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ANAT242 > Test 2 > Flashcards

Test 2 Flashcards

1
Q

Learning objectives

  • Identify the major structures of the brainstem and describe their general functions
  • Name the 12 cranial nerves and their sensory/motor properties
  • Describe the origin, course & major function of cranial nerves I and II
  • Understand how visual field deficits arise
A

jfkms

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2
Q

Brainstem

Consist of the?

Positioned b/w?

Connected dorsally to the?

Provides a pathway for …. running b/w the forebrain, cerebellum & spinal cord

Associated w/ 10 of the 12 pairs of?

A

Brainstem

Consist of the?

  • Midbrain
  • Pons
  • Medulla

Positioned b/w?
- The forebrain & spinal cord

Connected dorsally to the?
- Cerebellum

Provides a pathway for AXONAL TRACTS running b/w the forebrain, cerebellum & spinal cord

Associated w/ 10 of the 12 pairs of?
- Cranial nerves

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3
Q

Midbrain

Name the structures:

A

Midbrain

Name the structures:

  • Cerebral peduncles
  • Corpora quadrigemia (quadruplets)
    • Superior colliculi
    • Inferior colliculi
  • Substantia nigra
  • Red nucleus
  • Cranial nerves
    • oculomotor (III)
    • trochlear (IV)
  • Cerebral aqueduct
  • Superior cerebellar peduncles
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4
Q

Midbrain - Cerebral Peduncles

Includes axons that descend from the cerebral cortex to the?

Passes longitudinally on the …. surface of the ….

Help to … the cerebrum to the …

…… nerves emerges anterior

….. nerves emerges posterior

A

Midbrain - Cerebral Peduncles

Includes axons that descend from the cerebral cortex to the?
- Brainstem and spinal cord

Passes longitudinally on the VENTRAL surface of the MIDBRAIN

Help to ANCHOR the cerebrum to the BRAINSTEM

III CRANIAL nerves emerges anterior

IV CRANIAL nerves emerges posterior

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5
Q

Midbrain - Cerebral Peduncles

Locate the Aqueduct of syivius & Peduncle

  • L6, page 6
A

facklms

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6
Q

Midbrain - Corpora quadrigemia: Superior & Inferior Colliculus

Locate the Superior & Inferior Colliculus

  • L6, page 7
A

urefivjkns cvefibefi

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7
Q

Superior colliculi (visual reflex centres)

Receives inputs from the ….. & projects to ….

Concerned with the detection of …. in the visual field

Relay vision information to neurons innervating the …..

A

Superior colliculi (visual reflex centres)

Receives inputs from the RETINA/VISUAL CORTEX & projects to VISION-RELATED AREAS IN CORTEX

Concerned with the detection of MOVEMENT OF OBJECTS in the visual field

Relay vision information to neurons innervating the MUSCLES THAT CONTROL EYE MOVEMENT

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8
Q

Inferior colliculi (auditory relay nuclei)

Relaying …. information from hearing receptors of the ear to the …..

Act in …… responses to sound

A

Inferior colliculi (auditory relay nuclei)

Relaying AUDITORY information from hearing receptors of the ear to the SENSORY CORTEX

Act in REFLEXIVE responses to sound

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9
Q

Midbrain - Substantia Nigra

Located … to the cerebral peduncle

Contains …. (biochemically related to dopamine)

Functionally linked to ….

….. Disease

A

Midbrain - Substantia Nigra

Located ABOVE to the cerebral peduncle

Contains MELANIN PIGMENT (biochemically related to dopamine)

Functionally linked to BASAL NUCLEI/GANGLIA

DOPAMINE NEURONE DEGENERATION PARKINSONS Disease

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10
Q

Midbrain - Red Nucleus

Lies above the …

Rich bloody supply & contains ….

Relay nucleus in some ….

A

Midbrain - Red Nucleus

Lies above the SUBSTANTIA NIGRA

Rich bloody supply & contains IRON PIGMENT

Relay nucleus in some DESCENDING MOTOR PATHWAYS

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11
Q

Midbrain - Superior Cerebullar Peduncle

Comprises fibres that connect …. with ….

Major ….. fibres from the ….

