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Ch 46 CVHS
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Sexual : Fusion of haploid gametes: zygote Asexual : No fusion of sperm & egg Fission Parent separates Budding new organisms grows off of the parent Parthenogenesis Egg develops w/out fertilization Haploid or Diploid offspring
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Sexually @ specific times of year Sheep, deer, lions Sexually on a regular cycle Humans (ovulate monthly) Asexually or Sexually Daphnia (depending on environmental conditions) Asexually only Fission, budding, parthenogenic (may switch sexes) Hermaphroditisim Both sexes, typically sessile (stationary) organisms
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External Outside organism’s body Requires moist environment Amphibians, egg will desiccate if dry Parental Care: Usually none, offspring fend for themselves, many more produced than survive Exceptions: some insects, some fish Gamete Delivery: Eggs and sperm released in environment simultaneously Requires signals Chemical Day Length Temperature Internal Sperm placed in (or near) female reproductive tract Parental Care: Usually significant care, most survive Embryo protection from predation & water-loss: Maternal body Egg w/ Calcium & protein shell Gamete Delivery: Produced inside body May have gonads or may use body wall Courtship behavior, pheromones
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Complex reproductive systems (highly variable) Female has ovaries May have spermatheca (stores sperm, komodo dragons have one) Male has testes and penis
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Testes Site of gamete production Scrotum Holds testes in place & maintains temp 2 ْْْ C below body temp Epididymis Sperm mature & become motile Vas Deferens Muscular duct, propels sperm Ejaculatory Duct Further propels sperm Urethra Common reproductive & excretory opening extends length of penis Accessory Glands Seminal vesicles, prostate gland & bulbourethral glands Seminal Vesicles: 60% volume of semen, alkaline, fructose, prostaglandins (local regulators) Prostate Gland: anticoagulant & citrate Bulbourethral: mucus, neutralize acid in urine, contain live sperm
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Mitotic Spermatogonial Cell (2n) Mitotic Speratogionium (2n) Mitotic 1 ْ spermatocyte(2n) Meiosis I 2 ْ spermatocyte (n) Meiosis II Early Spermatocyte (n) Extensive changes to become sperm
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Hypothalmus GnRH: stimulate anterior pituitary to release FSH & LH Anterior Pituitary FSH Sertoli Cells in testes (nourish sperm ) Inhibin: stops production of FSH by anterior pituitary Spermatogenesis, when coupled w/ testosterone LH Leydig Cells in testes (produce androgens) Testosterone (steroid hormone) Two Negative Feeback Loops Inhibin: Inhibits Anterior Pituitary Testosterone: inhibits Hypothalmus & Anterior Pituitary
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Ovaries Contain follicles where oocyte matures Corpus Luteum: secretes estradiol & progesterone Degenerates if egg is not fertilized Oviduct Pathway from ovary to uterus Uterus Muscular organ where fetus develops Endometrium, lining, nourishes and protects fetus Cervix Opening to the uterus Vagina Muscular, flexible chamber where sperm are deposited labia minora & labia majora, protection @ opening of vagina
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Mitosis Oogonium (2n) Mitosis 1 ْ Oocyte (2n) prophase I of meiosis Meiosis I & II 2 ْ Oocyte (n) Ovulation & sperm entry Meiosis II completion Ovulation
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Uterine or Menstrual Cycle (changes in uterus) Menstrual Flow: endometrium shed Proliferative: regeneration & thickening of endometrium Secretory: endometrium thickens further, glands secrete nutritional glycogen OR menstrual flow phase
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Ovarian Cycle (changes in ovaries) Follicular: Several follicles in ovaries grow Ovulatory: Follicle & adjacent wall of ovary rupture & release 2 ْ oocyte Luteal Phase: Remaining follicular tissue becomes CORPUS LUTEUM which is endocrine tissue that secretes hormones
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Increased estrogen secreted by follicle stimulates endometrium to thicken: Proliferative Phase After Ovulation, estrogen & progesterone secreted by the CL stimulate development of endometrium: Secretory Phase Decrease Estrogen & progesterone due to CL breakdown reduces blood to endometrium and menstrual flow begins If embryo present, it secretes HCG which maintains estrogen & progesterone so endometrium is maintained
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Cessation of ovulation & menstruation Ages 46 to 54 Ovaries lose repsonse to FSH & LH secreted by the anterior pituitary Decline in Estrogen production
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Fertilization: sperm fuses w/ egg in oviduct Female Reroductive tract produces secretions which capacitate sperm cells The sperm releases enzymes to penetrate the Zona Pellucida
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Cleavage : zygote begins to divide 24 hrs. later Blastocyst forms Once implanted, embryo releases hCG (human chorionic gonadotropin) acts like a LH to maintain estrodial and progesterone levels Trophoblast begins to form Becomes part of endometrium to nourish fetus
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1 st Trimester: 2-4 weeks, embryo obtains nutrients from endometrium Placenta developing Organogenesis 2 nd Trimester: Fetus secrets progesterone to maintain pregnancy CL deteriorates Fetus is nourished through Placenta(material & fetal blood vessels for exchange of nutrients to fetus and wastes to mother) 3 rd Trimester: Fetus puts on length & mass, pushes agains mother’s internal organs
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High Estrogen levels during last weeks of pregnancy trigger formation of oxytocin receptors in uterus Oxytocin secreted by fetus & posterior pituitiary stimulate smooth muscle contractions of uterus POSITIVE FEEDBACK! Prolactin stimulates milk production
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Rhythm timing intercourse when conception is least likely (5 days before & after ovulation) IUD Prevents implantation Pills Estrogen & Progesin: prevent ovulation Progestin: increases vaginal secretions, prevents sperm movement Morning After: Prevents implantation Barriers Condoms: some protection against STD’s Diaphragm: prevents sperm from reaching oviduct Sterilization: Cuts pathway for egg or sperm Oviducts Vas Deferens
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