Pain and Management Flashcards
xwhat is the definition of Nociception
Nociception: the activation of neural pathways by stimuli that damage or threaten to damage tissues
what is the definition of Noxious Stimulus:
Noxious Stimulus: potentially damaging stimulus.
what is a Nociceptive stimulus:
Nociceptive stimulus: a stimulus that activates nociceptive pathways
what is the sensation for nociception
pain
what is the sensation for thermoreception
hot and cold
what is the sensation for mechanoreception
touch
what is the sensation for proprioception
position sense
what is the sensation for gustation
taste
what is the sensation for olfaction
smell
when you have pain radiated in healthy areas of the body. what is this called
referred pain
give an example when some pains, may not be painful
tumours
being born with a condition which, allows you to feel no pain can be dangerous. what is the name of this condition
congenital insensitivity
what is dentoalveolar pain
pain of the tooth and its surroundings
what is dentine sensitivity
when there is an increase sensitivity stimulus to the dentine, this is a result of erosion of the enamel.
what is reversible pulpitis
: occurs when there is inflammation of the pulp, however this inflammation can be reversed.
what is irreversible pulpitis
occurs when inflammation to the pulp causes vessel and nerve damage beyond repair.
what is periapical periodontitis
is an acute or chronic inflammatory lesion around the apex of a tooth root which is usually caused by bacterial invasion of the pulp of the tooth.
what is acute pericoronitis
is inflammation of the tissue surrounding a third molar. The condition most often occurs in molars that are partially impacted, or not fully visible. Most people with pericoronitis have a flap of gum tissue partially covering the crown of the erupting tooth.
what is a dry socket
: occurs when you have had a permanent tooth extracted and a blood clot fails to develop at the site of extraction. Or it dislodges or dissolves before the wound has healed. Causing allot of pain.
what is maxillary sinusitis
is the inflammation of the maxillary sinuses. The symptoms are usually a headache.
how are blocked salivary glands formed
salivary stones as a result of crystallized saliva block saliva ducts and direct the flow saliva back to the gland, causing it swell, resulting in pain.
which receptor is a a sense organ or cell that responds to mechanical stimuli such as touch or sound
mechanoreceptor
which receptor is a a sensory receptor for painful stimuli
nociceptors
where does perception of the stimuli occur
cerebral cortex
where is the stimulus processed before it is reaches the cerebral cortex
thalamus
what is a synapse
a synapse is gap between nerve pathways
there are two electrical potentials for signalling the body. what are they?
graded potential
action potential
which electrical potential is used for long and short distance
short distance: graded potential
long distance:action potential
where do the graded potential occur in a nerve
at the nerve endings
what can change the charge of the cellular membrane of the neuron
neurotransmitter molecules released from other neurons
and environmental stimuli
The lipid bilayer membrane that surrounds a neuron is impermeable to charged molecules or ions. how do ions enter/exit
via special proteins called ion channels
Ion channels that change their structure in response to voltage are called?
voltage gated ion channels
The difference in total charge between the inside and outside of the cell is called the?
membrane potential
what is the function of the sodium potassium pump
- Uses ATP
- Transports sodium out of the cell
- Transports potassium in to the cell
- Ratio: 3Na+ out for every 2K+ in
- Helps maintain concentration gradient
which ion is more permeable K+ or Na+
K+
Chemical gradient allows for K+ to flow out.
electrical gradient caused by what keeps the K+ inside to cause equilibrium
neagtively charged protein anion
what is nernst equation (equilibrium potential for K+ =)
-90mV
what is the equilibrium potential fo Na+
+60mV
will resting membrane potential be nearer to K+ or Na+ equilibrium potential
K+
the ion with greater membrane permeability will drive membrane potential
what does this image indicate
Image indicates that resting membrane potential has been achieved.
This is the equilibrium between the NA+ and K+ and is indicated at -70mV
what does this image indicate
Due to a stimulus from either a graded potential or a current from an APs.
It results in the rapid change. Due to an increase in positive gradient outside, the voltage gated Na+ channels rapidly open and increase its intake of Na+ ions.
The inside of the cell becomes more positive. This is indicated at -50mV
what does this image indicate
Due to the rapid influx of the Na+ ions, this causes a rapid depolarisation overshoot.
what does this picture indicate
As the depolarization peaks, this results in the depolarization of the cell.
K+ channels start to open after delay
As a result, the Na+ channels are now closed and inactivated.
