48 Somatic Sensations: II. Pain, Headache, and Thermal Sensations Dr. A.R. Jamshidi Fard 2011

Types of Pain Fast Pain –sharp pain –pricking pain –acute pain –electric pain Slow Pain –Burning pain –Aching pain –Throbbing pain –Nauseous pain –Chronic pain Three Types of Stimuli Excite Pain Receptors: »Mechanical »Thermal »Chemical Bradykinin, Serotonin, Histamine, Potassium, Ions, Acids, Acetylcholine, Proteolytic enzymes. + ( Prostaglandins - Substance P)

Threshold of Thermal Stimuli to Excite Pain Receptors Other causes of Pain Tissue Damage Tissue Ischemia Muscle Spasm

Dual Pathways for Transmission of Pain Signals into the Central Nervous System Capability of Pain Signals to Arouse Overall Brain Excitability

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

Visceral Pain True Visceral Pain - Ischemia - Chemical Stimuli - Spasm of a Hollow Viscus(cramps) - Overdistention of a Hollow Viscus “Parietal Pain” Caused by Visceral Disease

Referred Pain

Some Clinical Abnormalities of Pain and Other Somatic Sensations Herpes Zoster (Shingles) Hyperalgesia Tic Douloureux Brown-Séquard Syndrome

Some Clinical Abnormalities of Pain and Other Somatic Sensations Herpes Zoster (Shingles) Hyperalgesia Tic Douloureux Brown-Séquard Syndrome

Some Clinical Abnormalities of Pain and Other Somatic Sensations Herpes Zoster (Shingles) Hyperalgesia Tic Douloureux Brown-Séquard Syndrome

Some Clinical Abnormalities of Pain and Other Somatic Sensations Herpes Zoster (Shingles) Hyperalgesia Tic Douloureux Brown-Séquard Syndrome

Headache Headache of Intracranial Origin –Meningitis - Low Cerebrospinal Fluid Pressure – Migraine – Alcohol –Constipation Extracranial Types of Headache –Muscle Spasm - Irritation of Nasal and Accessory Nasal Structures - Eye Disorders Areas of the Head to Which Intracranial Headache Is Referred.

Inhibition of Pain Transmission by Simultaneous Tactile Sensory Signals TENSTENS ranscutaneus electrical erve timulation

Thermal Sensations Receptors: - Cold receptors - Warmth receptors -Pain receptors “freezing cold” “burning hot” Centers: -Reticular areas of the brain stem -Ventrobasal complex of the thalamus