Difference Between Cervix and Uterus

The main difference between cervix and uterus is that the cervix is the lower part of the uterus that protects the baby during pregnancy whereas the uterus is the major organ of the female reproductive system, which conceives a baby. Furthermore, the cervix is a cylindrical structure while the uterus is a pear-shaped structure.  

Cervix and uterus are two structures of the female reproductive system that play a major role in the fertilization as well as in conceiving a baby. 

Key Areas Covered 

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

Key Terms 

Cervix, Female Reproductive System, Myometrium, Uterus, Womb

What is the Cervix 

The cervix is the tapered inferior region or the neck of the uterus. Since it makes up one-third of the uterus, the tissues that make up the cervix is continuous with the uterus as well. The three main anatomical structures of the cervix are the cervical canal, external os, and internal os. The cervical canal is the hollow orifice that connects the uterine cavity to the lumen of the vagina. The external os connects the cervical canal to the vagina while the internal os connects the cervical canal to the uterus.  

Figure 1: Structure of the Cervix

It connects the large body of the uterus with the vagina. It also controls the movement in and out of the uterus, protects the baby during pregnancy, and helps the delivery of the baby by serving as a sphincter. During menstruation, the dilation of the smooth muscles of the cervix allows the passage of the menstrual flow, which causes the sensation of menstrual cramps.  

What is Uterus 

The uterus is the main organ of the female reproductive system. It is a hollow muscular organ that resembles a pear in both size and shape. It is located at the pelvic cavity, anterior to the rectum and posterior to the urinary bladder. The upper part of the uterus, which is attached to the Fallopian tubes, is called the fundus. The wider region is the body of the uterus where the fertilized egg is implanted. The lower part of the uterus is the cervix. 

Figure 2: Female Reproductive System

The three layers of the uterus are endometrium, myometrium, and perimetrium. The endometrium is the inner lining of the uterus made up of epithelial cells. It becomes thick and vascularized during ovulation as it prepares to implant a fertilized egg. If not, it is shed during menstruation. Myometrium is the smooth muscle layer responsible for the production of muscular contractions during the delivery of the baby. Perimetrium is the outer layer of the uterus covered by a serosa layer. When conceiving a baby, the uterus is known as the womb. 

Similarities Between Cervix and Uterus 

• Cervix and uterus are two anatomical structures of the female reproductive system. 
• Both facilitate fertilization, conceiving a baby, and childbirth. 
• The outer covering of both cervix and uterus is made up of simple squamous epithelium (perimetrium); the middle layer is made up of smooth muscles (myometrium); inner layer is made up of endothelial cells (endothelium). 

Difference Between Cervix and Uterus 

Definition 

Cervix refers to the narrow neck-like passage forming the lower end of the uterus, and it provides protection to the baby during pregnancy. Uterus refers to the organ in the lower body of a woman or female mammal where offspring are conceived and in which they gestate before birth.

Thus, the main difference between cervix and uterus is their role in the reproduction.

Shape 

While the cervix has a cylindrical shape, the uterus is pear-shaped. This is another important difference between cervix and uterus.

Conceiving the Baby 

Cervix protects the baby while the uterus conceives the baby. 

Thickness of the Myometrium 

The myometrium of the cervix is thinner while the myometrium of the uterus is thicker. 

Contractions of the Myometrium During Childbirth 

During childbirth, cervix contracts less forcefully while the uterus contracts more forcefully. 

Inner Lining 

The lining of the cervix continuously produces cervical mucus while the lining of the uterus sheds its mucosal layer every 28 days.  

Conclusion 

Cervix is the lower, narrow end of the uterus, which is the main organ of the female reproductive system. Cervix protects the baby during pregnancy while the uterus conceives the baby. The main difference between cervix and uterus is their role in the female reproductive system. 

Reference:

1. “Cervix of Uterus – Anatomy Pictures and Information.” InnerBody, Innerbody, Available Here
2. “Uterus – Female Reproductive System.” InnerBody, Innerbody, Available Here

Image Courtesy:

1. “Gray1167” By Henry Vandyke Carter – This is a retouched picture, which means that it has been digitally altered from its original version. Modifications: vectorization (CorelDraw). The original can be viewed here: Gray1167.png. Modifications made by Mysid. (Public Domain) via Commons Wikimedia   
2. “Scheme female reproductive system-en” By CDC, Mysid – Vectorized in Inkscape by User:Mysid from a CDC image. (Public Domain) via Commons Wikimiedia