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Chapter 32Female Reproductive

System

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Overview: Female Reproductive System

• Function– to produce offspring and thereby ensure

continuity of the genetic code– It produces eggs, or female gametes,

which each may unite with a male gamete to form the first cell of an offspring

– It also can provide nutrition and protection to the offspring for up to several years after conception

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– Reproductive organs are classified as essential or accessory• Essential organs

– gonads are the paired ovaries– Gametes are ova (eggs) produced by the ovaries

• Accessory organs– Internal genitals

» uterine tubes, uterus, and vagina» ducts that extend from the ovaries to the exterior

– External genitals» the vulva

– Mammary glands

Overview: Female Reproductive System

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Slide 5MRI Scan

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• Perineum– The perineum is the skin-covered region between the vaginal

orifice and the rectum– This area may be torn during childbirth– extends anteriorly from symphysis pubis to coccyx posteriorly– lateral boundary is the ischial tuberosity on either side

Overview: Female Reproductive System

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Ovaries• Location of the ovaries (ov = egg)

– Nodular glands located on each side of the uterus, below and behind the uterine tubes

– Large almonds

– 3 g each

Ectopic pregnancyEctopic pregnancy ( (ectopectop = = displaced)displaced)

development of the development of the fetus in a place other fetus in a place other than the uterusthan the uterus

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Ovaries

• Ovarian carcinoma

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• Microscopic structure of the ovaries

– Ovarian follicles

• contain the developing female sex cells = oocyte (oo = egg)

– Ovum

» A developed oocyte released from the ovary

Ovaries

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Ovaries

• Functions– Ovaries produce ova— the female gametes– Oogenesis— process that results in formation

of a mature egg– Endocrine organs that secrete the female sex

hormones- estrogens and progesterone

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Uterus • Structure

– Size and shape• Pear-shaped, has two main parts— the cervix and the body

– Wall of uterus is composed of three layers• inner endometrium• middle myometrium• Outer perimetrium

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Uterus

Endometrial carcinoma

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Uterus

– Cavities of uterus— cavities are small because of the thickness of the uterine walls

• Internal os = apex of cervix• External os = opening of cervix

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Cadaver dissection showing uterine cavity and cervical canal, exposed by removal of parts of their posterior walls

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Uterus

• Location of the uterus– Located in pelvic cavity between urinary

bladder and rectum– Position of uterus is altered by age,

pregnancy, and distention of related pelvic viscera

– Descends, between birth and puberty, from the lower abdomen to the true pelvis

– Begins to decrease in size at menopause

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Uterus

• Position of the uterus– Body lies flexed over the bladder– Cervix points downward and backward,

joining the vagina at a right angle– Several ligaments hold the uterus in place

but allow some movement

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Uterus

• Functions of the uterus– Part of reproductive tract, permits sperm to ascend

toward uterine tubes

– If conception occurs, offspring develops in the uterus• Embryo is supplied with nutrients by endometrial glands until

the production of the placenta

• Placenta is an organ that permits exchange of materials between mother’s blood and fetal blood but keeps the two circulations separate

• Myometrial contractions occur during labor and help push the offspring out of mother’s body

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Uterus

– If conception does not occur, outer layers of endometrium are shed during menstruation

• Menstruation is a cyclical event that allows the endometrium to renew itself

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Endometrial (Menstrual) Cycle

• 4 Phases over 28 days1. Menses, menstrual period

– Days 1-5

2. Postmenstrual phase or preovulatory phase– Estrogenic or follicular phase– Days 6-13

3. Ovulation– Days 14

4. Premenstrual or postovulatory– Luteal phase or secretory phase or progesterone phase– Corpus luteum is secreting progesterone– Days 15-28

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Endometrial (Menstrual) Cycle

• Hypothalamus stimulates ovaries to make mature follicle– FSH- Follicle Stimulating Hormone– LH- Luteinizing Hormone

– Maturing follicle releases estrogen and spikes (Day 13)

– Hypothalamus responds with a burst of FSH and LH to release ovum

• Ovulation (Day 14)

– LH corpus luteum– Corpus luteum produces progesterone suppresses FSH & LH

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The rupture of a mature follicle on the surface of an ovary results in the release of an ovum into the pelvic cavity. The ovum released during ovulation is surrounded by a mass of cells.

