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

OVARY

OVIDUCT

CLITORIS

LABIUM MINOR

LABIUM MAJOR

VAGINA

anus

opening of cervix

UTERUS

MYOMETRIUM

ENDOMETRIUMurinary bladder

urethra

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

primordial follicle

e Ovulation. Mature follicle ruptures and releases the secondary oocyte and the first polar body.

a Primary oocyte, not yet released from meiosis I. A cell layer is forming around it. A follicle consists of the cell layer and the oocyte.

f A corpus luteum forms from remnants of the ruptured follicle.

b A transparent and somewhat elastic layer, the zona pellucida, starts forming around the primary oocyte.

first polar body

secondary oocyte

d Mature follicle. Meiosis I is over. The secondary oocyte and first polar body are now formed.

ovary

c A fluid-filled cavity (antrum) starts forming in the follicle’s cell layer.

g The corpus luteum breaks down when the woman doesn’t get pregnant.

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 UterineCycles

GnRH

hypothalamus

anterior pituitary

blood levels of FSH( purple) and LH ( lavender)

midcycle peak of LH(triggers ovulation)

FSH LH LHFig. 39.18a, p.667

Hormonal Control of the Ovarian and Uterine Cycles

Fig. 39.18b-c, p.667

growth of follicle

estrogens

blood levels of estrogens(light blue), progesterone(dark blue)

progesterone, estrogen

ovulationcorpus luteum

Fig. 39.18d-e, p.667

FOLLICULAR PHASE OFMENSTRUAL CYCLE

LUTEAL PHASE OFMENSTRUAL CYCLE

28145

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 ControlHYPOTHALAMUS

PITUITARY

c Blood level of estrogens rises, will stimulate a surge in LH secretion

a GnRH prods anterior lobe cells to secrete FSH and LH

d Midcycle surge of LH triggers ovulation, then formation of corpus luteum

f The rise in progesterone, estrogen in blood will inhibit FSH, LH secretion during last phase of cycle

e Progesterone, estrogen secreted by corpus luteum will maintain the endometrium if pregnancy occurs

b In ovary, FSH and LH promote follicle growth and oocyte maturation, estrogen production, priming of endometrium, other reproductive events

(+)

(+)

(–)

(–)

Cycle Overview• GnRH secretion affects LH and FSH secretion

by pituitary

• LH and FSH affect follicle maturation

• Estrogen and progesterone from ovary affect uterus

Copyright ©2000 BMJ Publishing Group Ltd.

Wilcox, A. J et al. BMJ 2000;321:1259-1262

Probability of Pregnancy

“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

zona pellucida

follicle cell

egg nucleus

Fertilization

ovulation

oviduct

ovary

uterus

opening of cervix

vagina

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