Organs of the Female Reproductive System

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A. The female reproductive organs produce and transport the eggs, promote the success of fertilization by receiving the penis, and support the offspring during its first nine months of development

B. The primary female organs of reproduction are the ovaries—produce female gametes and sex hormones and are referred to as the female gonads

Organs of the Female Reproductive System

Ovary Attachments

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a. Structure1. Paired oval organs located opposite one another

against the lateral walls of the pelvic cavity2. 3.5 cm long and 2 cm wide, supported by

ligaments attached to the pelvic wall and uterus3. Externally covered by a single layer of visceral

peritoneum—thin membrane4. Below is a layer of epithelial cells called

germinal epithelium—female sex cells are not present here

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5. Deeper than the germinal epithelium is a tough, fibrous connective tissue that forms a protective shell around the ovary

6. Below the shell is the interior, divided into two regions—outer cortex and inner medullaa. Cortex consists of dense connective tissue

1. Within are numerous saclike ovarian follicles—in various stages of development—each follicle contains a single oocyte or female gamete

b. Medulla consists of connective tissue that is more loosely arranged—receives blood vessels, lymph vessels and nerves and it is continuous with the ligament that attaches the ovary to the uterus

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b.Oogenesis1. Production of female gametes differs from those of

male sperm cells2. The total number of oocytes that are produced in a

lifetime are present in the ovary at birth—500,000 oocytes

3. Maturation and release occur between puberty and about 50 years old, as a monthly cycle—menstrual cycle

4. The oocytes that are present in the ovary at birth are called primary oocytes—represent the first stage of oogenesis—egg development

5. At birth oogenesis stops, and does not resume until puberty is about to begin

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6. Each primary oocyte is surrounded by a single layer of flattened cells to form a structure called a primordial follicle

7. At puberty, hormonal changes stimulate some of the primary oocytes to resume development—about 20 oocytes are stimulated to being dividing by meiosis each month, but only one completes the division

8. The result of the first meiotic division is two unequal sized daughter cells—a large secondary oocyte and a smaller first polar body

9. The first polar body usually proceeds immediately into the second division of meiosis to produce to very small cells—second polar bodiesthese cells die and reabsorb

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10. The secondary oocyte does not yet begin another division—ready to be fertilizeda. If fertilized, the secondary oocyte will

quickly undergo its second meiotic division to produce a second polar body and a zygote—zygote is the fertilized egg & polar body degenerates

b. Zygote will become an embryo

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Oogenesis

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c. Follicle Development1. During childhood, primordial follicles

are in a state of suspended animation, as hormone levels begin to rise and puberty begins, a number of changes occur

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a. Flattened cells of the follicle begin to enlarge—primary follicle

b. Enlargement of the primary oocyte as it prepares for its first meiotic division—follicle cells then begin to rapidly divide by mitosis this forms a multiple-layered arrangement & increases the size of the primary follicle

c. A cavity called the antrum between the oocyte and follicle cells soon appears and fills with a clear fluid as it expands once formed it is now called a secondary follicle

Follicle Development

d. Follicle continues to enlarge until it reaches a diameter of about 10mm—then begin to secrete the hormone estrogen, as well as, a transparent membrane called the zona pellucida

e. At this time the size of the follicle has caused it to bulge from the ovary like a blister and it will soon be ready for ovulation—taken about 10 days and the mature follicle is now called the Graafian follicle

Follicle Development

Follicle Maturation

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2. The entire sequence is repeated every 28 days, beginning at puberty until about age 50

3. Only one follicle is permitted to mature at a time only about 400 to 500 of the 400,000 follicles are prepared for ovulation in a life time.

Follicle Development

d. Ovulation1. After 14 days, the Graffian follicle has matured

to the point of being ready for expulsion out of the ovary

2. This process known as ovulation begins when the wall of the ovary at the site of the ballooning follicle ruptures

3. The secondary oocyte is expelled into the peritoneal cavity as a result of this explosive event

4. The expelled oocyte remains surrounded by some of its protective follicle cells, forming an outer mantle called the corona radiate

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Ovulation

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5. After the oocyte and its corona radiate are swept by currents of fluid into a uterine tube where fertilization may occur—if not fertilized it will degenerate in about 5 days

6. After ovulation follicle cells remain within the ovary—transformed into a yellowish glandular mass called the corpus luteum

a. If oocyte becomes fertilized and pregnancy occurs the corpus luteum will enlarge—hormones maintain the state of pregnancy for the first 3 months until the placenta takes over

b. If pregnancy does not occur the corpus luteum persists for about 10 to 12 days before degeneration

