BI SC 004 Lecture Notes - Lecture 31: Qrs Complex, Skeletal Muscle, T Wave
Document Summary
The left ventricle is much more muscular than the right ventricle. It must pump blood to the entire body. The arteries are more muscular than veins to: withstand the higher pressure exerted on them. The veins have a: thinner wall, larger center. During systole: atria contract together, followed by the ventricles contracting together. Followed by diastole: a rest phase, chambers relax. This cardiac cycle, or heartbeat, occurs: 70 times/minute. The sinoatrial node (sa node) in the right atrium: Initiates the heartbeat: causes the atria to contract. This impulse reaches the av node, also in the right atrium: to send a signal down the av bundle, purkinje fibers that cause ventricular contraction. These impulses travel between gap junctions at intercalated disks. A record of the electrical changes in the heart muscle (myocardium) during a cardiac cycle. The atria produce an electrical current, called the p wave, when stimulated by the sa node. The contraction of the ventricles is the qrs complex.
