jK NEURO > Lecture 2 > Flashcards
Lecture 2 Flashcards
A ___ ___ _____ is an unspecialized, afferentnerve ending, meaning it brings information from the body’s periphery toward the brain. They function as cutaneous receptors and are essentially used by vertebrates to detect pain. They are the same as a ____ nerve.
Afree nerve ending(FNE) is an unspecialized, afferentnerve ending, meaning it brings information from the body’s periphery toward the brain. They function as cutaneous receptors and are essentially used by vertebrates to detect pain. They are the same as a cuteanous nerve.
Conduction velocity is proportional to fiber ___.
conduction velocity is proportional to fiber diameter (myelinization)
Alpha-betafibers are myelinated/unmyelinated? What are they useful for?What would happen if it was blocked?
MyelinatedThey are important for sharp, prickling pain and temperature. They are fast!You have pain relief and a loss of temperature sensation.
C fiber’s function is:Are they myelinated or unmyelinated?
C fiber’s function is slow pain, autonomic, postganglionic sympathetic, polymodal nociceptors.They are unmyelinated.If it is blocked, there is pain relief and a loss of temperature sensation.
Where are free nerve endings found?
All skin, epidermis and some viscera
Where are Meissner’s corpuscles found?
Glabrous skin (hairless skin)
What is the function of Meissner’s Corpuscles
Dynamic, fine/light touch.
Pacinian corpuscles are found where? What is their function?
Pacinian corpuscles are found in deep skin layers, ligaments and joints.They sense vibration and pressure.
Merkel Disc’s are large myelinated fibers found where?Function?
They are found in fingertips and superficial skin.They sense pressure, deep static touch (e.g. sharp edges), and position sense.
Ruffini Corpuscles are located where and function how?
They are located in finger tips and jointsThey sense pressure, slippage of objects along surface of skin, and joint angle change.
Dermatomes:C2C3C4C6T4T7T10L1L4S2,3,4
Dermatomes:C2 - posterior half of the skull “cap”C3 - high turtleneck shirtC4 - lower collared shirtC6 - includes thumbsT4 - nipplesT7 - Xiphoid processT10 - at the umbilicus (improtant for early appendicitis pain referral)L1 - inguinal ligamentL4 - includes kneecaps, medial ankle and big toeS2,3,4 - perianal area and genitals
A beta fibers carry ___ and ___ information. A delta and c fibers carry __ and __ information.
A beta fibers carry touch and pressureinformation. A delta and c fibers carry painand temperatureinformation.
List from largest to smallestA-betaA-deltaC fiber
A-beta > A-delta > C fiber (unmyelinated so slowest)
The more myleinated you are, the __ you are and the __ you are
Thicker and faster
Selective activation or inactivation depends on ___. For example, when you are injecting a local anesthetic into a part in the skin, you should know which fibers are inactivated. The ___ diameter fibers get inactivated first. So, the __ fibers which carry pain info will be the first to go. The next fibers to go will be the __ fibers.
Selective activation or inactivation depends on size. For example, when you are injecting a local anesthetic into a part in the skin, you should know which fibers are inactivated. The smallest diameter fibers get inactivated first. So, the Cfibers which carry pain info will be the first to go. The next fibers to go will be the A-delta fibers.
If you get compression on your limb, which fibers are first to get inactivated? The ___ diameter fibers get inactivated first, and the ___ diameter fibers remain active for a longer time.If you are doing electrical stimulation, then again, the ___ diameter fibers get activated at the lowest stimualation threshold.
If you get compression on your limb, which fibers are first to get inactivated? The larger diameterfibers get inactivated first, and the smallest diameterfibers remain active for a longer time.If you are doing electrical stimulation, then again, the larger diameter fibers get activated at the lowest stimualation threshold.
Externally applied pressure, such as compression of the skin above a nerve, first blocks the myelinated ___fibers, while ___fibers continue to conduct action potentials and allow the slow conducting pain to be carried.A low dose of local anesthesia applied to peripheral nerves blocks the unmyelinated __ fibers before the myelinated ___ fibers. Under this condition, the slow conducting pain information is blocked, and only the fast conducting pain information by A delta fibers is carried to the CNS. This experiment provides additional evidence that two different types of nerve fibers carry noxious information.
