Syncytium: Definition & Function

Instructor: Lauren Posey

Lauren has taught intermediate reading in an English Language Institute, and she has her Master's degree in Linguistics.

In this lesson you will learn about syncytia. You'll learn where they appear in nature and their function in the human body, particularly as the main part of skeletal muscles.

Syncytia: an Unlikely Connection

What do an unborn baby, human skeletal muscles, and white mold have in common? You might be inclined to say 'nothing,' but they actually do have a connection! All of these either use or are made up of a syncytium, a single cell that contains several nuclei. Syncytia are formed one of two ways: either a cell nucleus divides and never splits into multiple individual cells, or several cells merge together, retaining their nuclei but not their separate cell membranes. Syncytia serve important functions both within the human body and in other aspects of nature.

Syncytia in Humans

In humans, one of the main functions of syncytia is as part of skeletal muscle. Skeletal muscles are sometimes called 'voluntary muscles,' and they include the muscles directly attached to the skeleton, which can be moved consciously. Skeletal muscles are made up of many individual muscle fibers, twined together to provide strength and flexibility. These fibers are individual, long syncytia.

One advantage of this structure is fast communication and response between the brain and the muscles. The lack of separate membranes allows the impulses from the brain to quickly move between nuclei. The faster the impulses can move, the faster your muscles can react. So the next time you snatch something out of the air or catch something before it falls, thank your syncytia!

Skeletal muscles are made up of syncytia.
Skeletal muscle

During Pregnancy

Another place syncytia can be found in humans is in pregnant women. The formation of a syncytium happens very early in the development process, when the baby is still in the embryo stage. In humans, the embryo stage starts about four days after the egg is fertilized and continues through the eighth week of pregnancy.

The syncytium here serves as a barrier between the mother, and any foreign cells that might enter her body, and the embryo. The syncytium is made up of cells from the embryo and cells from the placenta. The cells fuse together and lose their separate membranes. The purpose of the barrier is to regulate what the embryo can be exposed to. It allows nutrients through the placenta so the embryo can grow, but it blocks potentially harmful cells, such as foreign bacteria. Interestingly, this same syncytia development occurs in other mammals, such as mice.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account