PHIS 206 1st EditionLecture 30Outline of Last Lecture I. 4 Processes of Large IntestineII. Motilitya. Haustral Contractionsb. Mass Movementc. Defecation ReflexIII. External Anal SphincterIV. Pre-Biotics + Pro-BioticsV. Absorption: What’s In Species?Outline of Current Lecture I. Endocrine SystemII. HormonesIII. Endocrine SystemIV. Hormones controlling secretions of other hormonesV. ComplexitiesVI. Hormones: Chemical StructuresVII. Peptides and SteroidsVIII. PeptidesIX. SteroidsX. AminesXI. Common Characteristics of All HormonesXII. Circulating Levels of HormonesXIII. Endocrine DisordersXIV. HypersecretionXV. Down RegulationCurrent LectureI. Endocrine System-onset of stimulation and decay is gradual opposite of CNS which is rapid-controls used for long-term regulationII. Hormones-secreted directly into bloodstream These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-cells located in endocrine glands-hormones produced by neurons: neurohormones caused by neuroendocrine cellsIII. Endocrine System-not anatomically continuous -distinct, discrete glands (physically separate)IV. Hormones controlling secretions of other hormones-tropic v. nontropic tropic: hormones controlling secretion of other hormones nontropic: do other things than control secretions of other hormonesV. Complexities-some endocrine glands produce more than 1 hormone-hormones have effects on many types of target cells-CCK: stimulates gallbladder contractions; inhibits gastric motility-most hormones have multiple mechanisms of actionVI. Hormones: Chemical Structures (TABLE 18.1)-peptides: chains of amino acids-steroids: hormones chemically derived from cholesterol-amines: neither peptides nor steroidsVII. Peptides and Steroids-all peptides have things in common small proteins that wind up in bloodstream synthesized in ribosomes; non-active (pre-cursors) go from E.R. to Golgi apparatus for packaging converted from pro-hormones to hormones stored until triggered for secretion vesicle fuses into cell membrane and exits through diffusion into the extracellular fluid (ECF)VIII. Peptides-water-soluble-dissolve into plasma-since large and water-soluble, cannot get into cells target cells have receptors with which a specific peptide hormone will interact response of cyclic Amp (2nd messenger)o winds up diffusing into cell and making a metabolic pathway-actions terminated by target cells internally target cells internalize hormone receptors put a vesicle around it lysozomes digest it-cannot be administered orally b/c of digestive system-must be injected to use peptide hormones therapeuticallyIX. Steroids-fat-soluble so cannot be stored-secreted as they are synthesized -if dissolved into 1st membrane they get to, will go to red cell membranes steroid hormones have binding proteins-target cells have binding proteins that bind tighter than the proteins on the surface of the cells-once protein is on the surface of cell, can diffuse, and NO barriers in cytoplasm-eventually, all get to cell nucleus and activate genetic pathways-NO 2ND MESSENGER-therapeutically, can be given orally since not metabolized or digested in stomachX. Amines-variety of compounds-some fat-soluble, some water-soluble XI. Common Characteristics of All Hormones-biologically effective at astonishingly low concentrations 10-8M to 10-12M-glucose secreted by liver muscle; “hormone-like,” but not a hormoneXII. Circulating Levels of Hormones-change rate of secretion-change rate of removal from circulation-Hormone levels actually controlled by change in rate of secretion, NOT the rate of removalXIII. Endocrine Disorders-can and do include situations in which pathological conditions in the plasma are high or low-hypersecretion: pathologically high-hyposecretion: pathologically low-target cell responsiveness: reductions in responses of target cellsXIV. Hypersecretion-usually caused by a hormone-secreting tumor b/c not subject to feedback control as normal endocrine cells are things slowing down secretion are not slowing it down2 possible mechanisms-treatment: radiation, surgical removal, chemotherapyXV. Down Regulation-if chronic high levels of hormones, target cells cannot synthesize enough receptors as they are being used up result: target cells become
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