Week 9

Question 1

transport of oxygen

Answer 1

98% of the oxygen in the blood is carried in red blood cells in chemical combination with hemoglobin

Question 2

arteriovenous oxygen difference (a-v)O2

Answer 2

represents how much oxygen is extracted or consumed by the tissues for each 100ml of the blood perfusing them

Question 3

stroke volume

Answer 3

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

Question 4

cardiac output

Answer 4

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

Question 5

cardiac output and oxygen transport

Answer 5

When cardiac output increases during exercise, more O2 will be transported to the working muscles.
- expressed by the Fick equation:
VO2 = HR x SV x (a-vO2) diff

VO2 = oxygen uptake or utilization by the tissues in the body
(a-vO2) diff = arterial-mixed venous oxygen difference – amount of O2 extracted at tissue capillary beds

Question 6

max heart rate=

Answer 6

220-age

Question 7

when is the heart rate at a given oxygen uptake higher

Answer 7

when the exercise is performed with the arms due to smaller muscle mass, increased intra-thoracic pressure, less effective muscle pump, feedback to control centre

Question 8

stroke volume during exercise

Answer 8

end diastolic volume minus end systolic volume
diastole: resting phase of the cardiac cycle between heart beats
systole: contraction phase of the cardiac cycle, when the ventricles pump out their stroke volumes

Question 9

end diastolic volume

Answer 9

the volume of blood in each ventricle at the nd of diastole -120ml

Question 10

end systolic volume

Answer 10

volume of blood that remains in each ventricle after the ventricles have finished contracting - 50ml

Question 11

ejection fraction

Answer 11

percentage of EDV ejected with each contraction
stroke volume/end diastolic volume

Question 12

distribution of blood flow during exercise

Answer 12

at rest 15-20% of systemic blood flow goes to muscles
during maximal exercise 85% of the cardiac output can be diverted to the working skeletal muscles

Question 13

increased blood flow to working muscles is caused by

Answer 13

increased blood pressure
dilation of arterioles in working muscles due to relaxation of the smooth muscle in the walls of arterioles
constriction of arterioles in the gut area and non working muscles
- due to sympathetic nervous system stimulation

Question 14

poiseuilles law

Answer 14

restante to flow= fluid viscosity x tube length/ radius of tube ^4

Question 15

psychological determents of VO2 max

Answer 15

provides an integrated measurement of the capacity of your physiological systems that contribute to
- O2 transport and O2 utilization while maintaining homeostasis

Question 16

The most important factors that determine VO2 max. in a given person are:

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 - oxidative enzyme levels, etc.

Question 17

mode of exercise for VO2 max

Answer 17

In most subjects, the highest VO2max. values obtained during:
– uphill treadmill running
however completive athletes are able to achieve VO2 max values equal to or higher than their treadmill scores while doing their own sport

Question 18

advantages of bicycle ergometers compared to treadmills

Answer 18

less expensive, portable, don’t require electricity, patient is more stables and body weight is supported- easier to collect psychological data during exercise- heart rate, blood pressure, oxygen uptake , easier to quantify work rate

Question 19

disadvantages of bicycle ergometers

Answer 19

can’t obtain as high a Vo2 max as on treadmill
cycling is not a common movement for most individuals

Question 20

reasons for sex difference

Answer 20

Differences in body composition - male has more muscle and less
fat - muscle is metabolically a more active tissue
2. Average male has a 10-14% higher hemoglobin concentration

Question 21

reasons for decrease with age

Answer 21

1. Decrease in maximum heart rate, stroke volume and cardiac output in addition to negative changes in other components of the oxygen uptake and transport systems.

Question 22

why use a predictive test

Answer 22

1. Less expensive and specialized equipment is required. 2. Tests can be submaximal - safety
2. Some tests can be administered to large groups
3. Less motivation is required from the subject

Question 23

predictions based on heart rate during exercise

Answer 23

Linear relationship between heart rate and oxygen uptake
in some subjects at heavy work rates VO2 increases relatively more than heart rate.
Similar maximum heart rate for all subjects - standard deviation is approximately ± 10 beats/min. about the average maximum heart rate for people of same age group.
In cases where VO2 is predicted from work rate. a fixed mechanical efficiency is assumed
mechanical efficiency may vary by 6% on a bicycle ergometer.
Day to day variation in heart rate - even under highly standardized conditions (environmental temperature, time of day, diet, drugs, preliminary rest, clothing) the variation in submaximal heart rate is
approximately ± 5 beats/min. with day to day testing at the same work rate.