The work of the respiratory system of the body is to extract oxygen from the atmosphere and transfer it to the bloodstream. It also collects carbon dioxide from the body and releases it into the atmosphere. Lungs are a critical part of the respiratory system and are located in the thoracic cavity of the chest. They are conical in shape and are divided by lobes and fissure.
The two lungs are known as the left lung and the right lung. The primary function of the lungs is to breathe in oxygen and breathe out carbon dioxide but there is a difference between the right and left lungs based on several factors. The experts at Vedantu have summarised these lung differences between right and left in an easy to understand format.
Left Lung
The left lung is located on the left of the heart and has a concave impression to accommodate the heart. This impression is known as the cardiac notch and it makes the left lung smaller than the right one. An important difference between the right lung and the left lung is the size.
Right Lung
The right lung is located on the right side of the respiratory system and is shorter than the left lung. It is to accommodate the diaphragm, which rises higher towards the right side over the liver.
1. What are the main anatomical differences between the right and left lung?
The primary differences between the right and left lungs relate to their size, number of lobes, and shape. The key distinctions include:
2. Why is the right lung larger and heavier than the left lung?
The right lung is larger and heavier because it does not need to accommodate the heart. The human heart is positioned in the middle of the chest but tilts towards the left, occupying space that would otherwise be taken by lung tissue. To make room for the heart, the left lung is smaller and has a distinct indentation known as the cardiac notch. The right lung, free from this constraint, has a more uniform shape and a larger volume, allowing for three lobes instead of two.
3. How do the lobes and fissures differ between the right and left lungs?
The division into lobes and fissures is a key anatomical difference. The right lung is divided by two fissures, the oblique and horizontal fissures, which create three distinct lobes: the superior, middle, and inferior lobes. In contrast, the left lung has only a single oblique fissure that separates it into two lobes: the superior and inferior lobes. This structural difference is a direct result of the right lung's larger size and the left lung's need to accommodate the heart.
4. What is the functional importance of the cardiac notch on the left lung?
The cardiac notch is a crucial anatomical feature that demonstrates the integrated design of the thoracic cavity. Its primary function is to provide space for the apex of the heart, which points towards the left side of the body. This adaptation ensures that the heart can function without being compressed by the surrounding lung tissue during inhalation and exhalation. It is a perfect example of how the structure of an organ (the left lung) is modified to accommodate the function and position of a neighbouring organ (the heart).
5. What is the main difference between the right and left primary bronchus?
The primary bronchi, which branch off the trachea, also show significant differences. The right primary bronchus is wider, shorter, and more vertical than the left one. Because of its more vertical orientation, inhaled foreign objects are more likely to get lodged in the right bronchus. The left primary bronchus is narrower, longer, and more horizontal as it has to pass underneath the arch of the aorta and in front of the esophagus to reach the left lung's hilum.
6. How do the anatomical differences between the lungs affect their total lung capacity?
The anatomical differences directly impact their respective capacities. Due to its larger size and three lobes, the right lung has a slightly greater volume and capacity for gas exchange compared to the left lung. The space occupied by the heart reduces the total volume of the left lung. While both lungs work together for respiration, the right lung contributes a marginally higher percentage to the total lung capacity and vital capacity of the respiratory system.
7. Is there a significant difference in the hilum of the right and left lung?
Yes, the arrangement of structures within the hilum (the 'root' of the lung) differs. The hilum is where the bronchi, blood vessels, lymphatic vessels, and nerves enter and exit the lung. In the right lung's hilum, the bronchus is typically located posterosuperior (behind and above) the pulmonary artery. In the left lung's hilum, the main bronchus is situated more superiorly (above) the pulmonary artery. These positional differences are important landmarks in medical imaging and surgery.