Neuroscience - Block 1 - Part 2

davidwurbel7's version from 2016-01-27 22:26


Question Answer
The area of skin supplied by one segment of the spinal cordDermatome
Dermatome T4 is at the level of theNipple
Dermatome T10 is at the level of theUmbilicus
The arm is innverated byC4 - T2
The back of the legs isS1 - S2
The front of the legs isL1 - L5
The back of the head isC2 - C3
The chest and back isT3 - T12
Biceps brachii tendon reflexC5 - C6
Triceps tendon reflexC6, C7, (C8)
Brachioradialus tendon reflexC5, C6, (C7)
Abdominal superficial reflex - UpperT6 - T7
Abdominal superficial reflex - MiddleT8 - T9
Abdominal superficial reflex - LowerT10 - T12
Patellar tendon reflexL2, L3, L4
Achilles tendon reflexS1 - S2
Receptor that fires upon stimulus, then stops until the next stimulus. Information about changes in stimulationRapidly adapting
Receptor that fires upon stimulus and continues to fire while stimulus is there. Provides information about ongoing stimulationSlowly adapting
Most peripheral receptors utilize these types of fibersA-beta Type Fibers
Free nerve endings (pain) which utilize these types of fibersC type Fibers
Unencapsulated exposed axon that responds to changes in potassium levelsFree Nerve Endings
Encapsulated receptor with wide but not homogenous distribution. Higher concentrations in areas like fingertips. Superficial skin layers. Slowly adapting, for pressure. Also helps with some two-point discriminationMerkel’s Discs
Unencapsulated free nerve endings wrapped around a hair follicle. Movement of hair causes mechanical activation of free nerve endingHair Follicle Receptors
Encapsulated receptor that is rapidly adapting, for fine touch (ie. two point discrimination). Distribution not homogenous; concentrated in areas for fine touch (fingers, etc). Also contributes to vibratory sensationMeissner's Corpuscles
Encapsulated receptor that is rapidly adapting, for vibration. Wide distribution. Also ‘deep’ pressure. Known alternatively as ‘lamellar’ corpusclesPacinian Corpuscles
Encapsulated receptor found in subcutaneous tissue and joints. Cutaneous function - Slow adapting stretch receptors. Musculoskeletal function - Contributes to proprioceptive information. Temperature - Also respond to heatRuffini’s Corpuscles
Encapsulated receptor for only cold sensationKrause’s End Bulbs (Bulboid Corpuscle)
Golgi tendon organ measures this on the muscleTension
Two-point discrimination as the same as thisFine Touch
Neuron goes from the spinal cord to the muscleAlpha Motor Neuron
Neuron goes from the spinal cord to the muscle spindle and provides proprioceptionGamma Motor Neuron
Innervates the extrafusal muscleAlpha Motor Neuron
Innervates the intrafusal muscleGamma Motor Neuron
In a reflex, the opposing muscle must relax for reflex to happenInverse Myotatic
Senses the length of a muscleMuscle Spindle
Senses the tension on a muscleGolgi Tendon Organ
Sends sensory information from the middle of the muscle spindleAnnulospiral Endings
Sends sensory information from the ends of the muscle spindleFlower Spray Endings

Spinal Cord 1

Question Answer
The cervical enlargement of the spinal cord in the cervical area is due toSensory and Motor Function of the Arms
2' order sensory neurons cross and go hereThalamus
3' order neurons go from the Thalamus to hereCortex
Extension of pia mater that anchors into the dura materDenticulate Ligament
Transmits sensory input from skin, muscle, bone and joints to CNSGeneral Somatic Afferent (GSA)
Sensory input from visceral organs to CNSGeneral Visceral Afferent (GVA)
Conveys motor output from ventral (anterior) horn motor neurons to skeletal muscleGeneral Somatic Efferent (GSE)
Conveys motor output to smooth muscle and visceral organsGeneral Visceral Efferent (GVE)
Part of the dorsal white column that receives sensory information from the legsFasciculus Gracilis
Part of the dorsal white column that receives sensory information from the armsFasciculus Cuneatus
Covey vibration, fine touch, and propraception from the arms and legsDorsal White Column
Damage to the lower motor neuron results inFlaccid Paralysis
Receives type A fibers, pain.Marginal Layer
Receives information on pain, temperature, and touch, predominantly C type fibersSubstantia Gelatinosa
Receives both A and C fibers from spinothalamic tractsNucleus Proprius
Proprioception from spinocerebellar tracts, and also from dorsal columnsNucleus Dorsalis (Clark’s column)
Receives visceral afferents informationVisceral Afferent Nucleus
Supplies the anterior 2/3 of the spinal cord with bloodAnterior Spinal Artery
Supplies the posterior 1/3 of the spinal cord with bloodPosterior Spinal Artery (2)
Supplies the superior 1/3 of the spinal cord with bloodAnterior Spinal Artery and Posterior Spinal Artery (2)
Supplies the inferior 2/3 of the spinal cord with bloodSegmental/Radicular Arteries
Supplies most of the blood in the lower cordGreat Anterior Radicular Artery
Anastomosis of radicular/spinal arteries is widespread and is called theArterial Vasocorona
Upper motor neurons (Corticospinal tract) cross hereForamen Magnum
Connects the right and left sides of the spinal cord gray matterGray Commissure
Motor tract found in the lateral white matterCorticospinal Tract
Protective Reflex. Stimulus (pain) causes withdrawal of limb. May be accompanied by crossed extensor reflex during which contralateral limb is extended to help support bodyFlexor Withdrawal Reflex