Involved in ….

A

Midbrain - Superior Cerebullar Peduncle

Comprises fibres that connect CEREBELLUM with MIDBRAIN

Major OUTPUT fibres from the CEREBELLUM

Involved in PROPRIOCEPTION

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12
Q

Pons

Structures:

A

Pons

Structures:

  • Cranial nerves
    • trigeminal (V)
    • abducens (VI)
    • facial (VII)
    • vestibulocochlear (VIII)
  • 4th ventricle
  • Middle cerebellar peduncle
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13
Q

Pons (bridge)

Composed of both … & …. tracts

Pomposed of various pontine nuclei: eg …

A

Pons (bridge)

Composed of both ASCENDING SENSORY & DESCENDING MOTOR tracts

Pomposed of various pontine nuclei: eg PNEUMOTAXIC CENTRE (RESPIRATORY CENTRE)

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14
Q

Pons - Middle Cerebellar Peduncle

Comprises fibres from the … to the …

Convey …. and …. command information

A

Pons - Middle Cerebellar Peduncle

Comprises fibres from the PONS to the CEREBELLUM

Convey MOTOR and SENSORY command information

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15
Q

Medulla

Structures:

A

Medulla

Structures:

  • Pyramids
  • Olives
  • Gracile & Cuneate Tubercles
  • Cranial nerves
    • glossopharyngeal (IX)
    • vagus (X)
    • accessory (XI)
    • hypoglossal (XII)
  • 4th ventricle
  • Inferior cerebellar peduncle
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16
Q

Medulla - Pyramids

Pyramids (open medulla)
formed by the large …. descending from the …

Pyramidal Decussation (closed medulla) axons of the ….. cross over to the opposite side at the level just above the ….

A

Medulla - Pyramids

Pyramids (open medulla)
formed by the large PYRAMIDAL (coricospinal) TRACTS descending from the MOTOR CORTEX

Pyramidal Decussation (closed medulla) axons of the PYRAMIDAL TRACTS cross over to the opposite side at the level just above the MEDULLA SPINAL JUNCTION

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17
Q

Medulla - Olives

Located in the …

Contains …. which relay sensory information to the …

A

Medulla - Olives

Located in the OPEN MEDULLA

Contains INFERIOR OLIVARY which relay sensory information to the CEREBELLUM

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18
Q

Medulla - Tubercles

Cuneate and Gracile tubercles (in closed medulla) receive …. from …. & …. from the upper and lower body respectively

A

Medulla - Tubercles

Cuneate and Gracile tubercles (in closed medulla) receive SOMATOSENSORY INFORMATION from CUNEATE FASCICULUS & GRACILE FASCICULUS SPINAL TRACTS from the upper and lower body respectively

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19
Q

Medulla - Inferior Cerebellar Peduncle

Comprises fibres to and from the …. to …

Carries … and …. important for … and …

A

Medulla - Inferior Cerebellar Peduncle

Comprises fibres to and from the MEDULLA/SPINAL CORD to CEREBELLUM

Carries SENSORY and MOTOR INFORMATION important for BALANCE and POSTURE

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20
Q

Reticular Formation

Composed of clusters of …. scattered throughout …

Covering the arousal of the brain via ….

A

Reticular Formation

Composed of clusters of GREY MATTER scattered throughout MIDBRAIN, PONS, AND MEDULLA

Covering the arousal of the brain via THALAMUS

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21
Q

Reticular Formation

Involved in …

Inhibited by …. located in the …

Depressed by …

Brainstem injury:

A

Reticular Formation

Involved in HABITUATION

Inhibited by SLEEP CENTRES located in the HYPOTHALAMUS & OTHER BRAIN REGIONS

Depressed by ALCOHOL, SLEEP-INDUCING DRUGS & TRANQUILISERS

Brainstem injury:
- permanent unconsciousness

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22
Q

Cranial Nerves

name them
- L6, page 3

A

yribfhks

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23
Q

A way of learning the Cranial Nerves

  • L6, page 34
A

gbhvnjcem

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24
Q

Olfactory Nerves

…. sensory nerves

Run from the nasal mucosa, pass through … of ethmoid bone to synapse w/ the …

Provide …

Damage causes ….

