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HORMONE PRODUCTION AND STORAGE

Understand key points about hormone production and storage, endocrine system functions, feedback control mechanisms, and hormone action mechanisms in the body. Learn how different types of hormones are produced and regulated.

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HORMONE PRODUCTION AND STORAGE

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  1. HORMONE PRODUCTION AND STORAGE DR AMNA TAHR ASSISTANT PROFESSOR PHYSIOLOGY DEPARTMENT KEMU

  2. HORMONE • A  hormone  is a chemical substance produced in particular parts of organisms by specific cells, glands, and/or tissues and then transported to other parts of the body, with the intent of influencing a variety of physiological and behavioral activities, such as the processes of digestion, metabolism, growth,reproduction and mood control. 

  3. ENDOCRINE SYSTEM • The endocrine systemis a ductless system referring to the collection of cells, glands, and tissues of an organism that secretehormones directly into the bloodstream to control the organisms' physiological and behavioral activities. • The endocrine system is in contrast to the exocrine system, which secretes its chemicals using ducts. • The word endocrine derives from the Greek words "endo" meaning inside, within, and "crinis" for secrete.

  4. ENDOCRINE ORGANS

  5. MAJOR CLASSES OF HORMONES 1- Proteinandpeptides including hormones secreted by anterior and posterior pituitary, the pancreas , parathyroid gland 2- Steroids secreted by the adrenal cortex, the ovaries, testes 3- Derivativeoftheaminoacidtyrosine, secreted by thyroid gland , adrenal medullae.

  6. HORMONE PRODUCTION AND STORAGE • Polypeptide and protein hormone are stored in secretory vesicles until needed. • Steroid hormones are usually synthesized from cholesterol and not stored. • Amine hormones are derived from tyrosine

  7. FEED BACK CONTROL OF HORMONE SECRETION • Negative feedback mechanism • Is most commonly applied principle for regulating hormone secretion • It prevents over activity of the hormone system • Is self -limiting • A hormone has biologic actions that, directly or indirectly , inhibit further secretion of the hormone

  8. FEED BACK CONTROL OF HORMONE SECRETION • Positive feedback mechanism • is rare • Is explosive and self – reinforcing • Surges of hormone can occur with positive feed back • A hormone has biologic actions that, directly or indirectly, cause more secretion of the hormone

  9. MECHANISM OF ACTION OF HORMONE • Hormone receptors and their activation • Location of receptors for different hormones • In or on the surface of cell membrane for protein , peptide and catecholamine hormones • In the cell cytoplasm for steroid hormones • In the cell nucleus for thyroid hormones

  10. INTRACELLULAR SIGNALING AFTER HORMONE RECEPTOR ACTIVATION • Ion Channel –linked receptors • G-Protein-linked Hormone receptors • Enzyme-linked hormone receptors

  11. Ion Channel –linked receptors

  12. G-Protein-linked Hormone receptors

  13. Enzyme-linked hormone receptors

  14. SECOND MESSANGER MECHANISM • AdenylCyclase – cAMP second messenger system • Cell Membrane Phospholipid second messenger system • Calcium -Calmodulin second messenger system

  15. AdenylCyclase – cAMP second messenger system

  16. Cell Membrane Phospholipid second messenger system

  17. Mechanism of interaction of lipophilic hormones

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