Difference Between Pulmonary Artery and Pulmonary Vein in Human Circulation

The pulmonary artery is a particular blood vessel that delivers deoxygenated blood (blood with less oxygen content) to the lungs, it pumps blood away from the heart in contrast to veins which deliver blood to the heart.  The difference concerning other arteries which carry oxygen-rich blood the pulmonary artery transports blood that has less oxygen.

The artery begins in the heart at the base of the right ventricle and this point is known as the pulmonary trunk which is a short and wide structure. The pulmonary trunk branches off in two directions which are the right and left pulmonary artery. The left pulmonary artery is short and it pierces through the sac around the heart which is the protective covering of the heart called the pericardium. From there, the pulmonary artery enters the left lung. The right pulmonary artery is longer and travels across the upper chest of the human body and enters the right lung

Pulmonary Artery Function

The right and left pulmonary artery branches bring deoxygenated blood to the corresponding right and left lungs. There, the blood is enriched with oxygen and pumped back into the heart via the pulmonary veins. This oxygen-rich blood flows into the heart's left atrium and is then pumped to the left ventricle. Finally, it is dispersed through the aorta to the arteries which carries the oxygenated blood throughout our body. Normally blood pressure in the pulmonary artery is 18 to 25mm of Hg (systolic pressure at rest). The mean pulmonary pressure ranges from 12 to 16 mm of Hg.

Pulmonary Vein

Four pulmonary veins in the body bring fresh oxygenated blood from the lungs to the left atrium. From the left atrium, the oxygenated blood travels to the left ventricle and from there it is pumped to various parts of the body.

The CO2 rich blood enters the capillaries where the CO2 is removed and O2 is obtained from the alveoli. From capillaries, blood enters bronchial veins and exits the lungs through the region known as the hilum, where both blood vessels and right and left main bronchi enter the lungs in the medial, central area of each lung.

After passing through the hilum, the right pulmonary vein passes posterior to the superior vena cava and right atrium to enter into the left atrium. The left pulmonary vein then passes in front of the descending aorta entering the left atrium.

Pulmonary Vein Function

Unlike other veins, pulmonary veins carry oxygenated blood from the lungs and back to the left atrium of the heart so it can be pumped to different parts of the body. The veins do the opposite job of pulmonary arteries by collecting the oxygenated blood and carrying it. The veins also go on to merge into larger veins. Each of the two lungs has two pulmonary veins that are used by the human body to deliver blood to the top left chamber of the heart or atrium.

Difference between Pulmonary and Systemic Circulation

What is the Function of the Aorta?

The aorta is a major part of the systemic circulation and pumps blood to the entire body except for the respiratory area of the lung. It also regulates the blood flow and velocity within vessels. Aorta functions are:

• Branches of ascending aorta supply blood to the heart.

• Branches of the aortic arch supply blood to the head, neck and arms.

• Branches from the thoracic descending aorta supply blood to the chest, excluding the heart and the respiratory zone of the lung.

• Branches from the abdominal aorta supply blood to the abdomen.

The aorta begins its path at the left ventricle of the heart, it then arches upwards in the direction of the neck, then bends back downhill, outspreading itself into the abdomen in the human body. It is the most important artery in the human body.

For a clear understanding, the aorta can be divided into four sections, and they are:

Ascending Aorta: The ascending aorta goes up from the heart and is as close to 2 inches in length. The coronary arteries subdivide like a branch from the ascending aorta to fulfil the purpose of supplying blood to the heart in the body.

Aortic Arch: The aortic arch bends on the human heart, resulting in many branches that work together to supply blood to a human’s head, neck, and arms for functioning.

Descending Thoracic: The descending thoracic aorta moves down through the chest in a human body. It has tiny branches that supply blood to the ribs and also some of the structures in the chest.

Abdominal Aorta: The abdominal aorta starts at the diaphragm in the human body, and then splits to get transformed into the paired iliac arteries that are located in the lower abdomen area. Almost all of the major organs get the supply of blood from these branches belonging to the abdominal aorta.

Differentiate Arteries from Veins

Arteries are commonly donated by the colour red and these are the blood vessels that carry blood to the body parts. Veins are commonly donated by the colour blue and are the blood vessels that bring the blood back to the heart. Deep veins, that are located in the center of a human’s leg near the leg bones, are surrounded by muscle. The iliac, popliteal, femoral, and tibial (calf) veins are known as the deep veins located in the legs.

The differences between pulmonary arteries and pulmonary veins are explained below:

Differentiate between Pulmonary Artery and Pulmonary Vein

The difference between arteries and pulmonary arteries are below:

Difference between Arteries and Pulmonary Arteries