Female reproductive organs

Summary

The female reproductive organs can be divided into the upper genital tract (i.e., uterus, fallopian tubes, ovaries, and cervix) and the lower genital tract (i.e., the vagina and vulva). The upper genital organs and the vagina are located in the pelvis, while the vulva is a part of the perineum. These organs participate in several hormonal and mechanical pathways that are responsible for secondary sexual development and reproduction. The uterine cavity is the site of embryonic implantation and fetal development. The cervix is the lower portion of the uterus and provides a passageway for the expulsion of uterine contents or the entry of spermatozoa into the uterine cavity. The ovaries are paired organs responsible for gametogenesis and sex hormone synthesis in females. In the middle of each menstrual cycle, a mature ovum ruptures out of a Graafian follicle and travels along the fallopian tubes, where it may be fertilized by sperm. The vagina is a hollow muscular structure that receives ejaculate during copulation and serves as a conduit for the expulsion of uterine contents. The vulva is the anterior portion of the perineum and is composed of the labia majora, the labia minora, the clitoris, and the mons pubis. The labia envelop the clitoris, the urethral orifice, and the vaginal introitus.

Overview

Uterus and cervix

Function [1]

Gross anatomy [1]

Overview

Structure

Vasculature

Course Function
Ovarian artery
  • Supplies the proximal portion of the uterine body
Uterine artery
Uterine vein

Lymphatics

Structure Drainage Course
Fundus
  • Pre-aortic nodes
  • Para-aortic nodes
  • Ovarian vessels
Body and Cervix
  • Internal iliac nodes
  • Uterine vessels
  • Obturator nodes
  • Obturator fossa

Innervation [2][1]

Course Function
Sympathetic
  • Uterine contraction
  • Vasoconstriction
Parasympathetic
  • Vasodilation
Viscerosensory

Ligation of the uterine arteries (e.g., during hysterectomy) → risk of ureter injury!

Ligaments

Microscopic anatomy [1]

Uterus

The uterus is composed of three layers. From internal to external:

  1. Endometrium: mucosal layer consisting of two layers
    1. Simple columnar epithelium with tubular glands
    2. Connective tissue (stroma)
  2. Myometrium: smooth muscle layer
  3. Serosa/adventitia:

Cervix

Composed primarily of fibroelastic connective tissue. Can be divided into:

  1. Endocervix: inner part of the cervix proximal to the uterine external os
  2. Cervical transformation zone: physiologic transition zone between the endocervix and ectocervix
  3. Ectocervix: outer part of the cervix distal to the uterine external os

Embryology [1][3]

Fallopian tubes

Function [1]

Gross anatomy [1]

Overview

  • Location
    • Extend bilaterally from the horns of the uterus
    • Contained in the proximal part of the broad ligaments
  • Neighboring structures: open near the ovaries into the abdominal cavity

Structure

Vasculature

Course Function
Ovarian artery
Uterine artery
Ovarian veins
Uterine veins

Lymphatics

Innervation

Course Function
Sympathetic
  • Contraction
  • Vasoconstriction
Parasympathetic
  • Vasodilation
Viscerosensory
  • Afferent fibers follow sympathetic efferent fibers to T11–L1

Ligaments

Microscopic anatomy [1]

The fallopian tubes are made up of three layers. From internal to external:

  • Mucosa: lined with simple ciliated columnar epithelium and secretory Peg cells
  • Muscular layer: smooth muscle layer that facilitates the transportation of the ovum
  • Serosa: highly vascular layer surrounding the fallopian tubes

Embryology [3]

Ovaries

Function

Gross anatomy [1]

Overview

  • Description: paired, ovoid-shaped reproductive organs
  • Location
  • Neighboring structures: close proximity to the cecum and appendix on the right side and the sigmoid colon on the left side

Vasculature

Course Function
Ovarian artery

Ovarian vein

Lymphatics

Innervation

  • Ovarian plexus and uterine plexus via the suspensory ligament

Ligaments

Microscopic anatomy [1]

Layers of the ovary

Ovarian follicle

The ovarian follicle is a functional unit of the ovaries that matures during the menstrual cycle (see folliculogenesis below).

