Talk:Hypoxia
From Bioblast
Systematic definition of normoxia as a reference for hypoxia
Categories of normoxia
- 1. Environmental conditions
- Normoxia may be defined arbitrarily (like altitude relative to sealevel) as air-level pO2 at sealevel in air or in the aqueous extra-organismic environment.
- 2. Compartmental respiratory cascade
- Normoxia may be defined arbitrarily as the pO2 in any given compartment of a living organism (alveolar, arterial, venous, mixed-venous, intracellular) obtained under environmental normoxia in a steady state of physiological routine activity (here βroutineβ is organismic physiological, whereas βROUTINEβ is cellular physiological).
- 3. Biological response
- For any function, normoxic performance is defined as the biological response that does not deviate from the physiological function measured under environmental or compartmental normoxia.
- 1. Environmental conditions
Causes of deviations from normoxia
- Starting from definitions of categories environmental normoxia, compartmental normoxia, and normoxic function, the causes for deviations from normoxia are considered:
- 1. Environmental hypoxia and hyperoxia
- Hypobaric conditions: high altitude or low-pressure chamber with air
- Hyperbaric conditions: high-pressure chamber, diving with air
- Normobaric: O2 deprivation in the environment (environmental normobaric hypoxia), O2 supplementation (environmental normobaric hyperoxia)
- 1. Environmental hypoxia and hyperoxia
- 2. Compartmental hypoxia and hyperoxia
- Environmentally induced hypoxia or hyperoxia on the compartmental level (living organism)
- Physiologically induced hypoxia on the compartmental level: tissue-work related (living organism at high work load of a tissue)
- O2-transport related hypoxia (pathological: ischemia and stroke, anaemia, chronic heart disease, chronic obstructive pulmonary disease, severe COVID-19, obstructive sleep apnea, CO poisoning)
- Experimental for isolated organs, tissues, cells, and organelles: deviations of incubation O2 levels of experimental preparations from compartmental or biological normoxia in the intact organism
- 2. Compartmental hypoxia and hyperoxia
- 3. Biological hypoxia and hyperoxia
- Compartmental: tissue-work related
- Compartmental: pathological
- Genetic: inhibition or acceleration of O2-linked pathways (mutations, knockout, knockin)
- Pharmacological-toxicological: inhibition or acceleration of O2-linked pathways (cyanide, rotenone, NO, ..; doping, ..)
- 3. Biological hypoxia and hyperoxia