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Ovaries

Ovaries. Each ovary is about the size and shape of an almond. In young women ovaries are the size of an almond; after menopause they tend to shrink. They produce eggs (also called ova); every female is born with a lifetime supply of eggs

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Ovaries

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  1. Ovaries • Each ovary is about the size and shape of an almond. • In young women ovaries are the size of an almond; after menopause they tend to shrink. • They produce eggs (also called ova); every female is born with a lifetime supply of eggs • They also produce hormones: Estrogen  & Progesterone

  2. Oogenesis • Before birth at 4 months oogonia form • At birth- some oogonia degenerate, the rest go through mitosis forming more oogonia & primary oocytes • 2 million 1˚oocytes @ birth by puberty only 300,000- 400,000 exist • Puberty primary oocytes finish developing • Primary oocytes grow & go through Meiosis I  secondary oocytes & polar bodies • Ovulation  release of 2˚oocyte • 2˚oocyte go through Meiosis II only if fertilization occurs

  3. Fallopian tubes [uterine tubes] • Tubes stretch from the uterus to the ovaries • 8 -13 cm in length; an in. wide near the ovary to the diameter of spaghetti • Cilia line the tubes • Cilia beat in waves catching the egg at ovulation & move it through the tube to the uterine cavity. • Fertilization typically occurs in the fallopian tube

  4. uterus • Pear-shaped muscular organ in the upper female reproductive tract. • Fundus = upper portion of the uterus where pregnancy occurs • Cervix = lower portion of the uterus connecting to the vagina • serves as a sphincter keeping the uterus closed during pregnancy until delivery • The uterus expands during pregnancy growing 10 to 20x its normal size during pregnancy.

  5. uterus • Body= firm outer coat of muscle (myometrium) and an inner vascular/glandular layer (endometrium) • Endometrium thickens during the menstrual cycle for implantation of a fertilized egg. • Pregnancy occurs when the fertilized egg implants in the endometrial lining. • If fertilization does not occur, the endometrium sloughs off and is expelled as menstrual flow.

  6. The Cervix • Neck of the uterus. • Lined with mucus, the quality and quantity depends on estrogen & progesterone. • Low estrogen levels= mucus is thick and sparse, hindering sperm from reaching the fallopian tubes. • High estrogen levels= mucus is thin and slippery, offering a “friendly environment” to sperm • At the end of pregnancy, the cervix= gateway to the vagina. • Cervical canal expands 50x its normal width for birth

  7. The Vagina • A muscular, ridged sheath connecting to the uterus • Two Functions: • Accepts the penis and sperm during intercourse • Avenue of birth

  8. External genetalia • The urethral orifice (external urinary) opening is below the clitoris on the upper wall of the vagina and is the passage for urine • The introitus or opening of the vagina is separate from the urinary opening (unlike males) and located below it. • The hymen is a thin cresentic fold of tissue which partially covers the opening of the vagina. • medically it is no longer considered to be a 100% proof of female virginity.

  9. Menstrual Cycle • Menstrual Cycle- cyclic changes in the uterus (includes hormone secretion in the uterus and ovaries) • 28 days long (btw. 18-40 days)

  10. Phases of Female Reproductive Cycle • Menstrual Phase- discharge of the blood & the uterine mucous membrane which is sloughed & expelled (menses) • First day of menstrual cycle; lasts 4-5 days • Preovulatory Phase- time btw. the ending of menses & ovulation • Lasts from days 6-13 in a 28 day cycle • rapid production of uterine mucosa/ lining • Ovulation- release of a secondary oocyte • Occurs on day 14 of 28 day cycle • Postovulatory Phase- period after ovulation & before next menses • Maturation of follicles • Lasts 14 days in a 29 day cycle

  11. Ovarian Cycle- events in the ovaries that occur during and after maturation of an oocyte • Oocyte matures erupts from ovary travels down oviduct uterus • Horomones from the hypothalmus & pituitary gland stimulate: • 1stmeitoic division of an oocyte • Development of the uterine wall

  12. Uterine Cycle- the endometrium of the uterus prepares for the fertilized ovum • Lining of uterus grows & prepares for embryo to implant if fertilization occurs • If fertilization has not occurred lining of uterus sloughs off in menstruation

  13. External genetalia • Vulva— runs from the pubic area downward to the rectum. • Labia majoraor "greater lips" are the part around the vagina containing • Labia minoraor "lesser lips" are the thin hairless ridges at the entrance of the vagina (anteriorly they split to enclose the clitoris) • Hymen- a thin fold of tissue partially covering the vagina • Urethral orifice or external urinary opening is below the clitoris

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