Respiratory System Anatomy - Bronchi and Bronchioles

The Respiratory System

• The respiratory system allows for gas exchange between the body and the environment.

Bronchi

• The structure of the bronchi is similar to the trachea, with C-shaped cartilage rings.
• As the bronchi get smaller, the cartilage is more spread out, and smooth muscle and elastin form more of the structure.
• Cilia and mucus work together to trap and remove dust and other particles from the airways.

Bronchioles

• Bronchioles are smaller airways that form when the tertiary bronchi divide.
• They continue to split until they end in millions of terminal bronchioles.
• Unlike bronchi, bronchioles do not contain cartilage; instead, they are made of smooth muscle and elastin.
• This allows the bronchioles to control the flow of air in the lungs, expanding when the body needs more oxygen.
• Cilia and mucus are also present in the bronchioles, protecting the lungs from contaminants.

Lungs

• The two lungs take up the whole of the chest cavity, except for the mediastinum, which is occupied by the heart and blood vessels.
• Each lung is divided into lobes, with the left lung having two lobes and the right lung having three.
• The pleura, a membrane, covers the surface of the lungs (visceral pleura) and also lines the inside of the chest (parietal pleura).
• A thin layer of pleural fluid is between the two layers of membrane, holding the lungs against the inside of the chest wall and allowing them to slide along the wall when breathing.

Alveoli

• The smallest bronchioles open into clusters of tiny air sacs called alveoli.
• Each alveolus has a wall that is only one cell thick and is surrounded by a network of blood capillaries.
• This is where gases move between the blood in the capillaries and the air in the alveoli.
• The alveoli are the functional units of the lungs, allowing for gaseous exchange between the airways and the blood.
• Oxygen passes from the airways into the blood, and carbon dioxide passes from the blood into the airways.

Learn about the structure and function of the bronchi and bronchioles in the respiratory system. Understand how the cartilage, smooth muscle, elastin, cilia, and mucus contribute to the process of gas exchange. Explore how tertiary bronchi divide to form bronchioles.