Lung Chemistry

Lung Chemistry

Lung chemistry involves the chemical processes of gas exchange, which is driven by the diffusion of oxygen (O2cap O sub 2𝑂2) and carbon dioxide (CO2cap C cap O sub 2𝐶𝑂2) based on concentration gradients, and the chemical properties of substances within the lungs like pulmonary surfactant and nitric oxide. Inhaled air’s O2cap O sub 2𝑂2 moves from high concentration in the alveoli to the blood, while CO2cap C cap O sub 2𝐶𝑂2, a byproduct of cellular metabolism, moves from the blood to the alveoli to be exhaled. The lungs also contain protective chemicals like the proteins in pulmonary surfactant, which has immune functions, and nitric oxide, which helps regulate blood flow. 

Gas exchange 

• Diffusion: The fundamental chemical process is diffusion, where gases move from an area of high concentration to one of low concentration.
• Oxygen transport: Oxygen from inhaled air enters the alveoli and diffuses across the alveolar and capillary walls into the red blood cells, where it binds to hemoglobin. This oxygen-rich blood is then pumped throughout the body.
• Carbon dioxide removal: Carbon dioxide, a waste product from the body’s cells, is carried by the blood to the lungs. It diffuses from the blood into the alveoli and is then expelled from the body when you exhale.
• Acid-base balance: This exchange of gases is critical for maintaining the body’s acid-base balance. 

Other chemical components and processes 

• Pulmonary surfactant: A complex mixture of lipids and proteins (like SP-A, SP-B, SP-C, and SP-D) that lines the alveoli.
  • Function: It prevents the collapse of alveoli, facilitates gas exchange, and has immune functions. SP-A and SP-D act as immune molecules, and SP-B and SP-C are crucial for the biophysical function of the lung.
• Nitric oxide (NO): A molecule that plays a role in regulating blood flow in the lungs.
• Reactive oxygen species (ROS): Molecules that can be signaling agents in both normal physiological and pathological processes in the lungs.
• Bronchial defense: The bronchial tubes are lined with mucus and cilia, a physical and chemical defense system to trap and remove inhaled particles. 

Chemistry of lung function and health 

• Blood flow: The chemical CO2cap C cap O sub 2𝐶𝑂2 plays a key role in regulating blood flow to tissues. Low levels of CO2cap C cap O sub 2𝐶𝑂2 can cause vasoconstriction, reducing blood flow and oxygen delivery to the body.
• Oxygen delivery: Low CO2cap C cap O sub 2𝐶𝑂2 levels can also make red blood cells less likely to release oxygen to the tissues, a phenomenon known as the Bohr effect.
• Inhaled substances: The lungs’ chemistry is also influenced by harmful inhaled substances, such as particulate matter from sources like burn pits, which can lead to toxicity and disease.