Source - Guyton and Hall, Physiology

1. Dr. Anupam Mittal
MBBS, MD
King George’s Medical University, Lucknow

2. Pain is an,
unpleasant sensory and emotional
experience associated with actual or
potential tissue damage

3. NOCICEPTION
The peripheral nervous system includes
sensory neurons specialised to detect tissue
damage and to evoke the sensation of touch,
heat, cold, pain and pressure.
The receptors that transmit pain sensation are
called Nociceptors.

4. Nociceptor ( from Peripheral )  Brain (CNS)

5. TRANSMISSION OF PAIN
1) Transduction
2) Transmission
3) Perception
4) Modulation

7. FAST
 Due to activity of myelinated alpha fibres
 It is elicited by mechanical and thermal type of stimuli
 Sharp bright and localised sensation
SLOW
 Due to activity of un-myelinated C fibres
 Dull and more diffuse

8. By Source
1. Superficial Pain –
Arising from Skin and mucous membrane
2. Deep (Somatic Pain/ Deep Pain) –
Arising from somatic structure – Deep to skin
3. Visceral pain -
Arising from different internal organs or viscera

9. •Ischemia
•Chemical Stimuli
•Spasm of hollow organs
•Overdistension of hollow organs

10. •The pain sensation produced in some part of the
body is felt in other structures away from the place
of development.
•The deep pain and some visceral pain are referred to
other areas but superficial pain is not referred.