Biology (Grade 7) - The heart and circulatory system

What is double circulation in the human body?

Double circulation means that blood passes through the heart twice for every complete circuit of the body.

What is the advantage of double circulation?

Blood loses pressure as it passes through the lungs; returning it to the heart allows it to be re-pressurized for pumping to the rest of the body at high speed.

What are the main chambers of the heart?

The heart has two types of chambers: Atria (top chambers that receive blood) and Ventricles (bottom chambers that pump blood out).

What differentiates the left ventricle from the right ventricle?

The left ventricle has a thicker muscular wall to pump blood at high pressure to the entire body, while the right ventricle pumps blood only to the lungs.

What are the adaptations of arteries?

Arteries have thick walls with elastic fibers to withstand and maintain high blood pressure as blood leaves the heart.

What are the adaptations of veins?

Veins have thinner walls and valves to prevent the backflow of blood, as blood in veins moves at much lower pressure.

What are the adaptations of capillaries?

Capillaries have walls that are only one cell thick, providing a short diffusion pathway for the fast exchange of substances like oxygen and glucose.

What is the function and adaptations of red blood cells?

Red blood cells have a biconcave shape to increase surface area for diffusion and lack a nucleus to provide more room for haemoglobin to carry oxygen.

What is plasma and its function?

Plasma is the liquid component of blood that transports dissolved substances, including carbon dioxide, glucose, urea, and hormones.