Ecg Lab

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The purpose of this experiment was to measure the electrical activity of the heart while resting and after exercising using electrocardiography. The expectation for this experiment was that the ECG would show an increase in activity or more pulses per second after exercise and a decrease in the change in time between intervals. For this experiment, ECG wires and electrode pads were used along with the software BioPac Pro to measure the electrical activity of the heart. The results measured matched the expected in the hypothesis. The measurements taken while at rest resulted in a normal resting heart rate and the measurements taken after exercise showed an increased heart rate. Pulse was also measured during this experiment and increased in…show more content…
The heart is a muscle that pumps blood through two pathways, the pulmonary circuit bringing deoxygenated blood to the lungs and the systemic circuit bringing oxygenated blood to the rest of the body. When the heart beats it produces signals that are part of what is called the cardiac cycle. This cycle begins when a special group of auto-rhythmic cells fire. This group of cells makes up the sinoatrial, SA, node which is the dominant pacemaker of the heart. These pacemaker cells keep the heart beat steady and can be affected by activation of the sympathetic or parasympathetic nervous system by the body. If the sympathetic nervous system is activated, the heart rate will increase due to epinephrine and if the parasympathetic nervous system is activated the heart rate will decrease due to…show more content…
This negative charge is due to the K+ leak channels that are always open and leaking K+ out. It is maintained by several ion channels and exchangers. When a cell is depolarized from a neighboring cell, Na+ and Ca2+ are leaked into the cell through gap-junctions, which triggers the process. Ca2+ triggers more Ca2+ release from the sarcoplasmic reticulum inside the cell to help induce muscle contraction. The heart is also affected by the sympathetic nervous system to increase the heart rate. The sympathetic nervous system kicks in during exercise and epinephrine (NE) is released. NE binds to β-adrenergic receptors which are connected to a membrane spanning G-protein in the heart cells. Activation of this receptor causes the α-subunit of this GPCR to bind to adenylyl-cyclase which uses ATP to create CAMP. Increased CAMP concentrations also increase the levels of Protein Kinase A, which is dependent on CAMP to open up L-type Ca2+ channels in the cell membrane and to open up Ryr channels in the sarcoplasmic reticulum. Both of these channels allow more calcium to flow into the cell. More calcium means increased number of muscle contractions and increase contractile force. (Silverthorn,
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