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ansc 224
exam 2 lec 2
| Term | Definition |
|---|---|
| the nervous system | transduces internal/external signal using neurochemical messengers (ddy length) |
| reproductive endocrine glands | secrete hormones by specialized cells travel in blood or extracellular fluids to influence target tissues -- endocrine: far away -- paracrine: adjacent -- autocrine: auto |
| how hormones regulate reproduction | soluble in water = peptides / proteins [insoluble in water = steroids / fatty acids - require protein carriers --- non-specific (albumin) --- specific (sex steroid binding protein (SBP) or globulins) |
| how hormones regulate reproduction pt2 | Cell receptors - while many cells exposed in blood and fluids - only those w receptors can bind |
| how hormones regulate reproduction pt 3 | protein hormones bind external receptor steroids dissociate from carrier and bind internalized/degraded processed for clearance |
| how hormones regulate reproduction pt 4 | pathways activated that cause: - synthesis of hormone/enzymes - release of stored hormones - cell division or growth - change rate of cell metabolic processes |
| control of reproduction | neuroendocrine: - neural cells in hypothalamus - endocrine cells of the pituitary, ovary, and placenta |
| control of reproduction pt 2 | responses: - most of reproductive control is endocrine --- slower onset but lasts longer -> steroids - some neural --- fast onset and short duration --- simple reflex (standing estrus or milk letdown) -> oxytocin |
| hormone patterns and half life | concentration in blood reflects production, releasees and clearance controls duration of action protein carriers and CHO chains increase size and extend T 1/2 (time to 50% gone) |
| hormone patterns and half life pt 2 | clearance (multiple passes) - small molecules cleared by kidney - larger molecules tagged in liver w sulfate or glucuronide to pass in urine and feces |
| blood concentrations | - insulin, FSH, LH, progesterone in extra cellular fluids (ng/ml) - estradiol 17 Beta (pg/ml) ------ potent steroid that induces estrus/estrus behavior for comparison in blood - albumin/glucose, amino acids, peptides, lipids (mg/ml) |
| blood concentrations pt2 | most reproductive hormones very potent at ng and pg levels |
| some hormones controlled in simple feedback systems | regulated by positive or negative feedback estrogen is positive feedback progesterone is neg feedback |
| reproductive glands pt1 | neuroendocrine - hypothalamus: releasing hormones GnRH - pineal gland: melatonin |
| reproductive glands pt2 | pituitary - anterior pituitary: tropins: gonadotropins, prolactin - posterior pituitary: neuroendocrine (oxytocin) |
| reproductive glands pt3 | reproductive system - ovaries: steroids and protein hormones - uterus: prostaglandin - placenta: steroids, protein hormones |
| peptides | vary small, about 10 aa GnRH, oxytocin |
| proteins | larger > amino acids alpha and beta chains inhibin, relaxin |
| glycoprotein | proteins + CHO side chains (> size and T 1/2) fsh and LH |
| peptide GnRH (gonadotropin releasing hormone) pt1 | shows quick pulses and feedback control small peptide synthesized on the hypothalamus - in neurons, in surge and tonic centers - synthesis and release of GnRH ---- from axon terminals into blood capillaries in the pituitary stalk (ME) |
| peptide GnRH (gonadotropin releasing hormone) pt2 | GnRH - binds pituitary gonadotrophs - cleared quickly (hard to measure) synthetics - agonists and antagonists |
| oxytocioxytocin | shows pulses but no feedback control hypothalamus - neutral inputs to hypothalamus induce oxytocin synthesis - stimulation of reproductive tract, mammary gland - neuron cell bodies clustered in hypothalamus (SON/PVN) produce oxytocin |
| oxytocin pt2 | oxytocin travels down axon into posterior pituitary (neural tissue) where it is released into blood small peptide (9aa) - binds receptors in smooth muscle cells in: --- oviduct, uterus and mammary gland --- causes contraction --- short (T 1/2) |
| luteinizing hormone (LH) + follicle stimulating hormone (FSH) | in blood: pattern of LH pulsatile; FSH not as much both under feedback control anterior pituitary gonadotrophs -- can produce either FSH or LH -- depends on ovary feedback, neutral input |
