Assignment No 1:

29/09/13

“How pain is transmitted and perceived?
What pain controlling strategies are used by physical
...
Neural Factors
Neurotransmitters:
These are the Chemical substances that allow nerve impulses to move from
one neuron to o...
Descending Neurons:
 Transmit impulses from the brain (corticospinal tract in the cortex) to
the spinal cord (lamina)
 P...
PAIN TRANMISSION
The transmission process occurs in three stages. The pain impulse is
transmitted:
 from the site of tran...
“Pain Gate Theory”
Gate control theory was described by Melzack and Wall in 1965.
This theory explains about a pain-modula...
PAIN CONTROLLING STRATIGIES BY PHYSICAL THERAPIST
Pain controlling strategies used by a physical therapist involves the us...
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Pain perception , transmission, control & role of physical therapist

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An assignment on what is pain? how it is perceived, transmitted & controlled. what is role of a physical therapist to control pain.

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Pain perception , transmission, control & role of physical therapist

  1. 1. Assignment No 1: 29/09/13 “How pain is transmitted and perceived? What pain controlling strategies are used by physical therapist?” PAIN: “An unpleasant sensory & emotional experience associated with actual or potential tissue damage, or described in terms of such damage” Physiological response produced by activation of specific types of nerve fibers Experienced because of nociceptors being sensitive to extreme mechanical, thermal, & chemical energy. Composed of a variety of discomforts Behavioral indicators of pain are crying, mood changes and from facial expression. One of the body’s defense mechanism Pain Sources: Fast Pain: Fast pain is transmitted through the A-delta neurons in the skin. These are the mylinated neurons can transmit the impulse with rate of 40 pulses /sec. Slow Pain: slow pain is transmitted via C fibers (unmylinated) , carry impulse 15 pulse /sec.
  2. 2. Neural Factors Neurotransmitters: These are the Chemical substances that allow nerve impulses to move from one neuron to other, found in synapses. “Substance P - thought to be responsible for the transmission of painproducing impulses” First Order Neuron: These are stimulated by sensory receptors in the skin. End in the dorsal horn of spinal chord A-alpha – non-pain impulse A-beta – non-pain impulse: Large, myelinated. Low threshold mechanoreceptor; respond to light touch & low-intensity mechanical response A-delta – pain impulses  due to mechanical pressure  Large diameter, thinly myelinated  Short duration, sharp, fast, bright, localized sensation (prickling, stinging, burning) C – pain impulses : due to chemicals or mechanical  Small diameter, unmyelinated Second Order Neurons: Receive impulses from the FON in the dorsal horn. Second order neurons then send their information via two pathways to the thalamus: the dorsal column medial-lemniscal system and the anterolateral system. The first is reserved more for regular non-painful sensation, while the lateral is reserved for pain sensation.
  3. 3. Descending Neurons:  Transmit impulses from the brain (corticospinal tract in the cortex) to the spinal cord (lamina)  Periaquaductal gray area (PAG) – release enkephalins  Nucleus Raphe Magnus (NRM) – release serotonin  The release of these neurotransmitters inhibit ascending neurons “Enkephalins” are endogenous opiod peptides produced by the body in response to painful stimuli.
  4. 4. PAIN TRANMISSION The transmission process occurs in three stages. The pain impulse is transmitted:  from the site of transduction along the nociceptor fibres to the dorsal horn in the spinal cord;  from the spinal cord to the brain stem;  through connections between the thalamus, cortex and higher levels of the brain. The pain impulse is transmitted from the spinal cord to the brain stem and thalamus via two main nociceptive ascending pathways. These are the spinothalamic pathway and the spinoparabrachial pathway. The brain does not have a discrete pain centre, so when impulses arrive in the thalamus they are directed to multiple areas in the brain where they are processed. PERCEPTION OF PAIN Perception of pain is the end result of the neuronal activity of pain transmission and where pain becomes a conscious multidimensional experience. The multidimensional experience of pain has affectivemotivational, sensory-discriminative, emotional and behavioural components. When the painful stimuli are transmitted to the brain stem and thalamus, multiple cortical areas are activated and responses are elicited. MODULATION OF PAIN: The modulation of pain involves changing or inhibiting transmission of pain impulses in the spinal cord. The multiple, complex pathways involved in the modulation of pain are referred to as the descending modulatory pain pathways (DMPP) and these can lead to either an increase in the transmission of pain impulses (excitatory) or a decrease in transmission (inhibition).
  5. 5. “Pain Gate Theory” Gate control theory was described by Melzack and Wall in 1965. This theory explains about a pain-modulating system in which a neural gate present in the spinal cord can open and close thereby modulating the perception of pain. The gate control theory suggested that psychological factors play a role in the perception of pain. The three systems located in the spinal cord act to influence perception of pain, viz;  the substantia gelatinosa in the dorsal horn,  the dorsal column fibers, and  the central transmission cells. The noxious impulses are influenced by a “gating mechanism.” Stimulation of the large-diameter fibers inhibits the transmission of pain, thus “closing the gate.” Whereas, when smaller fibers are stimulated, the gate is opened. When the gate is closed signals from small diameter pain fibers do not excite the dorsal horn transmission neurons. When the gate is open pain signals excite dorsal horn transmission cells. The gating mechanism is influenced by nerve impulses that descend from the brain. Factors which influence opening and closing the gate are:  The amount of activity in the pain fibers.  The amount of activity in other peripheral fibers  Messages that descend from the brain.
  6. 6. PAIN CONTROLLING STRATIGIES BY PHYSICAL THERAPIST Pain controlling strategies used by a physical therapist involves the use of physical agents,(electrotherapy )and exercise therapy .. Physical agents involve manual therapy,mechanical therapy, hot and cold packs, TENs , interferential therapy etc .This method remove stress from nociceptors thus decreasing the stimuli of pain. Other Exercises involves deep breathing and progressive muscle relaxation exercise and mobilization techniques thus stimulating mechanoreceptors that inhibit pain transmission. _______________________ END ________________________ To: Dr.Huma By: Tahir Ramzan Cms 3855

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