Alveoleissa

Alveoleissa is the Finnish locative plural form of alveolus, used in medical Finnish to refer to the alveolar spaces of the lungs. Alveoli are the tiny air sacs at the end of the respiratory tree where gas exchange occurs. Each alveolus has a thin epithelial lining and is surrounded by a dense capillary network; the inner surface is coated with a film of fluid containing surfactant, produced by type II pneumocytes, which reduces surface tension to prevent collapse during exhalation. The walls are permeable to gases, allowing oxygen to diffuse into the blood and carbon dioxide to diffuse out.

Ventilation and diffusion are coordinated so that fresh air reaches alveolar spaces with each breath. The alveolar–arterial gradient reflects the efficiency of gas exchange, and proper perfusion of the alveoli is essential for oxygen delivery to tissues. Alveolar macrophages patrol the spaces to remove inhaled particles and pathogens, contributing to innate immunity in the lower respiratory tract.

Clinical relevance is significant because the alveolar spaces are central to many pulmonary diseases. Pneumonia inflames and often fills alveoli with fluid or debris, impairing gas exchange. Pulmonary edema floods alveoli with fluid, reducing oxygenation. Acute respiratory distress syndrome damages the alveolar–capillary barrier, leading to severe impairment of gas exchange. Other conditions, such as alveolar proteinosis, involve abnormal accumulation of material within the alveolar spaces, further compromising ventilation.

In summary, alveoleissa denotes the alveolar spaces central to gas exchange in the lungs, highlighting the structure, function, and clinical importance of these tiny air sacs in respiratory physiology.