Difference Between Womb and Uterus

Main Difference – Womb vs Uterus

Womb and uterus are two terms used interchangeably to describe an anatomical structure of a female reproductive system of mammals. The female reproductive system is composed of a vagina, cervix, uterus, Fallopian tubes, and ovaries. The main difference between womb and uterus is that womb is the organ in which the young are conceived and grow until birth whereas uterus is the major organ of the female reproductive system. The term ‘womb’ is only used during pregnancy. The uterus is a hollow, muscular organ.

Key Areas Covered

1. What is Womb
– Definition, Anatomy, Physiology
2. What is Uterus
– Definition, Anatomy, Physiology
3. What are the Similarities Between Womb and Uterus
– Outline of Common Features
4. What is the Difference Between Womb and Uterus
– Comparison of Key Differences

Key Terms: Cervix, Embryo, Endometrium, Fertilized Egg, Fetus, Fundus, Myometrium, Perimetrium, Placenta, Umbilical Cord, Uterus, Womb, Zygote

What is Womb

Womb refers to an organ of a female mammal where the offspring is conceived and in which they gestate before birth. When the egg cell is successfully fertilized, the zygote may implant by itself into the lining of the endometrium. The zygote may develop into an embryo and then into a fetus. The lining of the endometrium develops the placenta, connecting the developing fetus with the wall of the womb. It allows the uptake of nutrients from the mother’s blood supply, thermo-regulation, gas exchange, and waste elimination. The conduit between the placenta and fetus is the umbilical cord. A womb with the placenta and the fetus in humans is shown in figure 1.

Figure 1: Womb

The wall of the womb plays a critical role at the end of the pregnancy. Oxytocin is the hormone involved in the contractions of the smooth muscles of the myometrium. The frequency of the contractions and their strength may increase gradually. The smooth muscles of the cervix may also dilate. The intensity and the duration of the contractions are increased until the fetus is pushed out from the womb.

What is Uterus

Uterus refers to the main organ of the female reproductive system in which the fertilized egg is implanted. It is a hollow, muscular organ, which resembles a pear in both size and shape. The uterus is located in the pelvic cavity, posterior to the urinary bladder and anterior to the rectum. Cervix is the narrow region of the uterus that connects it to the vagina. It serves as a sphincter, controlling the movement of material in and out of the uterus. The wider region of the uterus is referred to as the body in which the implantation of the fertilized egg occurs. Fundus refers to the superior, domed region of the uterus which attaches the Fallopian tubes to the uterus. The anatomy of the uterus is shown in figure 2.

Figure 2: Uterus

The uterus is composed of a strong wall. The three tissue layers that make up the uterus are perimetrium, myometrium, and endometrium. The outermost layer of the uterus is referred to as the perimetrium. The perimetrium is covered with a serosa layer. It secretes a watery, serous fluid, lubricating the organ. The middle layer of the uterus is referred to as the myometrium. It is composed of many layers of visceral muscle tissue. It allows the expansion of the uterus during pregnancy and contracts the uterus during the delivery. The endometrium is the epithelial layer that lines the lumen of the uterus. It is associated with endocrine glands as well as highly vascular connective tissue. A thick layer of vascular endometrium is produced at the time of ovulation, preparing to receive the zygote. If the egg cell is not fertilized, it is shed with the endometrium layer. This is called menstruation, occurring per every 28 days.

Similarities Between Womb and Uterus

Both womb and uterus refer to the main organ of the female reproductive system.
Both womb and uterus play a critical role during reproduction.

Definition

Womb: Womb refers to an organ of a female mammal where the offspring is conceived and in which they gestate before birth.

Uterus: Uterus refers to the main organ of the female reproductive system in which the fertilized egg is implanted.

Significance

Womb: Womb is responsible for the development of the embryo and fetus during pregnancy.

Uterus: Uterus is the main organ of the female reproductive organ in mammals.

Size

Womb: Womb is an enlarged organ.

Uterus: Uterus is smaller than the womb.

Anatomy

Womb: A womb is composed of a developing child, umbilical cord, and a placenta.

Uterus: A uterus is composed of three tissue layers: endometrium, myometrium, and perimetrium.

Role

Womb: Womb is involved in providing nutrients and support to the developing embryo.

Uterus: The main function of the uterus is to provide the space for the implantation of a fertilized egg.

Conclusion

Womb and uterus are two anatomical structures of the female reproductive system of mammals. The womb is the fetus-bearing uterus. The uterus is the main anatomical structure of the female reproductive system. The main difference between womb and uterus is the role of each anatomical structure in the female reproductive system.

Reference:

1. “Uterus – Female Reproductive System.” Innerbody, Available here.

Image Courtesy:

1. “Placenta” By Gray38.png: User Magnus Manske on en.wikipediaderivative work: Amada44 talk to me – Gray38.png (Public Domain) via Commons Wikimedia
2. “Illu cervix” By National Cancer Institute (Public Domain) via Commons Wikimedia