MICROANATOMY

BLOOD CARDIOVASCULAR SYSTEM LYMPHOID ORGANS

CARDIOVASCULAR SYSTEM

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Which of the following statements best describes blood flow in the human body?
A
As the thickness of the blood decreases, the rate of blood flow increases.
B
As the diameter of a blood vessel decreases, the rate of blood flow increases.
C
As the length of a vein decreases, the resistance to blood flow decreases
D
As blood pressure increases, the rate of blood flow decreases.
Explanation: 

Detailed explanation-1: -Mechanics of blood flow Therefore, blood flow is strongly proportional to the vessel radius. As the radius of the vessel lumen increases (called vasodilation), blood flow increases dramatically, and vice versa [1].

Detailed explanation-2: -As vessel diameter decreases, the resistance increases and blood flow decreases. Very little pressure remains by the time blood leaves the capillaries and enters the venules.

Detailed explanation-3: -Blood comes into the right atrium from the body, moves into the right ventricle and is pushed into the pulmonary arteries in the lungs. After picking up oxygen, the blood travels back to the heart through the pulmonary veins into the left atrium, to the left ventricle and out to the body’s tissues through the aorta.

Detailed explanation-4: -Vasodilation is the widening of blood vessels as a result of the relaxation of the blood vessel’s muscular walls. Vasodilation is a mechanism to enhance blood flow to areas of the body that are lacking oxygen and/or nutrients.

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