A & P II: Female reproductive system

Anatomy of the female reproductive system

Ovaries, fallopian (uterine) tubes, uterus, vagina, external genital organs, and mammary glands

Broad ligament

Extension of peritoneum, spread out on both sides of the uterus (ovaries and fallopian tubes are attached as well) to hold them in place

Ligaments of ovaries

• Mesovarium

• Suspensory ligament

• Ovarian ligament

Mesovarium

Peritoneal fold that attaches the ovary to the posterior surface of the broad ligament

Suspensory ligament

From mesovarium to body wall (contains ovarian arteries, veins, and nerves)

Ovarian ligament

From ovary to superior part of uterus (ovarian arteries, veins, and nerves enter the ovary through this ligament)

Histology of ovarian covering

• Outermost covering: ovarian (germinal) epithelium (visceral peritoneum)

• Tunica albuginea: capsule of dense fibrous connective tissue

Histology of the ovary itself

• Cortex: outer lining, dense (contains follicles with oocytes)

• Medulla: Inner lining, looser (contains blood vessels, nerves, and lymphatic vessels)

• Stroma: connective tissue of the ovary

Oogenesis & fertilization

• Oogonia divide by mitosis to produce other oogonia and primary oocytes

• Primary oocytes are surrounded by granulosa cells (primordial follicle)

• oocyte and granular cells enlarge, the primordial follicle becomes the primary follicle

• Primary follicle becomes the secondary follicle and enlarges to form mature (Graafian) follicle (usually only 1 is ovulated and the others degenerate)

Oogenesis

Production of a secondary oocyte in ovaries

Oogonia

Cells from which oocytes develop; 5 million oocytes are produced by the 4th month of prenatal life (about 2 million begin in the first meiotic division but stop at prophase - all stay in this state until puberty)

Ovulation

Release of a secondary oocyte from an ovary

Fertilization

Begins when a sperm cell binds the plasma membrane of a secondary oocyte and penetrates into the cytoplasm

• Secondary oocyte completes meiosis II, forming 1 polar body (fertilized egg is now a zygote)

Fate of the corpus luteum if fertilization occurs

Corpus luteum persists

Fate of corpus luteum if no fertilization occurs

Corpus luteum becomes corpus albicans

Mesosalpinx

Part of the broad ligament directly associated with uterine tube

• Opens directly into the peritoneal cavity to receive oocyte from ovary

• Transports oocyte/zygote from ovary to uterus

Fimbriae

• Long, thin processes that extend from the infundibulum

• Inner surface is ciliated

• The infundibulum is open to peritoneal cavity

Ampulla

Widest part of the uterine tube (where fertilization occurs)

3 layers of uterine tube

1. Outer serosa

2. Middle muscular layer

3. Inner mucosa

Mucosa

Simple ciliated columnar epithelium with longitudinal folds

• Provides nutrients for oocyte / embryonic mass

• Cilia move fluid and oocyte / embryonic mass through the tube towards the uterus

Uterus parts

Body, isthmus, cervix, and fundus

Ligaments of the uterus

Broad, round, and uterosacral

• Round: from uterus through inguinal canals to labia majora

• Uterosacral: attaches lateral wall of uterus to sacrum

3 layers of the uterus

1. Perimetrium (serous membrane)

2. Myometrium (smooth muscle)

3. Endometrium (mucous membrane)

Endometrium

• Simple tubular glands

• Functional layer: innermost, is replaced during the menstrual cycle (spiral arteries supply this layer)

• Basal layer: deepest

Cervix

More rigid and less contractile than the rest of the uterus

Cervical canal

Lined with mucous glands; mucous plug is present except near ovulation (consistency of secretion changes to seromucous)

Hymen

Covers vaginal opening / orifice

Vagina

• Muscular walls with mucous membrane lining (moist stratified squamous epithelium)

• Longitudinal columns and transverse rings

Fornix

Superior portion of vagina, attached to the sides of the cervix

Perineum

• Divided into anterior urogenital triangle and posterior anal triangle

• Clinical perineum: region between vagina and anus (skin here can tear during childbirth)

What is an episotomy?

Incision in clinical perineum to aid in childbirth

Mammary glands

• Organs of milk production in breasts

  • Consists of granular lobes of modified sweat glands and adipose tissue

External anatomy of breast

A raised nipple surrounded by pigmented areola that contains areolar glands (these lubricate and protect the nipple and areola)

What type of ligaments support the breasts?

Cooper ligaments

Adult female mammary gland

Has 15-20 lobes surrounded by fat (each lobe has a single lactiferous duct that enlarges into a lactiferous sinus that stores milk during letdown)

Myoepithelial cells

Surround alveoli and contract to expel milk

Gynecomastia

Breast development in males

Puberty in females

• Starts with menarche (first episode of menstrual bleeding)

• Increase in GnRH, as well as LH and FSH

Menstrual cycle

• Changes in the uterus

• About 28 days on average

Amenorrhea

Absence of a menstrual cycle

Menopause

Cessation of menstrual cycles

Follicular phase

• Occurs before ovulation (days 1-14)

  • Primordial follicle develops into a mature follicle as the primary oocyte within undergoes meiosis I

  • Follicles develop in response to FSH release from anterior pituitary

  • Follicles release estrogen, leading to a surge of LH and ovulation (also causes uterine endometrium proliferation)

Luteal phase

• Occurs after ovulation (days 15-28)

• Following ovulation, follicle forms the corpus luteum which secretes estrogen and progesterone

  • (Progesterone causes uterine endometrium to thicken and secrete fluid)

• End of luteal phase (if no fertilization): corpus luteum degenerates, progesterone levels drop and endometrium is shed (menses)

• End of luteal phase (if there is fertilization): hCG production occurs (keeps corpus luteum alive)

Menses

A period of mild hemorrhage that occurs about once a month (this is when the functional layer of the endometrium is sloughed and expelled from the uterus)

Menstruation

Discharge of the sloughed endometrial tissue and blood

Proliferative phase

The time between the ending of menses and ovulation

What happens in the proliferative phase?

Endometrium starts to regenerate, and remaining epithelial cells rapidly divide and replace the functional layer that was sloughed during the last menses

• A relatively uniform layer of low cuboidal endometrial cells is produced, cells later become columnar, and the layer cells fold to form tubular spiral glands