Nervous System (Part-I)

Introduction: Nervous system is the most complex system in human. Its uniqueness is due to vast complexity of thought process and control action it can perform (Figure 13.1). It co-ordinate physiological functions in human. Nervous tissue originates from ectoderm and is specialized for receiving stimuli and transmitted message. The nervous tissue consists of highly specialized cells called the neurons. Thus neurons are functional unit of nervous system. The detail structure of a neuron is shown in Figure 13.2.

Figure 13.1: An Over-view of Nervous System in animals.  

A neuron is mainly divided into two parts: 1) Cell body or cyton and 2) Cell process.

1. Cyton: It is broader part of neuron which contains uninucleated cytoplasm. Except centriole, all type of cell organelles is found in cytoplasm. Due to absence of centrioles, neurons can’t divide. Some other cells organelles like neurofibril and nissl’s granule found in neuron, which help in transfer of impulse to cyton. Nissl’s granule is formed by coiling of endoplasmic reticulum around the ribosome.