BIOM20002 Lecture 46: 46 Control systems 4 cardiovascular system A
Document Summary
Can sustain contraction but acts slower - good for vessels that require a certain diameter for a period of time. Not as much invagination in cardiac cells compared to skeletal muscle. Volume inside heart determines length of cardiac tissue. When at rest cardiac muscle is well below its optimum length. Want to pump more strongly as venous return increases. Starling"s law: force of heart contraction adjusts in each cycle according to venous return. Bundles of his provides pathway of conduction through fibrous barriers. Heart contracts from apex to base of the artery. Arrangement of smooth muscle often in bands or bundles. may be associated with connective tissue. in walls of hollow organs: circular layer, longitudinal layer, random arrangement. Smooth muscle cells are small so rely on extracellular calcium. Maintain steady blood flow to tissue beds (flow in all vessels is the same, flow not speed) Protect vital organs when stressed: brain, heart, kidney.
