Pain

pain

1. PAIN

2. Types of Pain
•Fast pain
–felt within about 0.1 second after a pain
stimulus is applied
•Slow pain
–begins only after 1 second or more and then
increases slowly over many seconds and
sometimes even minutes

3. Fast pain
‒sharp pain, pricking pain, acute pain, and
electric pain
‒not felt in most deeper tissues of the body
‒elicited by the mechanical and thermal
types of stimuli
‒transmitted in the peripheral nerves to the
spinal cord by small type Aᵟ fibers at
velocities between 6 and 30 m/sec

4. Slow pain
‒slow burning pain, aching pain, throbbing
pain, nauseous pain, and chronic pain
‒associated with tissue destruction
‒can lead to prolonged, unbearable suffering
‒occur both in the skin and in almost any deep
tissue or organ
‒elicited by mechanical, thermal, and chemical
pain stimuli.
‒transmitted to the spinal cord by type C
fibers at velocities between 0.5 and 2 m/sec

5. Dual Pain Pathways in the Cord
and Brain Stem
•Neospinothalamic Tract for Fast Pain.
•Paleospinothalamic Pathway for
Transmitting Slow-Chronic Pain.

6. glutamate
glutamate
substance P

8. Pain Suppression (“Analgesia”) System
in the Brain and Spinal Cord

9. REFERRED PAIN
branches of visceral pain fibers are shown to synapse in the
spinal cord on the same second-order neurons (1 and 2) that
receive pain signals from the skin

10. Causes of True Visceral Pain
•ischemia of visceral tissue
•chemical damage to the surfaces of the
viscera
•spasm of the smooth muscle a hollow
viscus
•excess distention of a hollow viscus
•stretching of the connective tissue
surrounding or within the viscus.

11. “Parietal Pain” Caused by
Visceral Disease
•When a disease affects a viscus, the
disease process often spreads to the
parietal peritoneum, pleura, or
pericardium
•extensive pain innervation from the
peripheral spinal nerves
•pain from the parietal wall overlying a
viscus is frequently sharp

12. Localization of Visceral Pain
•Visceral Pathways
•Parietal Pathway