Externally applied pressure, such as compression of the skin above a nerve, first blocks the myelinated A delta fibers, while C fibers continue to conduct action potentials and allow the slow conducting pain to be carried.A low dose of local anesthesia applied to peripheral nerves blocks the unmyelinated C fibers before the myelinated A delta fibers. Under this condition, the slow conducting pain information is blocked, and only the fast conducting pain information by A delta fibers is carried to the CNS. This experiment provides additional evidence that two different types of nerve fibers carry noxious information.
Most of touch information is relayed by what fibers?
A-beta fibers, which are large myelinated fibers.
All of the sensory fibers in the skin get turned on by special ion channels called ___ ___ ___ channels. All touch and pain fibers have these, and their channels that are repsonsive toparticular kinds of stimulation.
All of the sensory fibers in the skin get turned on by these special ion channels called transient receptor potentialchannels. All touch and pain fibers have these, and their channels that are repsonsive toparticular kinds of stimulation.
Four kinds of sensory receptors of skin:2 that are relatively superficial are the __ and ___.2 that are relatively deep in the skin and are the __ and __.___ cells are slowly adapting, whereas the ___ are rapidly adapting.
Four kinds of sensory receptors of skin:2 that are relatively superficial are the Meissner corpuscle and Merkel cell.2 that are relatively deep in the skin and are the Pacinian corpuscles and Ruffini endings.Merkelcells are slowly adapting, whereas the Meissner’s corpuscles are rapidly adapting.
The ___ corpuscles and ___ cells, since they are located more sperficially have small, relatively well-defined receptive fields, whereas the ___ corpuscles and __ ___,which are located deeper in the skin, have a broad, not-well defined receptive field.
The Meissners and Merkels, since they are located more sperficially have small, relatively well-defined receptive fields, whereas the Pacinian and Ruffini endings,which are located deeper in the skin, have a broad, not-well defined receptive field.
The ___ corpuscles are really good at detecting vibration. They have rapid on and off ability.
Pacinian
Two point discrimination:On the _____, you can distinguish two different stimuli that are really close together. Whereas when you get to the arm, back or belly or thigh, you can only detect stimuli that are ___ ___. This is because of the ___ ___.____ are highly innervated (lots of little receptors), so you have an ability to detect things that are close together.Things like your back, are areas that are not highly innervated so you cannot detect things that are close together because there aren’t enough receptors to do it.
Two point discrimination:On the fingers, you can distinguish two different stimuli that are really close together. Whereas when you get to the arm, back or belly or thigh, you can only detect stimuli that are far apart. This is because of the innervation density.Fingers are highly innervated (lots of little receptors), so you have an ability to detect things that are close together.Things like your back, are areas that are not highly innervated so you cannot detect things that are close together because there aren’t enough receptors to do it.
______: our ability to know where our limbs are in space.There are three sets of receptors which allow us to do this:What are they?
Proprioception:our ability to know where out limbs are in space.1. Muscle spindles - length detectors embedded in muscle. They contain specialized fibers called intrafusal muscle fibers which shorten and lengthen with the whole muscle (innervated by A-alpha fibers).Muscle spindles supply the input that drives the stretch reflex.2. Joint receptors - Golgi tendon organs and free nerve endings which detect muscle tension and give negative feedback.3. Cutaneous receptors - Pacinian corpuscles and Ruffini’s corpuscles, but they also reside in skin and joints.In addition, the brain knows where it told the limb to go. So we hae the motorcommand as part of the information about where the limb is supposed to be.
Muscle spindles are a specialized receptors that are embedded in muscles. Each muscle has many many muscle spindles whichdetect the ____of the muscle. They can also detect the ___with which the muscle is changing ___They consist of specialized muscle fibers inside a little fibrous capsule and the capsule is spindle shaped which is why it is called a muscle spindle. The muscle fibers inside the capsule are called ___ ___fibers andare in a capsule. These fibers have _____contractile ends. The middle of the fiber does not have any muscular element and so it can ___, like a rubber band. So, if the muscle lengthens and shortens, it is the ___ part of the intrafusal muscle fiber that is lengthening and shortening.Alternatively, if the ends of the fibers contract, they can pull on the middle and lengthen it, which is important for adjusting the guage or sensitivity of the fiber. This is controlled by the __ neurons.And finally, the sensory endings (the____, the fastest conducting fibers we have) will conduct quickly back to the ___.Regular muscle fibers are called ____.Intrafusal muscle fibers are innervated by large myelinated axons (____). ____ relay into the CNS information about the ___of the muscle. When the muscle is long, the fibers are___.When the muscle shortens, the fiber becomes____. This is the basis of the ___ reflex.When you take a reflex hammer and knock on a tendon, you stretch the muscle. When you stretch the muscle, the muscle spindle is ____, andsends a signal to the CNS, and the motor neuron shortens (contracts).
