Page 3 - LN-NEURAL CONTROL & COORDINATION

2. Dendrites (Dendrons)
Dendrites are usually shorter, tapering and much branched processes that
project out of the cell body. They also contain Nissl’s granules and may be one
to several in number.
They conduct nerve impulses towards the cell body and are called afferent
processes (receiving processes).
3. Axon

Axon is a single, usually very long process of uniform thickness. The part of
cyton from where the axon arises is called axon hillock (most sensitive part of
neuron).
The axon contains neurofibrils and neurotubules but does not have Nissl’s
granules, cell organelles and granular bodies. The axon ends (distal end) in a
group of branches, the terminal arborization (axon terminals).
When terminal arborisations of the axon meet the dendrites of another

neuron to form a synapse, each branch terminates as a bulb-like structure
called synaptic knobs, which possess mitochondria and secretory vesicles
(containing chemicals called neurotransmitters). The axons transmit nerve
impulses away from the cell body to a synapse or to a neuromuscular junction.
There are two types of axon
a. Myelinated
In myelinated nerve fibres Schwann cells form myelin sheath around the axon.
The gaps between two adjacent myelin sheaths are called nodes of Ranvier.

Myelinated nerve fibres are found in cranial and spinal nerves.