The Female Reproductive System Chapter 39-3 Part 2 Hormones Just like in males, the pituitary gland releases the hormones FSH & LHJust like in males, the pituitary gland releases the hormones FSH & LH FSH & LH cause the ovaries to produce estrogenFSH & LH cause the ovaries to produce estrogen Hormones cause the release of an egg (ovum or oocyte)Hormones cause the release of an egg (ovum or oocyte) Figure 43.9 Female Reproductive System Functions: Produce eggs Nourish & nurture the developing fetus Give birth to a new human being Female Gonads Ovaries: release eggs and produce estrogen & progesteroneOvaries: release eggs and produce estrogen & progesterone There are 2 ovaries Fallopian tubes: one tube goes to each ovaryFallopian tubes: one tube goes to each ovary Where fertilization takes place Carries the egg to the uterus Uterus: muscular cavity where an embryo can growUterus: muscular cavity where an embryo can grow Contains a lining rich in blood and nutrients Vagina: connected to the uterus by the cervixVagina: connected to the uterus by the cervix Acidic pH Where intercourse takes place E. Vulva: external genital organsE. Vulva: external genital organs 1. Labia: lips lining side of vaginal opening 2. Clitoris: erectile tissue Eggs Eggs are contained inside follicles (help egg mature)Eggs are contained inside follicles (help egg mature) FSH causes the follicle to undergo meiosis, forming:FSH causes the follicle to undergo meiosis, forming: One large haploid egg Three polar bodies (disintegrate) The ovary contains many eggs in various stages of developmentThe ovary contains many eggs in various stages of development A mature egg is about 200,000x the size of a sperm Figure 43.8ab The Menstrual Cycle A 28 day cycle in which an egg is released and the body prepares for possible fertilizationA 28 day cycle in which an egg is released and the body prepares for possible fertilization Four PhasesFour Phases 1. Follicular Phase: ~10 days FSH causes follicle to developFSH causes follicle to develop Follicle then secretes estrogenFollicle then secretes estrogen 2. Ovulation: 3-4 days FSH and LH are released from the pituitary glandFSH and LH are released from the pituitary gland Causes follicle to rupture, releasing the egg from the ovary to the Fallopian tubeCauses follicle to rupture, releasing the egg from the ovary to the Fallopian tube 3. Luteal Phase: days Follicle turns into corpus luteum:Follicle turns into corpus luteum: Releases estrogen and progesterone Progesterone causes lining of uterus to thicken to prepare to nourish fertilized eggProgesterone causes lining of uterus to thicken to prepare to nourish fertilized egg Egg travels through Fallopian tubeEgg travels through Fallopian tube 4. Menstruation: 3-7 days If fertilization did not occur, egg passes through uterusIf fertilization did not occur, egg passes through uterus Lining of uterus is shed (period)Lining of uterus is shed (period) Figure 43.8a Figure 43.10 Female Puberty Growth of breasts7-13 Growth of pubic hair7-14 Body Growth Begin Menstruation Underarm hairAbout two years after pubic hair Oil and sweat producing glands, acne About same time as underarm hair The Fertilized Egg Fertilization occurs when an egg (n) and sperm (n) combine to form a zygote (2n) (46 chromosomes)Fertilization occurs when an egg (n) and sperm (n) combine to form a zygote (2n) (46 chromosomes) The egg releases chemicals to prevent another sperm from entering fallopian tubesThis happens in the fallopian tubes which lead to the uterus Stages of Early Development The First Trimester Implantation1. Implantation blastocyst endometrium The blastocyst (ball of cells) attaches to the lining (endometrium) in the uterus Cell differentiation beginsCell differentiation begins to form different types of tissues from stem cells 2. Gastrulation Different types of tissues begin to develop Ectoderm forms skin and nervous system Endoderm forms digestive tract Mesoderm forms many internal organs a& tissues 3. Neurulation Development of nervous system placenta, the connection between the mother and embryo that serves as the embryos organ of respiration, nourishment, and excretionUterine lining develops into the placenta, the connection between the mother and embryo that serves as the embryos organ of respiration, nourishment, and excretion First Trimester drugs, disease, and other external factors are especially disruptive to developmentDuring this period, drugs, disease, and other external factors are especially disruptive to development fetusAt 8 weeks, the embryo is called a fetus Fetal Alcohol Syndrome (FAS) Later Development The Second & Third Trimesters fetus starts to moveHeart develops and can be heard, bones & hair grow, fetus starts to move organ systems matureDuring the last trimester, the organ systems mature, fetus doubles in mass, and lung development is finalized Childbirth oxytocinAt about 9 months, the hormone oxytocin will be secreted from the mothers pituitary gland to induce uterine contraction laborThese rhythmic contractions are known as labor cervix dilatesThe cervix dilates, opening wide enough for the baby to pass through amniotic sac breaks water breaksWhen the amniotic sac breaks, the fluid rushes out of the vagina (water breaks) Immediately after birth, breathing starts and the blood supply to the placenta begins to dry up The umbilical cord will be clamped and cut Episiotomy Caesarian Section Breech Premature Birth