Exam 3: Cardiac Output and Blood flow in Muscle Tissues

Question 1

Define cardia outpu

Answer 1

• Quantity of blood pumped into the aorta each minute by the heart
• Quantity of blood that flows through the circulation
• Sum of all the blood flows to all of the tissues of the body.

Question 2

Define Cardiac Index:

Answer 2

• Cardiac output/square meter of body surface
• normal is 3L/min/m²

Question 3

What are factors that directly affect cardiac output

Answer 3

• Basic level of body metabolism
• whether the person is exercising
• age
• size of the body

Question 4

What are the normal cardiac output for men, women and resting adult?

Answer 4

• Young, healthy men 5.6 L/min
• Women 4.9 L/min
• Resting adult 5.0 L/min

Question 5

Frank-starling Law:

Answer 5

Heart automatically pumps whatever amount of blood that flows into the right atrium***

*** therefore, peripheral factors are more important controllers of cardiac output.

Question 6

T/F stretching of the heart causes the heart to pump faster.

Answer 6

True

Question 7

When is the cardiac output controlled almost entirely by peripheral factors that determine venous return?

Answer 7

Under most normal non-stressful conditions.

Question 8

Ohm’s Law:

Answer 8

Any time the long-term level of total peripheral resistance changes the cardiac output changes quantitatively in exactly the opposite direction.

Question 9

Explain that the bainbridge reflex and the baroreceptor reflex control heart rate.

Answer 9

• This is not significant in humans, occurs after birth
• The B.R. (atrial stretch reflex) responds to changes in blood volumes as detected by stretch receptors in the right atrium
• baroreceptors which respond to changes in arterial pressure.