Electrical synapse Electrical synapse An electrical synapse is a mechanical and electrically conductive link between two neighboring neurons that is formed at a narrow gap between the pre- and postsynaptic neurons known as a gap junction. At gap junctions, such cells approach within about 3.8 nm of each other, a much shorter distance than the 20- to 40-nanometer distance that separates cells at chemical synapse. In many animals, electrical synapse-based systems co-exist with chemical synapses. Compared to chemical synapses, electrical synapses conduct nerve impulses faster, but, unlike chemical synapses, they lack gain—the signal in the postsynaptic neuron is the same or smaller
Systole Systole of the heart is initiated by electrically excitable cells situated in the sinoatrial node. These cells are activated spontaneously by depolarization of the electrical potential across their cell membranes, which causes voltage-gated calcium channels on the cell membrane to open and allow calcium ions to pass through into the sarcoplasm (cytoplasm) of cardiac muscle cells. Calcium ions bind to molecular receptors on the sarcoplasmic reticulum (see graphic), which causes a flux (flow) of calcium ions into the sarcoplasm. Calcium ions bind to troponin C, causing a conformational (i.e., structural) change in the troponin-tropomyosin protein complex, causing the myosin head