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.
A crown is a cap on a tooth. It looks like a cylinder that fits over the tooth after it has been prepared by a dentist. It is used to fix a tooth that has been severely broken or decayed to restore it to the proper shape, size, and color. It can also be used cosmetically to change the shape, size, and color of a tooth.