Blood Flow Velocity and Vessel Diameter

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What happens to the velocity of water when a narrow nozzle is attached to the end of a hose?

It becomes irregular

It remains the same

It slows down

It speeds up (correct)

Why does blood slow down as it moves from arteries to capillaries?

Because the capillaries have a smaller total cross-sectional area

Because the capillaries are longer

Because of the enormous increase in cross-sectional area (correct)

Because the blood cells become slower

What is the approximate ratio of blood flow velocity in the aorta to that in the capillaries?

10:1

100:1

500:1 (correct)

1000:1

What happens to the velocity of blood after passing through the capillaries?

It speeds up Signup and view all the answers

Why does the cross-sectional area increase in capillary beds?

Because each artery conveys blood to many capillaries Signup and view all the answers

How many capillaries are there in a human body?

7 billion Signup and view all the answers

What is the direction of blood flow due to contraction of the heart ventricle?

Away from the heart Signup and view all the answers

What role does the recoil of the elastic arterial walls play in the cardiac cycle?

Maintains blood pressure Signup and view all the answers

What is the main reason for the substantial resistance to flow in the arterioles and capillaries?

Narrow diameter of the vessels Signup and view all the answers

What happens to the pressure generated by the pumping heart by the time the blood enters the veins?

It is dissipated Signup and view all the answers

What is the force exerted by the contraction of the heart ventricle that stretches the wall of the artery?

Sideways force Signup and view all the answers

What is the primary direction of the force generated by the contraction of the heart ventricle?

In all directions equally Signup and view all the answers

What is the effect of the recoil of the elastic arterial walls on blood pressure?

It maintains blood pressure Signup and view all the answers

What is responsible for the flow of blood away from the heart?

The part of the force directed lengthwise in the artery Signup and view all the answers

What is the main reason for the decrease in blood pressure in the veins compared to the arteries?

The resistance to flow in the arterioles and capillaries Signup and view all the answers

What is the characteristic of blood flow that allows it to flow from areas of higher pressure to areas of lower pressure?

Its fluidity Signup and view all the answers

What happens to the water velocity when a narrow nozzle is attached to the end of a hose?

It speeds up Signup and view all the answers

Why does the blood flow velocity decrease in the capillaries?

Because of the increased cross-sectional area Signup and view all the answers

What is the significance of the large number of capillaries in the human body?

It increases the total cross-sectional area Signup and view all the answers

What happens to the blood flow velocity after passing through the capillaries?

It increases Signup and view all the answers

What is the reason for the analogy between the hose and the circulatory system?

Both have incompressible fluids Signup and view all the answers

What is the primary reason for the dramatic decrease in blood flow velocity from the arteries to the capillaries?

Enormous increase in cross-sectional area Signup and view all the answers