Abstract
Oxygen is transported by convection in blood, and by molecular diffusion down concentration gradients in tissues. Convective transport is enhanced by hemoglobin in red blood cells. Diffusive transport is enhanced by a dense network of tiny vessels, the microcirculation, which reduces diffusion distances. Tissue oxygen demand varies greatly during growth and development, from rest to exercise, and with organ activity. The structure of the microcirculation is inherently heterogeneous, resulting in nonuniform oxygen supply. Mechanisms of short-term flow regulation and long-term structural remodeling adjust oxygen supply according to changing levels of local oxygen demand, and compensate for the intrinsic heterogeneity. With these mechanisms, sufficient oxygen is delivered to tissues to meet the requirements of aerobic metabolism, even at very high rates of consumption as in maximal exercise. Disruption of regulatory mechanisms can reduce exercise capacity, compromise cellular functions, and ultimately result in tissue damage, even when overall oxygen supply is adequate.
Original language | English (US) |
---|---|
Title of host publication | On Oxygen |
Subtitle of host publication | From Air to Tissues |
Publisher | Elsevier |
Pages | 169-189 |
Number of pages | 21 |
ISBN (Electronic) | 9780443218774 |
ISBN (Print) | 9780443218767 |
DOIs | |
State | Published - Jan 1 2024 |
Keywords
- aerobic metabolism
- blood flow
- capillaries
- flow regulation
- mathematical modeling
- Physiological process
- transport processes
- vascular remodeling
ASJC Scopus subject areas
- General Medicine