Final answer:
The determinants of uterine blood flow include cardiac output, compliance, blood volume, viscosity, and blood vessel length and diameter. The most critical determinant is the radius of the blood vessels, which can be rapidly changed by vasoconstriction and vasodilation, impacting resistance and flow.
Step-by-step explanation:
Blood flow through the uterus is influenced by several determinants, including cardiac output, compliance, blood volume, viscosity, and blood vessel length and diameter. However, in the context of uterine blood flow, the most critical determinant is the radius of the blood vessels. The radius can be rapidly changed by vasoconstriction and vasodilation, resulting in significant impacts on resistance and flow. Small changes in the radius have a substantial effect on flow.