Unlike an electrical synapse, the chemical synapses are separated by a space called the synaptic cleft, typically measured between 15 and 25 nm. Transmission of an excitatory signal involves several steps outlined below.
Definition of cap. 1  1a : a head covering especially with a visor and no brimb : a distinctive head covering emblematic of a position or office: such as (1) : a cardinal's biretta (2) : mortarboard.
n. 1  1. A headdress consisting of a long piece of cloth wound around a small cap or directly around the head, traditionally worn in North Africa, the Near East, and Central and South Asia. 2  2. A hat that resembles a turban, especially a brimless, close-fitting cap of draped fabric.