Pain and Pain Theories

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Pain and Pain Theories
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Introduction

• What is pain?
• An unpleasant sensory and emotional experience
  associated with actual or potential tissue
  damage, or described in such terms as tissue
  damage

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Introduction

• Pain is subjective
• Does pain have a purpose?
• Types of Pain
• Acute Pain
• Chronic Pain
• Referred Pain
• Radiating

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Neurophysiology of Pain

• Afferent Peripheral Receptor Types
• Special Receptors
• Visceral Receptors
• Deep Receptors
• Superficial Receptors

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Afferent Peripheral Receptors

• Special
• Transmit taste, sight, smell
• Visceral Receptors
• Transmit hunger, distention, nausea
• Deep
• Kinesthesia, joint position sense, deep pressure
  and pain
• Muscle -- GTOs, muscle spindles
• Articular Structures fast and slow adapting
  mechanoreceptor and nociceptors

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Afferent Peripheral Receptors

• Superficial
• Warm/cold, touch, pressure, itch and pain from
  skin level
• 3 categories
• Mechanorecptors
• Thermoreceptors
• Nociceptors

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Mechanorecpetors

• Mechanical stimuli
• Touch, pressure, stroking

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Mechanorecpetors

• Mechanical stimuli
• Touch, pressure, stroking
• Fast-adapting Receptors
• Pacinian Corpuscles
• Meissner Cpropuscles
• Respond to pressure and touch very quickly

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Mechanorecpetors

• Mechanical stimuli
• Touch, pressure, stroking
• Fast-adapting Receptors
• Slow-adapting Receptors
• Merkel Cell Ending
• Ruffinni Endings
• Stimulated by sustained stimuli

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Thermoreceptors

• Respond to temp and temp changes
• Slow-adapting structures
• Warm vs cold receptor firing

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Nociceptors

• Transmit pain impulses
• Described as free nerve ending
• Stimulated by
• Mechanical
• Chemical
• Thermal

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What is the initial response to pain stimulus?
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Release of Chemical Mediators
Cell trauma

• Pain always begin with chemical response

Release dopamine and NE from Cell membrane
Activates phospholipase
Converted to prostaglandin or bradykinin
Release Arachidonic Acid