Nociception and Pain Response

Nociception

Definition: Nociception is the process by which the body detects and responds to painful stimuli.

Types of Nociceptors:

• Mechanoreceptors: respond to mechanical stimuli, such as pressure and vibration
• Thermoreceptors: respond to temperature changes
• Polymodal receptors: respond to multiple types of stimuli, including mechanical, thermal, and chemical

Nociceptor Activation:

• Threshold: the minimum intensity of stimulation required to activate a nociceptor
• Transduction: the conversion of a stimulus into an electrical signal
• Transmission: the transmission of the electrical signal to the spinal cord and brain

Neurotransmitters Involved in Nociception:

• Substance P: released by nociceptors, plays a key role in transmitting pain signals
• Glutamate: released by nociceptors, enhances pain transmission
• ** Bradykinin**: released by tissue damage, stimulates nociceptors

Pain Pathways:

• Spinothalamic tract: the primary pathway for pain transmission from the spinal cord to the brain
• Spinoreticular tract: a secondary pathway for pain transmission, involved in emotions and motivation

Modulation of Nociception:

• Inhibition: the reduction of pain transmission through mechanisms such as descending inhibition and opioid receptors
• Facilitation: the enhancement of pain transmission through mechanisms such as wind-up and central sensitization

Nociception

• Nociception is the process by which the body detects and responds to painful stimuli.

Types of Nociceptors

• Mechanoreceptors respond to mechanical stimuli, such as pressure and vibration.
• Thermoreceptors respond to temperature changes.
• Polymodal receptors respond to multiple types of stimuli, including mechanical, thermal, and chemical.

Nociceptor Activation

• The minimum intensity of stimulation required to activate a nociceptor is known as the threshold.
• Transduction is the conversion of a stimulus into an electrical signal.
• Transmission refers to the transmission of the electrical signal to the spinal cord and brain.

Neurotransmitters Involved in Nociception

• Substance P is released by nociceptors and plays a key role in transmitting pain signals.
• Glutamate is released by nociceptors and enhances pain transmission.
• Bradykinin is released by tissue damage and stimulates nociceptors.

Pain Pathways

• The spinothalamic tract is the primary pathway for pain transmission from the spinal cord to the brain.
• The spinoreticular tract is a secondary pathway for pain transmission, involved in emotions and motivation.

Modulation of Nociception

• Inhibition is the reduction of pain transmission through mechanisms such as descending inhibition and opioid receptors.
• Facilitation is the enhancement of pain transmission through mechanisms such as wind-up and central sensitization.