| luteinizing hormone (LH) + follicle stimulating hormone (FSH) pt2 | LH+FSH are very similar - - have common alpha sub unit -- unique beta subunits give them specific activity |
| LH + FSH pt3 | each binds their own receptor in ovary - FSH: follicle growth and health up to medium size --- and specific pathways = hormones (protein and steroids) |
| LH + FSH pt4 | - LH: follicle growth to large size and ovulation and CL function --- and specific steroid pathways = steroids and hormones --- (regulates how many follicles can ovulate) |
| inhibin and AMH | hormones produced by follicles -- produced by granulosa cells of follicles inhibin: a protein dimer (134 AA alpha and 115 AA beta chain) -- feedback to suppress FSH at pituitary |
| relaxin | small polypeptide dimer (8 kd, 24 aa alpha and 32 aa beta) has actions that weaken/remodel connective tissues (cervix) produced by CL/placenta -- near delivery, dilates the birth canal |
| sex steroids | derived from cholesterol (C-27) synthesized in the mitochondria and ER small 18-21 carbon molecules w 4 cyclic rings |
| sex steroids pt2 | not water soluble so require carrier (steroid BG (globulin) or albumin (steroid receptors in liver activate synthesis)) estrogen, progesterone, androgen |
| ovarian steroid synthesis | start w cholesterol (C-27) at cell surface, receptors bind and STAR = steroid acute regulatory protein moves it into mitochondria |
| ovarian steroid synthesis pt2 | in mito, converted from C27 to C21 and in smooth ER from C21 to C19 or C18 steroids not stored and diffuse out most (97%) is bound w only free active |
| progesterone | stimulated by LH in follicle or CL to convert c-27 to c-21 ng levels in blood = detectable (elevated patterns for days) |
| progesterone pt2 | actions: require for pregnancy uterine muscle: anti estrogen effects to decrease excitability uterine gland development, secretions + hormones |
| progesterone pt3 | actions: cervix= closes and thick mucus mammary development feedback to hypothalamus/pituitary = reduce LH pulse frequency |
| androgen | c-19 steroid certain tissues can produce (ovary major, adrenal minor) -- enzymes determine androgen and pathway |
| androgen pt2 | -- follicle produces androstenedione and testosterone in females, androgen intermediates in pathway to estrogen |
| estrogen | in the ovary - androgen (c19) converted to estrogen (c18 estradiol (E2) most potent and in equilibrium in blood w estrone |
| estrogen pt2 | actions - positive feedback to GnRH and LH - secondary sex characteristics - sexual behavior (brain) - muscle excitability (more sensitive to oxytocin) |
| estrogen pt3 | reproductive tissue growth and development -- uterus and oviduct and cervix and vagina and vulva -- dilates arteries / constrict veins -- = swelling and pressure in vulva, cervix, uterus, mammary |
| prostaglandin (PGF2 (alpha)) | small C20 bioactive lipid (FA) a cyclopentane ring + 2 straight unsaturated carbon chains w an acid at one end lipid soluble; travels bound and free |
| prostaglandin pt2 | produced in uterus (actually produced in most cells) induces contraction in uterine muscles |
| prostaglandin pt3 | can travel from uterus to ovary via countercurrent - constricts blood vessels to destroy the CL - to recyle - used for synchronization and induced parturition in some species |
| luteolysis and PGF | PGF binds a PGF R on luteal cells - blood flow changes may not be the cause binds luteal cells that eventually are destroyed apoptosis pathways in luteal cells to stop P4 |
| pheromones | small, volatile steroids or fatty acids; allow reproductive communications btw sexes chemical screted to the outside of one animal and received by another of the same species |
| pheromones pt 2 | cause a neutral rxn that modified hormones or behavior pheromones present in females (vagina, urine) or males sub-maxillary, urine), aerosolized, detected using (VNO) in the olfactory system, induces a hormone change |
| placental hormones | placenta = fetal and modified maternal membranes produce steroids and protein/glycoprotein hormones species differences for producing: |
| placental hormones pt2 | - steroids: progesterone, estrogen, cortisol, relaxin, IGF1 - chlorionic gonadotropins (>>CHO) ---- eCG (equine) (FSH like potent) ---- hCG (human) (LH like potent) |
Created by:
j_kasprzak