BIO 251 1st Edition Lecture 10 Outline of Last Lecture I. general principles a. endocrine system b. types of hormones c. general features d. 2 control systems II. Major classification of hormones a. General b. Peptides c. Animes d. Steroids III. General function a. Hydrophilic hormones b. Liphilic hormones IV. Non-tropic endo systemsa. Pineal glandb. PancreasV. Tropic endo systems a. Hypothalamus & pituitary 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.VI. Diabetes Outline of Current Lecture I. Thyroid hormones II. Male reproduction control III. Human female reproductive cycle IV. Human gestation Current LectureThyroid hormones -Role of thyroid hormones in body (6.1)oHelp regulate metabolic rateoHelp regulate growth & development in preadults oRequired for normal CNS activity in adults -T3 & T4 synthesis in thyroid gland (21.1b)oThyroid hormones produced from the amino acid tyrosine and form iodine -T3-Triiodonthyronine (triiodo means 3 iodine)-T4-Tetraiodothyronine (tetraiodo means 4 iondine)oTyrosine, is synthesized by the bodyoIodine must be ingested-Actively transported against steep concentration gradient into thyroid glandoT3 & T4 synthesized & stored in thyroid gland -T3 & T4 release and transporto90% of thyroid hormone released is T4 BUToT3 is 4x more functionally potent than T4oMost secreted T4 is converted to T3 by target cells-T3 is more active form, but more T4 made by thyroid -Represent another level of control and regulation oMore than 99% of the T3 & T4 in blood are bound to plasma proteins -Effects of T3 & T4oSlow acting; takes hours-days to see effects-Tends to be steady levels in plasma (not much variation)oMetabolic rate increasesoHeat production increasesoIntermediary metabolism-Complex, high levels of T3 & T4 favor consumption rather than storage of oSympathetic nervous system -Increases response of target cells to epi and NE by causing proliferation of receptors on membranes of target cellsoCardiovasc system-Increases heart rate & force of contraction and causes increased peripheral vasodilation to carry extra heat to body surfaceoStimulates growth hormone secretion & synthesis of structural proteins & skeletal muscle oRequired for CNS dev. & CNS function in adults -Regulation of thyroid function (21.18)oHypothalamus secretes thyrotropin releasing hormone (TRH)-Factors that regulate production of TRH by hypothalamus are not understood well-Stress to lower TRH production and cold in infants known to stimulate TRH production oTRH stimulates ant pituitary to produce thyroid stimulating hormone (TSH)oTSH stimulates thyroid to produce T3 & T4oIncreased T3 & T4 negatively feedback to reduce TRH & TSH production (T4=stronger negative feedback)-Abnormalities of thyroid function oHypothyroidism in adult -Caused by -Primary failure of thyroid gland-Deficiency of TRH and/or TSH-Inadequate iodine supply in diet -Effects -Reduced BMR-Poor cold tolerance -Tendency to gain weight -Easily fatigued -Slow weak pulse-Slow reflexes-Diminished alertness -Slow speech -Poor memory -Treatment -Replacement therapy (hormone or iodine0oHypothyroidism from birth-Normal growth and dev of CNS impaired-Leads to dwarfism and cretinism -Replacement therapy works only if started ASAPoHyperthyroidism: GRAVES DISEASE-Thyroid stimulating immunoglobin produced by immune system -Stimulate thyroid so it releases too much T3 & T4-Leads to -Excessive heat production-Poor heat tolerance -Increased food intake-Drop in body mass-Cardiovascular abnormalities -Bulging eyes-Treatment -Destroy the thyroid gland, give replacement T3 & T4 Male Reproduction Control (22.8)-GnRH from hypothalamus stimulates ant pituitary to release LH and FSHoNeural input to hypothalamus altered at start of puberty that causes GnRH to be released oConsistent release continues, peaking in 20s then slowly declining -FSH directly stimulates sperm production & release of inhibin by setoli cells in testes -LH stimulates release of testosterone in Leydeg cells in testes-Testosterone stimulates secondary sex characteristics & sperm production and inhibin setoli cells-Inhibin negatively feeds back on FSH productionoTestosterone negatively feeds back on GnRH production & negatively feedsback on LH and FSH production by pituitary oSmall but functionally significant amounts of estrogen produced in males Human female reproductive cycle (22.15 to 22.20)-Basic anatomy (22.15)oOvary oUterine tubeoUterus oEndometrium oCervix-Basic events oOvarian cycle -Follicular phase days 1-14-Menstruation to ovulation -Luteal phase 12-28 days -Ovulation to just prior to menstruation oUterine cycle -Menstrual phase days 1-5 -Menstruation -Proliferative phase days 5-14-Menstruation to ovulation -Secretory phase days 15-28 -Ovulation to just prior to menstruation -Early follicular phase (days 1-5)oEndometrial lining from prior cycle being shed=menstruation oEstrogen and progesteron low & decling as part of menstruation=minimal neg feedback on hypothalamus and pituitary which allows GnRH releaseoGnRH from hypothalamus stimulates ant pituitary to release LH and FSHoFSH stimualtes follicle growth (follicle contains oocyte=egg)oLH stimulates estrogen production by growing follicle -Mid follicular phase (days 6 to 13)oUterus enters proliferative phase -Prep for pregnancy oGrowing follicle secretes high levels of estrogenoEstrogen causes -Endometrium (lining of uterus) to thicken in prep for embryo implantation; follicle dev; prliferation of LH receptors on follicle oHigh levels of estrogen neg feedback on hypothalamus & pituitary, stopping rise in plasma LH; plasma FSH actually declines in response to increased estrogen and inhibin -Late follicular phase (days 13 & 14)oRise in estrogen stimulates GnRH release and LH and FSH release -Positive feedback loopoFollicle now has LH receptors that have been induced by estrogen & can respond to LHoHigh LH completes follicle deve in ~18 hroOvulation occurs on day 14 -Oocyte is released as follicle ruptures -Luteal phase (days 15-28)oUterus enters secretory phase oLH stimulates remains of follicular tissue to being to form corpus luteum oEstrogen levels temp drop b/c follicle no longer releasing it and corpus luteum not yet producing oDrop in estrogen causes