Components of Pain
There are two components of pain. These are the physical sensation of pain and
the psychological component. The physical sensation of pain occurs when nerve
endings are stimulated causing it to send an impulse along the nerve pathways
to the brain, which transmits a pain response.
The psychological component is a person’s emotional response to pain based
on a person’s pain threshold. The pain threshold is the level of nerve-ending
stimulation that causes the person to have the feeling of unbearable pain.
For example, applying heat to the skin will cause the sensation of pain.
However, the point beyond which pain becomes unbearable (pain tolerance)
varies widely among individuals. Pain tolerance is also different for the same
person depending on the circumstance in which sensation is detected. For exam-
ple, a toothache might hurt more when you’re home than at work where you
have a lot of distractions from the pain.
The Gate Control Theory
The gate control theory is an attempt to describe the mechanism of pain trans-
mission. The dorsal horn of the spinal cord contains a gate mechanism that alters
the transmission of painful sensations from peripheral nerve fiber to the thala-
mus and cortex of the brain. The thalamus and the cortex is where painful sen-
sations are recognized as pain.
The transmission flows through the gate mechanism. The gate is closed by
large diameter, low-threshold afferent fibers and is opened by small diameter,
high-threshold afferent fibers. In addition to these two sets of fibers, the gate is
also influenced by descending control inhibition from the brain to close the gate.
When the patient experiences slower-acting painful stimuli, the large-diameter
fibers are stimulated. This causes the gate to close, stopping transmission of the
painful stimuli.
Nonpharmacological pain relief treatments, such as a massage, are based on
the gate control theory to ease the patient's pain.
Defining Pain
Pain is whatever the patient who is experiencing pain says it is. Healthcare
providers describe pain in terms of intensity, duration, frequency, and type of
pain. However, these terms are subjective and characterized by the patient.
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