Search results
Results from the WOW.Com Content Network
In respiratory physiology, the ventilation/perfusion ratio (V/Q ratio) is a ratio used to assess the efficiency and adequacy of the ventilation-perfusion coupling and thus the matching of two variables: V – ventilation – the air that reaches the alveoli. Q – perfusion – the blood that reaches the alveoli via the capillaries.
Local venous pressure falls to -5 at the apexes and rises to +15 mmHg at the bases, again for the erect lung. Pulmonary blood pressure is typically in the range 25–10 mmHg with a mean pressure of 15 mmHg. Regional arterial blood pressure is typically in the range 5 mmHg near the apex of the lung to 25 mmHg at the base.
The V/Q ratio in the apex is roughly 3.3 and 0.63 in the base, which indicates that perfusion is greater than ventilation towards the base, and the ventilation rate is greater than perfusion towards the apex. [3] Towards the base of the lungs, the fluid volume in the pleural cavity increases due to gravity, resulting in greater intrapleural ...
Lung compliance. Lung compliance, or pulmonary compliance, is a measure of the lung 's ability to stretch and expand (distensibility of elastic tissue). In clinical practice it is separated into two different measurements, static compliance and dynamic compliance. Static lung compliance is the change in volume for any given applied pressure. [1]
Arterial blood. 95-100 (P a O 2) Venous blood. 40-50. Non-lung Capillaries. 20-40. The alveolar oxygen partial pressure is lower than the atmospheric O 2 partial pressure for two reasons. Firstly, as the air enters the lungs, it is humidified by the upper airway and thus the partial pressure of water vapour (47 mmHg) reduces the oxygen partial ...
Cardiac systole is the contraction of the cardiac muscle in response to an electrochemical stimulus to the heart's cells (cardiomyocytes). Cardiac output is the volume of blood pumped by the ventricles in one minute. The ejection fraction is the volume of blood pumped divided by the total volume of blood in the left ventricle.
A pressure system is a peak or lull in the sea level pressure distribution. The surface pressure at sea level varies minimally, with the lowest value measured 87 kilopascals (26 inHg) and the highest recorded 108.57 kilopascals (32.06 inHg). High- and low-pressure systems evolve due to interactions of temperature differentials in the atmosphere ...
Cochlear hydrops preferentially affects the apex of the cochlea where low-frequency sounds are interpreted. Due to the fluid imbalance in this area, parts of the cochlea are stretched or under more tension than usual, which can lead to distortions of sound, changes in pitch perception, or hearing loss, all usually in the low frequencies.