The lung in the balance: arginine, methylated arginines, and nitric oxide

Nitric oxide (NO), an inorganic gas, acts as a potent second messenger in most animal and plant tissues. NO diffuses out of the cells that produce it and enters the neighboring cells to generate a downstream response. NO synthase (NOS) catalyzes NO production by the deamination of the amino acid arginine. There are three isoforms of NOS. Endothelial cells have endothelial NOS (eNOS), nerve and muscle cells have neuronal NOS (nNOS), and macrophages produce inducible NOS (iNOS) upon exposure to...

The lungs are a pair of vital organs connected to the trachea via the left and right bronchi. The base of these organs meets the dome-shaped muscle known as the diaphragm. Encased by the pleurae, the lungs contact the mediastinum. The right lung is shorter yet wider, and has a larger volume than the left lung. The left lung has an indentation known as the cardiac notch. The superior region of the lungs is referred to as the apex, whereas the base is the lower region near the diaphragm. The...

Introduction
Breathing, a seemingly passive process, is regulated by the respiratory center in the brainstem. This center coordinates the involuntary control of respirations, which means it occurs without conscious effort, ensuring a smooth and uninterrupted pattern.
Regulation of Ventilation
The body maintains ventilation by monitoring levels of carbon dioxide (CO2), oxygen (O2), and hydrogen ion concentration (pH) in the arterial blood. Among these factors, the level of CO2 plays a crucial...

Respiratory compensation is a vital physiological process that stabilizes blood plasma pH by regulating the partial pressure of carbon dioxide (PCO2), a key determinant of pH levels. Most carbon dioxide in the blood dissolves and converts into carbonic acid (H2CO3). It dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3⁻). There is also an inverse relationship between PCO2​​ and pH.
When carbon dioxide levels increase in the blood, more H+ and HCO3⁻ are produced, leading to a...

The lower respiratory tract is anatomically composed of several vital structures, including the larynx, trachea, bronchial tree, alveoli, lungs, and pleurae. Each component has a specific function, and all are intricately connected to ensure efficient respiration.
The Larynx
It is located between the pharynx and the trachea, acts as a passageway for air, and hosts several critical structures, such as the epiglottis, vocal cords, and glottis. The epiglottis acts as a gateway, guiding food to the...

The process of breathing, inhaling and exhaling, involves the coordinated movement of the chest wall, the lungs, and the muscles that move them. Two muscle groups with important roles in breathing are the diaphragm, located directly below the lungs, and the intercostal muscles, which lie between the ribs. When the diaphragm contracts, it moves downward, increasing the volume of the thoracic cavity and creating more room for the lungs to expand. When the intercostal muscles contract, the ribs...