Answer: (2) Capillaries
The heart, the blood cells, the lymphatic system and the blood vessel network are the human circulatory system. Blood vessels are called networks of hollow tubes, such as pipes, that carry blood to all areas of the body. Blood is transported in both directions by these vessels, i.e. one from the heart to all other parts and one from other parts of the body to the heart.
Various types of blood vessels
The various types of blood vessels are
- The main blood vessels carrying and transporting oxygenated blood or oxygen-rich blood from the heart to other areas of the body are the arteries.
- With thicker walls, they are the strongest blood vessels and are muscular in nature. It consists of three different, rigid, thicker and highly muscular layers.
- Deep inside the body, arteries are found and are red in colour.
- Veins are small elastic blood vessels, similar to tubes, that are closer to the surface of the skin. These transparent blood vessels are coloured blue and bring unclean or deoxygenated blood to the heart from all areas of the body.
- Capillaries are called short and narrow blood vessels located inside the tissues.
- The exchange of substances between blood and tissues is carried in by capillaries.
- These blood vessels also operate by linking the arterial systems to the venous system and assisting in the cellular exchange of substances.