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The respiratory center is responsible for generating and maintaining the rhythm of respiration, and also of adjusting this in homeostatic response to physiological changes. The respiratory center receives input from chemoreceptors , mechanoreceptors , the cerebral cortex , and the hypothalamus in order to regulate the rate and depth of breathing.
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 pressure to about 150 mmHg.
However, the ray's levels were still higher than the more hypoxia-tolerant Epaulette shark (Hemiscyllum ocellatum), which potentially sees hypoxia due to the bouts of low tides that can be seen in reef platforms. [90] Subtidal scallops will see both a decrease in maximal respiration and a depolarization of the membrane during reoxygenation. [101]
The normal relaxed state of the lung and chest is partially empty. Further exhalation requires muscular work. Inhalation is an active process requiring work. [4] Some of this work is to overcome frictional resistance to flow, and part is used to deform elastic tissues, and is stored as potential energy, which is recovered during the passive process of exhalation, Tidal breathing is breathing ...
The CO 2 compensation point (Γ) is the CO 2 concentration at which the rate of photosynthesis exactly matches the rate of respiration. There is a significant difference in Γ between C 3 plants and C 4 plants: on land, the typical value for Γ in a C 3 plant ranges from 40–100 μmol/mol, while in C 4 plants the values are lower at 3–10 μmol/mol. Plants with a weaker CCM, such as C2 ...
Respiration rates may increase with fever, illness, or other medical conditions. [2] Inaccuracies in respiratory measurement have been reported in the literature. [3] One study compared respiratory rate counted using a 90-second count period, to a full minute, and found significant differences in the rates. [citation needed].
The energy yield of anaerobic respiration and fermentation (i.e. the number of ATP molecules generated) is less than in aerobic respiration. [8] This is why facultative anaerobes , which can metabolise energy both aerobically and anaerobically, preferentially metabolise energy aerobically.
Moving from a molecular and cellular level to an ecosystem level, various processes account for the exchange of O 2 and CO 2 between the biosphere and atmosphere. Field measurements of the concurrent consumption of oxygen (-ΔO 2 ) and production of carbon dioxide (ΔCO 2 ) can be used to derive an apparent respiratory quotient (ARQ). [ 14 ]