PHIS 206 1st Edition Lecture 30 Outline of Last Lecture I 4 Processes of Large Intestine II Motility a Haustral Contractions b Mass Movement c Defecation Reflex III External Anal Sphincter IV Pre Biotics Pro Biotics V Absorption What s In Species Outline of Current Lecture I Endocrine System II Hormones III Endocrine System IV Hormones controlling secretions of other hormones V Complexities VI Hormones Chemical Structures VII Peptides and Steroids VIII Peptides IX Steroids X Amines XI Common Characteristics of All Hormones XII Circulating Levels of Hormones XIII Endocrine Disorders XIV Hypersecretion XV Down Regulation Current Lecture I Endocrine System onset of stimulation and decay is gradual opposite of CNS which is rapid controls used for long term regulation II 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 cells III 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 hormones V 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 action VI Hormones Chemical Structures TABLE 18 1 peptides chains of amino acids steroids hormones chemically derived from cholesterol amines neither peptides nor steroids VII 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 therapeutically IX 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 stomach X 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 hormone XII Circulating Levels of Hormones change rate of secretion 2 possible mechanisms change rate of removal from circulation Hormone levels actually controlled by change in rate of secretion NOT the rate of removal XIII 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 cells XIV 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 chemotherapy XV Down Regulation if chronic high levels of hormones target cells cannot synthesize enough receptors as they are being used up result target cells become sensitive
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