2Female Reproductive System Produce hormones (estrogen and progesterone) for secondary sexual characteristics.Produce one large oocyte at regular intervals and release it in such a way that it enters the oviduct (“Fallopian tube”,“uterine tube”).Receive semen from the male and transport it into the oviduct.Produce hormones (estrogen and progesterone) which prepare the uterus for pregnancy each cycle by thickening its inner lining; Getting rid of this thickened lining each cycle if pregnancy does not occur.Protect and nourish the embryo and fetus during pregnancy, then expel it through the vaginaProduce milk to nourish the newborn
4Ovary:Located within pelvis, 2 to 5 cm (1 to 2 inches) lateral to the uterusApproximately 3cm x 2cm x 1cmCentral region, or “medulla”, consists of connective tissue with many blood vessels.Outer region, or “ ”, has all of the oocytes. One or two of these oocytes may be developing before ovulation; undeveloped ones are stored here.Also contains the remnant from the previous cycle’s ovulation, called a“ “ , which secretes progesterone to keep uterus ready for implantation of the embryo
5Maturation of an oocyte is called oogenesis, which leads to ovulation During oogenesis, the oocyte is surrounded by follicular cells granulosa cells in one or more layers, forming a
6The developing oocyte and its follicle: Four stages before ovulation :All formed before birth - hundreds in each ovaryHave not yet begun development – remain dormant until pubertyConsists of primary oocyte surrounded by a single layerof flat follicular cells
7The developing oocyte and its follicle: Four stages before ovulation :Develop only after puberty; 3 to 4 enter this stage each cycleNo change in primary oocyteFollicle has begun development – cells are larger
8The developing oocyte and its follicle: Four stages before ovulation :1 or 2 primary follicles progress to this stage each cyclePrimary oocyte larger, finishes first division of meiosis to become a secondary oocyte, also forming a polar body.Follicle grows larger as follicular cells divide to form many layers; spaces begin to develop in center of follicle
9The developing oocyte and its follicle: Four stages before ovulation Most follicles which made it to “secondary” will reach this stageFollicle is very large; Many layers of cells surrounding fluid-filled center called antrumSecondary oocyte covered with thick, clear membrane called zona pellucida; pushed to one side in follicle and surrounded by mass of follicular cells called cumulus oophorus
10Big Question: How is this process of oogenesis regulated? Oogenesis, as well as ovulation and many other things, is regulated by the pituitary gland, which lies just below the brain
11Oogenesis and growth of the follicle in the ovary are initiated and stimulated by from the pitutitaryDuring this oogenesis under the stimulation of FSH, follicular cells surrounding the oocyte secrete the hormone , which stimulates the inner lining of the uterus to thicken and begin secreting mucus, getting ready for pregnancyThis estrogen from the follicular cells also inhibits the pituitary gland from secreting any more FSH.Thus, no more follicles will be stimulated to develop until it stops.
12Rupture of the follicle is ovulation. The secondary oocyte, surrounded by the zona pellucida and cumulus oophorus, is released from the surface of the ovary, where it can be captured by the open end of the oviduct.The cumulus oophorus now called the corona radiata.
13Ovulation is triggered when the pituitary gland secretes a different hormone, called . Luteinizing hormone also causes the follicular cells of the now empty follicle to develop into a. This structure secretes the hormone
14Before ovulation: FSH stimulates cells of follicle to secrete , which stimulates the lining of the uterus to develop. After ovulation: LH stimulates cells of the corpus luteum to secrete , which maintains the uterine lining in this “ready for pregnancy” conditionIf fertilization and pregnancy occur, the placenta of the embryo secretes a hormone called , which stimulates the corpus luteum to keep secreting progesterone, which in turn keeps the lining of the uterus thick and full of blood vessels.If fertilization and pregnancy do not occur, after a few days the corpus luteum deteriorates and stops producing progesterone. Without its stimulus, the uterus can not maintain its thick lining, so this falls off and is shed as menstruation.
16When the oocyte is released from the surface of the ovary during ovulation, it is picked up by the oviduct, or Fallopian Tube, a hollow muscular tube which leads from near the uterus to the ovaries.
17Oviduct:Lateral End: Wide opening, or , surrounds the surface of the ovary. The edge is surrounded by finger-likeMiddle Part: WideMedial End: Narrowleads into uterus. Cavity of oviduct is continuous with cavity of uterus
18By mechanisms not completely understood: The oviduct moves the oocyte toward the uterusThe oviduct moves sperm away from the uterusFertilization occurs in ampulla of oviduct, forming the zygote, which goes through repeated mitotic cell divisions to eventually form the embryo.Oviduct moves this growing mass of pre-embryo cells toward uterus: takes 3 or 4 days.Secretions from oviduct are necessary to keep sperm, oocyte, and embryo alive.
19Uterus: Anterior to rectum; Posterior & superior to bladder Narrowed inferiorly to form cervix, which projects into vagina
20Two layers of endometrium: Uterus:Outer layer = : Thick layer of muscleInner layer = : Lots of glands & blood vesselsTwo layers of endometrium:: Closer to myometrium; Remains after menstruation; Regrows functional layer: Closer to cavity; Thickens every cycle; Embryo implants here during pregnancy; Dies and falls off during menstruationInferior end narrows to form , which projects down into vagina
21Mass of Uterus: At end of pregnancy: Immediately before menstruation: – 150 gramsImmediately after end of menstruation: – 100 gramsEnd of pregnancy: ,000 – 1,500 gramsAt end of pregnancy:Uterus extends from vagina inferiorly to bottom of sternum superiorlyLies anterior to all other abdominal organs except bladder
22Vagina: Thin-walled, tubular Inferior to uterus; Anterior to rectum Posterior to bladder & urethraReceives penis and semen during sexual intercoursePassage for delivery of fetus or menstrual flow
23External Genitalia: The vagina opens between the into a space called theOutside of those are theAt the anterior junction of theouter labia is theNote that
24The head, or glans, of the clitoris which is visible externally is only a small part of this organ.Two shafts of erectile tissueextend backwards along thepelvic floor on either side ofthe urethra and vagina.
25Lateral to uterus Oviduct Ovary Uterus Pubic Bone Bladder Rectum ClitorisLabium minoraVaginaLabium majoraUrethrax