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.
The hat is a caret-shaped symbol commonly placed on top of variables to give them special meaning. The symbol is voiced -hat (or sometimes as -roof) in mathematics, but is more commonly known as the circumflex in linguistics (Bringhurst 1997, p. 274). Uses of the hat in mathematics include: 1.