Overview of the Female Reproductive System and Oogenesis

Gonads-ovaries

Produce gametes, secrete estrogen and progesterone

Gametes

Ova

Accessory organs

Uterine tubes, uterus, vagina: receive sperm, provide a place for fertilization and fetal development

External genitalia

Labia and clitoris

Mammary glands

Produce milk through secretory alveoli and lactiferous ducts.

Ifundibulum

Wide open lateral ends of fallopian tubes

Fimbrae

Finger-like extensions of ifundibulum; drape over ovary and catch released ovum

Uterine tubes (fallopian tubes)

2, receives ovum from ovary through fimbrae, site of fertilization, transports fertilized ovum to uterus

Suspensory ligament

Contains blood vessels

Broad ligament

Attaches uterus, uterine tubes, and ovaries to pelvic cavity, continuous with peritoneum

Uterus

Single muscular organ, receives fertilized ovum, provides a place for fetal development, presses on the bladder

Endometrium

Innermost layer of the uterus, site of implantation, shed during menses

Myometrium

Thickest layer, middle layer, smooth muscle; contracts during labor

Perimetrium

Outermost layer of the uterus, continuous with peritoneum

Cervix

Inferior portion of uterus, opens into the vagina

Vagina

Muscular tube-shaped organ, receives penis and semen, birth canal for fetus, passageway for menstrual blood

Vaginal orifice

External vaginal hole

Clitoris

Contains erectile tissue, produces sexual sensations (homologous with the penis)

Labia minora

Inner pair of skin folds, creates vestibule

Vestibule

Houses vaginal orifice, external urethral meatus, and clitoris. Contains vestibular glands (bartholin glands) that secrete mucus for lubrication

Hymen

Epithelial tissue, separates vestibule and vagina and partially blocks vaginal orifice

Labia majora

Outer pair of skin folds, cover labia minora

Primordial follicles

Produced before/at birth. 400,000. First stage of follicular development

Primary oocyte

Unfertilized egg within primordial follicles; arrested in prophase one of meiosis

Primary follicles

Second stage of follicular development, 20 mature each ovarian cycle; secrete estrogen through its cells

Secondary follicle

Third stage of follicular development

Tertiary follicle

Fourth stage of development- the largest dominant follicle; releases a secondary oocyte at ovulation

Ovulation-follicular phase

Fifth stage. Tertiary follicle ruptures.

Secondary oocyte

Will complete meiosis 2 if it is fertilized. n×2

Primordial follicle anatomy

In clusters called egg nests; 1 layer of cells surrounding Primary oocyte.

Primary follicle anatomy

Several layers of granulosa cells, thecal cells form outermost layer. Zona pellucida is a clear species-specific ring that develops.

Secondary follicle anatomy

Layers of cells continue to increase, follicular wall becomes thicker; fluid pockets develop.

Tertiary follicle (graafian follicle) anatomy

Fully mature. Fluid pockets fuse to form the antrum.

Corpus luteum

Made from remaining follicular cells after ovulation. Secretes progesterone and some estrogen.

Corpus albicans

Scar tissue; remnants of corpus luteum if fertilization doesn't occur.

Tunica albuginea

Dense connective tissue layer underlying germinal epithelium (shared with the male reproductive system).

Germinal epithelium

Outermost layer of the ovary. Continuous with visceral peritoneum.

Oogenesis

Step by step process involving mitosis and meiosis. Ovum production

Mitosis-before birth and during childhood.

Oogonia divide

Meiosis 1-before birth and during childhood.

Oogonia become primary oocytes arrested in prophase 1.

Prophase 1-before birth and during childhood.

Primary oocytes remain inactive until puberty. 2n×2

First polar body- from puberty to menopause monthly

Released after secondary oocyte development during meiosis 1

Completion of meiosis 1 within tertiary follicles -from puberty to menopause monthly

Produces secondary oocyte

Ovulation- from puberty to menopause monthly

Releases secondary oocyte arrested in metaphase 2.

Meiosis 2

Completed after fertilization; secondary oocyte releases second polar body.

Zygote

Formed when secondary oocyte becomes fertilized. 2n

The uterine cycle

Regulated by estrogen and progesterone.

Menses

Days 1-5, degeneration and sloughing off of the functional layer of the endometrium; triggered by a decrease of hormones.

Proliferative phase

Days 6-14, functional layer regenerates, uterine glands enlarge and spinal arteries increase; triggered by increase in estrogen.

Secretory phase

Days 15-28+, endometrium prepares for implantation, uterine glands secrete glycoproteins and spiral arteries elongate; triggered by progesterone. Continues as long as fertilization occurs

Contraceptives

Methods to prevent pregnancy.

Condom

Prevents semen from reaching the vagina.

Diaphragm and spermicide

Prevents sperm from entering the uterus and kills sperm cells.

Vasectomy

Cuts and ties performed on the vas deferens that prevent sperm from traveling through the ducts.

Tubal ligation

Tubes are cut and tied to prevent sperm in one side of the tube from reaching the oocyte on the other side.

Birth control

Either prevent Oogenesis or ovulation.

IUD

Implanted in the endometrium.

Emergency contraception

Prevents ovulation, thickens cervical mucus, thins the endometrial lining.