NUR612 Exam 1: Pain Questions with Correct Answers 100% Verified By Experts| Latest
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What are Rexed Laminae organized areas in the spinal cord, primarily within the dorsal
horn, that correspond to specific types of sensory and motor nerves. These laminae serve as
distinct regions where different sensory and motor signals synapse, ensuring that information is
transmitted in a highly structured and predictable manner. The laminae play a key role in
processing and modulating sensory and motor information.
Ascending pain pathway: Nociceptors: Receptors in the periphery respond to heat, intense
cold, mechanical distortion, changes in pH, and chemical irritants (e.g., ADP, bradykinin,
serotonin, histamine)
Afferent nerve conduction → 1st-order neuron
Ascending pain pathway: Neuron cell bodies The cell bodies of 1st-order neurons are
located in the dorsal horn and dorsal root ganglia of the spinal gray matter (or trigeminal
ganglia)
Glutamate, SP, and CGRP are the main neurotransmitters released by primary afferents
Ascending Pain Pathway: 2nd-order neuron: After synapsing in the spinal cord, the 1st-order
neurons project to 2nd-order neurons
2nd-order neurons cross the midline at the anterior white commissure
These neurons then ascend to the thalamus via the contralateral spinothalamic tract, carrying
both pain and temperature sensations
Ascending pain pathway: Thalamus From the thalamus, the stimulus is sent to the
somatosensory cerebral cortex via fibers in the posterior limb of the internal capsule
Other thalamic neurons project to areas of the cortex associated with emotional responses
(e.g., cingulate gyrus, insular cortex)
, Descending pain pathways The hypothalamus and cortical regions process painful stimuli
and signal for the release of inhibitory mediators and hormones (e.g., opioid peptides,
norepinephrine, glycine, and GABA) that make pain suppression more effective → pain
modulation
Descrribe Visceral Pian Poorly localized
Unpleasant
Associated with nausea and autonomic symptoms
Visceral pain—Nociception Process 1. Nociceptor Activation: Nociceptors in the walls of
internal organs detect distention or inflammation, triggering receptor and action potentials.
2. Pain Characteristics: Pain intensity changes, being sharp during organ contractions (e.g.,
peristaltic movements in the intestines) and dull during relaxation.
3. Signal Transmission: Action potentials travel via afferent fibers through sympathetic and
parasympathetic nerves in the myenteric plexus.
4. Dorsal Horn: The signals reach the neural bodies in the dorsal (and cranial) nerve ganglia and
continue to the dorsal horn of the spinal cord.
5. Convergence-Projection: Visceral afferent fibers converge with somatic afferent fibers on the
same neurons in the dorsal horn. The signal is then sent to the thalamus and somatosensory
cortex.
6. Referred Pain: Pain is perceived in somatic structures that correspond to the somatic fibers
converging with the visceral fibers (e.g., heart attack pain referred to the left arm; ureteral pain
referred to the testicle in men).
7. Motor/Sudomotor Manifestations: Somatic structures related to the corresponding spinal
segment may show motor (muscle spasms) or sudomotor (sweating) responses, which are
Update Guaranteed Success
What are Rexed Laminae organized areas in the spinal cord, primarily within the dorsal
horn, that correspond to specific types of sensory and motor nerves. These laminae serve as
distinct regions where different sensory and motor signals synapse, ensuring that information is
transmitted in a highly structured and predictable manner. The laminae play a key role in
processing and modulating sensory and motor information.
Ascending pain pathway: Nociceptors: Receptors in the periphery respond to heat, intense
cold, mechanical distortion, changes in pH, and chemical irritants (e.g., ADP, bradykinin,
serotonin, histamine)
Afferent nerve conduction → 1st-order neuron
Ascending pain pathway: Neuron cell bodies The cell bodies of 1st-order neurons are
located in the dorsal horn and dorsal root ganglia of the spinal gray matter (or trigeminal
ganglia)
Glutamate, SP, and CGRP are the main neurotransmitters released by primary afferents
Ascending Pain Pathway: 2nd-order neuron: After synapsing in the spinal cord, the 1st-order
neurons project to 2nd-order neurons
2nd-order neurons cross the midline at the anterior white commissure
These neurons then ascend to the thalamus via the contralateral spinothalamic tract, carrying
both pain and temperature sensations
Ascending pain pathway: Thalamus From the thalamus, the stimulus is sent to the
somatosensory cerebral cortex via fibers in the posterior limb of the internal capsule
Other thalamic neurons project to areas of the cortex associated with emotional responses
(e.g., cingulate gyrus, insular cortex)
, Descending pain pathways The hypothalamus and cortical regions process painful stimuli
and signal for the release of inhibitory mediators and hormones (e.g., opioid peptides,
norepinephrine, glycine, and GABA) that make pain suppression more effective → pain
modulation
Descrribe Visceral Pian Poorly localized
Unpleasant
Associated with nausea and autonomic symptoms
Visceral pain—Nociception Process 1. Nociceptor Activation: Nociceptors in the walls of
internal organs detect distention or inflammation, triggering receptor and action potentials.
2. Pain Characteristics: Pain intensity changes, being sharp during organ contractions (e.g.,
peristaltic movements in the intestines) and dull during relaxation.
3. Signal Transmission: Action potentials travel via afferent fibers through sympathetic and
parasympathetic nerves in the myenteric plexus.
4. Dorsal Horn: The signals reach the neural bodies in the dorsal (and cranial) nerve ganglia and
continue to the dorsal horn of the spinal cord.
5. Convergence-Projection: Visceral afferent fibers converge with somatic afferent fibers on the
same neurons in the dorsal horn. The signal is then sent to the thalamus and somatosensory
cortex.
6. Referred Pain: Pain is perceived in somatic structures that correspond to the somatic fibers
converging with the visceral fibers (e.g., heart attack pain referred to the left arm; ureteral pain
referred to the testicle in men).
7. Motor/Sudomotor Manifestations: Somatic structures related to the corresponding spinal
segment may show motor (muscle spasms) or sudomotor (sweating) responses, which are