Muscle spindles are a specialized receptors that are embedded in muscles. Each muscle has many many muscle spindles whichdetect the lengthof the muscle. They can also detect the speedwith which the muscle is changing lengthThey consist of specialized muscle fibers inside a little fibrous capsule and the capsule is spindle shaped which is why it is called a muscle spindle. The muscle fibers inside the capsule are calledintradusal musclefibers andare in a capsule. These fibers have striatedcontractile ends. The middle of the fiber does not have any muscular element and so it can stretch, like a rubber band. So, if the muscle lengthens and shortens, it is the middle (stretchy)part of the intrafusal muscle fiber that is lengthening and shortening.Alternatively, if the ends of the fibers contract, they can pull on the middle and lengthen it, which is important for adjusting the guage or sensitivity of the fiber. This is controlled by the gamma neurons.And finally, the sensory endings (the A-alpha fibers, the fastest conducting fibers we have) will conduct quickly back to the CNS.Regular muscle fibers are called extrafusal.Intrafusal muscle fibers are innervated by large myelinated axons (A-alpha fibers). A-alppha fibersrelay into the CNSinformation about the lengthof the muscle. When the muscle is long, the fibers areactive.When the muscle shortens, the fiber becomesinactive. This is the basis of the stretchreflex (knee jerk).When you take a reflex hammer and knock on a tendon, you stretch the muscle. When you stretch the muscle, the muscle spindle is active, andsends a signal to the CNS, and the motor neuron shortens (contracts).
Muscle spindles are __ detectors, and the __ motor neurons can adjust the sensitivity of the muscle spindle.___ motor neurons can reset the sensitivity of the spindle to measure length even when the muscle is contracting.This figure illustrates the important role of gamma motor neuron activity in regulating the responses of muscle spindles.The figure on the left illustrates that when muscles contract the spindle is no longer able to measure ____. The spindle afferent falls silent.The figure on the right shows how the ____ motoneuron resets or retightens the spindle so it can again report stretch even when the muscle is contracting. The gamma motor neurons can regulate the gain of muscle spindles so that they can operate efficiently at any length of the parent muscle.Alpha and Gamma motoneurons are typically __-____so the that while the muscle contracts, the ends of the intrafusal fibers also contract. This keeps enough tension on the middle of the fiber, so that there is constant feedback from the spindle on muscle length.If the Gamma motoneurons are activated alone (in some pathological states), the spindle becomes abnormally ____ even at the normal resting length of the muscle. The spinal cord interprets this as muscle ____ and sends commands to the muscle to ___(this is the stretch reflex). This constant contraction is called ___.Activation of gamma motoneurons is thought to be one of the mechanisms for the ____ seen after upper motoneuron damage
Muscle spindles are lengthdetectors, and the gammamotor neurons can adjust the sensitivity of the muscle spindle.Gamma motor neurons can reset the sensitivity of the spindle to measure length even when the muscle is contractingThis figure illustrates the important role of gamma motor neuron activity in regulating the responses of muscle spindles.The figure on the left illustrates that when muscles contract the spindle is no longer able to measure length.The spindle afferent falls silent.The figure on the right shows how the gamma motoneuron resets or retightens the spindle so it can again report stretch even when the muscle is contracting. The gamma motor neurons can regulate the gain of muscle spindles so that they can operate efficiently at any length of the parent muscle.Alpha and Gamma motoneurons are typically co-activated so the that while the muscle contracts, the ends of the intrafusal fibers also contract. This keeps enough tension on the middle of the fiber, so that there is constant feedback from the spindle on muscle length.If the Gamma motoneurons are activated alone (in some pathological states), the spindle becomes abnormally sensitive even at the normal resting length of the muscle. The spinal cord interprets this as muscle stretch and sends commands to the muscle to contract(this is the stretch reflex). This constant contraction is called spasticity.Activation of gamma motoneurons is thought to be one of the mechanisms for the spasticity seen after upper motoneuron damage.
