Cardiac Muscle Contraction Lab Report

Through the process of each heartbeat, cardiac muscle contraction follows an electrical sequence. This sequence is initiated at the SA node generating an impulse which spreads through the AV node causing atrial systole. The electrical impulse then follows the AV bundle, bundle branches and the purkinje fibers producing ventricular systole. Series of electrical currents through the heart are able to be traced on the body surface by an electrocardiogram or ECG machine, a device that records voltage and time through the activity of each cardiac cycle. As stated above, the ECG recordings are shown by deflection waves that represent electrical events, starting with the baseline which is broken by the P wave caused by atrial depolarization. The QRS

The heart rate will be lowest when the subject is relaxed because the heart will have enough blood to pump in less beats per minute. When the subject sits up, it will increase its heart rate. However, the heart rate will be at its highest after the subject had exercised due to the body trying to satisfy itself by sending more oxygenated blood to where it is needed most.

Materials and

This relaxed state confirms that the heart rate is pumping the lowest amount of blood because your body’s need of oxygen is already fulfilled. There might be a slight change in heart rate when your body changes position. In this experiment, when the subject transitioned from relaxed state to sitting up his heart rate increased slightly to 74.93 BPM, followed by an even more elevated heart rate of 84.11 BPM after the subject had exercised, which affirms the increase of the heart because it has to work harder by pumping more blood to provide oxygen to where it is needed most, in this case, the