GLOSSARY
A-delta fibers: The fast-conducting, myelinated nerve fibers that transmit pain and
temperature signals. Produces the initial burst of bright pain sensation.
Acute Pain: Pain that comes on quickly, can be severe, but lasts a relatively short time.
Amygdala: A critical processor area of the senses located in the middle of the brain.
Connected to the hippocampus, the amygdala plays a role in emotion laden
memories.
Autonomic Nervous System: the part of the nervous system of vertebrates that
controls involuntary actions of the smooth muscles and heart and glands.
C fibers: The slow-conducting nerve fibers which are unmyelinated and most often
postganglionic sympathetic fibers, meaning on the back of ganglionic nerves
located along the spinal cord. Responsible for the longer lasting nagging pain
sensation.
Central Nervous System (CNS): The central nervous system is composed of the brain
and spinal cord.
Chronic Pain: Pain (an unpleasant sense of discomfort) that persists or progresses over a
long period of time. In contrast to acute pain that arises suddenly in response to a
specific injury and is usually treatable, chronic pain persists over time and is often
resistant to medical treatments.
DNA: A nucleic acid that carries the genetic information in the cell.
Endorphin: An opioid (morphine-like) chemical produced by the body to suppress
pain. Produced in the brain, spinal cord and other parts of the body, endorphins
are released to serve the body as a natural painkiller.
Leucotrienes: A neurotransmitter.
Limbic System: A group of neural structures including the olfactory cortex, the amygdale,
the hippocampus, the piriform cortex and the entorhinal cortex. The limbic system
is involved in memory and emotion.
Neurotransmitter: A chemical substance used in neuronal communication at synapses.
Nociceptor: Sensory neuron receptors that lie in the tissue sheath that
surrounds the muscles of the cutaneous layer. Nociceptors are also located in the
cornea and mucosa (mucous membranes lining cavities such as the nostrils, lips, ears,
genital area, anus, respiratory system, etc), as well as internal organs such as muscles,
joints, the bladder and gut.
Parasympathetic Nervous System: originates in the brain stem and lower part of the spinal
cord; opposes physiological effects of the sympathetic nervous system: stimulates
digestive secretions; slows the heart; constricts the pupils; dilates blood vessels
Peripheral Nervous System (PNS): The PNS contains only nerves and connects the
brain and cord (CNS) to the rest of the body.
pH: A measure of acidity or alkalinity of a solution. The pH scale ranges from zero to
fourteen, where seven is neutral, less than seven is acidic and greater than seven is
basic (alkaline).
Prefrontal Cortex: Region of the brain concerned with cognition and executive control.
Prostaglandin: A naturally occurring fatty acid, hormone-like substance produced in
various body tissues that mediate a range of physiological functions. Examples
include metabolism, nerve transmission, smooth muscle contraction, blood pressure
and body temperature.
Receptor: A molecule on the surface or within a cell that recognizes and binds with
specific molecules, producing a specific effect in the cell.
Serotonin: A neurotransmitter.
Substance P: A short-chain polypeptide that functions as a neurotransmitter especially in
the transmission of pain impulses from peripheral receptors to the central nervous
system.
Sympathetic Nervous System: a branch of the autonomic nervous system. It is always
active at a basal level and becomes more active during times of stress. Its actions
during the stress response comprise the fight-or-flight response.
Thromboxone: A neurotransmitter.