Women's health

ORGANS THAT MAKE UP THE FEMALE GENITAL TRACT

The anatomy of the female reproductive system comprises of structures or organs of different functions located at different areas through out the female genital tract. The female genital tract is housed in the pelvis of the woman. The external organs which include the vagina and vulva are in the lesser pelvis whiles the internal organs are in the greater pelvis. The internal organs comprises of the ovaries, Fallopian tubes and uterus. Each organ in the female genital tract receives it’s blood supply and nerve supply from different blood vessels and nerves through out the body.

INTERNAL ORGANS

images-3

OVARIES

The ovary is anteriorly attached to the broad ligament and oval in shape. Eggs (ova) are first released into the peritoneum before they are swept into the Fallopian tubes. The ovaries are not bound by any structure posteriorly but inferiorly bound by ovarian ligament and superiorly bound by the fimbraie of the F. Tubes.

The ovary is divided into two segment, the cortex (which forms the major part)  and the medulla. The cortex contain ovarian follicles where egg grows and the medulla contains the blood vessels. The main blood vessel that supply the ovaries is the ovarian artery (a branch of the descending aorta) and the venous drainage is from the ovarian veins. The left ovarian vein drains directly into the renal vein while the right ovarian vein drains into the inferior Vena cava.

Nerve supply is from post-ganglionic sympathetic nerve. Parasympathetic nerve from vagus and autonomic afferent nerves.

FALLOPIAN TUBES

The Fallopian tubes, also called oviducts, are about 10-12cm long in the upper part of the broad ligament. Each tube opens medially into the uterine cavity and laterally into the peritoneum. The Fallopian tubes are divided into four parts.

  • Infundibulum : is the funnel shaped part of the tube which has fimbriated ends like fingers lined with coloured epithelium  that sweep the ovum into the tubes.
  • Ampullar : is the longest portion of the tube which forms about half the length of the tube and has the widest luminar diameter of about 1cm. It is in the ampullar that fertilisation takes place.
  • Isthmus : is rounded and muscular about 2.5cm long with a small lumenar diameter. The isthmus is the most common point of ectopic pregnancy.
  • Intramural : is sometimes referred to as intrauterine or interstitial and lies within the wall of the uterus. This part is about 1cm long.

Blood supply to the Fallopian tubes is from uterine artery and ovarian artery. Venous drainage is from uterine vein and ovarian vein.

Nerve supply is from ovarian and uterine plexus. Sympathetic supply from T11 – L1 and parasympathetic supply is from the vagus nerve.

UTERUS

The uterus or womb is the organ of gestation. It is pear shaped with thick muscular wall and situated between the rectum and urinary bladder. The upper part of the uterus is attached to the Fallopian tubes whiles the lower part continues into the vagina. A non-pregnant uterus weighs about 30g – 40g and measures about 7.5cm long, 5cm wide and 2.5cm thick.

The lower part of the uterus is called the cervix which projects into the vaginal vault. The cervix is about 2.5cm long in the non-pregnant uterus.

The uterine wall has 3 layers namely, endometrium (innermost), myometrium (middle muscular) and perimetrium or serosa (outermost).

The endometrium is further divided into two layers:

  1. Stratum functionalis : is the superficial layer with tortuous blood vessels. This is the layer that is shed during menstruation.
  2. Stratum basalis : is the deeper part of the endometrium which contains straight arteries. It is this layer that regenerates to form the functionalis layer again.

The blood supply to the uterus is from the uterine artery which comes from the internal iliac artery. Venous drainage is from uterine vein which empties into the internal iliac vein.

Lymphatic drainage into the preaortic and lateral aortic lymph nodes and some into the superficial inguinal lymph nodes. Sympathetic nerve supply from  T10 – L1 and parasympathetic nerve supply from the pelvic splanchnic nerve.

EXTERNAL ORGANS

images-2

VAGINA

The vagina is the female organ of copulation and forms the lower portion of the female genital tract. It is about 7cm – 9cm long except at the fornices. The anterior wall of the vagina is 1cm shorter than the posterior wall.

Blood supply to the vagina is from the vaginal artery which comes from the uterine artery or internal iliac artery. The vagina also receives blood supply from the internal pudendal and middle rectal arteries. Venous drainage from the vaginal veins into the internal iliac veins.

Lymphatic drainage is from 3 vessels. The upper part drains into the internal and external iliac lymph nodes, the middle part drains into the internal iliac lymph nodes and the vestibules drain into the superficial inguinal lymph nodes.

THE VULVA

The vulva or external genitalia, lies in the urogenital triangle in the upper perenium and comprises of the mons pubis, major and minor labia, clitoris, vestibule, bulb of vestibule and greater vestibular gland (bartholins gland).

Blood supply is mainly from internal pudendal artery. The Mons pubis and anterior part of the labia receives blood from the external pudendal branches of the femoral artery. Venous drainage is from internal and external pudendal veins.

Lymphatic drainage is into the superficial inguinal lymph nodes. The clitoris and labia minora drains into the deep inguinal lymph nodes.

Sensory nerve supply from the ilio-inguinal nerve and genital branch of the genito-femoral nerves.

 

SOURCE

S. Campbell, A. Monga (2006), “Gynaecology by Ten Teachers ” 18th edition.

Wikipedia : “Anatomy of the female reproductive system ”

 

 

Categories: Women's health