Presentation on theme: "REPRODUCTIVE SYSTEM Reproductive system: carries out the process so organisms can produce new individuals of their own kind. It stores, nourishes, and."— Presentation transcript:
1 REPRODUCTIVE SYSTEMReproductive system: carries out the process so organisms can produce new individuals of their own kind.It stores, nourishes, and releases gametesSEXUAL DEVELOPMENTDuring 7th week, if male testes develop and produce androgens developing into male reproductive organs.If female, the ovaries produce estrogens which develop female reproductive organs.Puberty: Period of rapid growth and sexual maturation when sexual reproductive organs become fully functional.Gonads: Male and female reproductive organs.Puberty begins w/a change in the hypothalamus telling the pituitary to release the hormones FSH and LH affecting the gonads.
2 MALE REPRODUCTIVE SYSTEM Scrotum: Sac where the testes remain after birth regulating temp.Seminiferous tubules: Tightly compacted forming the testes where sperm are produced.FSH and LH stimulate production of testosterone and sperm.Secondary sex characteristics: deep voice, beards, muscles??SPERM DEVELOPMENTSee fig. 43-4Epididymis:comma-shaped structure for storing mature spermFrom the epididymis the sperm travel into the vans deferens tubeFrom there the vas deferens passed into the abdominal cavity where three glands produce seminal fluid for sperm storage.Semen: combination of sperm and seminal fluid (fig. 43-4)million sperm/ ml or 5,000,000/drop (2-3 ml/ejaculation)The vas deferens merges into the urethra then to penisEjaculation: Contraction of smooth muscle lining vas deferens
3 FEMALE REPRODUCTIVE SYSTEM Fig. 43-5Ovary: Primary reproductive organ located in the abdominal cavityProduce usually only one egg/month (ovum;ova) which signals the need to nourish a developing embryo.Puberty is signaled when the hypothalamus signals the release of FSH and LHFSH signals the production of estrogen causing reproductive system to developSecondary sex characteristics: enlarged breasts, wide hips, controlled hair growthOVA DEVELOPMENT: (FSH completes the meiosis for an ova)An ovary has about 400,000 primary follicles surrounding an ovumBorn w/400,000 immature ova but fewer than 500 actually release
4 OVULATIONOVULATION: Follicle has completely matured and ovum is released.Follicle ruptures, ovum moves into one of two Fallopian Tubes. (43-6)Cilia move ovum along. Fertilization can take place during this time.After a few days the ovum moves into the Uterus, which is designed to receive a fertilized ovum. This opens into the vagina.Menopause: Follicle development no longer occurs, no babies possibleTHE MENSTRUAL CYCLE:The interaction of the endocrine and reproductive systemsAverage occurrence every 28 daysControlled by hormones on the negative feedback mechanismFollicle Phase:Level of estrogen in low causing a releasing hormone released by the hypothalamus (FSH & LH to cause a follicle to develop into maturity.Level of estrogen goes up dramatically, uterus thickens, (10 days)
5 MENSTRUAL CYCLE Leteal Phase: corpus luteum: ruptured follicle continues to release estrogenprogesterone: hormone released increasing blood supply, tissue matures, and lining is fully prepared to accept fertilized egg.During first 2 days egg fertilization is greatestIf fertilized a zygote develops and attaches to uterusMENSTRUATION:If egg is not fertilized, the corpus luteum begins to disintegrate, and less & less estrogen and progesterone are released.When level of estrogen is below a certain point, lining of uterus detaches. The tissue along with blood and the unfertilized ovum are discharged through the vagina.Lasts 3-7 days;After a few days estrogen levels are low enough, so hypothalamus produces releasing hormones, secreting FSH and LH etc…..
6 FERTILIZATION FERTILIZATION When sperm unites with the egg in the Fallopian tube.Sperm are released during sexual intercourse.Sperm swim actively through the uterus and up into the Fallopian tubes.Hundreds of millions of sperm are released only a few reach the ovum, and it only takes one to fertilize the egg.The ovum has receptor sites for sperm. Once a sperm cell reaches it, the sperm head ruptures, release an enzyme that breaks down the wall creating a pathway for the sperm nucleus.Once this happens, cell membrane changes; no other sperm entersZygote: fertilized ovum after two haploid fuse into a single diploid.After a few divisions the zygote attaches to wall of the uterus and begins to grow.