• alveoli
  • It appears, therefore, that as VT increases, the gas transport mechanism changes from a relative inefficient dispersive mechanism, dependent on VT X f, to the more efficient mechanism of direct fresh gas convection to alveoli with high regional tidal volume-to-dead-space ratio. (biomedsearch.com)
  • Gas diffusion occurs rapidly across the walls of the alveoli and nearby capillaries. (faqs.org)
  • Lung alveoli are the ends of the respiratory tree, branching from either alveolar sacs or alveolar ducts, which like alveoli are both sites of gas exchange with the blood as well. (wikipedia.org)
  • Type I cells are thin and flat and form the structure of the alveoli Type II cells secrete surfactant to lower the surface tension of water and allows the membrane to separate, therefore increasing its capability to exchange gases. (wikipedia.org)
  • Reinflation of the alveoli following exhalation is made easier by pulmonary surfactant, which is a phospholipid and protein mixture that reduces surface tension in the thin fluid coating within all alveoli. (wikipedia.org)
  • At the dependent region smaller volumes mean the alveoli are more compliant (more distensible) and so capable of wider oxygen exchanges with the external environment. (wikipedia.org)
  • The test gas is held in the lung for about 10 seconds during which time the CO (but not the tracer gas) continuously moves from the alveoli into the blood. (wikipedia.org)
  • However, in most larger organisms, which have a small surface-area to volume ratios, specialised structures with convoluted surfaces such as gills, pulmonary alveoli and spongy mesophyll provide the large area needed for effective gas exchange. (wikipedia.org)
  • Cardiac
  • Ventilatory limitationIncreased dead space ventilation Impaired gas exchange Increased ventilatory demands due to peripheral muscle dysfunction Gas exchange limitationCompromised functional inspiratory muscle strength Compromised inspiratory muscle endurance Cardiac dysfunctionIncrease in right ventricular afterload due to increased peripheral vascular resistance. (wikipedia.org)
  • On the other hand, HAPE may be due to general vasoconstriction in the pulmonary circulation (normally a response to regional ventilation-perfusion mismatches) which, with constant or increased cardiac output, also leads to increases in capillary pressures. (wikipedia.org)
  • capillary
  • In respiratory physiology, the diffusing capacity has a long history of great utility, representing conductance of gas across the alveolar-capillary membrane and also takes into account factors affecting the behaviour of a given gas with hemoglobin[citation needed]. (wikipedia.org)
  • This test gas mixture contains a small amount of carbon monoxide (usually 0.3%) and a tracer gas that is freely distributed throughout the alveolar space but which doesn't cross the alveolar-capillary membrane. (wikipedia.org)
  • positive-pressure ve
  • This person must be capable of initiating resuscitation, including administration of positive-pressure ventilation and chest compressions. (ahajournals.org)
  • The 1856 works of English physician and physiologist Marshall Hall recommended against using any type of bellows/positive pressure ventilation, views that held sway for several decades. (wikipedia.org)
  • Artificial Ventilation
  • Cumarasamy N, Nüssli R, Vischer D, Dangel P, Duc G (1973) Artificial Ventilation in hyaline membrane disease: The use of positive endexspiratory pressure. (springer.com)
  • In 1773, English physician William Hawes (1736-1808) began publicizing the power of artificial ventilation to resuscitate people who superficially appeared to have drowned. (wikipedia.org)
  • necessitates
  • Consequently, the total liquid ventilation necessitates a dedicated liquid ventilator similar to a medical ventilator except that it uses a breatheable liquid. (wikipedia.org)
  • ventilatory
  • Subsequent investigation has enlightened us to the physiology and even pathophysiology of ventilatory support, facilitated the development of alternate modes of conventional ventilation, and identified those situations for which each is most suitable. (springer.com)
  • Uptake
  • Conversely, in oxygenic photosynthetic organisms such as most land plants, uptake of carbon dioxide and release of both oxygen and water vapour are the main gas-exchange processes occurring during the day. (wikipedia.org)
  • blood
  • The fluid coating is produced by the body in order to facilitate the transfer of gases between blood and alveolar air. (wikipedia.org)
  • Ideally, the oxygen provided via ventilation would be just enough to saturate the blood fully. (wikipedia.org)
  • When lacerations fill with blood, the result is pulmonary hematoma, a collection of blood within the lung tissue. (wikipedia.org)
  • Diffusing capacity of the lung (DL) measures the transfer of gas from air in the lung, to the red blood cells in lung blood vessels. (wikipedia.org)
  • It is part of a comprehensive series of pulmonary function tests to determine the overall ability of the lung to transport gas into and out of the blood. (wikipedia.org)
  • Thus, it is critical to choose the appropriate PFC for a specific biomedical application, such as liquid ventilation, drug delivery or blood substitutes. (wikipedia.org)
  • Stated mathematically: R = λ λ + V A / Q {\displaystyle R={\frac {\lambda }{\lambda +VA/Q}}} From this equation, we can measure the levels of each inert gas retained in the blood. (wikipedia.org)
  • Moreover, a similar understanding exists for the relationship between the distribution of blood flow and the distribution of ventilation. (wikipedia.org)
  • chronic
  • Since patients with chronic obstructive pulmonary disease (COPD) suffer enhanced oxidative stress during exercise, it was hypothesised that the mtDNA content will be further reduced. (biomedsearch.com)
  • It is a broad program and may benefit patients with lung diseases such as chronic obstructive pulmonary disease (COPD), sarcoidosis, idiopathic pulmonary fibrosis (IPF) and cystic fibrosis, among others. (wikipedia.org)
  • fluid
  • General strategies to improve pulmonary function and gas exchange include balanced fluid resuscitation to targeted volume-based resuscitation end points, positioning therapy, and pain management. (aacn.org)
  • COPD
  • It is indicated not only in patients with COPD, but also in:[citation needed] Cystic fibrosis Bronchitis Sarcoidosis Idiopathic pulmonary fibrosis Before and after lung surgery It appears not to be harmful and may be helpful for interstitial lung disease. (wikipedia.org)
  • carbon dioxide
  • In calibration experiments using a gas-mixing technique a high degree of linearity was found, both in the determination of the fraction of oxygen and carbon dioxide (r equal to 0.9996). (biomedsearch.com)
  • Other gas-exchange processes are important in less familiar organisms: e.g. carbon dioxide, methane and hydrogen are exchanged across the cell membrane of methanogenic archaea. (wikipedia.org)
  • membrane
  • The alveolar membrane is the gas exchange surface. (wikipedia.org)
  • In these creatures the gas exchange membrane is typically the cell membrane. (wikipedia.org)
  • D is the diffusion coefficient, which will differ from gas to gas, and from membrane to membrane, according to the size of the gas molecule in question, and the nature of the membrane itself (particularly its viscosity, temperature and hydrophobicity). (wikipedia.org)
  • If the two compartments are individually well-mixed, then this is simplifies to the difference in concentration of the gas between the inside and outside compartments divided by the thickness of the membrane. (wikipedia.org)
  • Fick's Law for gas-exchange surface Gases must first dissolve in a liquid in order to diffuse across a membrane, so all biological gas exchange systems require a moist environment. (wikipedia.org)