The heart is a tireless muscle with four chambers. It pumps blood and heat throughout our bodies by contracting.
Arteries are blood vessels that carry blood from the heart to various parts of the body, transporting oxen and heat.
Veins are blood vessels that carry blood to the heart. The blood flows in the right direction because of muscle contractions and valves.
The capillaries exchange substances through their thin walls. The exchange of gases (oxygen and carbon dioxide) in the lungs is handled by the pulmonary circulation.
The circulatory system carries oxygen and nutrients throughout our body. Blood transferred to the tissues is transported back to the bloodstream through the lymphatic system and the lymph nodes.
