ABSTRACT
Communication among cells plays a crucial role in the human body mechanism by sending and receiving signals. It conveys information for sensation, feeling, emotional responses, thoughts, learning, memory, cause of mental disorders, and any other function of the human brain [1]. The nerve cell communication model is as shown in Figure 13.1, where the signals from the surrounding environment or other cells such as a response trigger signal must be communicated across a cell membrane. Signal information can cross the membrane passed through the movement of an electrical impulse and contact both outside and inside of the cell interacting with receptor proteins [2]. In this case, the correct cell receptors will respond to the signal on their surfaces [3]. Generally, a neuron or nerve cell is the key player in the nervous system activity. Within the neuron, two types of phenomena, chemical and electrical, are involved in the nerve impulse process. There are three main parts of a neuron. First, a dendrite is the thin fiber that extends for hundreds of micrometers in many branched tendrils that arise from the cell body, to receive information from other neurons. Second, soma or the cell body, is the majority of the neuron’s basic cellular functioning. For instance, the soma of a neuron can vary from 4 to 100 micrometers in diameter. The last important one, a long thin fiber called an axon, transmits nerve impulses to other neurons [4]. Neurons present in many different shapes and sizes, which can be categorized into two types by their function and morphology. Type I with long axons are used to move signals over long distances; the basic morphology represented by spinal motor neurons, consists of a soma and a long thin axon covered by the myelin sheath. The end of the axon has branching terminals called axon terminals, which are used to release neurotransmitters into a gap called the synaptic cleft between the terminals and the dendrites of the next neuron (4 nm). The adult human brain is estimated to contain from 1014 to 5 × 1014 synapses. Around the soma there is a dendrite branching tree that receives signals from other neurons. Type II have short axons, which can often be confused with dendrites. The emergence of rhythmic structure contributes to different activity in the cell communication network [5,6].
