Which term describes opposition to blood flow caused by friction of the blood vessel walls?

Which term describes opposition to blood flow caused by friction of the blood vessel walls?

• A. Peripheral resistance
• B. Vasodilation
• C. Vasoconstriction
• D. Tissue perfusion

Answer: (A)

Opposition to blood flow caused by friction between the moving blood and the inner walls of vessels is known as peripheral resistance. This resistance is what the heart must overcome to push blood through the systemic circulation, and it largely depends on the diameter of the vessels: smaller diameters (vasoconstriction) raise resistance, while larger diameters (vasodilation) lower it. The concept also encompasses the whole systemic vasculature, not just a single vessel. Tissue perfusion is the actual flow reaching tissues, not the resistance to flow, and vasodilation or vasoconstriction describe changes in vessel size that modify resistance rather than define the opposition itself.

Opposition to blood flow caused by friction between the moving blood and the inner walls of vessels is known as peripheral resistance. This resistance is what the heart must overcome to push blood through the systemic circulation, and it largely depends on the diameter of the vessels: smaller diameters (vasoconstriction) raise resistance, while larger diameters (vasodilation) lower it. The concept also encompasses the whole systemic vasculature, not just a single vessel. Tissue perfusion is the actual flow reaching tissues, not the resistance to flow, and vasodilation or vasoconstriction describe changes in vessel size that modify resistance rather than define the opposition itself.