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Questions and Answers
What characterizes somatic pain compared to visceral pain?
What characterizes somatic pain compared to visceral pain?
What type of pain is typically felt first in response to a stimulus?
What type of pain is typically felt first in response to a stimulus?
Which of the following sensations is typically associated with slow pain?
Which of the following sensations is typically associated with slow pain?
Which nerve fibers are primarily associated with fast pain?
Which nerve fibers are primarily associated with fast pain?
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What is an example of cutaneous pain?
What is an example of cutaneous pain?
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What type of nerve fibers carry fast pain sensations?
What type of nerve fibers carry fast pain sensations?
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What characterizes visceral pain?
What characterizes visceral pain?
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Which of the following is a common cause of visceral pain associated with inflammation?
Which of the following is a common cause of visceral pain associated with inflammation?
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What phenomenon describes pain perceived at a site adjacent to the actual site of injury?
What phenomenon describes pain perceived at a site adjacent to the actual site of injury?
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Which substances can stimulate pain receptors during ischemia?
Which substances can stimulate pain receptors during ischemia?
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What does the convergence-projection theory explain about referred pain?
What does the convergence-projection theory explain about referred pain?
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Which of the following structures is NOT part of the descending analgesic pathway?
Which of the following structures is NOT part of the descending analgesic pathway?
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What roles do the neurotransmitters released by the analgesic pathway play in pain transmission?
What roles do the neurotransmitters released by the analgesic pathway play in pain transmission?
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How does the gate control theory propose to block pain stimuli at the spinal level?
How does the gate control theory propose to block pain stimuli at the spinal level?
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Which type of afferent fiber is involved in the synapses of the afferent pain pathway?
Which type of afferent fiber is involved in the synapses of the afferent pain pathway?
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Flashcards
Cutaneous pain
Cutaneous pain
Pain originating from the skin and subcutaneous tissues, characterized by a sharp, burning quality and easy localization.
Deep somatic pain
Deep somatic pain
Pain originating from deeper structures like tendons, muscles, and joints, often more diffuse and less easily localized.
Visceral pain
Visceral pain
Pain originating from internal organs and tissues within the chest or abdominal cavities, often described as a dull or aching sensation and difficult to pinpoint exactly.
Fast pain
Fast pain
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Slow pain
Slow pain
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Free Nerve Ending
Free Nerve Ending
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Pain Pathway
Pain Pathway
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Referred Pain
Referred Pain
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A-delta Fibers
A-delta Fibers
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Convergence-projection theory of referred pain
Convergence-projection theory of referred pain
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Convergence of visceral and somatic afferents
Convergence of visceral and somatic afferents
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Analgesic pathway
Analgesic pathway
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Origin and termination points of the analgesic pathway
Origin and termination points of the analgesic pathway
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Neurotransmitters involved in the analgesic pathway
Neurotransmitters involved in the analgesic pathway
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Study Notes
Physiology of Pain
- Pain is an unpleasant sensation triggered by tissue damage.
- The body reacts to pain stimuli to remove the cause.
- Pain can be categorized as somatic or visceral.
Somatic Pain
- Cutaneous pain (superficial): Located in the skin and subcutaneous tissues. Examples include pinpricks, and burns. Pain is sharp, easily localized.
- Deep somatic pain: Located in deeper structures including muscles, tendons, joints, periosteum, and blood vessels. Pain is often more diffuse than cutaneous pain, and can result from pressure, ischemia, or tissue damage.
Visceral Pain
- Located in the organs and tissues within the thoracic and abdominal cavities.
- Can be difficult to pinpoint since it is often widespread and not precisely localized.
- Frequently accompanied by autonomic nervous system responses like nausea, vomiting, sweating, pallor, raised blood pressure.
Types of Pain
- Fast pain: Felt almost immediately (within 0.1 seconds) after a stimulus. Often felt as sharp, prickling pain. It is usually limited to superficial parts of the body.
- Slow pain: Develops slowly after the stimulus. More diffuse and can lead to prolonged, intense, or even unbearable suffering. It can be associated with tissue damage or destruction. It can affect any part of the body.
- Fast pain is usually carried by myelinated A-delta fibers.
- Slow pain is carried by unmyelinated C fibers.
Types of Pain Receptors
- Free nerve endings: These receptors can detect mechanical, thermal, or chemical changes. They do not adapt, meaning they continue to send signals as long as the stimulus persists.
Types of Nerve Fibers
- A table with fiber types, subtypes, radii (µm), and conduction velocities (m/s) is presented.
Pain Pathway
- Afferent nerve fibers carry pain signals differently
- Fast pain signals carried by A-delta fibers (myelinated)
- Slow pain signals carried by C fibers (unmyelinated)
- Painful stimulation releases substance P or glutamate from afferent fibers in the dorsal horn of the spinal cord.
- The signals are relayed to the somatosensory cortex.
Referred Pain
- Pain perceived in a location other than the site of the actual injury.
- An example is chest pain during a heart attack being felt in the arm, shoulder, or back.
- The convergence-projection theory explains it. Afferent signals from visceral and somatic areas converge on the same neurons. This leads to the brain misinterpreting the location of the pain source.
Analgesic Pathway
- Analgesic pathway interferes with pain transmission.
- It's a descending pain pathway.
- Afferent pain fibers transmit pain signals to the brain
- Fibers originate from the frontal lobe of the cerebral cortex and hypothalamus.
- They terminate in the (periaqueductal gray matter).
- Fibers descend to the brainstem, ending on nuclei (nucleus raphe magnus, nucleus reticularis, paragigantocellularis).
- These fibers synapse with neurons and inhibit pain signals from the spinal cord.
Neurotransmitters (Analgesic Pathway)
- Substances involved in the analgesic pathway include serotonin and opiate receptor substances such as enkephalin, dynorphin, and endorphin.
Gate Control Theory
- Pain stimuli transmitted by afferent pain fibers are blocked by a gate mechanism.
- The gate mechanism involves the interplay of touch and pain receptors in the spinal cord.
- Touch impulses inhibit the release of pain transmitting substances (e.g., glutamate, substance P).
- The activation of touch sensory receptors closes the gate, modulating pain transmission.
Significance of Gate Control
- Similar to presynaptic inhibition in the spinal cord.
- Based on various techniques that may stimulate the release of endogenous pain relievers (e.g., opioid peptides) to block pain signals.
- This can help in pain relief through various techniques like rubbing, ice packs, etc.
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Description
Test your understanding of the physiology of pain, including its definitions, types, and classifications. Explore the differences between somatic and visceral pain, as well as the body's responses to pain stimuli. This quiz will help solidify your knowledge of how pain functions in the human body.
