BPK 205 Lecture Notes - Lecture 18: Intercalated Disc, Cardiac Muscle, Myocyte

• School: Simon Fraser University
• Department: Biomedical Physio & Kines
• Course: BPK 205
• Professor: Nadine Wicks

Document Summary

Structure and function of cardiac muscle and the heart. Most of the cells (~99%) are force-producing: myocardial cells (myocytes, the force-producing cells striated muscle fibers. ~1% are autorhythmic (pacemaker) cells: generate spontaneous, rhythmic aps, the signal for myocyte contraction, do not contribute to the contractile force, very few contractile fibers, no organized sarcomeres. Irregular shaped and branching cells connected by intercalated disks: t-tubules are larger, sr is smaller. 2: mitochondria take up 1/3 of the cell volume, heart is constantly pumping = uses up lots of atp, skeletal muscle is neatly organized with 1 nuclei per fiber. The role of the cardiovascular system = transport: the arteries take blood away from the heart, the veins bring blood back to the heart. The heart is surrounded by a fluid-filled sac made of connective tissue = the pericardium. The bulk of the heart is composed of myocardium (cardiac muscle cells: there are myocardial cells of the atria and the ventricles.