Science: The Circulatory System
How blood, the heart, and blood vessels work together
Science: The Circulatory System
How blood, the heart, and blood vessels work together
Biology - Grade 6-8
- 1
What is the main job of the circulatory system in the human body?
Think about what blood transports to and from body cells.
The main job of the circulatory system is to move blood throughout the body so cells receive oxygen, nutrients, and other needed materials while wastes are carried away. - 2
Name the four chambers of the heart.
The four chambers of the heart are the right atrium, right ventricle, left atrium, and left ventricle. - 3
Explain the difference between arteries, veins, and capillaries.
Focus on the direction blood moves and the size of each vessel.
Arteries carry blood away from the heart, veins carry blood back to the heart, and capillaries are tiny blood vessels where materials like oxygen and nutrients move between the blood and body cells. - 4
What is the role of red blood cells in the circulatory system?
Red blood cells carry oxygen from the lungs to the body cells and help carry some carbon dioxide back to the lungs. - 5
What is the role of white blood cells in the body?
These cells are part of the body's defense system.
White blood cells help protect the body by fighting germs, infections, and other harmful invaders. - 6
What do platelets do in the blood?
Platelets help blood clot, which slows or stops bleeding when a blood vessel is damaged. - 7
Why is the left ventricle of the heart more muscular than the right ventricle?
Compare how far blood must travel from each ventricle.
The left ventricle is more muscular because it must pump blood to the entire body, which requires more force than pumping blood only to the lungs. - 8
Describe what happens to blood as it travels through the lungs.
As blood travels through the lungs, it releases carbon dioxide and picks up oxygen before returning to the heart. - 9
What is plasma, and why is it important?
Think about the part of blood that acts like a transport fluid.
Plasma is the liquid part of blood. It is important because it carries blood cells, nutrients, hormones, wastes, and other substances throughout the body. - 10
A student says that all veins carry blood without oxygen. Explain why this statement is not completely correct.
This statement is not completely correct because most veins carry blood with less oxygen, but the pulmonary veins carry oxygen-rich blood from the lungs to the heart. - 11
How does exercise affect heart rate, and why does this happen?
Think about what active muscles need during movement.
Exercise increases heart rate because the muscles need more oxygen and nutrients and produce more wastes, so the heart must pump blood faster to meet the body's needs. - 12
Explain how the circulatory system works with the respiratory system.
The circulatory system works with the respiratory system by carrying blood to the lungs to pick up oxygen and release carbon dioxide, then delivering that oxygen to body cells.