FAQ answers - Final exam

Question 1

explain how oxygen moves from high pressure to low pressure

Answer 1

It refers to the oxygen cascade including the main ‘steps’ involved as well as typical pressures (i.e. 100mmhg in the alveolar/arterial blood)
It also refers to the standard delta P for gas exchange to occur in the alveoli and the skeletal muscle which is ~60mmHg (100 in the alveolus, 40 in the muscle)

Question 2

SV increases during exercise due to

Answer 2

Increased preload via increased venous return
Increased contractility via increased sympathetic drive
Increased contractility due to the Frank Starling Mechanism relating to stretch

Question 3

interpret ‘extra strain’ as afterload

Answer 3

The heart is working harder to overcome afterload which is the pressure of the entire circulatory system during contraction (during systole). This would increase during exercise due to vasoconstriction in non-active areas to increase BP
The increase in afterload means higher contractility is required to overcome that resistance. If higher contractility can’t be reached the ESV would increase thus decreasing SV.
Remember this is all in reference to just systole. Total peripheral resistance still decreases during exercise.

Question 4

composition of room air

Answer 4

0.2093

Question 5

central peripheral factors

Answer 5

involve blood (stroke volume, heart rate, Q, blood flow, blood volume etc)

Question 6

Peripheral factors

Answer 6

involve O2 diffusion/extraction into/by the local skeletal muscle (capillary bed, mitochondria, muscle fibers etc)

Question 7

In strength training exercise we can see dramatic increases___ BP

Answer 7

systolic
-which is going to increase MAP as well, to higher levels then in aerobic exercises. The amount it increases will depend on changes in diastolic, which can go up as well, just not as much as systolic.

Question 8

Major points on the O2 cascade

Answer 8

Once gas exchange
happens (diffusive),
we must transport
oxygen via blood to
it’s destination

Question 9

Is the sympathetic and parasympathetic outflow intrinsic or extrinsic?

Answer 9

Extrinsic (affective signals received by CNS, efferent signals sent to periphery)

Question 10

vasodilation during exercise

Answer 10

increase blood flow and supply more o2 to working muscles, while vasoconstriction occurs to increase BP to main cerebral blood flow

Question 11

vasoconstriction during exercise

Answer 11

Sympatholysis occurs at a local level to attenuate vasoconstriction and increase blood flow, but at higher intensities, the sympathetic nervous system often ‘wins’ and our active muscle is constricted more than what is needed to meet the O2 demand.

Question 12

What are the rate of gases that diffuse through the tissues proportional to?

Answer 12

Surface area, pressure change, diffusion constant for the molecule

Question 13

air pressure

Answer 13

159 mmhg

Question 14

normal level of cardiac output

Answer 14

5-6 L/min

Question 15

normal level of stroke volume and HR

Answer 15

normal SV 50-100 (100 is untrained )
HR 80bpm