Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store

Difference Between Pulmonary Artery and Pulmonary Vein

share icon
share icon

An Introduction

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

Category

Pulmonary circulation

Systemic circulation

Anatomy

Thin vessels with minimal smooth muscle. The vessels are dependent on alveolar pressure.

Thick vessels with abundant thick smooth muscle. The vessels are embedded in tissues.

 Blood Volume

Approximately 500ml in a 70Kg person.

Approximately 4500 in a 70kg person.

Reservoir Function

10% of the total blood volume is circulated via the system.

90% of the total blood volume is circulated through this system.

Blood Pressure

18-25 mm of Hg for normal PA Systolic pressure.


8-15 mm of Hg for normal PA of Diastolic pressure.

120mm of Hg for normal PA systolic pressure.

80mm of Hg for normal PA diastolic pressure.

Circulatory Regulation

Minimum capacity to actively regulate or control blood flow, except via hypoxic pulmonary vasoconstriction.

Regional blood flow regulation is carried out at the level of arterioles.

Synthetic Functions

It is the source of thromboplastin and heparin which can degrade filtered clots.

Synthesis of nitric oxide, as well as pro and anti-coagulants


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

Pulmonary Arteries

Pulmonary Veins

There’s one pair of pulmonary arteries branching out from the pulmonary aorta.

There are two pairs of pulmonary veins with one pair branching out from each lung.

The pair of pulmonary arteries take blood away from the heart to the lungs of the respective side.

The two pairs of pulmonary veins carry oxygen-rich blood from the lungs to the heart.

Blood in pulmonary arteries is deoxygenated.

Blood in pulmonary veins is oxygenated.

Pulmonary arteries carry the blood from the right ventricle of the heart.

Pulmonary veins carry blood towards the left auricle of the heart.

Blood pressure is higher in pulmonary arteries.

Blood pressure is lower compared to pulmonary veins.

The walls of the pulmonary arteries are thick and elastic.

The walls of the pulmonary veins are thinner compared to pulmonary arteries.


The difference between arteries and pulmonary arteries are below:

Difference between Arteries and Pulmonary Arteries

Category

Arteries

Pulmonary Arteries

Definition

Thick-walled blood vessels supply oxygenated blood to all parts of the body.

Thick-walled blood vessels that carry blood with less oxygen to the lungs. 

Function

Transports oxygen-rich blood to the entire body.

Supplies blood with CO2 to lungs for purification.

Location

Arteries are present over the heart.

Pulmonary arteries originate from the pulmonary trunk towards the right ventricle beneath the aorta artery.

Type of Circulation

Arteries perform systemic circulation.

These arteries perform pulmonary circulation.

Want to read offline? download full PDF here
Download full PDF
Is this page helpful?
like-imagedislike-image

FAQs on Difference Between Pulmonary Artery and Pulmonary Vein

1. What is the function of the aorta in the heart?

The aorta is the primary and the largest artery of the human body that transports blood away from the heart to the rest of the body. After the blood is carried out from the heart through the aortic valve, it travels across the aorta, making a cane-shaped curve that connects with other major arteries to deliver oxygenated blood to the brain, muscles, and other cells. By doing this, the aorta takes part in the systemic blood circulation in the body.

  • The ascending aorta supplies blood to the heart.

  • The aortic heart supplies blood to the left side of the brain and neck and the left arm

  • The descending aorta supplies blood to the oesophagus, pericardium, diaphragm, lump nodes, ribs and some structures of the heart.

  • The abdominal aorta carries blood to several parts of the body which includes 

    •  The liver 

    •  Diaphragm, 

    •  Stomach 

    •  Spleen 

    •  Abdominal oesophagus 

    •  Intestines 

    •  Kidneys 

    •  Spinal cord 

    •  Pancreas.

2. What is the primary function of the pulmonary artery?

The pulmonary arteries bring blood with less oxygen content to the lungs where the blood is enriched with oxygen and is transported back into the heart with the help of the pulmonary veins. This oxygenated blood travels into the heart's left atrium and is then pumped to the left ventricle. Then it is circulated through the aorta to the arteries which carry it throughout all parts of the human body.

3. Where do Pulmonary Veins carry blood to the human body?

Pulmonary veins typically perform the opposite functions as pulmonary arteries and collect the oxygenated blood and take it from the lungs to supply it back to the human heart. These veins can be seen merging into larger veins in the body. Each of the lungs in our bodies has two pulmonary veins that carry blood from our hearts to the top left chamber also known as the atrium.

4. How many Pulmonary Veins are there in our bodies?

In normal conditions, there are four pulmonary veins in our bodies that carry oxygenated blood from both the lungs separately into the left atrium, these four pulmonary veins work as follows:


(a) the right superior pulmonary vein does the work of draining the upper right along with middle lobes; (b) the left superior pulmonary vein does the work of draining the left upper lobe along with lingula, and (c) then there are also two inferior pulmonary veins.


The left inferior pulmonary vein does the work of draining the lower left lobe. The right superior pulmonary vein does the work of draining the upper right along with the middle lobe. The right inferior pulmonary vein does the work of draining the lower right lobe.

5. Which part of the body does the Pulmonary Vein eventually flow into?

On the right and left, both sides of the human heart work in collaboration. Blood comes inside the heart by way of two big veins, the inferior and superior vena cava. These veins empty the oxygen-poor blood inside the human body straight into the right atrium. The pulmonary vein then does the work of emptying oxygen-rich blood, inside the lungs straight into the left atrium.