Question Answer
Biceps reflex C5/C6
Triceps reflex C6/C7
Brachioradialis reflex C5/C6
Patellar reflex L2-L4
Achille’s reflex S1/S2

Spinal Cord 2

Question Answer
Vibration, fine touch, continence, proprioceptionDorsal Column/Medial Leminiscus Tract
Pain, temperature and light touchAnterolateral Spinothalamic Tract
Proprioception of the legsDorsal Spinocerebellar Tract
Proprioception of the trunkVentral Spinocerebellar Tract
Proprioception of the armsCuneocerebellar Tract
Fine skill movementCorticorspinal Tract
Coarse skill movementRubrospinal Tract, Olivospinal Tract, Vestibulospinal Tract, and Tectospinal Tract
Cell bodies of these are located in the dorsal root ganglion; the peripheral portion of this nerve forms the sensory nerve ending, while a central process enters the spinal cord 1st Order Neuron
Cell body located in spinal cord or brainstem; axon ascends, crosses the midline2nd Order Neuron
Cell bodies usually located in thalamus, axons ascend to sensory areas of cortex3rd Order Neuron
Conveys pain and temperature and basic tactile sensation. 2nd order neurons of this tract cross over immediately in the spinal cord and ascend contralaterallyAnterolateral Spinothalamic Tract
Dorsal horn has ‘entry zone’ for axons. Lateral spinothalamic axons branch 1-3 segments up and down here before synapsing with 2nd order neuronsPosterolateral Tract of Lissauer
Direct pathway to thalamus and on to primary somatosensory cortex (post central gyrus). ‘Sensation’ of pain, etcNeospinothalamic
Indirect pathway, does go to thalamus and cortex, but gives afferents along the way to reticular formation. Cortical locations are more widespread, including cingulate gyrus and limbic structures. ‘Affective’ and ‘arousal’ component of painPaleospinothalamic
2nd order neuron of this tract cross over in the caudal medulla and go the ThalamusDorsal Column/Medial Lemniscus Tract
2nd order neurons of the Dorsal Column/Medial Lemniscus Tract are found in the medualla and are calledNucleus Gracilis and Nucleus Cuneatus
Located medially in the dorsal white matter, contains axons arising from dorsal root ganglia at T7 and belowFasciculus Gracilis
Located laterally in the dorsal white matter, contains axons from dorsal root ganglia at T6 and aboveFasciculus Cuneatus
Located in caudal medulla, location of 2nd order neurons of the Dorsal ColumnNucleus Gracilis and Cuneatus
Axons decussate as these, ascend to VPL of thalamusArcuate Fibers
Axonal access from the cerebellum to the spinal cordCerebellum Peduncle
Ipsolateral tract that goes through the inferior cerebellar peduncle consisting of two neuronsPosterior Spinocerebellar Tract
Both an ipsolateral and contralateral tract that enters the cerebellum through the superior cerebellar peduncle. The contralateral part of the tract crosses back over in the cerebellumAnterior Spinocerebellar Tract
Mediates information of proprioception from the lower extremities. 1st order neurons synapse in nucleus dorsalis. 2nd order neurons ascend ipsilaterally then enter cerebellum via inferior cerebellar pedunclesPosterior Spinocerebellar Tract
Mediates proprioception from the upper extremities. 1st order neurons ascend in the dorsal column then synapse in the lateral cuneate nucleus in the medulla. 2nd order neurons stay ipsilateral and enter the cerebellum via inferior pedunclesCuneocerebellar Tract
Transmits information from the thoracolumbar levels. 1st order neurons synapse with interneurons in the dorsal horn; interneurons send axons to 2nd order neurons in the lateral and ventral horns. 2nd order neurons cross via the ventral white commissure, ascend contralaterally and enter the cerebellum via the superior cerebellar peduncle. They then cross back to the ipsilateral cerebellumAnterior Spinocerebellar Tract
Contralateral loss of pain and temperature, and simple tactile sensations, 1-2 below the level of the lesionSpinothalamic Tract Lesion
Ipsilateral loss of vibratory sense, position, and tactile discrimination at the level of the lesionDorsal Column System Lesion
Selective damage to these tracts (i.e. without UMN damage) is rare. Symptoms when damaged would include loss of propioception and ataxia (typically ‘masked’ by the UMN damage: can’t see ataxia if the patient can’t walk)Spinocerebellar Tract Lesion

