Female Reproductive System Ovaries (__________) Duct System Oviducts(fallopian tubes) Uterus Vagina ___________ is NOT part of reproductive system in females External genitalia

Female Reproductive Organs

Female Reproductive Organs Figure 39.16, pg 664

Ovaries Produces _______ Secrete ____________________ Composed of ovarian follicles (sac-like structures) Follicle Structure Oocyte Follicular cells Figure 16.7

Ovarian Follicle Stages Primary follicle – contains immature oocyte Follicle grows with a maturing oocyte Ovulation – egg is mature and the follicle ruptures Occurs about every ____________ Ruptured follicle is transformed into a ___________ ____________

Fallopian Tubes (Oviducts) Receive the ovulated oocyte Cilia move the oocyte towards the uterus (takes 3–4 days) Provide a site for ______________ Attaches to the uterus Does not physically attach to the ovary

Uterus Hollow organ Functions of the uterus Receives a fertilized egg Retains the fertilized egg Nourishes the fertilized egg __________________ Inner layer Allows for implantation of a fertilized egg Sloughs off if no pregnancy occurs (menses)

Regions of the Uterus Myometrium – thick muscle layers of the uterus ___________________________________ Cervix – narrow outlet that protrudes into the vagina Secretes mucus to help sperm enter uterus Defends embryo against ________

Vagina Extends from cervix to exterior of body Serves as the birth canal Receives sperm during sexual intercourse

Oogenesis Making eggs Total supply of eggs are present at birth About ___________ immature eggs Ovulation begins at puberty Many eggs “die off” in earlier stages of development, before ovulation occurs Reproductive ability ends at menopause Oocytes are matured in developing ovarian follicles

Oogenesis Girl is born with primary oocytes already in ovaries Each oocyte has entered meiosis I and stopped Meiosis resumes, with the first menstrual cycle Meiosis completed only after fertilization Unfertilized egg: ______________________

Ovarian Cycle Figure 39.17

Menstrual Cycle Function: produce an environment that is hospitable to the growing embryo Lining of uterus builds up cyclically Bleeding is a by-product resulting from no pregnancy The fertile period for a human female occurs on a cyclic basis

Menstrual Cycle Cyclic changes of the endometrium Regulated by cyclic production of estrogens and progesterone Menstrual cycle lasts about ___________ Day 1: first day of bleeding Ovulation around day 14 Stages of the menstrual cycle Menses: endometrium is sloughed Follicular phase: ________ to ovulation Luteal phase: _________ ovulation

Hormonal Control of the Ovarian and Uterine Cycles hypothalamus GnRH anterior pituitary blood levels of FSH ( purple) and LH ( lavender) midcycle peak of LH (triggers ovulation) FSH LH LH Fig. 39.18a, p.667

Hormonal Control of the Ovarian and Uterine Cycles Fig. 39.18b-c, p.667 growth of follicle ovulation corpus luteum blood levels of estrogens (light blue), progesterone (dark blue) estrogens progesterone, estrogen

Hormonal Control of the Ovarian and Uterine Cycles 5 14 28 FOLLICULAR PHASE OF MENSTRUAL CYCLE LUTEAL PHASE OF MENSTRUAL CYCLE Fig. 39.18d-e, p.667

Hormone Production by the Ovaries Estrogens Produced by follicle cells Cause secondary sex characteristics Enlargement of accessory organs Development of breasts Appearance of pubic hair Increase in fat beneath the skin Widening and lightening of the pelvis Onset of menses

Hormone Production by the Ovaries Progesterone Produced by the corpus luteum Production continues until LH diminishes in the blood Helps maintain pregnancy

Female Hormonal Control

Cycle Overview GnRH secretion affects LH and FSH secretion by pituitary LH and FSH affect follicle maturation Estrogen and progesterone from ovary affect uterus

Probability of Pregnancy Wilcox, A. J et al. BMJ 2000;321:1259-1262 Copyright ©2000 BMJ Publishing Group Ltd.

“Female Troubles” Premenstrual syndrome (PMS): related to discomfort a week or two before menstruation Cycle induced changes cause depression, irritability, anxiety, headaches, sleeping disorders, and breast tenderness Menstrual pain: Prostagladins secreted stimulate contractions of smooth muscle in the uterine wall

Fertilization Ejaculation in the male and similar smooth muscle contractions in the female are called orgasm ____________________________ sperm are deposited in the vagina after intercourse Only a few hundred will reach the upper region of the oviduct where fertilization occurs Sperm may live for about ___________ following ejaculation

Fertilization Sperm penetrates to egg cytoplasm Only one sperm will enter after digesting its way through the ____________________ Secondary oocyte undergoes meiosis II; forms mature egg Egg nucleus and sperm nucleus fuse to form diploid zygote

A Look at Fertilization

FSH and twins High levels of FSH can cause two eggs to mature, possibly leading to fraternal twins Fraternal twins: two genetically unique zygotes formed when two oocytes are released in one menstrual cycle Identical twins: one zygote or early embryo splits ________________________ Fraternal twins run in families

Pregnancy Humans prevent pregnancy by: Abstinence Surgery (vasectomy or tubal ligation) Physical or chemical barriers Affecting female sex hormones Total abstinence is the _______ form of birth control that is 100% effective

Fertility Control Options Rhythm method: tracking cycle to know when egg can be fertilized (74% effective) Withdrawal before ejaculation (74% effective) Pre-ejaculation fluids can hold some sperm Douching: chemically rinsing vagina after sex Sperm travel out of reach of douching fluids in _____ Spermicidal foam and jelly: toxic to sperm Only effective when used with a ________________ Diaphragm and cervical cap: fits over cervix and prevents entry of sperm

Fertility Control Options Condoms: prevent sperm deposition in vagina ONLY latex condoms protect against STDs Even the best brands can tear or leak Birth control pill (and patch): contains synthetic female hormones and prevents ovulation MUST be taken faithfully according to directions Raises risk of breast, cervical, and liver cancer Reduces menstrual cramps Can interact with antibiotics and be made less effective

Fertility Control Options Progestin injections (Depo-Provera) or implants (Norplant) inhibit ovulation over several months “Morning-after pills” (emergency contraception): intercept pregnancy by blocking fertilization or preventing implantation

Birth Control Options

Regarding Abortion 10% of women who become pregnant lose the embryo or fetus in a spontaneous abortion, or miscarriage Some estimate that 50% of all fertilized eggs are lost, most due to genetic problems About half of all unplanned pregnancies end in an induced abortion The deliberate dislodging and removal of an embryo or fetus from the uterus Generally a low risk procedure during the first three months of pregnancy

Assisted Reproductive Technology In vitro fertilization is conception outside the body Hormone injections prepare ovaries for ovulation Oocyte is withdrawn and sperm is injected into it A few days later, ball of cells is transferred to woman’s uterus or oviduct Procedures are costly and have low success rates