growth Hormone • Gastrin
Hormones • Some glands produce one hormone, some produce many kinds and even other chemicals. • Hormones must be produced and travel through the blood to a target cell or organ. • Levels of hormones vary throughout the day.
Coordination • The nervous system and the endocrine system work together to allow the body to function. • Nervous System --> SHORT TERM corrections • Endocrine System --> LONG TERM stability
HORMONES • Two types of hormones: • Steroid hormones: made from cholesterol, complex ring structures, fat soluble • Sex hormones, cortisol • Protein hormones: amino acid chains • Insulin, growth hormone • To be susceptible to the effects of a hormone, a cell must have a specific receptor.
Mechanism of Action: Steroid Hormones • hormones diffuse out of blood stream and into the target cells • combine with receptor molecules in cytoplasm
Mechanism of Action: Steroid Hormones • hormone-receptor complex diffuses into nucleus • attaches to chromosomes and activates a gene, initiating transcription and protein synthesis.
Mechanism of Action: Protein Hormones • hormones diffuse out of blood stream • attach to receptors on the cell membranes of target cells
Mechanism of Action: Protein Hormones • the receptor-hormone complex activates the production of enzyme that converts ATP into cyclic AMP (cAMP) • cAMP is a messenger that activates various enzymes inside the cell to begin their normal functions.
PITUITARY GLAND • This is known as the master gland because it controls a lot of other endocrine glands. • A small sac connected to the hypothalamus. • Pituitary gland stores hormones while the hypothalamus stimulates it to release them.
PITUITARY GLAND • The pituitary gland has two lobes: • The posterior lobestores and releases hormones produced by the hypothalamus (ex. ADH, oxytocin) • The anterior lobeproduces and stores its own hormones (ex. TSH, prolactin)
Presentation adapted from Rebecca Martin http://schools.alcdsb.on.ca/hcss/teacherpages/martinreb/default.aspx