The first step of cardiac conduction is impulse generation. The sinoatrial (SA) node (also referred to as the pacemaker of the heart) contracts, generating nerve impulses that travel throughout the heart wall. This causes both atria to contract. The SA node is located in the upper wall of the right atrium.What occurs first in a nerve impulse?
As an action potential (nerve impulse) travels down an axon there is a change in polarity across the membrane of the axon. In response to a signal from another neuron, sodium- (Na+) and potassium- (K+) gated ion channels open and close as the membrane reaches its threshold potential.How are nerve impulses initiated and transmitted?
Top Answer. Impulses are initiated either by the binding of neurotransmitter to Na+ channel... The opening of Na+ channels in one region causes Na+ to flow in, causing membrane depolarization as the electrical charge inside the cell jumps from slightly negative to positive.