Uloshengitys

Uloshengitys is the Finnish term for expiration, the exhalation phase of respiration. In English, it is called expiration or exhalation. It represents the process by which air is expelled from the lungs as part of the breathing cycle.

In normal, quiet breathing, exhalation is primarily passive. After inhalation, the diaphragm and external intercostal muscles relax, and the elastic recoil of the lungs and chest wall drives air out. During this phase, intrapulmonary pressure becomes slightly higher than atmospheric pressure, and air flows down its pressure gradient until the lungs return to their resting volume.

Active expiration occurs when greater expiratory effort is required, such as during exercise, coughing, or vocalization. In these situations the internal intercostal muscles and abdominal muscles contract to decrease thoracic volume and raise intrathoracic pressure, accelerating air expulsion.

Neural control of uloshengitys originates in the respiratory centers of the brainstem, with higher brain centers capable of voluntary control. Chemoreceptors monitor carbon dioxide and pH levels in the blood, helping regulate the rate and depth of exhalation to maintain acid-base balance.

Clinically, expiration is assessed in pulmonary function testing. Measures such as forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) gauge the efficiency and speed of the expiratory phase and help differentiate obstructive from restrictive lung conditions. Expiratory dysfunction can indicate diseases like COPD, asthma, or interstitial fibrosis.