Its giving the brief idea about the various widely accepted classification details. Also mentioned about the protein synthesis and metabolism in the nerve fibers

1. NERVE

2. Protein Synthesis
- Soma have ribosomes & Golgi apparatus.
- Axons do not have these organelles, hence all the protein
synthesis including neurotransmitters occurs in the cell body.
- It is then transported along the axon to the synaptic knobs by
axoplasmic flow.
Metabolism & Heat Production
- Metabolism occurs at low rate.
- 70% of total energy require is used to maintain the polarization
of the membrane by Na+- K+ ATPase.
- Main energy sources are sugars & phospholipids.
- Heat is produced as Resting heat, Initial heat & Delayed or
recovery heat.

3. Nerve Fiber Types
1) Depending on Myelin sheath
Medullated/ Myelinated
Unmedullated/ Unmyelinated
2) Depending upon their origin
- Cranial nerve
- Spinal nerve
3) Depending upon the neurotransmitter secreted
- Cholinergic
- Adrenergic
- Dopaminergic

4. 4) Depending upon the distribution of supply
- Somatic nerves:- Supplying the skeletal muscles
- Visceral/ Autonomic:- Supplying the viscera/ internal
of the body.
5) Erlanger & Gasser Classification (Letter
classification)
- Based on diameter & the conduction velocity of the nerve
fibers.
- Fiber type A, B & C.
- A & B fibers are myelinated; C fibers are unmyelinated.

5. Fiber
Type Function
Fiber
Diameter
(μm)
Conduction
Velocity
(m/s)
Spike
Duration
(ms)
Absolute
Refractory
Period (ms)
A
α Proprioception;
somatic motor
12-20 70-120
0.4-.0.5 0.4-1
β Touch, pressure,
motor
5-12 30-70
γ Motor to Muscle
Spindle
3-6 15-30
δ Pain, cold, touch 2-5 12-30
B Preganglionic
autonomic
< 3 3-15 1.2 1.2
C
Dorsal
root
Pain, Temperature,
mechanoreception,
reflex response
0.4-1.2 0.5-2 2 2
Sympa
thetic
Postganglionic
Sympathetic
0.3-1.3 0.7-2.3 2 2

6. 6) Numerical/ Sensory classification
- Sometimes used for sensory neurons.
- Based on the origin of nerve fibers.
Number Origin Fiber Type
Ia Muscle spindle, Annulospiral ending Aα
Ib Golgi tendon organ Aα
II Muscle spindle secondary ending,
kinaesthesia, touch, pressure
Aβ
III Pain & temperature receptors; crude
touch & pressure receptors
Aδ
IV Pain, touch, pressure, temperature Dorsal root “C”
fibers

7. 7) Physio-clinical classification
- Depending upon the relative susceptibility of mammalian
A, B and C nerve fibers to conduction block produced by
various agents;
Susceptibility Most
susceptible
Intermediate Less susceptible
Sensitivity to
‘Hypoxia’
B A C
Sensitivity to
‘Pressure’ A B C
Sensitivity to
‘Local
Anesthetics'
C B A

8. Thank you