The Human Circulatory System: Parts and Functions

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: What Is the Composition of Blood?

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:08 Function of the…
  • 1:18 Parts of the…
  • 2:18 Circulatory System
  • 4:05 Pulmonary Circuit
  • 4:41 Systemic Circuit
  • 5:13 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Speed Speed

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Rebecca Gillaspy

Dr. Gillaspy has taught health science at University of Phoenix and Ashford University and has a degree from Palmer College of Chiropractic.

In this lesson, you will take a ride on the transportation system of the body called the circulatory system and its two parts: the pulmonary circuit and the systemic circuit. Take a look inside and see how every inch of your body receives the oxygen and nutrients it needs.

Function of the Circulatory System

The circulatory system provides oxygen to cells in the body
Circulatory System Cells

The trillions of cells in your body require a continuous supply of oxygen and nutrients to carry out their vital functions, but cells can use these substances only when they are in the immediate vicinity. Like a busy factory that delivers its products to various stores, your body must have a transportation system to carry its gasses and nutrients to its various cells. This system is called your circulatory system, and in this lesson, you will learn about the different parts of the circulatory system and how these parts help move needed substances throughout your body.

To illustrate, let's take a look at Mr. Smith's Widget Factory. Mr. Smith's factory is a very busy place. His factory runs 24 hours a day, 365 days a year. Mr. Smith's workers must work hard to keep up with the continual demand for his widgets; if his workers quit working, his business would not survive. Even though Mr. Smith's factory is very busy, it is nothing compared to the non-stop activity going on in your body at this very minute. Every second of every day, trillions of cells in your body pick up nutrients and drop off waste.

Parts of the Circulatory System

In the same way that Mr. Smith's employees use roads to get his products to and from stores, your body uses blood vessels, which are hollow tubes for carrying blood. The blood found within your blood vessels is a fluid that transports oxygen, nutrients, and cell wastes throughout your body. Keep in mind that these vital substances must make their way to every cell in your body. As you can imagine, this is a very big job. In fact, if laid end to end, all of the blood vessels in the human body would travel around the earth two and a half times. It seems hard to believe, but because the blood vessels have to carry blood to so many cells in your body, your body contains roughly 62,000 miles of blood vessels.

62,000 miles of blood vessels are in the human body
Blood Vessel Length

Mr. Smith uses trucks that run on gasoline to get his widgets where they need to be. Your body does not run on gasoline; instead, it relies on a pumping station known as your heart, which is a hollow organ that pumps blood through the blood vessels. Your heart is the ultimate workaholic, and the amount of work it does is almost too hard to believe. In one 24-hour period your heart pumps your body's complete supply of blood - about 6 quarts - through the blood vessels over 1000 times. Good thing your heart does this for you without your conscious input, or you wouldn't get much else done. The heart, along with the miles of blood vessels found throughout your body, make up your circulatory system, which is defined as a closed system of blood vessels for the transport of gasses and nutrients.

Back at Mr. Smith's factory, we see that his truck drivers have returned from making their deliveries. Now is a good time for us to take a closer look inside Mr. Smith's factory to see just how he runs such an efficient operation. Mr. Smith's factory is divided into two separate departments. So distinct are the goals of the two departments that it's easier for us to think of Mr. Smith's factory as two factories in one. The factory on the right is responsible for piecing together the widgets. In the right factory, widgets pick up their needed parts, and unneeded parts are discarded. The factory on the left takes the freshly-made widgets and transports them all over the country.

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