VISCERAL SENSATION

Question 1

List all types of pain and explain for each type of pain

Answer 1

1. Fast pain
   > Pain that is felt less than 0.1s after the pain stimulus is applied
   > Also known as first pain
2. Slow pain
   > Pain that is occur after fast pain
   > Also known as second pain
   > Dull diffuse intense unpleasant feeling
   > Example: feeling sore at the whole thumb area after it is pricked by a needle
3. Cutaneous/ superficial pain
   > Pain that occur at the skin
4. Deep pain
   > Pain coming from the deep tissues such as bones, ligaments, tendons, skeletal muscle
5. Visceral pain
   > Pain coming from the visceral organ
   > Visceral is the internal organ of the body such as stomach and heart
6. Acute pain
   > Sudden onset, usually the result of a clearly defined cause such as an injury or infection and usually resolves with the healing of its underlying cause
7. Chronic pain
   > Persists for weeks or months and is usually associated with an underlying condition, such as inflammation like arthritis or neuropathic pain

Question 2

State the definition of pain

Answer 2

Pain is an unpleasant sensory and emotional experience that associated with actual or potential damage of tissue. It has protective purpose or function to the body where pain will warn the body about the actual or potential injury

Question 3

What is referred pain?

Answer 3

> Referred pain is pain that actually coming from/ originates from the visceral organ is referred to an area of the body surface.
Pain that is not felt in the organ but felt in the somatic structure (other organ)

Question 4

Give 3 examples of referred pain

Answer 4

1. Cardiac pain is referred to the left shoulder, inner aspect of left arm, tip of fingers
2. Diaphragmatic pain is referred to the shoulder area
3. Ovarian pain is referred to the lower abdominal area

Question 5

What is the difference of A(delta) and C fibers?

Answer 5

A(delta) fibers are myelinated and has small diameter. Due to the presence of myelin, the conduction velocity is rapid. A(delta) fibers respond to mechanical and also thermal stimuli. It is an initial reflex response to acute pain and the NT is glutamate

While, C fibers are unmyelinated and has small diameter. Due to the absent of myelin, the conduction velocity is slow. It is the smallest type of primary afferent fiber. Polymodal respond to chemical, mechanical as well as thermal stimuli. Since the conduction velocity is slow, activition of C fibers causes slow, burning pain. The NTs are glutamate and substance P

Question 6

Explain the neospinothalamic tract

Answer 6

> Neospinothalamic tract for fast pain
The A(delta) fibers will be terminate in the lamina I in the dorsal horn.
The glutamate which is the NT are release
This causes the second order neurone to be excited
The second order neurone cross over immediately to the opposite side of the cord and travel upwards to the brain in anterolateral pathway.
The fibers pass onto the ventrobasal complex of the thalamus along with the dorsal column-medial lemniscal tract for tectile sensation
This is to help with localisation of the fast pain

Question 7

Explain the paleospinothalamic tract.

Answer 7

> Paleospinothalamic tract for slow pain
The type C fibers carrying the slow pain are terminate in the lamina II and III of dorsal horn.
Glutamate and substance P are release as their NTs
Most of the signals pass through one or more additional short fiber neurons within the dorsal horn before they enter the lamina V of the dorsal horn.
They cross over immediately to the opposite side of the cord and travel upwards to the brain in anterolateral pathway

Question 8

What can influence the pain modulation?

Answer 8

> By neuron within spinal cord
By neuron or substances within the area of somatosensory region
via descending pathway
at the site of receptors

Question 9

What is gate control theory?

Answer 9

> Gate control theory states that:
Ascending nociceptive signals can be suppressed by the activity of inhibitory interneurons that function as gates to decrease the transmission by the second order neurons
As for example:
Rubbing the area that hurts stimulates mechanoreceptor
These mechanoreceptors will send signal along the A(beta) fibers that stimulate inhibitory interneurons that in turn inhibit the signalling in the second order neuron.
Inbiting the second order neuron will stop the pain signal from being send to the brain for interpretation.

Question 10

What is the function of inhibitory interneuron?

Answer 10

To reduce the transmission of second order neuron so that pain sensation can be reduced

Question 11

Why rubbing the pain area can make you feel better?

Answer 11

> During unmodulated pain, stimulation of pain receptors activates C fiber.
This causes the excitation of second order neuron.
The excitation of second order neuron leads to inhibition of inhibitory interneuron.
Hence, the nociceptive receptor will send the information to the thalamus then to the brain for interpretation.
The brain will interpret and send information on the action to the damaged tissues to feel pain
However, when we rub on the pain area, it will activate mechanoreceptor which also going to activate A(beta) fiber.
Since the A(beta) fiber is activated, it will stimulate the inhibitory interneurone.
The activation of inhibitory interneurone causes the activation of second order to be reduced
Reduced second order neuron leads to decreasing flow of nociceptive signals
Hence, the pain sensation is reduced and feels better.

Question 12

State 2 NTs acting at inhibitory interneurones

Answer 12

Glycine, gamma- aminobutyric acid (GABA)

Question 13

What does it mean convergence theory?

Answer 13

> The first order neuron supplying both the visceral afferent as well as the somatic sensory nerve of the same dermatome converge onto the same second order neuron in the dorsal horn
Somatic pain is really common
The visceral pain is interpreted as somatic pain originating from the nerve by the brain

Question 14

What does it mean facilitation theory?