Spinal Cord 3

Motor tracts originate in the cortex and brainstem
Question Answer
Supratentorial area in the brain that contains axons of the corticospinal tract that is the most common place of hypertensive strokesInternal Capsule
Only tract that originates in the cortex (supratentorial)Corticospinal Tract
Tracts that control the trunkMedial Motor Tracts
Tracts that control the arms and legsLateral Motor Tracts
Responsible for voluntary movementCorticospinal Tract
The other name for the CSTPyramidal Tract
The other name for the infratentorial tractsExtrapyramidal Tracts
Voluntary, discrete, skilled motor movementsCorticospinal Tract
Facilitation of voluntary and reflex movements via modulation of motor neurons in anterior horn. (there are two reticulospinal, lateral and medial, see reticulospinal slide)Reticulospinal Tract
Reflex postural movements in response to visual stimuli (visuo-postural reflex)Tectospinal
Facilitates flexor muscles, inhibits extensor muscles. Originates in the Red NucleusRubrospinal Tract
Facilitates extensor muscles, inhibits flexor muscles. Also involved in postural control and balance. (there are two vestibulospinal, lateral and medial, see vestibulospinal slide)Vestibulospinal Tract
Muscle activityOlivospinal
Corticospinal tract descends through brain ipsilaterally, then crosses in the medulla and descends contralaterally in cordLateral Corticospinal Tract
Corticospinal tract descends ipsilaterally all the way to the cord, then innervates bilaterallyAnterior Corticospinal Tract
Derived from precentral gyrus (4), postcentral gyrus (1,2,3), and premotor cortex (6)Corticospinal Tract
In the spinal cord, CST symptoms are alwaysIpsilateral
Take care of ‘gross body movements’, i.e. the stuff we don’t want to have to think about while performing skilled tasksExtrapyramidal Tracts
Reticulospinal tract that is ipsilateral, extensorsMedial (pontine) Reticulospinal Tract
Reticulospinal tract that is mostly ipsilateral, flexorsLateral (Medullary) Reticulospinal Tract
One of its functions of this tract is to inhibit reflex contractions, so that only noxious (painful) stimuli can illicit a flexor reflexReticulospinal Tract
We respond reflexively to motion or light. Motion in periphery of vision, our eyes ‘jump’ to it. Since the head and eyes are turning, the body needs to make reflex postural adjustmentsTectospinal Tract
Originates from the red nucleus of the midbrain. Crosses over immediately in the midbrain and moves down the spinal cord contralaterally. Important for cerebellum coordinationRubrospinal Tract
Responsible for balance and balance correction. Connections to motor and balance centersVestibulospinal Tract
Vestibulospinal tract that adjusts body posture (ispilateral only)Lateral Vestibulospinal Tract
Vestibulospinal tract that adjusts head posture (bilaterally)Medial Vestibulospinal Tract
Tract that originates in the olivary nucleusOlivospinal Tract
This test tests for dorsal column damageRomberg Test
This test is done with the feet together and eyes closedRomberg Test
Babinski sign, Hoffman’s, sign, loss of abdominal and cremasteric reflexes are only seen in damage to this tractCST
The symptoms of this type of motor neuron damage are paresis (hemiparesis), Babinski sign ‘present’, Hoffman’s sign present, abdominal reflex absent, cremasteric reflex absent. Spasticity, which is hyper-reflexia of DTR’s, clonus, and increased muscle tone (rigidity)UMN Damage
The symptoms of this type of motor neuron damage are flaccid paralysis, atrophy of muscles, Loss of reflexes, muscular fasciculation, muscular contracture (shortening of muscles) and reaction of degeneration (decreased response of muscle to electrical stimulation)LMN Damage

Recent badges