pain Flashcards
the most commonly experienced symptoms in dentistry
pain
describes as sharp, burning, aching, cramping, dull, or throbbing experience
pain
is a thin elastic covering composed of a layer of lipid between two layers of protein
nerve cell membrane
refers to the transmission of electrical signals along nerve fibers
nerve conduction
in resting state, where is anion and cations greater?
anion ( - ) are greater inside the cell membrane
cation ( + ) equal number are gathered outside
what ions are concentrated inside the resting state of the membrane?
potassium ions
when can a membrane potential develop by the creation of an ionic imbalance?
by an active diffusion of ions through the membrane
&
diffusion of ions across the membrane because of a gradient difference
what ions are concentrated outside the resting state of the membrane?
sodium and chloride
what is the mv of a resting state outside the membrane?
-70 to -90
is there a chloride diffusion inside the membrane?
no, chloride remains outside the nerve membrane as a result of the opposing electrostatic influence forcing outward migration
the maintenance of the resting potential is mainly a result of an active mechanism known as??
sodium pump
the “jumping” of the impulse from node to node through the surrounding interstitial tissue is called??
saltatory conduction
who provides energy source for the sodium pump?
ATP
during this 3 to 4msec interval of repolarization, the membrane has a reserve potential and cannot be stimulated. Thus, the nerve is in ____ period??
absolute refractory period
when the normal ionic distribution pattern begins to return, the nerve can be stimulated, but only by a greater than usual stimulus. The nerve is said to be in the _____ period??
relative refractory period
a principle that states that the response of a nerve cell of muscle fiber is independent of a strength of the stimulus, as long as the stimulus exceeds a certain threshold
all or nothing law
who provided a classical description of specificity theory
Rene Descartes in 1644
what is a specificity theory?
pain system as a straight through channel from the skin to the brain
who postulates the theory of information transmission only by way of sensory nerves in specificity theory?
johannes muller 1839
who developed the concept of specific cutaneous receptors for the mediation of touch, heat, cold and pain ?
von frey
who was the first to propose that stimulus intensity and central summation are the critical determinants of pain?
goldscheider 1894
types of pain theories
specificity theory
pattern theory
gate control theory
___ results when the total output of the cells exceeds a critical level
pain
who proposed the gate control theory
melzack and wall in 1965
where does descending control system originate?
brain
brain receives messages about injury by way of the gate control system, which is influenced by??
- injury signals
- afferent impulses
- descending control
are believed to be conducted into the CNS system by two types of nerve fibers
pain impulse
what nerve fiber is large and small? are they myelinated or unmyelinated?
a delta fibers - large myelinated fibers
c fibers - small unmyelinated fibers
what peripheral nerve fibers transmit signals that are initiated by pressure, vibration and temperature?
a delta fibers
what peripheral nerve fiber transmit noxious or painful sensation?
C fibers
PN fiber that conducts fast or first pain (sharp, localized) pain
A delta fibers
PN fiber that conducts slow or second pain
C fibers
facilitation and inhibition occurs within the?
dorsal horn of the spinal cord and the nucleus of the fifth cranial nerve
in the dorsal horn? in which laminae does many large afferent nerve fibers terminate in this area?
laminae II and III
an action system which identifies pain duration, and exact location, analyzes where is the exact location and duration of pain
sensory discriminative system
an action system which is more of the emotion, suffering aspects associated with painful experience
motivation-affective system
where are the nerves in the teeth are located?
located only in the most pulpal portion of the dentin
results of the 2 action system; reaction to painful stimulus
activation of motor mechanism
fluid movement stimulates the pain mechanism in the dentinal tubules by mechanical disturbance
hydrodynamic theory
what are the chemical transmitters in peripheral nerve fibers
substance P and glutamate
a very potent substance that elicits the kind of pain that mimicked the clinically experienced sensation
bradykinin
what is the main contribution of prostaglandins?
sensitize the nociceptors to the effects of bradykinin, thereby accentuating its action.
an anti-inflammatory steroids that reduce the availability of prostaglandin precursor by means of synthesis of a protein or peptide that block phospholipase A2 activity
glucocorticoids
