3. CARDIOVASCULAR SYSTEM
The cardiovascular system, also known as the circulatory system, is responsible for transporting blood, nutrients, oxygen, carbon dioxide, and hormones throughout the body. It consists of the heart, blood vessels, and blood.
| Heart: | The heart is a muscular organ that pumps blood throughout the body. It has four chambers: two atria (upper chambers) and two ventricles (lower chambers). The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs for oxygenation. The left side receives oxygenated blood from the lungs and pumps it throughout the body. The heart’s pumping action is regulated by electrical impulses that initiate each heartbeat. |
| Blood Vessels: | Blood vessels are the network of tubes that carry blood throughout the body. There are three main types of blood vessels: arteries, veins, and capillaries. Arteries carry oxygenated blood away from the heart to the body’s tissues, while veins return deoxygenated blood back to the heart. Capillaries are tiny blood vessels where the exchange of oxygen, carbon dioxide, nutrients, and waste products occurs between blood and tissues. |
| Blood: | Blood is a specialized bodily fluid that delivers essential substances like oxygen and nutrients to cells and removes waste products. It is composed of red blood cells (which carry oxygen), white blood cells (which fight infection), platelets (which aid in blood clotting), and plasma (the liquid component that transports blood cells, nutrients, hormones, and waste products). |