PHIS 206 1st Edition Exam 4 Study Guide Lectures 30 37 Lecture 30 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 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 change rate of removal from circulation 2 possible mechanisms 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 Lecture 31 I II III IV 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 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 gland Mammals except humans intermediate secretes hormones non functional in humans modifies darkening of skin 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 stimulation V VI 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 ThyroidStimulating Hormone Adrenocorticotropin Follicle Stimulating Hormone Luteinizing Hormone Interstitial Cell Stimulating Hormone Gonado tropic Follicle Stimulating Hormone Secretions of Anterior Pituitary direct feedback from target cells 2 Levels of Secretion 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 the anterior 5L Hypothalamo Hypophyseal Portal System o arteriole capillary arteriole capillary venule VII 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 Essential to the growth of all tissues inhibition of protein breakdown Has a general metabolic effect fat mobilizing effect decreases glucose intake by muscles Muscles metabolize faster as fuel when increases plasma glucose levels Growth Hormone increases Also stimulates tissue growth increases rate of amino acids and protein synthesis Effect on Bone growth cartilaginous plate thickens and bones ossifies behind it long bones synthesize more at the end can only happen until the cartilaginous plates are totally ossified Chemical Situations of Growth Hormone Deficiency Causes defective anterior