What does the water film do in the alveoli?

The alveoli are the tiny air sacs in the lungs where gas exchange happens. And their walls are lined by a thin film of water, which creates a force at their surface called surface tension.

Why is there a film of moisture on the inside surface of the air sac?

The bronchi split into smaller and smaller tubes called bronchioles, which then end in microscopic alveoli (air sacs). The alveoli are lined with mucus and are surrounded by a network of blood capillaries. The layer of moisture in the alveoli allows gases to dissolve so that they can diffuse quickly.

How does moisture help gas exchange?

Moist walls – gases dissolve in the moisture helping them to pass across the gas exchange surface. Permeable walls – allow gases to pass through. Extensive blood supply – ensuring oxygen rich blood is taken away from the lungs and carbon dioxide rich blood is taken to the lungs.

How does fluid build up affect oxygen diffusion?

Pulmonary edema occurs when the alveoli fill up with excess fluid seeped out of the blood vessels in the lung instead of air. This can cause problems with the exchange of gas (oxygen and carbon dioxide), resulting in breathing difficulty and poor oxygenation of blood.

What is the effect of surfactant on water molecules in the alveoli?

The surfactant reduces surface tension within all alveoli through hydrophilic and hydrophobic forces. Insufficient pulmonary surfactant in the alveoli can contribute to atelectasis (collapse of part or all of the lung ).

How do alveoli help in gas exchange?

There are three overall processes involved in your breathing: moving air in and out of your lungs (ventilation) oxygen-carbon dioxide exchange (diffusion) pumping blood through your lungs (perfusion)

Why is gaseous exchange important?

During gas exchange oxygen moves from the lungs to the bloodstream. At the same time carbon dioxide passes from the blood to the lungs. Gas exchange allows the body to replenish the oxygen and eliminate the carbon dioxide. Doing both is necessary for survival.

What are the factors responsible to affect the diffusion of gases?

Rate of diffusion is affected by concentration gradient, membrane permeability, temperature, and pressure. Pressure plays an important role in the diffusion of gases as gases diffuse from a region of higher partial pressure to a region of lower partial pressure.

How do gases move during respiration?

Gas exchange during respiration occurs primarily through diffusion. Diffusion is a process in which transport is driven by a concentration gradient. Gas molecules move from a region of high concentration to a region of low concentration.

How does fluid imbalances affect the gas exchange?

Lung fluid balance is critical for efficient gas exchange. Alveolar flooding, which may occur in many different pathological states, disturbs normal lung fluid balance, impairs gas exchange, and can lead to significant morbidity and mortality.

How does surfactant reduce surface tension in alveoli?

By adsorbing to the air-water interface of alveoli, with hydrophilic head groups in the water and the hydrophobic tails facing towards the air, the main lipid component of surfactant, dipalmitoylphosphatidylcholine (DPPC), reduces surface tension.