Short-term adaptation to hypoxia exposure
| Organs & systems | Mechanisms | Effects |
| Breathing system | Activation of afferent impulses from carotid chemoreceptors in response to lowered раО2 and increasedраCO2 →
↑ Breath depth and frequency |
↑ Alveolar ventilation volume |
| ↑ Number of functioning alveoli | ||
| Heart | Activation of sympathic system → ↑Pulse rate and stroke volume | ↑ Minute volume of blood flow |
| Blood vessel system | Accumulation of metabolites with vascular dilating effect in myocardium and brain tissues; adenosine, prostacyclin, PgE, cynines → vasodilation in myocardium and brain | Centralisation of blood circultation (brain, heart) |
| Activation of sympathetic system and release of catholamines → peripheral vasoconstriction | ||
| Blood system | High blood concentrations of CA, thyroid and corticosteroid hormones → release of RBC from depot | ↑ Blood oxygen capacity volume |
| ↑ Affinity of Hb to oxygen | ||
| ↑ Dissociation of oxyhaemoglobyn in tissues |
Long-term adaptation to hypoxia exposure
| Organs & systems | Mechanisms | Effects |
| Breathing system | ↑ Number of alveoli and capillaries | ↑ Degree of blood oxygenation on lungs |
| Heart | ↑number of capillaries in myocardium
↑ number of mitochondria in miocardium ↑ efficacy of heart regulation systems (lowered sympathetic activity) |
↑ Minute blood circulation volume |
| Blood vessels | ↑ Number of functioning capillaries
NO-dependent vasodilation |
↑ Tissue perfusion levels |
| Blood | Activation of erythropoiesis
↑ Hb affinity to oxygen ↑ Dissociation of oxyhemoglobin in tissues |
↑ Blood oxygen capacity |