The Circulatory System
Identify and name the main parts of the human circulatory system and describe the functions of the heart, blood vessels, and blood
What a learner can do afterwards
- Name the main components: heart, arteries, veins, capillaries, blood
- Describe the heart as a pump that pushes blood around the body in a continuous loop
- Explain that blood carries oxygen and nutrients to cells and removes waste products like carbon dioxide
The lesson
You already know your heart pumps blood in a loop around your body. That blood travels through tubes called blood vessels. There are three kinds: arteries, veins, and capillaries.
Arteries carry blood away from your heart. Veins carry blood back toward your heart. Capillaries are so small and thin that oxygen and nutrients can pass right through their walls into your cells.
When Maya goes for a run, her heart beats faster and pushes more blood into her arteries. That blood carries oxygen to her leg muscles. At the same time, her veins carry blood full of carbon dioxide back toward her heart.
Blood does more than carry oxygen. It also delivers nutrients to your cells and picks up waste like carbon dioxide to carry away. Your heart keeps this loop moving nonstop, day and night.
Blood travels in a loop, out through arteries, across capillaries, back through veins, delivering oxygen and nutrients and carrying away waste.
Watch it
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.