A

Olfactory Nerves

TINY sensory nerves

Run from the nasal mucosa, pass through CRIBIFORM PLATE of ethmoid bone to synapse w/ the OLFACTORY BULB

Provide SENSE OF SMELL

Damage causes IMPAIRED SENSE OF SMELL (ANOSMIA)

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25
Q

Olfactory Projection Pathways:

  • L6, page 39
A

OOHHAR

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26
Q

Optic nerves

Axons arising from the …. of the eye to form …

Each optic nerve passes through its … of the orbit

Nerves converge to form the … (axons partially cross over) & continue on as …

Enables …

A

Optic nerves

Axons arising from the RETINA of the eye to form OPTIC NERVE

Each optic nerve passes through its OPTIC FORAMEN of the orbit

Nerves converge to form the OPTIC CHIASM (axons partially cross over) & continue on as OPTIC TRACTS

Enables VISION

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27
Q

Visual Processing: 1) Retina Processing

Steps:

A

Visual Processing: 1) Retina Processing

Steps:

Local currents produce in response to light

Rods & Cones > Bipolar neurons > Ganglion cells > Optic nerve > Subcortical & cortical visual areas

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28
Q

Visual Processing

Each nasal retina sees a …

Each temporal retina sees …

Left side of each retina sees the ….

Right side of each retina sees the …

A

Visual Processing

Each nasal retina sees a TEMPORAL VISUAL FIELD/WORLD

Each temporal retina sees NASAL VISUAL FIELD/WORLD

Left side of each retina sees the RIGHT VISUAL FIELD/WORLD

Right side of each retina sees the LEFT VISUAL FIELD/WORLD

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29
Q

VIsual processing

Optic Tract: Crossed axons from …. & uncrossed axons from …

A

VIsual processing

Optic Tract: Crossed axons from NASAL RETINA & uncrossed axons from TEMPORAL RETINA

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30
Q

L7 learning objectives

  • Identify the location of each cranial nerve root in the brainstem
  • Describe the origin, course and major function of each cranial nerve
  • Understand the physical consequences of damage to each cranial nerve
A

5exdtcfvytgbhui

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31
Q

Cranial nerves

L7, page 4

A

rbksvj

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32
Q

Oculomotor Nerves

Axons extend from … & pass through the … to the …

A

Oculomotor Nerves

Axons extend from VENTRAL MIDBRAIN & pass through the SUPERIOR ORBITAL FISSURE to the EYE

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33
Q

III. Oculomotor Nerves: Somatic (voluntary) motor axons

to … of the 6 extrinsic eye muscles - move …

to … superior muscle - raising …

A

III. Oculomotor Nerves: Somatic (voluntary) motor axons

to 4 of the 6 extrinsic eye muscles - move EYEBALL

to LEVATOR PALPEBRAE superior muscle - raising UPPER EYELID

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34
Q

III. Oculomotor Nerves: Parasympathetic (autonomic) motor axons

to … muscles of … - causing pupil to …

to … muscle - controlling shape of … for visual focusing

A

III. Oculomotor Nerves: Parasympathetic (autonomic) motor axons

to CONSTRICTOR muscles of IRIS - causing pupil to CONSTRICT

to CILIARY muscle - controlling shape of LENS for visual focusing

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35
Q

III. Oculomotor Nerves

In sum: provides most of the … of each eye

ALSO:

A

III. Oculomotor Nerves

In sum: provides most of the MOVEMENT of each eye

ALSO:

  • Opening of eyelid
  • Constriction of pupil
  • Focusing
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36
Q

IV. Trochlear Nerves

Axons emerge from …., course ventrally around midbrain, pass through the … to the …

A

IV. Trochlear Nerves

Axons emerge from DORSAL MIDBRAIN, course ventrally around midbrain, pass through the SUPERIOR ORBITAL FISSURE to the EYE

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37
Q

IV. Trochlear Nerves

Provide …

Damage causes … & inability to rotate eye …

A

IV. Trochlear Nerves

Provide EYE MOVEMENT

Damage causes DOUBLE VISION & inability to rotate eye INFEROLATERALLY

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38
Q

V. TRIGEMINAL NERVES

Axons extend from … & ….