Golgi tendon organs detect muscle____(force of contraction). It provides ___feedback to motor neurons. It is embedded in tendonsthat attachthe muscle to bone. The tendon is not stretchable, so it cannot detect length, but it can detect ____. The musclespindle gives posititve feedback, whereas the golgi tendon organ gives negativefeedback. When muscle spindlesgetstretched, it tells the nervous system to become activated and contract the muscle to the normal length again.The golgi tendon organ does the opposite. This createsa nice positive and negative feedback which is going to the spinal cord, telling it about the tension and length of muscle. This helps to create a____ muscle contraction. GTO’s may prevent tissue damage by setting ____onstrength ofmuscle contraction.It also has clinical significance in ___.In ___, the limbs become very stiff and you really cannot move them. You have to push really hard to move the limbs. It resists movement and untilall of a sudden itcollapses when you put enough pressure(this is the ___-___response). It is not entirely clear what underlies this response but many people think it is the golgi tendon activity. It becomes so active because of the tension, that it finally overcomes everything and inhibits the motor neurons causing thisresponse.GTO is innervated by____–super fast report on muscle force.
Golgi tendon organs detect muscle tension(force of contraction). It provides negativefeedback to motor neurons. It is embedded in tendonsthat attachthe muscle to bone. The tendon is not stretchable, so it cannot detect length, but it can detect tension. The musclespindle gives posititve feedback, whereas the golgi tendon organ gives negativefeedback. When muscle spindlesgetstretched, it tells the nervous system to become activated and contract the muscle to the normal length again.The golgi tendon organ does the opposite. This createsa nice positive and negative feedback which is going to the spinal cord, telling it about the tension and length of muscle. This helps to create a smooth muscle contraction. GTO’s may prevent tissue damage by setting limits onstrength ofmuscle contraction.It also has clinical significance in spasticity.In spacticitiy, the limbs become very stiff and you really cannot move them. You have to push really hard to move the limbs. It resists movement and untilall of a sudden itcollapses when you put enough pressure on it (clasp knife response). It is not entirely clear what underlies this response but many people think it is the golgi tendon activity. It becomes so active because of the tension, that it finally overcomes everything and inhibits the motor neurons causing the clasp-knife response.GTO is innervated by A-alpha sensory axons –super fast report on muscle force.
The dorsal column carries what kind of info?___, light touch and vibration. Basically, all touch info. Since it also carries proprioceptive info, the muscle spindles send a collateral into the ____ column.Since thespindle also has direct control of ____ neurons,it sends another collateral into the ___horn, where it makes a connection with an alpha motor neuron, which will project out to the periphery to innervate a ___. So the spindle goes both to the __ column and into the __ horn of the spinal cord. The GTO does the same thing.
The dorsal column carries what kind of info?Propioception, light touch and vibration. Basically, all touch info. Since it also carries proprioceptive info, the muscle spindles send a collateral into the dorsalcolumn.Since thespindle also has direct control of A motorneurons,it sends another collateral into the ventralhorn, where it makes a connection with an alpha motor neuron, which will project out to the periphery to innervate a muscle.So the spindle goes both to the dorsalcolumn and into the ventralhorn of the spinal cord. The GTO does the same thing.
Dorsal column end in a set of nuclei called the __ __ __. The axons thar arise in this nuclei form a pathway called the ___ ___ ___ ___ pathway. This is the touch system.If there is a stroke in the brain stem, you will get symptoms that include the medial lemniscus systemand corticospinal tract system, so you will be ___ and you won’t be able to feel ____.
Dorsal column end in a set of nuclei called the dorsal column nuclei. The axons thar arise in this nuclei form a pathway called the dorsal column/medial lemniscuspathway. This is the touch system.If there is a stroke in the brain stem, you will get symptoms that include the medial lemniscus systemand corticospinal tract system, so you will be paralyzedand you won’t be able to feel fine touch.
Alateral pontine syndromeis a lesion which is similar to thelateral medullary syndrome, but because it occurs in thepons, it also involves thecranial nerve nucleiof the pons.It can be caused by an interruption to the blood supply of the___ ___ ____artery.Which areas are affected?
Alateral pontine syndromeis a lesion which is similar to thelateral medullary syndrome, but because it occurs in thepons, it also involves thecranial nerve nucleiof the pons.It can be caused by an interruption to the blood supply of theanterior inferior cerebellar artery.Lateral pons (vestibular nuclei, facial nucleus, trigeminal nucleus, cochlear nuclei, sympathetics), middle/inferior cerebellar peduncles
The spinal thalamic tract is located next to the _____ nucleus (which is responsible for __ and ___. in the face). It receivesfibers from the ipsilateral face, whereas in the brainstem the spinal thalamic tract are fibers from the contralateral body. So, when you see a person who has loss pain and temp. on one side of the face and opposite side of the body, it is probably an ___ stroke because it includes the STT and the trigeminal nucleus of the spinal nerve.
