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 definition of a hat is a covering for the head, or someone's role in a job or in life. An example of a hat is a fedora. An example of a hat is the role of teacher. a covering for the head, usually with a brim and a crown.