Contents of the pelvis cavity

Contents of the pelvis cavity

1. The bladder

The bladder is the urinary reservoir which stores the urine until it is convenient for it to be voided.

Position:- In the non-pregnant female, the bladder liesimmediately behind the symphysis pubis and infront of the uterus and vagina. The bladder when empty is of simillar size to the uterus but when full of urine it becomes, much larger. Its capacity is around 600ml but it is capable of holding more, particularly under the influence of pregnancy hormones.

2. The Ureters 

The tubes which convey the urine from the kidneys to the bladder are the ureters.

Function – They assist the passage of the urine by themuscular peristaltic action of their wall.

The upper end is funnel shaped and merges in to the pelvis of the kidney where the urine is received from the renal tubules. 

3. Urethra

The female urethra is about 4cm long and courses downward and anterior to the bladder neck. It terminates in the vestibule of the vagina between the labia minora and about 2.5cm posterior to the glans of the clitoris.

4. The uterus

The uterus is a hallow, muscular, pear shaped organ situated in the true pelvis.

Function:-exists to shelter the fetus during pregnancy. Ifprepares for this possibility each month and following pregnancy it expels the uterine contents.

Position - It leans forward, which is known as anteversion, itbends forwards on itself, which is known as anteflexion

Relation- anteriorly the bladder and posteriorly rectum

Inferior - Below the uterus is the vagina

Superior - above the uterus lie the intestine

Lateral-on both sides of the walls are the broad ligaments, thefallopian tubes and the ovaries.

Supports - supported by the pelvic floor and maintained inposition by several ligaments. Ligaments are;

Pertonial ligament ƒ Broad ligament

i.                     Genito inguinal ligament

a.              Round ligament

ii.                     Ligaments formed by pelvic fascia 

a.              Transverse cervical ligament 

b.              Utero sacral ligament

Structures - the non pregnant uterus 7.5 cm long, 5cm wideand 2.5cm in depth, each wall being 1.25 cm thick. The Cervix forms the lower third of the uterus.

Parts of the uterus

·                 The body or corpus - the upper 2/3 of the uterus and is the greater part.

·                 The fundus - the domed upper wall between the insertions of the fallopian tubes.

·                 The cornua - are the upper outer angle of the uterus where the fallopian tubes join.

·                 The cavity - is a potential space between the anterior and posterior walls.

·                 The isthmus - is a narrow area between the cavity and the cervix, which is 7mmlong. It enlarges during pregnancy to form the lower uterine segment.

·                 The cervix or neck - protrudes in to the vagina.

·                 The internal os (mouth) is the narrow opening between the isthmus and the cervix

·                 The external os is a small round opening at the lower end of the cervix.

Layers:-The uterus has three layers, of which the middlemuscle layer is by far the thickest.

The endometrium: - forms a lining of ciliated epithelium(mucous memberane) on a base of connective tissue or stroma. It is constantly changing in thickness through out the menustral cycle. 

The myomatrium or muscle coat: - is thick in the upper partof the uterus and is sparser in the isthmus and cervix. It has three parts: Outer longitudinal, middle oblique and inner circular.

The perimetrium is a double serous memberane, anextension of the peritoneum, which is dragged over the uterus.

Blood supply – The uterine artery arrives at the level of thecervix and is a branch of the internal iliac artery. The blood drains through corresponding veins.

Nerve supply – from the autonomic nervous system,sympathetic and para smpathetic via pelvic plexus.

5. Fallopian tube or uterine tube

Function-Propels the ovum towards the uterus

i.                     Receives the spermatozoa as they travel up wards provides a site for fertilization

ii.                     It supplies the fertilized ovum with nutrition during its continued journey to the uterus

Position - extend laterally from the cornea of the uterustowards the side walls of the pelvis

Supports - are held in place by their attachment to the uterus.

Structure - Each tube is 10cm long. It has four portions

·                 The interstitial portion is 1.25cm long and lies with in the wall of the uterus. Its lumen is 1 mm wide.

·                 The isthmus is another narrow part which extends for 2.5cm from the uterus

·                 The ampoule is the wider portion where fertilization usually occurs. It is 5 cm long.

·                 The infundibulum is the funnel - shaped fingered end which is composed of many process known as fimbriae. One fimbria is elongated to form the ovarian fimbria which is attached to the ovary.

6. The ovaries

Function: - produce ova and the hormones estrogen andprogesterone

Position: - they are attached to the back of the broadligamentnear the fimbriated end of the fallopian tube.

Blood supply: - Supplied by the ovarian arteries and drainsby the ovarian veins.The right ovarian vein join the inferior venecava, but the left returns its blood to the left renal vein.

Lymphatic drainage is to the lumbar glands

Nerve supply is from the ovarian plexus.

Figure 7. Anterior view of female reproductive organs