Exercise Physiology Flashcards
Venous blood enters which heart chamber?
Right atrium
Which side of the heart receives venous blood?
The right side
Where in the lungs does the exchange of gasses occur?
The pulmonary capillaries
Where does blood from the pulmonary veins enter the heart?
left atrium
describe the two circulatory patterns
1) pulmonary
2) systemic
what are the two phases in the rhythmic pattern of cardiac contraction and relaxation?
systole and diastole
what is systole? what happens during systole?
the contraction phase; the atria contract first, pumping blood to the ventricles - which themselves contract a fraction of a second later, sending blood to the lungs and body.
what happens during diastole?
as the heart muscle relaxes blood fills the left and right chambers of the heart in preparation for the next contraction. During diastole the heart itself is supplied with oxygenated blood through the coronary arteries.
describe one benefit of cardiopulmonary fitness as it pertains to the cardiac cycle
in people with a high level of cardiopulmonary fitness the heart spends more time in diastole at any submaximal exercise intensity.
what is cardiac output (Q)?
the amount of blood that is pumped out of each ventricle each minute.
what is the ratio of Q between each ventricle?
1 - the cardiac output from each ventricle is the same
which ventricle generates the most force during systole? why?
blood from the left ventricle is ejected with significantly greater force because blood from the left ventricle has to be pumped with enough force to reach the entire body; blood from the right ventricle only has to travel to the lungs and back
cardiac output (Q) is the product of which two factors?
heart rate and stroke volume
what is stroke volume?
the amount of blood pumped from each ventricle each time the heart beats
what are the units of SV?
ml/beat
what is a fairly typical SV? Q at rest?
a typical SV is ~70ml. a typical Q at rest is ~4200ml (about a gallon).
what is ejection fraction?
the amount of blood that fills the ventricles during diastole is not always completely ejected during systole. the percentage of the total volume of blood in the ventricle at the end of diastole that is subsequently ejected during contraction is called the ejection fraction.
what is the ejection fraction at rest?
about 50%
what is oxygen extraction?
the amount of oxygen taken from hemoglobin to be used by exercising muscles
what is the major limitation to exercise performance?
the capacity of the muscles to extract oxygen from circulating hemoglobin
where does anaerobic ATP production occur?
in the cell, outside the mitochondria
what is ischemia?
diminished blood flow
what is the primary substrate for anaerobic ATP production?
glycogen
aside from glycogen, name another source of anaerobic ATP production
creatine phosphate
what are phosphagens?
creatine phosphate and ATP
in a well trained athlete approximately what duration of maximal effort can be fuelled by phosphagens?
~10s
what is maximal oxygen consumption or VO2 max?
the total capacity to consume oxygen at the cellular level
what two factors determine VO2 max?
the delivery of oxygen to the working muscle by the blood (cardiac output (Q)) and the ability to extract the oxygen from the blood at the capillaries for use by mitochondria (oxygen extraction)).
cardiac output(Q) max * oxygen extraction max = ?
VO2 max
how is VO2 max expressed?
as either mL of oxygen consumed per kg of body weight per minute (mL O2/kg/min) or as litres of oxygen consumed per minute (l O2/min)
what is arterio-venous oxygen difference (A-VO2 diff)?
the increase in oxygen extraction during exercise resulting from increases in temperature, acidity, and CO2 levels in the bloodstream