| Abstract: | This study was performed with an indicator-dilution technique that allowed quantitative and separate investigation on the cat small intestine, of the “mucosal” as well as of the “villous” intravascular flows and volumes. When reducing arterial inflow pressure from about 100 to about 30 mm Hg “villous” plasma volume and mean transit time increased while “villous” plasma flow remained largely unaltered. Concomitantly, total intestinal blood flow decreased significantly indicating that a larger fraction of total plasma flow was diverted to the villi at low inflow pressure. When intestinal blood flow was reduced by increasing venous outflow pressure villous hemodynamics was largely unaffected. “Mucosal” red cell and plasma flows were affected in the direction of and, generally speaking, in proportion to total intestinal blood flow. These results suggest that the autoregulatory capacity of the villous vessels is larger than that of the vessels in the deeper parts of the mucosa. |
