yläkuolokohtassa

Yläkuolokohtassa is a Finnish term that translates to "upper dead space" in English. It refers to the anatomical dead space in the respiratory system, specifically the portion of the airway that is involved in breathing but does not participate in gas exchange. This includes the nasal cavity, pharynx, larynx, trachea, and bronchi down to the terminal bronchioles.

The volume of the anatomical dead space is approximately 150 ml in an average adult. This volume is a constant factor in every breath. During inspiration, air enters the lungs, and the initial portion of this inhaled air fills the dead space before reaching the alveoli, where gas exchange occurs. During exhalation, the air from the dead space is exhaled first, followed by the air from the alveoli.

While the dead space does not contribute to oxygen uptake or carbon dioxide removal, it plays a crucial role in warming, humidifying, and filtering the inhaled air before it reaches the delicate lung tissues. This conditioning of the air protects the lower respiratory tract from irritants and temperature changes.

Physiological dead space is a related concept that encompasses both the anatomical dead space and any alveoli that are ventilated but not perfused with blood, meaning gas exchange is not occurring effectively in those areas. In healthy individuals, physiological dead space is very close to anatomical dead space. However, in certain lung diseases, physiological dead space can be significantly larger than anatomical dead space due to impaired blood flow to ventilated lung regions.