LAB 3 Quiz

Question 1

Explain any difference recorded in heart rate between the two positions

Answer 1

If heart rate goes up while standing, stroke volume decreases to balance cardiac output (5L/min).
Laying down, heart rate will decrease, stroke volume will increase to balance cardiac output (5L/min).
Standing: more muscles contracting. Afterload is affected, more resistance (increased). Less blood coming back to the heart. Preload: Less blood already in the heart. Which is why heart rate increases.
Accelerator nerve
Lying down is good for venous return/ preload. Resulting in larger stroke volume coming out. Higher end diastolic volume.

Question 2

Relate this experiment to a practical example.

Answer 2

Upright/ recumbent bike

Question 3

Identify and explain the blood pressure AND heart rate response (at rest, during the contraction and immediately after the contraction) to this task

Answer 3

While doing the exercise blood pools in legs. When stopped the blood rushes back to the heart so for the heart to get rid of all the blood it increases heart rate. Ventricles are pumping harder.
Because of muscle pump being squeezed during contraction.
Isometric vs. isotonic: breathing will help blood flow go back to the heart. Valsalva is holding your breath for intense exercise. Fills up chest cavity with air. Purpose is to stabilize the spine and core while performing. Blood pressure will decrease.
MVIC: maximal voluntary isometric contraction
Increase heart rate to increase the pressure in the blood to force the blood through the contracted muscles.

Question 4

Explain a piece of advice (pertaining to this specific experiment) would you now give to a personal trainer working in a fitness facility?

Answer 4

Importance of breathing while exercising.

Question 5

Explain the components of a typical ECG trace, specifically the “PQRST” complex (include a diagram or drawing to explain your answer).

Answer 5

P-WAVE: Depolarization of atria in response to SA node triggering
PR Interval: Delay of AV node to allow filling of ventricles
QRS Complex: Depolarization of ventricles, triggers main pumping contractions.
ST Segment: Beginning of ventricle repolarization, should be flat.
T-wave: Ventricle repolarization

Question 6

Define “ventricular ischemia” and describe (and show) what it would look like on an ECG trace (compared to a healthy ECG trace).

Answer 6

Decrease of blood supply to the tissue.
Discolouration in the heart due to less new blood going into it.
Muscles won’t work well or contract as easily.
Heart won’t stretch or contract as much if there less blood going to a certain area.
Feeling lightheaded, blood pressure and heart rate go up.
ST segment is depressed: taking longer for ventricles to fill/ repolarization is taking longer due to less blood flow and less electrolytes.