Embryology

Oogenesis and folliculogenesis

Oogenesis [1][3]

Steps of oogenesis

Period Events Resulting cell Chromosome count
Fetal period 4th week of gestation
Until ∼ 4 weeks before birth
Until ovulation
During ovulation
  • Meiosis I resumes → secondary oocytes form
Until fertilization
Fertilization If it does not occur
If it occurs

Folliculogenesis [1]

Follicle stage Description
Birth Primordial follicle
Puberty Primary follicle
Menstrual cycle: 1st week Secondary follicle
Menstrual cycle: 2nd week Tertiary follicle (Graafian follicle)
After ovulation Corpus luteum


The primary oocyte is arrested in prophase I of meiosis I until ovulation. The secondary oocyte is arrested in metaphase II of meiosis II until fertilization.

Primary oocytes are formed prior to birth to serve as an ovarian reserve.

Vagina and vulva

Function [1]

Gross anatomy [1]

The vagina and vulva collectively make up the lower genital tract.

Vagina

Position

Structures

Hymen atresia causes complete occlusion of the vagina, which obstructs blood flow at menarche, causing primary amenorrhea.

Vulva

Position

  • Location: external to the pelvis
  • Neighboring structures: continuous with the perineum

Structures

Estrogen stimulates proliferation and keratinization of the vulvar epithelium. Menopause with decreased estrogen levels results in vulvar atrophy.

Vasculature, lymphatics, and innervation [1]

Vagina Vulva
Arteries
Veins
  • Lateral plexus → vaginal veinsinternal iliac veins
Lymphatics

Parasympathetic innervation

  • Pelvic splanchnic nerves (S2–4)
  • Pelvic splanchnic nerves (S2–4)
Sympathetic innervation
  • Uterovaginal plexus (L1–2)
    • Contraction of the proximal vagina
  • Uterovaginal plexus (T12–L2)
Sensory innervation
Motor innervation

Pudendal nerve block is often used for anesthesia prior to vaginal procedures, childbirth, or episiotomy.

Microscopic anatomy [1][3]

Vagina

The vagina is a fibromuscular structure with numerous transverse vaginal rugae.

Vulva

Embryology [1][3]

References:[4][5]

Ligaments of the female pelvis

Structures connected Description Structures contained

Broad ligament

Round ligament of the uterus
  • Embryonic derivate of the gubernaculum
  • Responsible for the anteversion-anteflexion position of the uterus
  • Passes through the inguinal canal, above the artery of Sampson

Cardinal ligament

  • Cervix with the lateral pelvic wall
  • Distal portion of the broad ligament
  • Close to the ureter risk of ureter injury during hysterectomy
Ovarian ligament
  • Medial pole of the ovary with the lateral uterus horn
Infundibulopelvic ligament
  • Ovaries with the lateral pelvic wall
  • Suspensory ligament of the ovaries

During ligation of the ovarian artery and vein, care must be taken not to damage the ureter, which is located directly posterior to the infundibulopelvic ligament, close to the medial leaf of the broad ligament.

References: [1][3]

Clinical significance

General conditions

Uterine conditions

Cervical conditions

Ovarian conditions

Vaginal and vulvar conditions

  • 1. Standring S. Gray's Anatomy: The Anatomical Basis of Clinical Practice. Elsevier Health Sciences; 2016.
  • 2. Netter FH. Atlas of Human Anatomy. Saunders W.B.; 2018.
  • 3. Le T, Bhushan V,‎ Sochat M, Chavda Y, Abrams J, Kalani M, Kallianos K, Vaidyanathan V. First Aid for the USMLE Step 1 2019. New York, NY: McGraw-Hill Medical.
  • 4. Ogeng'o J. Chapter 36: Female Reproductive System and the Contents of the Female Pelvis. http://www.oganatomy.org/projanat/gross/36/six.htm. Updated January 1, 2018. Accessed November 24, 2018.
  • 5. Miranda AM. Vaginal Anatomy. In: Gest TR. Vaginal Anatomy. New York, NY: WebMD. https://emedicine.medscape.com/article/1949237. Updated September 24, 2018. Accessed November 24, 2018.
  • Gilman S. Neurobiology of Disease. Academic Press; 2007.
last updated 06/21/2019
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