Question

med surge CH 8

1. Define Pain

2. Explain the physiologic basis for pain.

Answer 1

1. Whatever the person experiencing Bheem says it is, existing whenever the person says it does.
Marg McCaffery
An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in in terms of such damage.
The International Association for the Study of Pain (IASP)

2. Physiology of Pain

The physiology of pain includes genetics, anatomy and physical determinants of pain.

PAIN MECHANISM

Nociception is the physiologic process by which information about tissue damage is communicated to the central nervous system.

The Process of Nociception
This process involves four stages;

• transduction
• transmission
• perception
• modulation

TRANSDUCTION

It is the conversion of mechanical thermt or chemical stimulus into a neural action potential.
•Noxius stimuli courses cell damage with the release of sensitizing chemicals.
postaglandin, histamine, serotonin etc
• this substances activate nociceptors and lead to generation of action potential.

TRANSMISSION

Action potential continues from
• site of injury to spinal cord
• spinal cord to brainstorm and thalamus
• thalamus to cortex for processing

PERCEPTION

Perception occur when pain is recognized defined and responded to b youy the individual experience the pain.
• in the brain nociceptive input is perceived as pain.
• pain perception involves several brain structures.
• example - Reticular activating system, anterior central gyrus

MODULATION

Neurons originating in the brainstem descend to the spinal cord and release substances that inhibit nociceptive impulse.
Chemicals include- nor epinephrine, endogenous opioids, GABA etc.