Main Blood Vessels

Arteries

• Carry blood away from the heart (always oxygenated apart from the pulmonary artery which goes to the lungs)

• Arteries face high levels of blood pressure as they carry blood being pushed from the heart under great force. To withstand this pressure, the walls of the arteries are thicker, more elastic, and more muscular.

• They contain a high percentage of elastic tissue that allows them to stretch and accommodate the pressure of the heart.

• They have narrower arteries called arteries that branch off from the ends of arteries and carry blood to capillaries as well as are able to use smooth muscle to regulate blood flow and blood pressure

Veins

• Carry blood to the heart (always de-oxygenated apart from the pulmonary vein which goes from the lungs to the heart)

• Have thinner, less elastic and less muscular since they are subjected to very low blood pressures.

• Have valves to prevent blood flowing backwards

• They have small vessels called Venules that pick up blood from many capillaries and deposit it into larger veins for transport back to the heart.

Capillaries

• Found in the muscles and lungs

• They are microscopic

• Very low blood pressure

• Where gas exchange takes place. Oxygen passes through the capillary wall and into the tissues while carbon dioxide passes from the tissues into the blood.

NA. (2013). The Cardiovascular System: Blood Vessels. [Web Portal]. Retrieved from http://anatomyandphysiologyi.com/cardiovascular-system-blood-vessels/