Cell bodies of sensory neurons are located in large …

A

V. TRIGEMINAL NERVES

Axons extend from FACE TO PONS & PONS TO MUSCLES

Cell bodies of sensory neurons are located in large TRIGEMINAL GANGLION

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39
Q

V. Trigeminal Nerve

Axons run from … via …

Convey …. from skin of anterior scalp, upper eyelid & nose, & from nasal cavity mucosa, cornea & lacrimal (tear) gland

A

V. Trigeminal Nerve

Axons run from FACE TO PONS via SUPERIOR ORBITAL FISSURE

Convey SENSORY IMPULSES from skin of anterior scalp, upper eyelid & nose, & from nasal cavity mucosa, cornea & lacrimal (tear) gland

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40
Q

V. Trigeminal Nerves: Mandibular division (V3) SENSORY BRANCH

Axons pass through skull via …

Convey …. from anterior tongue (except taste bud), lower teeth, skin of chin, & temporal region of scalp

A

V. Trigeminal Nerves: Mandibular division (V3)

Axons pass through skull via FORAMEN OVALE

Convey SENSORY IMPULSES from anterior tongue (except taste bud), lower teeth, skin of chin, & temporal region of scalp

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41
Q

V. Trigeminal Nerves: Mandibular division (V3) MOTOR BRANCH

Supply …. to (carry proprioceptor axons from) muscles of mastication

A

V. Trigeminal Nerves: Mandibular division (V3) MOTOR BRANCH

Supply MOTOR AXONS to (carry proprioceptor axons from) muscles of mastication

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42
Q

V. Trigeminal Nerves

…. cranial nerve

….. (transmitting afferent impulses from touch, temperature & pain receptors)

Supply motor axons to …

… produces loss of sensation & impaired chewing

A

V. Trigeminal Nerves

LARGEST cranial nerve

MAIN SENSORY NERVE TO FACE (transmitting afferent impulses from touch, temperature & pain receptors)

Supply motor axons to MUSCLES OF MASTICATION

DAMAGE produces loss of sensation & impaired chewing

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43
Q

VI. Abducens Nerves

Axons leave … & pass through … to … (lateral rectus muscle)

Provide … (abducts the eyeball)

… results in inability to rotate eye laterally & at rest eye rotates medially

A

VI. Abducens Nerves

Axons leave INFERIOR PONS & pass through SUPERIOR ORBITAL FISSURE to EYE (lateral rectus muscle)

Provide EYE MOVEMENT (abducts the eyeball)

DAMAGE results in inability to rotate eye laterally & at rest eye rotates medially

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44
Q

VII. Facial Nerves

Axons emerge from …, enter temporal bone via … and run w/in bone (through inner ear cavity) before emerging through styloid foramen; course to …

A

VII. Facial Nerves

Axons emerge from PONS enter temporal bone via INTERNAL AUDITORY MEATUS and run w/in bone (through inner ear cavity) before emerging through styloid foramen; course to LATERAL ASPECT OF FACE

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45
Q

VII. Facial Nerves

Major …

Supply motor axons to (convey proprioceptor impulses from) skeletal muscles of face (….) Except for chewing muscles served by cranial nerve V

Transmit … impulses to lacrimal (tear) glands, nasal & salivary glands

Convey …. of anterior 2/3 of tongue

… Produces sagging facial muscles & disturbed sense of taste (missing sweet, salty & umami)

A

VII. Facial Nerves

Major MOTOR AXONS OF FACE

Supply motor axons to (convey proprioceptor impulses from) skeletal muscles of face (MUSCLES OF FACIAL EXPRESSION) Except for chewing muscles served by cranial nerve V

Transmit PARASYMPATHETIC (AUTONOMIC) MOTOR impulses to lacrimal (tear) glands, nasal & salivary glands

Convey SENSORY IMPULSES FROM TASTE BUDS of anterior 2/3 of tongue

DAMAGE produces sagging facial muscles & disturbed sense of taste (missing sweet, salty & umami)

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46
Q

VII. Facial Nerves - Bells Palsy

Characterised by … (affected side) & ….

