Kinesiology 2222A/B Lecture Notes - Lecture 21: Vertebra, Brachiocephalic Artery, Brachiocephalic Vein
11 Apr 2019
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Audio recording started: 2:34 pm thursday, april 4, 2019 ads. Pacemaker cells: dictate the pace of the heart beat at about 80 beat per minute on average. As the sa node depolarizes, it sends a pulse through the heart at the atrial level --> leads contract. This signal reaches next group of specialized cells that can depolarize by themselves and s (60 times per minute) = av. Av node is about 60 beats per minute. Without the sa node, the av node can generate depolarization of the heart, but at muhc rate. Av delay: atria have enough time to contract to force blood into ventricle. A tract of specialized cells arise from av node and run into septum. From the bundle of his, you have bundle branches that carry this impulse rapidly to the b the heart. Very little time for the walls in the septum to contract because the signal moves downwar.
