Blood vessels
Arteries carry oxygen-rich blood from the heart to various organs of the body.
1. Pulmonary artery is the only artery that carries CO2-rich blood from heart
to lungs.
2. The walls of arteries are thick and elastic in order to tolerate high
pressure of the blood.
3. Pulse is the rhythmic contraction and expansion of arteries with each beat
of heart. The number of beats per minute is the pulse rate.
4. A resting person usually has a pulse rate between 72 to 80 beats per
minute.
Veins carry CO2-rich blood from various organs towards the heart.
1. They are thin-walled, non-elastic vessels that do not possess valves.
2. Pulmonary veins carry oxygen-rich blood from lungs to heart.
Capillaries are thin-walled blood vessels. They connect arteries with veins.