The rapid outflux of K+ results in repolarization.
what does this picture indicate
Due to the rapid outflux of the K+ the threshold value reaches hyperpolarization.
Here we will begin to see the K+ channels close.
And the Na+ channels reset.
what does the image indicate
the cell has reached resting membrane potential.
Membrane will become permeable to K+.
The K+ will be closed
how does Local Anaesthesia work
Anaesthesia chemical compound works by moving in to the neuron and then sitting in the N+ channels.
This blocks the channels, thus blocking action potential propagation.
can an action potential occur, during absolute refractory period
no
Na+ channels not in their resting configuration (-50mV)
can an action potential occur, in relative refractory period
The K+ channels are open
Membrane is hyperpolarised (increased in negativity)
An action potential can occur, but it requires a larger stimulus.
what does an increase in axon width do.
- Results in lower resistance and faster conduction
does myelination increase or decrease speed of transmission
increase
- Myelin sheath: acts as insulator
- Node of Ranvier – exposed axon – ion channels
- Local currents flow node to node
- Depolarisation jumps from node to node.
which nerve fibres are associated with nociception
C nerve fibres
alpha delta nerve fibres
what is the function of afferent neurons
carry sensory signals from the body to the brain (input neurons)
what is the function of Efferent neurons:
carry signals from the brain, such as those directed towards the muscles in the body.
what is dorsal
Dorsal: on or relating to the upper side or back of an animal, plant, or organ
what is ventral
Ventral: on or relating to the underside of an animal or plant; closer to the abdominal.
what are first order neurons
first order neurons conduct impulses from receptors of the skin and from proprioceptors (receptors located in a join, muscle or tendon) to the spinal cord or brain stem, where they synapse with second-order neurons
what are second order neurons
Second order neurons: the second-order neurons carry signals from the spinal cord to the thalamus (these neurons are generally located in the brain stem or spinal cord).
what are third order neurons
Third order neurons: the third-order neurons carry signals from the thalamus to the primary sensory cortex.
what is Somato (somatosensory):
relating to the human or animal body.
how many roots does the trigeminal nerve have
two roots
sensory and motor
The trigeminal sensory nuclear complex consists of the following:
- Nucleus oralis
- Nucleus interpolaris
- Nucleus caudalis
- Main sensor nucleus
If there was damage to the nucleus caudalis or a V tractotomy, what would you experience:
Loss of ipsilateral facial pain, hot/cold
Still fee touch
what is trigeminal neuralgia
is a chronic pain condition that affects the trigeminal nerve, which carries sensation from your face to your brain
what occurs at nucleus oralis
Carry nociceptive inputs to N. Oralis, especially from teeth
Possibly the site of synapses for oral + dental pain
what occurs at nuclear interpolaris
reflexes
what occurs at nuclear caudalis
Synapses for facial pain and hot/cold
Possibly the site of synapse for oral + dental pain
what is transduction
Transduction: transduction in the nervous system typically refers to stimulus-alerting events wherein a physical stimulus is converted into an action potential, which is transmitted along axons towards the central nervous system for integration.
- All or none event
- Propagates along a nerve
- Voltage gated channels
these are examples of what
action potentials
- Local change in membrane potential
- Triggering event in – synaptic, post synaptic membrane
- Triggering event in – receptor, action of stimulus
- These triggers respond to mechanical, chemical or thermal gated channel
these are examples of what
graded potential
action potential vs graded potential
trigger = depolarisation to threshold
action potential
action potential vs graded potential
trigger = stimulus neurotransmitter
graded potential
action potential vs graded potential
ion movement = Na+ then K+ through voltage gated channels
action potential
action potential vs graded potential
net movement of Na+ K+ Cl- or Ca2+
graded potential
action potential vs graded potential
coding of magnitude = all or none, frequency
action potential
action potential vs graded potential
coding of magnitude = size of potential changes
graded potential
action potential vs graded potential
duration = fixed
action potential
action potential vs graded potential
duration = variable
graded potential
action potential vs graded potential
propagation = self regenerating propagation
action potential
action potential vs graded potential
propagation = decays with distance
graded potential
action potential vs graded potential
refractory period = yes
action potential
action potential vs graded potential
refractory period = no
graded potential
action potential vs graded potential
direction of potential change = depolarisation then hyperpolarisation
action potential
action potential vs graded potential
direction of potential change = depolarisation or hyperpolarisation
graded potential
action potential vs graded potential
location = voltage gated channels
action potentials
action potential vs graded potential
location = receptors and post-synapse
graded potential
which receptors convert stimulus energy to elctrical energy
graded potential receptors
what is transduction
transduction is the conversion of a sensory stimulus to another.
