How does alveoli adapt

The alveoli are arranged in clusters throughout the lungs. They sit at the ends of the branches of your respiratory tree. This is the term used to describe the tree-like structure of passageways that brings air into the lungs. The walls of the alveoli are very thin. This lets oxygen and CO2 pass easily between the alveoli and capillaries, which are very small blood vessels.

One cubic millimeter of lung tissue contains around alveoli. Human lungs have a surface area of roughly 70 square meters. Though the total number varies from person to person, this means there are millions of alveoli in a person's lungs.

The alveoli are made up of two different types of cells. Each type has different functions:. Alveoli also contain immune cells called alveolar macrophages. Macrophages are like the garbage trucks of the immune system. These cells phagocytize , or eat debris. Macrophages clean up any particles that are breathed in and make it to the alveoli. They also remove dead cells and bacteria.

Alveoli are the endpoint of the respiratory system. The respiratory process starts when you inhale air into your mouth or nose. The air travels down the trachea , also called the windpipe. Then the air travels through airways called the bronchi and into the lungs. From there, the air is directed through smaller and smaller passages, called bronchioles. The air moves through a tiny duct called the alveolar duct and finally enters an individual alveolus.

Alveoli are lined by a fluid called surfactant. This fluid maintains the shape of the air sac and helps keep it open so that oxygen and CO2 can pass. At this point, the oxygen molecules move through a single layer of lung cells in the alveolus, then through a single cell layer in a capillary to enter the bloodstream. CO2 is a byproduct of the process in cells that uses oxygen to produce energy. As oxygen moves out of the alveolus, CO2 molecules pass into it.

They are then breathed out of the body through the nose or mouth. Oxygen can pass from the alveoli to the capillaries because the concentration of oxygen is lower in the capillaries than in alveoli. Similarly, CO2 moves the other way because the concentration of carbon dioxide is lower in the alveoli than in the capillaries.

Your diaphragm is the muscle that controls your breathing. When you inhale, your diaphragm contracts. This creates negative pressure in your chest, causing the alveoli to expand and pull in air. When you exhale, your diaphragm relaxes. This causes the alveoli to recoil or spring back, pushing out air. The alveoli exchange oxygen and carbon dioxide in the lungs.

Oxygen is needed for the body's cells to make energy. Carbon dioxide is a waste product of that process. Certain medical conditions can directly affect the alveoli. These are called alveolar lung diseases. These diseases can cause the alveoli to become inflamed and scarred. Some diseases may also cause them to fill with water, pus, or blood. Inflammation or infection within the alveoli can damage them. The alveoli will only function correctly if they're inflated the right amount.

Some conditions and injuries can cause this balance to be off:. A number of medical conditions involve the alveoli. These include:. Pneumonia is a lung infection. It can be caused by bacteria, viruses, or fungus. Pneumonia causes inflammation in the alveoli in one or both lungs.

The inflamed alveoli fill with pus, which makes breathing difficult. Emphysema is a chronic, or long-term lung disease. It usually develops in people with a long history of smoking. Emphysema patients have inflammation in their lungs.

This causes the destruction of alveoli. The alveoli that remain do not work as well. They lose their ability to stretch or spring back when a patient exhales. This leads to a condition called air trapping, which means air remains in the lungs even after exhaling. Emphysema patients usually have more trouble exhaling than inhaling. The inability to expel air from the lungs leads to more stretching of the alveoli.

This increases the loss of function. Tuberculosis TB is an infectious disease caused by bacteria. The disease causes the growth of nodules masses in lung tissue. TB bacteria multiply in the alveoli. The disease can cause the destruction of alveolar cells. Pulmonary alveolar proteinosis PAP is a rare disease. PAP causes proteins to accumulate in the alveoli. It is most often an autoimmune condition, in which the immune system attacks healthy cells.

PAP usually occurs in adults aged 20 to It may also occur as a congenital condition. Congenital conditions are present at birth. Bronchioloalveolar carcinoma BAC is a type of lung cancer. It is a subtype of lung adenocarcinoma , one of the most common types of lung cancer. BAC begins in the alveoli and is often found in one or both lungs. Acute respiratory distress syndrome ARDS is a life-threatening lung condition.

In ARDS, fluids accumulate in the alveoli. This prevents oxygen from getting to the lungs. ARDS is common in critically ill patients. Respiratory distress syndrome RDS is seen in premature babies. Babies born too early do not have enough surfactant lining the alveoli. This means there is less surface area available for the exchange of oxygen and CO2.

Pulmonary edema is a condition caused by excess fluid in the lungs. This fluid collects in the alveoli and can cause respiratory failure. Respiratory failure is when your blood does not get enough oxygen. Many medical conditions involve the alveoli. These conditions can be long-term or short-term. Some can lead to respiratory failure. Smoking is an important risk factor for lung disease. Tobacco smoke affects the respiratory tract at every level.

This includes the alveoli. Cigarette smoke affects how the alveoli work. Ventilation The lungs are well-ventilated, so that a new supply of air is constantly brought in. This is critical for maintaining the concentration gradients that make gas exchange possible. Essentially, carbon dioxide diffuses from an area of its higher concentration the blood to one of its lower lungs. Oxygen does the opposite. The excellent ventilation in the lungs makes this possible. What are four ways the lungs are adapted to their function?

May 16, Some adaptations are related to the alveoli, exercise, surface area, and ventilation. Explanation: Alveoli The alveoli are the location of gas exchange in the lungs. Related questions What is the significance of the fact that human tracheal cartilage rings are incomplete How is oxygen, carbon dioxide, and other waste gases exchanged in the lungs and body tissues? What is the function of the lungs in connection with the circulatory system?

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