… Causing inflammation of facial nerve

….: Lower eyelid droops, corner of mouth sags, tears drip continuously, eye cannot be completely closed, paralysed face is ‘pulled’

…: Steroids, rest

A

VII. Facial Nerves - Bells Palsy

Characterised by PARALYSIS OF FACIAL MUSCLES (affected side) & PARTIAL LOSS OF TASTE SENSATION

VIRAL INFECTION causing inflammation of facial nerve

Symptoms: Lower eyelid droops, corner of mouth sags, tears drip continuously, eye cannot be completely closed, paralysed face is ‘pulled’

Treatment: Steroids, rest

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47
Q

VIII. Vestibulocochlear Nerves

Axons arising from hearing & equilibrium apparatus w/in …., passing through … to enter …

A

VIII. Vestibulocochlear Nerves

Axons arising from hearing & equilibrium apparatus w/in INNER EAR OF TEMPORAL BONE, passing through INTERNAL ACOUSTIC MEATUS to enter BRAINSTEM AT THE PONS-MEDULLA BORDER

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48
Q

VIII. Vestibulocochlear Nerves

Provide … (cochlea nerves) and sense of … (vestibular nerves

…. produces

  • Deafness
  • Dizziness, nausea
  • Loss of balance
  • Vestibular nystagmus (rapid involuntary eye movements)
A

VIII. Vestibulocochlear Nerves

Provide HEARING (cochlea nerves) and sense of BALANCE (vestibular nerves

DAMAGE produces

  • Deafness
  • Dizziness, nausea
  • Loss of balance
  • Vestibular nystagmus (rapid involuntary eye movements)
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49
Q

Temporal Lobe - Primary Auditory Cortex

…. (inside lateral fissure) extending to superior margin of the ….

Processes ….

…. = hearing loss

….. = cortical deafness

A

Temporal Lobe - Primary Auditory Cortex

TRANSVERSE TEMPORAL GYRUS (inside lateral fissure) extending to superior margin of the SUPERIOR TEMPORAL GYRUS

Processes AUDITORY INFO

UNILATERAL DAMAGE (MIDDLE CEREBRAL ARTERY) = hearing loss

BILATERAL DAMAGE = cortical deafness

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50
Q

IX. Glossopharyngeal Nerves

Axons emerge from …. & leave skull through …

A

IX. Glossopharyngeal Nerves

Axons emerge from MEDULLA & leave skull through JUGULAR FORAMEN

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51
Q

IX. Glossopharyngeal Nerves

Supply … axons to (carry proprioceptor fibres from) a …. - stylopharyngeus

Provide …. to parotid ….

A

IX. Glossopharyngeal Nerves

Supply MOTOR axons to (carry proprioceptor fibres from) a PHARYNGEAL MUSCLE- stylopharyngeus

Provide PARASYMPATHETIC MOTOR AXONS to parotid SALIVARY GLAND

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52
Q

IX. Glossopharyngeal Nerves

Sensory axons conduct …. from … & posterior 1/3 of …

Conducts sensory impulses from …. in the … & … of …

A

IX. Glossopharyngeal Nerves

Sensory axons conduct TASTE & GENERAL SENSORY IMPULSES from PHARYNX & posterior 1/3 of TONGUE

Conducts sensory impulses from CHEMORECEPTORS in the CAROTID BODY & PRESSURE RECEPTORS of CAROTID SINUS

53
Q

IX. Glossopharyngeal Nerves

Provide control over …. from posterior 1/3 of tongue, control of …

… results in loss of bitter & sour taste & impaired swallowing

A

IX. Glossopharyngeal Nerves

Provide control over SWALLOWING, SALIVATION, GAGGING, SENSATION from posterior 1/3 of tongue, control of BLOOD PRESSURE & RESPIRATION

DAMAGE results in loss of bitter & sour taste & impaired swallowing

54
Q

X. Vagus Nerve

Axons emerge from …, pass through skull via … descend through neck region into …

A

X. Vagus Nerve

Axons emerge from MEDULLA, pass through skull via JUGULAR FORAMEN, descend through neck region into THORAX & ABDOMEN

55
Q

X. Vagus Nerves

Motor:

