Blood Flow Resistance and Viscosity

The video discusses the factors affecting resistance to blood flow, including viscosity, vessel length, and diameter. Viscosity, mainly influenced by hematocrit, directly affects resistance. Longer vessels increase resistance, while narrower vessels have resistance inversely proportional to the fourth power of the radius. The video also covers resistance in series and parallel vessel arrangements, and briefly touches on the peripheral resistance unit.

Which of the following is NOT a factor affecting resistance to blood flow?

• Diameter of the blood vessels

• Viscosity of the blood

• Temperature of the blood

• Length of the blood vessels

What primarily contributes to the viscosity of blood?

• White blood cells

• Plasma proteins

• Red blood cells

• Platelets

How does anemia affect blood viscosity?

• Varies depending on the individual

• No effect on viscosity

• Decreases viscosity

• Increases viscosity

Why do children experience less resistance in blood flow compared to adults?

• They have more red blood cells

• They have thicker blood

• They have shorter blood vessels

• They have wider blood vessels

What is the relationship between the diameter of a blood vessel and resistance?

• Inversely proportional to the fourth power of the radius

• Directly proportional to the radius

• Directly proportional to the fourth power of the radius

• Inversely proportional to the radius

In a narrow blood vessel, what happens to the fastest-flowing streams of blood?

• They increase in speed

• They are lost first

• They slow down gradually

• They remain unchanged

How does the arrangement of blood vessels in series affect total resistance?

• Resistance is divided

• Resistance is unchanged

• Resistance is added up

• Resistance is reduced

What is the effect of parallel arrangement of blood vessels on resistance?

• Increases resistance

• Decreases resistance

• Doubles the resistance

• No effect on resistance

What is the unit of resistance in blood vessels?

• Ohm

• Pascal

• Peripheral Resistance Unit

• Newton

When the pressure difference is 1 mmHg and the flow is 1 ml/s, what is the resistance?

• 1 Pascal

• 1 Ohm

• 1 Newton

• 1 Peripheral Resistance Unit