BIPN 105 Lecture Notes - Lecture 8: Purkinje Fibers, Cardiac Electrophysiology, Intercalated Disc

• School: UCSD
• Department: Bioinformatics
• Course: BIPN 105
• Professor: Catalina Reyes Gonzalez

Document Summary

Also has gap junctions so action potentials in one cell can travel to the other almost immediately and all the heart contracts simultaneously: use lots of atp compared to skeletal and smooth. Types of cells in heart: contractile cells: form the chambers (bulk of heart, striated fibers, organized in sarcomeres, main role: generate pressure. 300 msec: skeletal vs. cardiac, ap in skeletal muscle 1-5 msec. Can generate another ap -> summation -> tetanus. In cardiac muscle, ap so long, so refractory period is same length of time. By the time we can generate a 2nd ap, the muscle has already contracted and relaxed. Cannot produce summation in the heart, which is good. In humans, bundle of his also considered a pacemaker cell. Frogs don"t have bundle of his: bundle of his can still depolarize, but mainly conduct aps very quickly through bottom of heart, do not contract, conduction velocity: 3. 4 m/sec.