The diagram of Alveoli shows it is composed of the lungs’ terminal bronchioles containing small, balloon-like structures called alveoli. Alveoli are found at the ends of bronchioles and the diagram of alveoli gas exchange shows them allowing carbon dioxide to be expelled from the body and oxygen entering the circulation. The diagram of alveoli in class 10 and class 11 is important for understanding the respiration chapter in the biology syllabus.
The labeled diagram of alveoli is given below:
Diagram of Alveoli
Table of Content
Alveoli Meaning
The lungs‘ terminal bronchioles contain tiny, air-filled sacs called alveoli. Alveoli function as the place where gases are exchanged, enabling carbon dioxide to leave the body and oxygen to enter the circulation during breathing. For effective gas diffusion between the air inside the alveoli and the blood in the surrounding capillaries, specific cells lining the thin walls of the alveoli are present. Carbon dioxide, a waste product of cellular metabolism, is eliminated from the circulation and oxygen is supplied to the body’s cells through this process.
Also Read: Exchange Of Gases – Class 11 Notes
Structure of Alveoli
The diagram of alveoli shows the internal and exterior structure of alveoli is carefully planned to enable effective gas exchange, assuring that the circulation is appropriately oxygenated and that carbon dioxide is expelled from the body.
Type I Pneumocytes
- These are the main cells that cover the alveolar inner surface. They have a lot of surface area for gas exchange since they are flat and quite thin.
- Pneumocytes of type I are specialized in promoting gas diffusion, which permits carbon dioxide to enter the bloodstream from the alveoli and oxygen to enter the circulation from the alveoli.
Type II Pneumocytes
- They are in charge of producing a surfactant, which lessens the surface tension in the alveoli. Surfactant helps keep the alveoli stable and keeps them from collapsing during exhale.
Alveolar Macrophages
- These are specialized immune cells that live inside the alveoli and are also referred to as dust cells.
- Their primary role is to absorb and eliminate any infections, dirt, or foreign objects that the person may have breathed. In order to keep the lungs healthy and free from infection, alveolar macrophages are essential.
Capillaries
- Every alveolus is surrounded by a thick capillary network.
- The thin walls of these small blood veins permit gas exchange between the circulation and the alveoli. While carbon dioxide from the circulation diffuses into the alveoli to be expelled, oxygen from the alveoli diffuses into the capillaries.
Interstitial Tissue
- Interstitial tissue, a delicate network of connective tissue, supports the alveoli.
- This tissue supports the alveoli structurally and aids in preserving their integrity and form.
Surfactant Layer
- The inside of the alveoli is covered with a thin coating of surfactant. By lowering the alveolar fluid’s surface tension, this surfactant keeps the alveoli from constricting and adhering to one another during exhale.
- It also facilitates effective gas exchange and aids in keeping the alveoli stable.
Alveolar Ducts
- The respiratory bronchioles and the alveolar sacs are connected by narrow passageways called alveolar ducts.
- They act as pathways, allowing air to enter the alveoli from the larger airways.
- Alveoli are lined by alveolar ducts along their walls.
- Similar to alveoli, the walls of alveolar ducts are made of simple squamous epithelium, which permits gas diffusion between the duct’s air and the nearby capillaries.
- Carbon dioxide is discharged into the alveoli for exhalation and oxygen is taken up by the bloodstream when air passes through the alveolar ducts.
Alveolar Sacs
- Clusters of alveoli gathered at the termini of alveolar ducts are known as alveolar sacs.
- They are encircled by networks of pulmonary capillaries and have a grape-like appearance. Because alveolar sacs have a wide surface area for gas exchange, carbon dioxide and oxygen may diffuse through them more effectively.
- Type I pneumocytes, specialized for gas exchange, and Type II pneumocytes, which generate surfactant to preserve the integrity of the alveoli, make up the walls of alveolar sacs.
- During breathing, alveolar sacs are essential for maintaining proper blood oxygenation and the body’s elimination of carbon dioxide.
Pores of Kohn
- The Kohn pores are microscopic holes in the walls of nearby alveoli
- They provide collateral ventilation and pressure equalization in the lung parenchyma.
Conclusion – Diagram of Alveoli
In summary, the alveoli are vital components of the respiratory system that facilitate the exchange of gases between the blood and the lungs. Their complex structure can be studied with the help of labeled diagram of alveoli. It consists of capillaries around thin-walled sacs, facilitates the effective transfer of carbon dioxide and oxygen. Alveolar macrophages and type I and II pneumocytes support the healthy operation of the alveoli by preserving structural integrity, generating surfactant, and fighting off infections.
Also Read:
FAQs – Alveoli Diagram
What is the Structure of Alveoli?
The alveoli consist of thin-walled sacs lined with specialized epithelial cells, surrounded by capillaries, facilitating efficient gas exchange in the lungs.
What is Alveoli Class 7?
Alveoli are tiny air sacs in the lungs where oxygen is absorbed into the bloodstream and carbon dioxide is released for exhalation.
What is the Main Function of Alveoli ?
The function of alveoli is to facilitate the exchange of oxygen and carbon dioxide between the lungs and the bloodstream during respiration.
What are Alveoli Made of?
Alveoli are primarily composed of thin epithelial cells, including Type I and II pneumocytes, surrounded by a network of capillaries.
What Surrounds Alveoli?
Alveoli are surrounded by networks of pulmonary capillaries.
What are Alveoli Walls Called?
The walls of alveoli are called alveolar walls.
What are the 3 Types of Alveoli?
The three types of alveoli are type I, type II, and type III. They work together in the lungs to facilitate gas exchange and maintain respiratory function.