lecture 11 - regional blood flow control

Question 1

What must be maintained in order to have control over blood flow?

Answer 1

High pressure

Question 2

How can the heart be described as a series circuit?

Answer 2

There is equal flow into and out of the heart for both circuits

Question 3

How can the heart be considered a parallel circuit?

Answer 3

There is continual branching in the arterial network that divides blood flow among the regional (organ) circulations, but maintains a total flow that is the same as the venous flow entering the heart

Question 4

During exercise, what parts of the body have an increase in blood flow?

Answer 4

Skeletal muscle, heart, skin

Question 5

During exercise, which parts of the body shows distinct decreases in blood flow?

Answer 5

GI tract, kidneys

Question 6

During exercise, how is blood flow to the brain modified?

Answer 6

It remains constant

Question 7

During exercise, how is MAP maintained?

Answer 7

Cardiac output increases, so total peripheral resistance decreases

Question 8

Which parts of the body increase their peripheral resistance during exercise?

Answer 8

Kidneys, GI tract, etc. to decrease blood flow. - Only by a small degree as overall resistance must decrease

Question 9

Which parts of the body decrease their peripheral resistance during exercise?

Answer 9

Skin, muscles, heart - to increase blood flow and maintain mean arterial pressure

Question 10

What is the equation for the resistance of a resistance vessel/arterioles?

Answer 10

R=1/r^4 (inverse of radius of the vessel ^4)

Question 11

How does the resistance change if the radius of a resistance vessel is changed by a factor of 2?

Answer 11

Changes by a factor of 16

Question 12

Halving the radius of a vessel will increase its resistance by what degree?

Answer 12

16 times larger