9 - Blood Flow & Gas Transport

Question 1

def: the amount of blood pumped by either the left or the right ventricle per beat

Answer 1

stroke volume(SV)

Question 2

def: the amount of blood pumped by either the left or right ventricle of the heart per minute

Answer 2

cardiac output (Q)

Question 3

what is the formula for cardiac output?

Answer 3

heart rate x stroke volume

Question 4

T or F: the left and right ventricles must have the same cardiac output for blood flow to be maintained equally

Answer 4

true

Question 5

what does the fick equation represent?

Answer 5

how much oxygen will be transported to the working muscles as cardiac output increases

Question 6

how does heart rate usually increases until maximum heart rate is reached?

Answer 6

linearly increasing

Question 7

def: the contraction phase of the cardiac cycle, when the ventricles pump out their stroke volumes

Answer 7

systole

Question 8

def: the resting phase of the cardiac cycle, between heart beats

Answer 8

diastole

Question 9

def: the volume of blood in each ventricle at the end of diastole - 120 ml in an untrained person at rest

Answer 9

end-diastolic volume

Question 10

def: the volume of blood that remains in each ventricle after the ventricles have finished contracting - 0 ml in an untrained person at rest

Answer 10

end-systolic volume

Question 11

def: the percentage of EDV ejected with each contraction

Answer 11

ejection fraction

Question 12

at rest, what percentage of the systemic blood flow goes to the skeletal muscles

Answer 12

15-20%

Question 13

during exercise, what percentage of the cardiac output can be diverted to the working skeletal muscles?

Answer 13

85%

Question 14

what is increased blood flow to the working muscles caused by?

Answer 14

1. increased blood pressure
2. dilation of arterioles in working muscles due to the relaxation of smooth muscle in the walls or the arterioles
3. constriction of arterioles in the gut area and non-working muscles

Question 15

what conclusion can we make about the relationship between blood vessel radius and blood flow?

Answer 15

only a small change in blood vessel radius dramatically alters blood flow

Question 16

what are the physiological determinants of VO2 max? (5)

Answer 16

1. the ability to ventilate the lungs and oxygenate the blood passing through the lungs
2. the ability of the heart to pump blood -cardiac output
3. the oxygen carrying capacity of the blood
4. the ability of the working muscles to accept a large blood supply
5. the ability of muscle fibers to extract oxygen from the capillary blood and use it to produce energy

Question 17

what are some of the criteria for reaching VO2 max?

Answer 17

1. oxygen consumption increases linearly with increasing work rate and reaches a plateau
2. heart rate should be close to age predicted max
3. blood lactate levels should be 8 millimoles or greater, 3-5 mins post exercise
4. respiratory exchange ration should be greater than 1.15
5. subjective observations, do they look exhausted

Question 18

in most subjects, the highest VO2 max values can be obtained during what kind of exercise?

Answer 18

uphill treadmill

Question 19

what are the two kinds of bicycle ergometers?

Answer 19

1. mechanical

2. electrically braked bicycle ergometer

Question 20

what are 3 advantages of bicycle ergometers?

Answer 20

1. less expensive
2. portable
3. don’t require electricity

Question 21

what are the two disadvantages of bicycle ergometers?

Answer 21

1. can’t obtain as high of VO2 max as on treadmill

2. cycling is not a common mode of movement for most individuals. (vs.walking)

Question 22

T or F: some portion of VO2 max is genetically determined

Answer 22

true

Question 23

when does VO2 max peak?

Answer 23

between ages 18-25

Question 24

how much does VO2 max decline by each year?

Answer 24

about 1% per year

Question 25

how much larger is the male VO2 max after puberty?

Answer 25

20-25% higher

Question 26

what are the reasons for decrease in VO2 max with age?

Answer 26

1. decrease in max heart rate, stroke volume and cardiac output
2. individuals generally become less physically active

Question 27

what assumptions do we make when using sub max heart rate to predict VO2 max?

Answer 27

1. linear relation between heart rate and oxygen uptake
2. similar max heart rate for all subjects in the same age group
3. fixed mechanical efficiency is assumed
4. day to day variation in heart rate