Pulmonary artery is the artery of the pulmonary circulation, which transports oxygen-deficient blood from the right side of the heart to the lungs. The major pulmonary artery is known as the pulmonary trunk. It is the largest pulmonary artery. Arterioles are the smaller pulmonary arteries that form the capillaries surrounding pulmonary alveoli.
The pulmonary artery branches into the right and left pulmonary arteries. These arteries transport blood high in carbon dioxide and low in oxygen to the lungs.
Blood picks up oxygen in the lungs while extra carbon dioxide is “dropped off” to be expelled from the body during exhalation.
The meaning and function of the pulmonary artery will be discussed in this article. Readers will also learn about the clinical significance associated with pulmonary arteries.
Table of Contents
Location
The pulmonary artery begins from the right ventricle of the heart. The valves of the heart permit the blood flow only in one direction – from the ventricles to the pulmonary artery or aorta and from the atria to the ventricles. These heart valves prevent the backflow of blood.
The right pulmonary artery inserts into the aortic arch in front of the descending aorta and behind the ascending aorta. The left pulmonary artery is located close to the left aortic side.
These vessels pass through the connective tissue encircling the heart (pericardium). Because the heart is located on the left side of the chest, the left pulmonary artery is nearer to the lung than the right pulmonary artery.
The left pulmonary artery divides into smaller branches after it enters the left lung. The right pulmonary artery enters the right lung after crossing the upper chest. The artery then splits into smaller branches.
Parts and Anatomy
The pulmonary arteries, a component of pulmonary circulation, are essential for oxygenating blood and eliminating carbon dioxide.
There are three layers to them:
- Intima, an inner layer
- Media, a middle layer
- Adventitia, an outer layer for protection
Pulmonary Arteries
The truncus arteriosus is the embryological origin of the pulmonary arteries.
The pulmonary artery is a short and broad structure around 5 cm long and 3 cm wide. The main pulmonary artery, also known as the pulmonary trunk, starts near the right ventricle’s base in the adult heart. The right and left pulmonary arteries supply deoxygenated blood to their respective lungs.
Pulmonary Veins
Large blood vessels called pulmonary veins collect oxygenated blood from the lungs to the heart. There are four pulmonary veins, two from each lung (left and right), draining into the heart’s left atrium.
Each lung has two pulmonary veins originating from the hilus. The pulmonary veins receive blood from three to four bronchial veins before emptying into the left atrium.
Functions
The pulmonary arteries play an important part in pulmonary circulation, along with the pulmonary capillaries and veins.
Pulmonary circulation transfers carbon dioxide and oxygen between the inhaled and exhaled air in the lungs and the blood in the body.
Its function is to transport blood deficient in oxygen and rich in waste carbon dioxide to the pulmonary capillaries, wherein the exchange occurs.
The pulmonary arteries carry deoxygenated blood compared to other arteries in the body.
The blood returns to the left atrium of the heart by the pulmonary veins after being cleansed of carbon dioxide waste and oxygenated.
The blood is pumped to the left ventricle before being sent to the arteries that deliver oxygenated blood throughout the body via the aorta.
Usually, each pulmonary artery has 3 to 7 branches. The arterial branches in the lungs correlate with the pulmonary arteries’ most common anatomical variations.
Significance
The pulmonary artery is significant in various clinical conditions. Pulmonary embolism (PE) and pulmonary arterial hypertension are the two main conditions that impact the pulmonary arteries in humans.
When a blood clot lodges in the pulmonary artery and prevents blood from reaching the lungs, the condition is known as a pulmonary embolus (PE).
A blood clot that originates in the body (often in the legs) and moves into the heart before being trapped in a pulmonary artery might result in a PE. Blood coagulation disorders, malignancy, and protracted physical inactivity are some risk factors for getting a PE.
The arteries in and around the lungs narrow, stiffen, and thicken due to pulmonary arterial hypertension, a rare form of pulmonary hypertension (high blood pressure).
Pulmonary arterial hypertension is characterised by fatigue, breathlessness, blood coughing, and leg oedema.
When a person with pulmonary arterial hypertension is unable to tolerate regular activity, it can escalate into severe heart failure and disability. Prescription drugs, however, can help prevent severe conditions.
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