The following parameters were measured in a trained athlete

The following parameters were measured in a trained athlete and a sedentary university administrator, at rest and during a bout of exercise: A) Fill in the blanks above. B) Give a possible explanation as to why stroke volume in the administrator didn\'t change in the same way with exercise as it did the trained athlete. The wall thickness of an essentially spherical left ventricle can be considered constant at 1.5 cm throughout the cardiac cycle. Measured transmural pressures are as follows: 19 mm Hg as the AV valve opens, 24 mm Hg as the AV valve closes, 71 mm Hg as the semilunar valve opens, 80 mm Hg as the semilunar valve closes, and maximally, 99 mm Hg when 80% of the stroke volume has been ejected. Suppose that the ventricular end diastolic volume (EDV) is 362 m/s and the cardiac output is 4.9 L/min at a heart rate of 75 bpm. A) The left ventricular stroke volume (SV) = _______ B) The left ventricular preload in mm Hg = ______. Define \"preload\" and \"afterload\" as these terms pertain to the contraction of cardiac muscle.

Solution

Answer:

A) Cardiac output(CO)=Heart rate(HR)*stroke volume(SV)

7.2*1000/180=7200/180

=40

B) we use the terms heart rate (HR) to describe the number of heartbeats per minute and stroke volume (SV) to describe the volume of blood pumped by the ventricles with each heartbeat. Therefore, our equation looks like this: CO = HR x SV.

Cardiac output change for athelet is 9.8L-5L=4.8 L

Cardiac output change for university president is 7.2L-4.3L=2.9 L

Heart rates increase as the intensity of activity increases. This is because the working muscles demand more energy, so the heart beats increasingly faster in order to deliver the nutrients and O₂ needed to meet these increased energy demands. Since the athele can do more exercise so the cardiac output is more for the athlete.

The normal resting heart rate range for an adult is between 60-100 bpm. However when a resting heart rate is greater than 100bpm it is called ‘tachycardia’ and when it’s below 60bpm it is called ‘bradycardia’.

	CO	HR	SV
rest- Trained Athlete(TA)	5L=5000 ml	66	5000/66=75.75
exercise-TA	116*85=9860 ml=9.8 L	116	85
rest - University president(UP)	72*60=4320 ml=4.3 L	72	60
exercise-UP	7.2	180	7.2*1000/180=7200/180 =40