what activates TRPV4
temperatures greater than 27 degress
what activates TRPV3
temperatures greater than 31 degrees
what activates TRPV1
>45°C
capsaisin
what activates TRPV2
>50°C
what does this picture indicate
Image indicates that a strong stimulus must occur in order for an action potential to occur.
what do these drugs act on
- Glutamate
- GABA (gamma-aminobutyric acid)
- Acetylcholine
- Serotonin
- Noradrenaline
Many drugs act at synapses and affect the neurotransmitters that relay between the synapses
what is Temporal summation
occurs when a high frequency of action potentials in the presynaptic neuron elicits postsynaptic potentials that summate with each other. This allows the membrane potential to reach the threshold to generate an action potential.
what is Spatial summation:
Spatial summation is the effect of triggering an action potential in a neuron from one or more presynaptic neurons. This occurs when more than one excitatory postsynaptic potential (EPSP) originates simultaneously and a different part of the neurone
- Pain is associated with two speeds. Fast and slow.
which nerve fibres are responsible for fast , sharp pain
alpha delta nerve fibres
- Pain is associated with two speeds. Fast and slow.
which nerve fibre is associated with slow, burning pain
C nerve fibres
which nerve fibre has a conductive velocity of 5-30ms
alpha delta nerve fibres
which nerve fibre has a conductive velocity of 0.2-2ms
c nerve fibres
what do polymodal c fibre nociceptors respond to
respond to all pain stimuli
what do alpha delta mechanical nociceptors respond to
respond to strong mechanical stimuli
what do alpha delta polymodal nociceptors respond to
responds to all types of noxious stimuli
what is carried to the trigeminal nuclei
Primary afferent sensations are carried from the periphery to the trigeminal nuclei. These are known as 1st order neurones.
which order neurons transcend from the trigeminal nuclei to the thalamus
2nd order neurons
3rd order neurones transcend from where
thalamus to the cerebral cortex
what acts as a relay for the thalamus for nociceptive stimulus
ventrobasal nuclei
where does perception occur
cerebral cortex
where does processing occu
thalamus
where does detection occur
at receptors
what is divergence
Any individual neuron can make divergent connections to many different postsynaptic cells.
what is convergence
One postsynaptic cell receives convergent input from a number of different presynaptic cells.
Convergence allows a neuron to receive input from many neurons in a network
what does this image show
Discrete pain image shows the following:
If there is a noxious stimulus in a specific area. It follows the same pathway from the primary afferent to the 2nd order neurones
It also diverges on to another postsynaptic cell.
what does this image show
Hyperalgesia image shows the following:
2nd order neurones can be sensitised by external factors (prostaglandin, serotonin)
As a result of this sensitised, they transmit a bigger signal to the consciousness along with the other 2nd order neurones.
This causes an increased in pain referred to as hyperalgesia.
what does this image show
radiating image shows the following:
2nd order neurones can be sensitised by external factors (prostaglandin, serotonin)
As a result of this sensitised, they transmit a bigger signal to the consciousness along with the other 2nd order neurones.
This causes an increased in pain area. Which means pain can be perceived as originating from a larger area than the stimulus area.
what does this image show
Referred image shows the following:
2nd order neurones can be sensitised by external factors (prostaglandin, serotonin)
As a result of this sensitised, they transmit a bigger signal to the consciousness along with the other 2nd order neurones.
The consciousness can perceive the location of the pain site somewhere else.
Usually deep to superficial structure:
- Heart to left arm
- Maxillary sinus to teeth
- Appendix to abdominal skin
How does chemical signalling work over different distances?
What speed does it work at?
Short distance (e.g. synapse)
Long distance (e.g. hormones)
Relatively slow
How does electrical signalling work over different distances?
At what speed does it work at?
over short distances by graded potentials
over long distances by action potentials
very fast- up to 120m/s or around 270mph
what are two properties of copper wire? how do they make it an excellent conductor?
- covered by a great insulator: plastic
- copper is an excellent conductor of electricity
This means that electricity is conducted rapidly by copper, and is not lost to the external environment because the plastic coating seals it in
why are nerves not as good as copper wire?
What do we need to improve conductivity?
membrane is a poor insulator in an aqaeous environment
cytoplasm is a relatively poor conductor
Signal decays over a short distance (2-3mm), bad as nerves can be longer than a metre
This means we need a propagrating material: action potential
