Tiny air sacs in the lungs are called

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SGPGI Staff Nurse Official Paper (Held On: 28 Feb, 2024 Shift 1)

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Answer 1

Correct Answer: Alveoli

Rationale:

The alveoli are tiny, balloon-like air sacs located at the end of the bronchioles in the lungs. They are the primary site for gas exchange, where oxygen from the inhaled air passes into the bloodstream and carbon dioxide from the blood is expelled into the lungs to be exhaled.
Each alveolus is surrounded by a network of capillaries, enabling efficient gas exchange between the air in the lungs and the blood. The walls of alveoli are extremely thin (about one cell thick) to facilitate this exchange.
Alveoli are coated with a substance called surfactant, which prevents them from collapsing by reducing surface tension. This is critical for maintaining proper lung function during breathing.
The human lungs contain millions of alveoli, providing a large surface area for gas exchange — approximately 70 square meters in adults.

Explanation of Other Options:

Bronchus

Rationale: The bronchus (plural: bronchi) is a large airway that branches off from the trachea and leads into each lung. While bronchi are involved in transporting air into the lungs, they are not directly involved in gas exchange. Instead, they serve as conduits to direct airflow toward smaller airways like bronchioles and eventually alveoli.

Bronchioles

Rationale: Bronchioles are smaller airways that branch off from the bronchi. They carry air deeper into the lungs, eventually leading to alveoli. While bronchioles are important in directing air and regulating airflow, they do not play a direct role in gas exchange.

Glottis

Rationale: The glottis is part of the larynx and refers to the opening between the vocal cords. It plays a role in producing sound and regulating airflow into the trachea, but it is not involved in the process of gas exchange in the lungs.

Conclusion:

Among the given options, alveoli are the correct answer because they are the functional units of the lungs responsible for gas exchange. Understanding the structure and function of alveoli is essential for comprehending how the respiratory system works to supply oxygen to the body and remove carbon dioxide.