Female Reproductive System
Essential & Accessory Organs Gonads - ovaries Accessory Organs Ducts - uterine tubes, uterus, vagina Sex glands - bartholin’s and breasts External genitals - vulva
Ovaries Pair of them Uneven surface Weight: 3g Attached to ligaments in pelvic cavity Each side of uterus 1 million ovarian follicles in baby girl
Follicle development Each follicle contains an oocyte By puberty 400,000 develop into primary follicle During lifetime, 350 - 500 will develop into mature follicles These ovulate and release an ovum for pot’l fertilization - Graafian follicle
Primary follicle to Ovulation Granulosa cell layer around oocyte increases Forms hollow chamber (antrum) & secondary follicle is formed Mature follicle (Graafian follicle) ruptures during ovulation Remaining follicle is transformed into hormone secreting glandular structure (corpus luteum)
Oogenesis Production of female sex cells via meiosis Two meiotic divisions reduce chromosome number in half but cytoplasm is divided unequally b/t 4 cells One large ovum & 3 small polar bodies
Estrogen and Progesterone Granulosa cells around oocyte produce estrogen Female sex characteristics Stimulates growth of epithelial cells lining uterus Initiates 1st period Secreted by Corpus luteum Stimulated by pituitary gland to last for 11 days Stimulates proliferation and vascularization of epithelial lining of uterus Initiates menstrual cycle with estrogen
Reproductive Ducts Uterine tubes (fallopian tubes or oviducts) - serve as duct for ovaries Uterus - small, but strong organ
Fallopian Tubes Outer end has fringelike projections called fimbriae Fimbriae produce wavelike movement to “catch” the ovum Ovum travels toward uterus
Uterus Size of a pear Extremely strong Holds baby during pregnancy 2 parts - body & cervix 3 layers - endometrium, myometrium, perimetrium Functions in menstruation, pregnancy and labor
Vagina Distensible tube about 10 cm long Smooth muscle and lined with mucous membrane Sperm enters on journey to reach ovum Also called birth canal
Accessory and supportive sex glands Bartholin’s glands - secretes mucuslike fluid to genetalia Breast - lie over pectoral muscles 15-20 lobes that contain milk-secreting glandular cells
Menstrual Cycle Days 1 - 5 - Menses (menstrual) period - small patches of dead cells of uterine lining slough off, leaving torn blood vessels Days 6 - 13 Proliferative phase - epithelial cells reproduce, repairing uterine lining Day 14 - Ovulation - ovum is released from ovary and moves into fallopian tube for possible fertiliaztion Days 15 - 28 - Secretory phase - uterine lining prepares for pregnancy by growing thicker, secreting, more blood supply. On last day, blood supply goes down, causing cells to die.