Gravid uterus showing fetus and placenta
This specimen shows the fetus in its third trimester inside the uterus.
The uterus is a female reproductive organ that undergoes physiological changes during each menstrual cycle. It is a child-bearing organ, that is capable of expanding to hold the growing fetus along with the other structures, such as the placenta and the umbilical cord, during pregnancy.
The uterus is a thick-walled, muscular organ situated in the pelvis between the urinary bladder and the rectum. The broad ligaments are lateral. It is divisible into the fundus, the body and the cervix. It has three layers in its wall, namely the endometrium, the myometrium and the perimetrium from inside outwards. The muscles in the myometrium are capable of increasing in number and increasing in size during pregnancy, which is very essential for the expansion of the uterus.
The placenta is a disc-shaped which develops at the site of implantation. It is a mass of tissue comprised of the chorionic villi. It weighs about 500 grams and is discarded after birth. Normally it is formed at the upper segment of the uterus. If it is formed in the lower segment of the uterus, it is known as the placenta praevia, in which case, the normal vaginal delivery of the child becomes difficult.
The umbilical cord is a connection between the placenta (mother) and the fetus. It consists of umbilical arteries and umbilical vein. It is necessary for the exchange of substances between the mother and the fetus.