Related Experiment Videos
Temperature effects on dog hindpaw series and parallel vascular circuits
The American Journal of Physiology
|July 1, 1983
Summary
Environmental temperature significantly impacts blood flow distribution in paws. Lower temperatures increase peripheral resistance, while higher temperatures enhance capillary availability and flow, regardless of nerve presence.
Area of Science:
- Physiology
- Vascular Biology
- Environmental Medicine
Background:
- Environmental temperature influences physiological processes.
- Understanding blood flow regulation is crucial for thermoregulation and tissue perfusion.
Purpose of the Study:
- To investigate the effect of environmental temperature on blood flow distribution in parallel vascular circuits.
- To assess the role of neural and non-neural mechanisms in temperature-mediated vascular responses.
Main Methods:
- Vascularly and neurally isolated hindpaws were perfused at constant pressure.
- Hindpaws were exposed to controlled water temperatures (10, 20, 30, 40°C).
- Blood flow distribution, peripheral resistance, and capillary availability were measured using 85Sr microspheres and diffusion capacity assessments.
Main Results:
- Peripheral resistance increased as temperature decreased in both innervated and denervated paws.
- Capillary availability (diffusion capacity and filtration coefficient) increased with rising temperatures.
- At lower temperatures, arteriovenous (AV) shunt flow was higher, while capillary flow was reduced, particularly in denervated paws.
Conclusions:
- Environmental temperature is a key determinant of blood flow distribution in the paw's vascular circuits.
- Increased temperature promotes capillary flow through an enlarged capillary bed, with minimal changes in arteriovenous anastomoses (AVAs).
- Neural and non-neural pathways contribute to regulating vascular resistance and blood flow distribution in response to temperature changes.