The spinal thalamic tract is located next to the trigeminal nucleus (which is responsible for pain and temp. in the face). It receivesfibers from the ipsilateral face, whereas in the brainstem the spinal thalamic tract are fibers from the contralateral body. So, when you see a person who has loss pain and temp. on one side of the face and opposite side of the body, it is probably an AICA stroke because it includes the STT and the trigeminal nucleus of the spinal nerve.
VPM receives info from the ___ and VPL receives info from the ___ and they relay this info to the cerebral cortex to the first somatic sensory area which is the post central gyrus.
VPM receives info from the FACE and VPL receives info from the LIMBS and they relay this info to the cerebral cortex to the first somatic sensory area which is the post central gyrus.
If you have a patient who cannot move their face or speak, what type of stroke do they have? MCA or ACA?
MCA
Lesions of the _____ are impaired perception of light touch, severely impaired proprioception, severely impaired discriminative touch.
Lesions of the somatosensory area (S1) are impaired perception of light touch, severely impaired proprioception, severely impaired discriminative touch (two point discrimination thing).The sensory loss is somatotopically appropriate.
Higher order processing of body info ends up in one place which is the ____. Damage to this area causes people to completely neglect the opposite side of the world. It is called neglect, and they behave as if that part of the world does not exist.
Right parietal cortex.
Pain fibers are called ___. They are simply afferent fibers that give us information about destruction or potential detruction. There are different types of receptors that detect different types of pain. In this case, the receptors are the TRP channels. All the nociceptors are very fine unmyelinated, undifferentiated axon terminals but they have different TRP receptors.There are two kinds of nociceptor fibers:___ fibers - rapidly adapting and relay info about sharp prickly pain__ fibers - unmyelinated, slowly conducting, summating and late onset, which carry different types of information.
Pain fibers are called nociceptors. They are simply afferent fibers that give us information about destruction or potential detruction. There are different types of receptors that detect different types of pain. In this case, the receptors are the TRP channels. All the nociceptors are very fine, unmyelinated, undifferentiated axon terminals but they have different TRP receptors.There are two kinds of nociceptor fibers:A-delta fibers- rapidly adapting and relay info about sharp prickly painC fibers - unmyelinated, slowly conducting, summating and late onset, whichcarry different types of information.
Pain is not well localized on the body the way touch is. The reason why, is because when pain fibers enter the dorsal horn, they travel in __ tracts, which is the most dorsal part of the dorsal horn. They then ascendor descend1 or 2 levels within Lissau’s fasiculus, leaving off terminals as they go. This is why pain is not well localized. It then synapses onto a cell body in layers __, __ and __,of the __ ___ inthe grey matter. The axons from layers__ and __then decussates (anterior white commisure) and ascends via spinal thalamic fasiculus.The STT is the pathway for pain and temperature (crude touch). Layer _and layer _are the origins of the spinal thalamic tract.Layer 5 fibers are interesting because they receive convergent inputs from ____(pain fibers) and from ___ (touch fibers).If you bang your elbow, rubbing it helps the pain. How does this happen? Explain.The ___ fibers and ___ fibers can both terminate on layer 5. But it turns out, that they also terminate on an ____ which gives them the ability to inhibit each other.The one that has the strongest input will win and inhibit the other one. Inititally, when pain info comes in, that is the strongest input, which is why youfeel pain! Then, when you start rubbing that area, the rubbingbecomes the strongest input. The reason why you don’t feel pain any more is because ____ fibers has activated the inhibtory neuron which inhbits the ____ fibers. So this system creates a kind of a balance between __ and __ fibers. When one of them wins, it will block out the other, preventing one from getting onto the spinal thalamic tract.This is called the __ theory of pain.
