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