PHIS 206 1st EditionExam #4 Study Guide Lectures: 30 - 37Lecture 30I. 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 -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 circulation2 possible mechanisms-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 down-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 sensitiveLecture 31I. Location + Anatomy of Pituitary-line going through your head and intersection is pituitary-adeno-hypophysis: arises from connective tissue ; anterior gland-neuro-hypophysis: posterior pituitary with cell bodies in the hypothalamus (neurohormones of neurocells)II. Blood Supply in Anterior Pituitary Gland-consists of blood already in arteries and capillaries in hypothalamus-hypothalamus secretes a lot of tropic hormones affecting pituitary glandIII. Mammals (except humans)-intermediate: secretes hormones (non-functional in humans) modifies darkening of skinIV. 2 Kinds of Hormones of Posterior Pituitary-Vasopressin=ADH cells that secret it are osmoreceptors increase rate of water; plasma osmolarity increases classic negative feedback released in bloodstream-Oxytocin promotes uterine contraction promotes lactation entirely neural stimulationV. Anterior Lobe-site of synthesis; secretion-6 hormones ―Peptide Hormones Prolactin, Growth Hormone, Thyroid-Stimulating Hormone, Adrenocorticotropin, Follicle-Stimulating Hormone, Luteinizing Hormone = Interstitial Cell-Stimulating Hormone Tropic (hormones that stimulate activities of other hormones): Thyroid-Stimulating Hormone, Adrenocorticotropin, Follicle-Stimulating Hormone, Luteinizing Hormone = Interstitial Cell-Stimulating Hormone Gonado tropic: Follicle-Stimulating HormoneVI. Secretions of Anterior Pituitary -direct feedback from target cells -control by secretions from hypothalamus since circulation in anterior has blood which has already been in the capillaries of the hypothalamus, the hypothalamus secretes directly into the bloodstream Advantages: o Hypothalamic Hormones: don’t get diluted when it is on its way to theanterior (< 5L) Hypothalamo- Hypophyseal Portal System:o arteriole, capillary, arteriole, capillary, venuleVII. Hormones of Anterior Lobe-Thyrotropin Releasing Hormone = TRH-Corticotropin Releasing Hormone=CRH-Prolactin Releasing Hormone = PRH-Prolactin Inhibiting Hormone =PIH : ONLY ONE THAT IS NOT A PEPTIDE ; NOT TROPIC-Growth Hormone Releasing =GRH: NOT TROPIC-Growth Hormone Inhibiting=GHI-Gonadotropin Releasing Hormone=GnRH*The ones without inhibitors have inhibitors, but they are not released by the hypothalamus.VIII. Growth Hormone-Major effect it has: promotion of growth; extension of long bones-Additional Effects stimulation of protein synthesis inhibition of protein breakdown-Has a general metabolic effect/fat-mobilizing effect decreases glucose intake by muscles increases plasma glucose levels-Also stimulates tissue growth increases rate of amino acids and protein synthesis2 Levels of SecretionEssential to the growth of all tissuesMuscles metabolize faster as fuel when Growth Hormone increases-Effect on Bone growth
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