Ovulation

Female Internal Accessory Organs

• uterine tubes• uterus• vagina

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Other female reproductive organs provide a site for the birth process and receive the penis during sexual intercourse

a. Uterine Tubes1. The paired uterine tubes are also called the

fallopian tubes or oviducts2. Located along one side of the pelvic cavity wall—

extend between an ovary and the centrally located uterus

3. 10 cm long and about 1 cm in diameter—and lined with a ciliated mucous membrane

4. At the end near the ovary—widen to form a funnel-shaped part that opens directly into the peritoneal cavity—called the infundibulum and is fringed along its outer margin with fingerlike projections called fimbriae

Female Accessory Organs

5. Fimbriae nearly touch the surface of the ovary as they wave about in the peritoneal fluid—collect the oocyte during ovulation and their cilia sweep it into the uterine tube

6. Fertilization usually occurs within the uterine tube near the infundibulum—if successful, the actions of the cilia combined with contractions of the tube’s muscular wall transports the developing embryo to the uterus

Uterine Tubes

Uterine Tubes

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b. Uterus1. A pear shaped organ about the size

of a woman’s clenched fist.2. Located near the floor of the pelvic

cavity between the urinary bladder and the rectum—suspended by ligaments that tilt it downward toward the vagina

Female Accessory Organs

3. Hollow thick-walled structure that provides support for the developing embryo and fetus—consists of two main regionsa. Body—dome-shaped, receives the

uterine tubes and the lower narrow cervix

b. Internally space within the body is the uterine cavity and within the cervix is the cervical canal—cervical canal opens into the vagina by way of the external os

Uterus

4.Powerful contractions provide the force necessary to push the fetus out during birth

5.Also site of menstruation6.Walls consist of 3 layers—serous,

muscular and vascular layer

Uterus

a. serous layer—outermost consists of a thin membrane

b. myometrium—bulk of the uterine wall—made up of smooth muscle and elastic connective tissue

c. endrometrium—inner lining of the uterus—epithelium with a highly vascular connective tissue underneath—contains mucous glandseach month the superficial layers are sloughed off during menstruation

Uterus

Uterus

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Uterine Wall

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c. Vagina

1. Receives the penis during intercourse—often called the birth canal since it provides a passage during childbirth

2. Passage for menstruation as well

3. Thin walled tube about 8 to 10 cm long—extends from cervix to the outside

4. At the end near the cervix, the walls curve around to form shallow pockets known as the fornix

Female Accessory Organs

5. Wall of the vagina consists of an outer layer of smooth muscle and an inner mucous membrane—muscle allows the vagina to increase in size to accommodate the penis and the passage of a child during childbirth

6. Mucous membrane provides protection7. Lacks mucous glands so it relies upon secretions from

other places for lubrication8. Opening to the outside is the vaginal orifice—in young

females the mucosa may extend across the opening forming a thin barrier called the hymen

9. The hymen contains blood vessels, so when ruptured it may bleedrupture may be caused by tampon insertion, physical activity, pelvic examination or sexual intercourse

Vagina

Vagina

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Female External Reproductive Organs

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A. Reproductive structures located external to the vagina—structures are collectively called the vulva

B. The upper border of the vulva is marked by an elevated rounded area—mons pubis1. After puberty this area will be covered with hair

C. Extending downward from the mons pubis are two narrow folds of skin that are also covered with hair after puberty—labia majora1. Female counterpart of the male scrotum—come from the same embryonic tissue

Female External Reproductive Organs

D. Medial to the labia majora are two thin, hair free folds called the labia minora—covered with mucous membrane that is richly supplied with oil glands1. Forms the outer margins of a region called the vestibule—contains the clitoris, external urethral orifice, & vaginal orifice

a. clitoris—female counterpart of the penis contains a prepuce—hood like covering formed by the union of the labia minor

b. Near the vaginal orifice are numerous glands whose secretions help to moisten the vagina and vestibule—vestibular glands.

c. Region between the vestibule and the anus is the perineum—overlies the pelvis outlet—sometimes tears between the vaginal opening and the anus during childbirth—usually will cut to widen the birth canal opening—this procedure is called an epistiotomy.

Female External Reproductive Organs

A. The organs that produce milk for infant nourishment

B. Located in the breast or mammae—modified sweat glands

C. Contain heavily pigmented areola that surrounds a centrally elevated nipple—sensitive to touchcontain smooth muscle that cause them to become erect

D. In children breast structure is similar between males and femalesunder increasing levels of estrogen and progesterone, the breasts enlarge by accumulating large amounts of fat and a glandular system develops

Mammary Glands

Mammary Glands

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E. Adult females have 15 to 20 lobes that radiate around each nipple—padded with fat, ligaments form between them and the underlying muscular tissue

F. Within each lobe are smaller chambers called lobules which contain alveolar glandsproduce milk when the woman is lactatingsecreted into ducts to the outside opening at the nipple

Mammary Glands