Search results
Results from the WOW.Com Content Network
This leads to a temporary increase [clarification needed] in both the concentrations and partial pressures of oxygen and carbon dioxide in the alveoli. The effect is named after Bernard Raymond Fink (1914–2000), whose 1955 paper first explained it.
Gas exchange in plants is dominated by the roles of carbon dioxide, oxygen and water vapor. CO 2 is the only carbon source for autotrophic growth by photosynthesis, and when a plant is actively photosynthesising in the light, it will be taking up carbon dioxide, and losing water vapor and oxygen.
During the closed phase of discontinuous gas exchange cycles, the spiracle muscles contract, causing the spiracles to shut tight. At the initiation of the closed phase, the partial pressure of both O 2 and CO 2 is close to that of the external environment, but closure of the spiracles drastically reduces the capacity for the exchange of gases with the external environment. [2]
These filaments have many functions and are involved in ion and water transfer as well as oxygen, carbon dioxide, acid and ammonia exchange. [4] Each filament contains a capillary network that provides a large surface area for the exchange of gases and ions. Fish exchange gases by pulling oxygen-rich water through their mouths and pumping it ...
The acini are the basic units of respiration, with gas exchange taking place in all the alveoli present. [6] The alveolar membrane is the gas exchange surface, surrounded by a network of capillaries. Oxygen is diffused across the membrane into the capillaries and carbon dioxide is released from the capillaries into the alveoli to be breathed ...
The sum of these partial pressures (water, oxygen, carbon dioxide and nitrogen) comes to roughly 900 mbar (675 mmHg), which is some 113 mbar (85 mmHg) less than the total pressure of the respiratory gas. This is a significant saturation deficit, and it provides a buffer against supersaturation and a driving force for dissolving bubbles. [26]
The sum of partial pressures of the gas that the diver breathes must necessarily balance with the sum of partial pressures in the lung gas. In the alveoli the gas has been humidified and has gained carbon dioxide from the venous blood. Oxygen has also diffused into the arterial blood, reducing the partial pressure of oxygen in the alveoli.
This blood–air barrier is extremely thin (approximately 600 nm-2μm; in some places merely 200 nm) to allow sufficient oxygen diffusion, yet it is extremely strong. This strength comes from the type IV collagen in between the endothelial and epithelial cells. Damage can occur to this barrier at a pressure difference of around 40 millimetres ...