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General anatomy of the Female Reproductive System. Points to Ponder. How many chromosomes do body and sex cells each have? Understand the anatomy of both the male and female. What are the 3 parts of a sperm? How do hormones play a role in the male?
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General anatomy of the Female Reproductive System
Points to Ponder • How many chromosomes do body and sex cells each have? • Understand the anatomy of both the male and female. • What are the 3 parts of a sperm? • How do hormones play a role in the male? • Explain the ovarian and uterine cycles. • Where do fertilization and implantation occur? • What is infertility? What can cause this?
Genital tract: Ovaries Oviducts Uterus Cervix Vagina External genitals (vulva): Labia major Labia minor Mons pubis Clitoris 16.3 Female reproductive system Female anatomy
16.3 Female reproductive system Female anatomy: Genital tract • Ovaries – produce eggs and sex hormones • Oviducts – moves eggs and normal site of fertilization • Uterus – normal site of implantation and fetal development • Cervix – opening to the uterus that can dilate during childbirth • Vagina – birth canal
16.3 Female reproductive system Female anatomy: Genital tract
VAGINAL OPENING • Opening may be covered by a thin sheath called the hymen • Using the presence of an intact hymen for determining virginity is erroneous • Some women are born without hymens • The hymen can be perforated by many different events
PERINEUM • The muscle and tissue located between the vaginal opening and anal canal • It supports and surrounds the lower parts of the urinary and digestive tracts • The perineum contains an abundance of nerve endings that make it sensitive to touch • An episiotomy is an incision of the perineum used during childbirth for widening the vaginal opening
INTERNAL GENITALIA • The internal genitalia consists of the: • Vagina • Cervix • Uterus • Fallopian Tubes • Ovaries
VAGINA • The vagina connects the cervix to the external genitals • It is located between the bladder and rectum • It functions : • As a passageway for the menstrual flow • For uterine secretions to pass down through the introitus • As the birth canal during labor • With the help of two Bartholin’s glands becomes lubricated during SI
CERVIX • The cervix connects the uterus to the vagina
The cervical opening to the vagina is small • This acts as a safety precaution against foreign bodies entering the uterus • During childbirth, the cervix dilates to accommodate the passage of the fetus • This dilation is a sign that labor has begun
UTERUS • Commonly referred to as the womb • A pear shaped organ about the size of a clenched fist • It is made up of the endometrium, myometrium and perimetrium • Consists of blood-enriched tissue that sloughs off each month during menstrual cycle • The powerful muscles of the uterus expand to accommodate a growing fetus and push it through the birth canal
FALLOPIAN TUBES • Serve as a pathway for the ovum to the uterus • Are the site of fertilization by the male sperm • Often referred to as the oviducts or uterine tubes • Fertilized egg takes approximately 6 to 10 days to travel through the fallopian tube to implant in the uterine lining
OVARIES • The female gonads or sex glands • They develop and expel an ovum each month • A woman is born with approximately 400,000 immature eggs called follicles • During a lifetime a woman release @ 400 to 500 fully matured eggs for fertilization • The follicles in the ovaries produce the female sex hormones, progesterone and estrogen • These hormones prepare the uterus for implantation of the fertilized egg
16.3 Female reproductive system Female anatomy: External anatomy • Labia major – 2 large folds of fatty skin • Labia minor – 2 small folds just inside the labia major that contain the opening to the urethra and vagina • Mons pubis – fatty skin covered in coarse hair • Clitoris – erectile organ
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The ovarian cycle: The ovary • Contains many follicles each containing an immature egg (oocyte) • At birth a female has ~300,000-400,000 follicles • During the lifetime of a female only ~400 follicles mature • One follicle matures each cycle from puberty until menopause • Ovulation is the monthly release of an oocyte from the ovary when a follicle ruptures
16.4 Female hormone level Anatomy of the ovary
16.4 Female hormone level The ovarian cycle • This is the formation and release of an immature egg • 2 phases: • Follicular phase: • FSH promotes the development of a follicle that secretes estrogen • An estrogen spike leads to a surge in LH and ovulation around day 14 in the 28-day cycle • Luteal phase: • LH promotes the develop of the corpus luteum that functions to secrete progesterone • If pregnancy does not occur menstruation begins
16.4 Female hormone level The uterine cycle • A 28-day cyclic event in the uterus: • Days 1-5: low level of estrogen and progesterone causing the inner uterine lining (endometrium) to disintegrate and menstruation occurs • Days 6-13 (proliferative phase): increase in estrogen causing the endometrium to thicken • Day 14: ovulation usually occurs • Days 15-28 (secretory phase): increase in progesterone causes endometrium to double or triple in thickness in preparation for the developing embryo. If the egg is not fertilized then the corpus luteum regresses and the endometrium breaks down
16.4 Female hormone level Hormones in the ovarian and uterine phase
16.4 Female hormone level Fertilization and Pregnancy • Fertilization – union of a sperm and egg nucleus normally in the oviduct to form a zygote • Pregnancy – beginswith implantation usually ~6 days after fertilization
16.5 Control of reproduction Some common birth control methods • Abstinence – not engaging in sexual intercourse • Hormonal control: • Birth control pills: blocks FSH and LH release to stop follicular development and ovulation • Contraceptive injections: injection of hormones (progesterone and/or estrogen) to stop ovulation • Contraceptive implants: synthetic progesterone to prevent ovulation • Barrier methods: • IUD: small plastic piece inserted into the uterus to prevent implantation • Condom (male and female): blocks fertilization • Diaphragm: soft latex cup that covers the cervix so sperm cannot enter the uterus • Sterilization: • Vasectomy: cutting and sealing the vas deferens • Tubal ligation: cutting and sealing the oviducts