uterus

 Uterus

Uterus is called hystera. 

Womb; child bearing organ in females.

Location;

Hollow muscular organ, located in pelvic cavity in front of retum and behind he urinary bladder.

Size and Shape

Like inverted pear shaped.

Length; 7.5 cm

Width; 5cm

Thickness of walls; 2.5cm

Weight; 30-40 grams

Parts of Uterus

1. Fundus

Wide upper dome shaped portion of uterus called fundus. It covers with peritoneum. Uterine tube or fallopian tube enter uterus from below the fundus.

2. Body

Main parts of uterus is body. It narrow inferiorly at internal OS where it continues with the cervix.

3. Cervix

Cervix is junction between uterus and vagina.

It communicates above with uterine cavity at the internal OS and below with vaginal at external OS. 

During childbirth, contractions of uterus will dilate the cervix up to 10cm in diameter.

4. Isthmus

Isthmus is slightly constricted region between body of uterus and cervix.

Structure of Uterus

Layers of uterus made up three layers of tissues;

1. Perimetrium

Perimetrium is outer serosal layer.

2. Myometrium

Myometrium is middle muscular layer. 

It thickest layer, makes up bulk of uterine wall.

It consist of smooth muscle fibers interlaced with areolar tissues, blood vessels, nerve and lymphatics.

Three distinct layer are;

1. Outer longitudinal layer

2. Middle interlacing

3. Inner circular

Functions of Myometrium

1. Produce labour contaction; help in expel fetus.

2. Muscle are capable of stretching during pregnancy.

3. Contract during orgasm.

3. Endometrium/ mucous membrane

Endometrium lined with mucus membrane.

It contains large number of mucus secreting tubular gland. 

This layers contains abundant supply of blood vessels.

Layers of Endometrium

Composed of two layers;

1. Functional layer or stratum functionalis

Thicker superficial layer.

Occurs menstrual changes and shade off during each menstrual cycle.

2. Basal layer or Stratum Basalis

Deeper layer.

This layer is permanent and gives rise to or regenerate functional layer after each menstruation.

Support of the uterus

Uterus is supported in pelvic cavity by surrounding organs, muscles of pelvic floor and ligaments that hold from walls of pelvis.

1. Primary supports

Uterus is primarily supported by pelvic diaphragm, perineal body and urogenital diaphragm.

2. Secondary support

Suppored by ligaments.

a. Two broad ligaments

Broad ligaments are double folds of peritoneum. One on each side of uterus.

b. Round ligaments 

One on each side of uterus. It is fibromuscular flat bands between two layers of broad ligaments.

c. Two uterosacral ligaments

Originate from posterior walls of uper part of cervix and from vagina. 

These ligaments connect uterus to sacrum.

d. Cardinal ligaments (two transverse lateral cervical ligaments)

These ligaments extend from sides of cervix and vagina to the side walls of the pelvis 

e. Pubocervical ligaments

These ligaments extend from cervix to posterior surface of symphysis pubis.

f. Posterior ligaments

It attaches uterus to the rectum.

g. Anterior ligaments

It attaches uterus to the urinary bladder.

Function of Uterus

1. Assist reproduction

Primary function of uterus is to assist reproduction.

2. Menstrual flow

Uterus is source of menstrual flow.

3. Chennel for sperm transport

Uterus serves as part of pathway for sperms deposited in vagina to reach uterine tubes.

4. Site for implantation 

Uterus is site of implantation of fertilized ovum (zygote) and placentation.

5. Growth and development of fetus

Site of development of fetus during pregnancy.

6. Paaturition 

Uterus helps in labourand delivery.