Answer 14

> The visceral irritation is inadequate for producing pain by itself
However, there are collateral connections from visceral afferents to the dorsal horn neurons receiving pain impulses from the somatic structure
Increased in the visceral afferents lead to an increase in the excitation of neurons from somatic structure

Question 15

Where can we find convergence theory and facilitation theory?

Answer 15

During referred pain

Question 16

Pain can be modulated by…..

Answer 16

Analgesics and anesthetics

Question 17

What is analgesia?

Answer 17

Analgesia is pain relief without loss of consciousness and without total loss of feeling or movement

Question 18

What is anesthesia?

Answer 18

Anesthesia is the loss of physical sensation with or without loss of consciousness

Question 19

What is the example of opiate analgesia

Answer 19

Morphine, heroin

Question 20

List 3 examples of endogenous opioids

Answer 20

Endorphin
Enkephalin
Dynorphin

Question 21

What is endogenous opioids

Answer 21

Endogenous opioids is internally produce molecules with opioids like action which regulate the transmission of nociceptive signals

Question 22

Where we can found:

1. Endorphins
2. Enkephalins
3. Dynorphins

Answer 22

1. In the hypothalamus and pituitary gland
2. In the brain stem and spinal cord
3. In the brain stem and spinal cord but in lesser amount

Question 23

Where we can find the nerve cells with endogenous opioids receptors?

Answer 23

In spinal cord, medulla, periaduqductal gray matter (PAG)

Question 24

How the transmission of nociceptive signals are regulated?

Answer 24

By:

1. Blocking the NTs released by inhibiting the Ca2+ influx into the presynaptic terminal
2. Opening the potassium channels so hyperpolarisation happened

Question 25

Describe the mechanism of endogenous opioids

Question 26

What is hyperalgesia?

Answer 26

Hyperalgesia is a condition of increased sensitivity to pain, when the magnitude of the response to a nociceptive stimulus is higher than normal

Question 27

List cause of hyperalgesia?

Answer 27

1. Excessive sensitivity of the pain receptors

2. Facilitation of sensory transmission

Question 28

What is the example of excessive sensitivity of the pain receptors?

Answer 28

Extreme sensitivity of sunburned skin, which result from sensitization of the skin pain endings by local tissue products such as histamine and prostaglandin

Question 29

What is opioid- induced hyperalgesia?

Answer 29

increased pain sensitivity after taking opioids such as heroin, morphine and fentanyl

Question 30

What is the allodynia?

Answer 30

> Allodynia is a condition when normally non-painful stimuli cause pain such as touch, light pressure and cold.
It involves changes in the synaptic sensitivity of the nociceptive neurons in the spinal cord now become responsive to non-noci stimuli

Question 31

List the type of allodynia?

Answer 31

1. Static (tactile) allodynia
2. Dynamic (mechanical) allodynia
3. Thermal allodynia

Question 32

What is static allodynia?

Answer 32

Static allodynia is the pain that result from an object moving across the skin such as when putting on a shirt, wear glasses or putting head on a pillow.

Question 33

What is dynamic allodynia?

Answer 33

Dynamic allodynia is the pain that results from gentle touch or pressure such as touching a person’s hand, running a brush through hair, water falling on the head in the shower

Question 34

What is thermal allodynia?

Answer 34

Thermal allodynia is the pain that results from mild changes in temperature such as breathing in cold air.

Question 35

State the f(x) of thalamus

Answer 35

Functions of thalamus are:

1. sensory integration and relay station for all the sensory pathway except olfactory
2. recognition of pain, temperature and touch
3. influences voluntary movement by receiving impulses from basal ganglia and cerebellum and relay them to motor cortex
4. maintenance of state of wakefulness and alertness through reticular-activating system (RAS)
5. involves in emotion and memory

Question 36

What does it mean Dejerine Roussy syndrome? Explain.

Answer 36

Dejerine Roussy syndrome also known as thalamic syndrome. It is due to the thrombosis of the posteriror cerebral artery supplying the posteroventral portion of the thalamus causing thalamic stroke and degeneration of the nuclei in this area.

The symptoms of the thalamic syndrome are loss of sensation, difficulties with movement or maintaining balance, speech difficulties, vision loss or disturbance, sleep disturbances, lack of interest or enthusiasm, changes in attention span, memory loss, and thalamic pain.

Thalamic pain also called as central pain syndrome which involves burning or freezing sensations in addition to intense pain usually in the head, arms or legs.

Question 37

List 5 signs of Dejerine Roussy syndrome.

Answer 37

1. Loss of sensation
2. Difficulties with movement or maintaining balance
3. Speech difficulties
4. Vision loss
5. Sleep disturbances

Question 38

What factor that can lead to post-stroke brain?

Answer 38

Any lesion that disrupts the spinothalamic tract through its course

Question 39

What is phantom pain and causes it to happen?

Answer 39

Phantom pain is the perception that a limb that has been removed or amputates is still present in the body. Patients with amputation often have burning or tingling pain in the body part removed.

It is caused when the nerve fibers at the stump are stimulated and the brain interprets the signals as originating in the amputated portion. It is also maybe caused due to rearrangement within the cortical areas so that area for example the hand now responds to signals from other parts of the body but still interprets them as coming from the amputated hand.

Question 40

List the possible caused of phantom pain.

Answer 40

1. nerve fibers at the stump are stimulated and the brain interprets the signals as the originating in the amputated portion
2. rearrangement within the cortical areas so that area for example the hand now responds to signals from other parts of the body but still interprets them as coming from the amputated hand