does human respiration occur externally ? Justify
Answers
Answer:
Key Points
External respiration describes the exchange of gasses between the external environment and the bloodstream.
The components of external respiration include alveolar surface area, ventilation and perfusion matching, and partial pressure gradients.
Partial pressure gradients allow gasses to flow from areas of high pressure to areas of lower pressure.
Ventilation and perfusion in the alveoli must be balanced to maintain efficient gas exchange.
Key Terms
passive diffusion: The net movement of material from an area of high concentration to an area of lower concentration without any energy input.
perfusion: The blood supply to the alveolar capillaries that must be balanced with ventilation.
Equilibrium: The rate of change of the gasses in the alveoli and capillary become equal to eachother at the end of gas exchange.
External Respiration
External respiration is the formal term for gas exchange. It describes both the bulk flow of air into and out of the lungs and the transfer of oxygen and carbon dioxide into the bloodstream through diffusion. While the bulk flow of air from the external environment happens due to pressure changes in the lungs, the mechanisms of alveolar gas exchange are more complicated. The primary three components of external respiration are the surface area of the alveolar membrane, the partial pressure gradients of the gasses, and the matching of perfusion and ventilation.