Pain is not well localized on the body the way touch is. The reason why, is because when pain fibers enter the dorsal horn, they travel in Lissau’stracts, which is the most dorsal part of the dorsal horn. They thenascendor descend1 or 2 levels within Lissau’s fasiculus, leaving off terminals as they go. This is why pain is not well localized. It then synapses onto a cell body in layers 1 , 2, and 5 of the dorsal columninthe grey matter. The axons from layers1and 5then decussates (anterior white commisure) and ascends via spinal thalamic fasiculus.The STT is the pathway for pain and temperature (crude touch). Layer 1and layer 5are the origins of the spinal thalamic tract.Layer 5 fibers are interesting because they receive convergent inputs from A-beta(pain fibers) and from A-delta (touch fibers).If you bang your elbow, rubbing it helps the pain. How does this happen? Explain.The A-betafibers and A-delta fibers can both terminate on layer 5. But it turns out, that they also terminate on an interneuron which gives them the ability to inhibit each other.The one that has the strongest input will win and inhibit the other one. Inititally, when pain info comes in, that is the strongest input, which is why youfeel pain! Then, when you start rubbing that area, the rubbingbecomes the strongest input. The reason why you don’t feel pain any more is because A-delta fibers has activated the inhibtory neuron which inhbits theA-beta fibers. So, this system creates a kind of a balance between pain (A-beta)and touch (A-delta)fibers. When one of them wins, it will block out the other, preventing one from getting onto the spinal thalamic tract.This is called the Gaittheory of pain.
Visceral afferents (like in stomach, gall bladder, etc.) will terminate on the same spinal thalamic neuron as the pain afferents (__ fibers) from the ___,which is why pain from the viscera is often reffered to locations on body the surface because they are both using the same spinal thalamic neuron to get to the brain.
Visceral afferents (like in stomach, gall bladder, etc.) will terminate on the same spinal thalamic neuron as pain afferents from the skin, which is why pain from the viscera is often reffered to locations on body the surface because they are both using the same spinal thalamic neuron to get to the brain.
The spinothalamic system (aka ___) relays pain and temperature information to consciousness.It plays a major role in localizing pain and discriminating among different types of pain. _____and ______projections feed into emotional responses to pain.The _____ system plays a major role in eliciting arousal and attention. It has ascending projections to the limbic system and also feeds into the descending pain modulating pathways.The ____ pathway is the most direct pathway to the limbic system and elicits the autonomic nervous system response to pain.
The spinothalamic system (aka spinal thalamic tract)relays pain and temperature information to consciousness. It plays a major role in localizing pain and discriminating among different types of pain. Thalamocortical and corticocortical projections feed into emotional responses to pain.The spinoreticular system plays a major role in eliciting arousal and attention. It has ascending projections to the limbic system and also feeds into the descending pain modulating pathways.The spinohypothalamic pathway is the most direct pathway to the limbic system and elicits the autonomic nervous system response to pain.
The midbrain is also called the___. The info coming from the face is weird. The info comes in and goes through a tube called the __ __ of the __ __.It is a long tube that extends from the mesencephalondown into the upper cervical spinal cord. Pain and temp axons come in the trigeminal nerve and go down this tube for some distance and then terminates on some axon which sends anotheraxon across the midline to join the STT. This spinal nucleus at thetrigeminal nerve travels right next to the spinal thalamic tract from a contralateral body. So, if you get an infarct that occludes thisarea, you will get loss of pain and temperature on the ___ side of the face and on the ___ side of body. Spinal thalamic tract and spinal nucleus are right next to each other. A lesion that gets them both gets trigeminal stuff before it hits the midline
The midbrain is also called the mesencephalon. The info coming from the face is weird. The info comes in and goes through a tube called the spinal nucleusof the trigeminal nerve.It is a long tube that extends from the mesencephalondown into the upper cervical spinal cord. Pain and temp axons come in the trigeminal nerve and go down this tube for some distance and then terminates on some axon which sends anotheraxon across the midline to join the STT. This spinal nucleus at thetrigeminal nerve travels right next to the spinal thalamic tract from a contralateral body. So, if you get an infarct that occludes thisarea, you will get loss of pain and temperature on the sameside of the face and on the oppositeside of body.
What is circled in hot pink?What happens if you get a stroke in PICA?
The spinal nucleus of trigeminal nerveand the STT. They are both included in the PICA. So you can lose pain and temp in one side of the face and the opposite side of the body. The medial leminscus is preserved so fine touch is preserved.
Pain, Temperature and Crude Touch Summary Slide:Primary afferents enter ___tractFirst synapse in layers __, __ and __.Second order fibers cross midline and enter ____ tractsTrace pathway to thalamusSynapse in VPLalso intralaminar and other nucleiThird order neurons project ___Also SII, insula and other cortical areas
Primary afferents enter Lissauer’s tractFirst synapse in layers I, II, VSecond order fibers cross midline and enter spinothalamic tractsTrace pathway to thalamusSynapse in VPLalso intralaminar and other nucleiThird order neurons project primary somatosensory cortexAlso SII, insula and other cortical areas
