Lungs: Definition, Location & Structure - Human Anatomy | Kenhub

Summary

This Kenhub tutorial by Matt explains the structure and function of the lungs, a key part of the respiratory system. The right lung has three lobes, while the left has two. Fissures divide the lobes, with the right lung featuring both horizontal and oblique fissures. The lungs connect to the mediastinum via the root, which contains bronchi, pulmonary vessels, and more. Air travels through the respiratory tract, branching into bronchioles and alveoli where oxygen and carbon dioxide exchange occurs. Kenhub offers more engaging anatomy resources, replacing traditional textbooks.

Takeaways

• 🫁 The lungs are composed of light and soft elastic tissue.
• 🔲 The right lung is larger than the left and has three lobes: superior, middle, and inferior.
• 🔳 The left lung has two lobes: superior and inferior.
• 🗺️ Fissures separate the lobes, with the oblique fissure dividing the left lung and the horizontal fissure dividing the right lung.
• 🌐 Each lung has three surfaces named after adjacent structures: costal, mediastinal, and diaphragmatic.
• 🔗 The mediastinal surface connects the lungs to the mediastinum via the lung's root.
• 🌿 The lung's root contains the mainstem or lobar bronchi, pulmonary vessels, bronchi, bronchiole vessels, lymphatics, and autonomic nerves.
• 🌬️ The respiratory airways and lungs are lined with respiratory epithelium.
• 🔄 The path of respiration involves air moving from the larynx, through the trachea and bronchi, to bronchioles and alveoli where gas exchange occurs.
• 🔄 Oxygen diffuses into the blood from the air in the alveoli, while carbon dioxide exits the body through exhalation.
• 📚 Kenhub offers interactive anatomy learning resources as an alternative to traditional textbooks.

Q & A

What are the main structural differences between the right and left lungs?

The right lung is larger and consists of three lobes: superior, middle, and inferior. The left lung, in contrast, has only two lobes: superior and inferior. This difference is due to the positioning of the heart, which causes the left lung to have less space.

What is the function of the fissures in the lungs?

Fissures separate the lobes of the lungs. The right lung has an oblique fissure that separates the middle and lower lobes and a horizontal fissure that separates the superior and middle lobes. The left lung has an oblique fissure that separates its upper and lower lobes.

What are the three surfaces of each lung, and how are they named?

Each lung has three surfaces: the costal, the mediastinal, and the diaphragmatic. These surfaces are named after the adjacent anatomical structures they face. For example, the costal surface faces the ribs, the mediastinal surface faces the mediastinum, and the diaphragmatic surface faces the diaphragm.

What is the root of the lung, and what structures does it contain?

The root of the lung connects it to the mediastinum and contains important structures such as the mainstem or lobar bronchi, pulmonary vessels, bronchiole vessels, lymphatics, and autonomic nerves.

What type of epithelium lines the respiratory airways and lungs?

The respiratory airways and lungs are lined with respiratory epithelium, which is specialized for the function of gas exchange and protection of the respiratory tract.

Describe the path of air through the respiratory organs starting from the larynx.

Air enters the larynx and moves down to the trachea, which then bifurcates into the left and right main bronchi. These further branch out into bronchioles, which continue to divide into smaller respiratory bronchioles. The terminal branches contain alveolar ducts, sacs, and alveoli, where gas exchange occurs.

Where does gas exchange occur in the lungs?

Gas exchange occurs in the alveoli, where oxygen diffuses into the blood, and carbon dioxide diffuses out of the blood to be expelled during exhalation.

Why is the left lung smaller than the right lung?

The left lung is smaller because it shares space with the heart, which is positioned slightly towards the left side of the chest, making the left lung less spacious.

What happens to carbon dioxide in the lungs?

Carbon dioxide leaves the hemoglobin molecules in the erythrocytes (red blood cells) and diffuses out of the blood into the alveoli to be exhaled out of the body.

What is the purpose of the alveolar sacs and ducts in the lungs?

Alveolar sacs and ducts increase the surface area of the lungs, allowing for efficient gas exchange between the air and blood. They contain the terminal alveoli, where oxygen and carbon dioxide diffusion occur.