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Uterine Tubes

• Uterine tubes = fallopian tubes = oviducts• Structure of uterine tubes

– Consist of mucous, smooth muscle, and serous lining• Tubal mucosa is continuous with vagina and uterus

can become infected with organisms introduced into the vagina

• Function of the uterine tubes– Serve as transport channels for ova and as the site of

fertilization

Slide 28Tubal ligation

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Vagina

• Vagina is a tubular organ located between the rectum, the urethra, and the bladder

• Structure of the vagina– Collapsible tube capable of distention– 7 or 8 cm long (3 inches)– composed of smooth muscle– lined with mucous membrane arranged in rugae– Hymen— a mucous membrane that typically forms a

border around the vagina in young premenstrual girls

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Vagina

• Functions of the vagina– Lining of the vagina lubricates and stimulates

the penis during sexual intercourse and acts as a receptacle for semen

– Lower portion of the birth canal– Transports tissue and blood shed during

menstruation to the exterior

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Vulva • The vulva consists of the female external genitals:

– mons pubis (pad of fat over symphysis pubis)– labia majora and minora– Clitoris– urinary meatus (urethral orifice)– vaginal orifice– greater vestibular gland

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Vulva

• Functions of the vulva– The mons pubis and labia protect the clitoris

and vestibule– The clitoris contains sensory receptors that

send information to the sexual response area of the brain

– The vaginal orifice is the boundary between the internal and external genitals

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Breasts• Location and size

– The breasts lie over the pectoral muscles

– Estrogens and progesterone control breast development

– 15-20 lobes– Breast size is determined by

the amount of fat around glandular tissue not related to functional ability

– Areola- becomes darker during pregnancy

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Breasts• Function of the breasts

– Lactation• Mechanism of lactation

– Ovarian hormones make breasts structurally ready to produce milk

» Estrogen promotes duct development» Progesterone promotes development of alveoli, the

secreting cells– Shedding of placenta decrease of estrogens

stimulates prolactin stimulates lactation» Suckling also stimulates lactation

– Secretion starts about 3-4 days after delivery– Oxytocin is released to facilitate bonding between mother

and child

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Breasts

– Lactation can provide nutrient-rich milk to offspring for up to several years from birth

– Some advantages are the following:• Nutrients• Passive immunity from antibodies present in

colostrum and milk• Emotional bonding between mother and child

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Female Reproductive Cycles• The female reproductive system has many cyclical changes that start

with the beginning of menses

– Ovarian cycle— ovaries from birth contain oocytes in primary follicles

• at the beginning of menstruation each month, several of the oocytes resume meiosis

• meiosis will stop again just before the cell is released during ovulation

– Menstrual cycle (endometrial cycle) is divided into four phases:

• Menses

• Postmenstrual phase

• Ovulation

• Premenstrual phase

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Female Reproductive Cycles• Control of female reproductive cycles

– Hormones control cyclical changes

– Cyclical changes in ovaries result from changes in gonadotropins (FSH and LH) secreted by pituitary gland

– Cyclical changes in uterus are caused by changes in estrogens and progesterone

– Low levels of FSH and LH cause regression of the corpus luteum if pregnancy does not occur

• this causes a decrease in estrogen and progesterone, which triggers endometrial sloughing of the menstrual phase

– Control of cyclical changes in gonadotropin secretion is caused by positive and negative feedback mechanisms and involves estrogens, progesterone, and the hypothalamus’s secretion of releasing hormones

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Female Reproductive Cycles

• Importance of the female reproductive cycles– Ovarian cycle’s primary function is to produce an ovum at

regular intervals• Secondary function is to regulate endometrial cycle through

estrogen and progesterone– Function of endometrial cycle is to make uterus suitable for

implantation of a new offspring– Cyclical nature of the reproductive system and the fact that

fertilization will occur within 24 hours after ovulation mean that a woman is only fertile a few days of each month

• Menstrual flow begins at puberty, and menstrual cycle continues for about three decades

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The Big Picture: The Female Reproductive System and the Whole Body

• The female reproductive system shares a special relationship with the following:– The urinary system because of their close

proximity and because they share the vulva– The skeletal muscles in the perineum– The integumentary system because breasts

are actually modifications of the skin

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• Pictures of gynecological system pathology

• http://www.uphs.upenn.edu/path/web_docs/p200/GYN200/GYN95.html

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Hydrops fetalis- abnormal accumulation of fluid in fetal compartments

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• Placenta percreta– Placenta attaches

itself too firmly to the uterus, going through the myometrium and serosa (ruptures the uterus)

– 1: 2500 pregnancies