ABSTRACT
After reading this chapter you should be able to:
outline the ultrastructure and functions of the sarcomere, sarcoplasmic reticulum (SR), transverse tubules and gap junctions (3.2);
explain how the interactions between calcium (Ca2+), actin and myosin produce contraction (3.3);
sketch a ventricular action potential, label the various phases and name the ion channels responsible for each (3.6; 3.7);
explain the link between the action potential plateau and contractility (3.9);
describe Ca2+ cycling in cardiac myocytes and the factors affecting Ca2+ store size (3.9);
state the effect of diastolic length on contractile force (3.9; 3.10);
outline the effect of the following agents on contractile force: catecholamines; Ca2+ channel blockers; phosphodiesterase inhibitors; digoxin (3.8; 3.9);
draw and explain a delayed afterdepolarization (3.11).