  • Supply motor axons to (carry proprioceptor fibres from) skeletal muscles of …
  • Parasympathetic (autonomic) motor fibres supply … & …

Sensory:

  • Conduct sensory impulses from .. & …
  • Transmit sensory impulses from … in the … & … & …. of ….
  • Conduct sensory impulses from … of posterior tongue & pharynx
A

X. Vagus Nerves

Motor:

  • Supply motor axons to (carry proprioceptor fibres from) skeletal muscles of PHARYNX & LARYNX
  • Parasympathetic (autonomic) motor fibres supply HEART, LUNGS & ABDOMINAL VISCERA

Sensory:

  • Conduct sensory impulses from THORACIC & ABDOMINAL VISCERA
  • Transmit sensory impulses from CHEMORECEPTORS in the CAROTID & AORTIC BODIES & PRESSURE RECEPTORS of CAROTID SINUS
  • Conduct sensory impulses from TASTE BUDS of posterior tongue & pharynx
56
Q

X. VAGUS NERVES

The only cranial nerve extending beyond the head & neck to the … & …

Majority of motor axons are …

Provide … & …; regulate activities of …

…. causes hoarseness or loss of voice, impaired swallowing & digestive system mobility

…. implicated in hypertension, anxiety disorders & depression

A

X. VAGUS NERVES

The only cranial nerve extending beyond the head & neck to the THORAX & ABDOMEN

Majority of motor axons are PARASYMPATHETIC (AUTONOMIC)

Provide SWALLOWING & SPEECH; regulate activities of MAJOR VISCERA

DAMAGE causes hoarseness or loss of voice, impaired swallowing & digestive system mobility

HYPOACTIVITY implicated in hypertension, anxiety disorders & depression

57
Q

XI Accessory Nerves

… root joins with axons of vagus nerve (X) to supply motor axons to …, … & …;

…. causes hoarseness or loss of voice & impaired swallowing

…. roots supplies motor axons to trapezius & sternocleidomastoid muscles, therefore provides …….

… causes impaired head, neck & shoulder movement eg unable to shrug on one side if unilateral injury

A

XI Accessory Nerves

CRANIAL root joins with axons of vagus nerve (X) to supply motor axons to LARYNX, PHARYNX & SOFT PALATE

DAMAGE causes hoarseness or loss of voice & impaired swallowing

SPINAL roots supplies motor axons to trapezius & sternocleidomastoid muscles, therefore provides HEAD, NECK & SHOULDER MOVEMENTS

DAMAGE causes impaired head, neck & shoulder movement eg unable to shrug on one side if unilateral injury

58
Q

XII. Hypoglossal Nerves

Axons arise by a series of roots from …, exit from skull via …. to …

Axons emerge b/w the …

A

XII. Hypoglossal Nerves

Axons arise by a series of roots from MEDULLA, exit from skull via HYPOGLOSSAL CANAL to TONGUE

Axons emerge b/w the PYRAMID & OLIVE

59
Q

XII. Hypoglossal Nerves

Supply somatic motor axons to muscles of …

Provide …. of speech, food manipulation & swallowing

… causes dificulties in speech & swallowing

  • Both sides - inabiluty to protrude tongue
  • One side - tongue deviates (leans) toward injured side & eventually results in ipsilateral atrophy
A

XII. Hypoglossal Nerves

Supply somatic motor axons to muscles of TONGUE

Provide TONGUE MOVEMENTS of speech, food manipulation & swallowing

DAMAGE causes dificulties in speech & swallowing

  • Both sides - inabiluty to protrude tongue
  • One side - tongue deviates (leans) toward injured side & eventually results in ipsilateral atrophy
60
Q

Cerebellum

Consist of …, …. & ….

40 x more ….. than …

very …. structure

concerned primarily with:

  • ….., precisely timed movement
  • control of …
  • maintenance of …

Receives vast amount of sensory info, but does not give rise to …. …. perceptions

A

Cerebellum

Consist of CORTEX, WHITE MATTER & DEEP NUCLEI

40 x more AFFERENT than EFFERENT

very ORDERED structure

concerned primarily with:

  • SYNCHRONISED, precisely timed movement
  • control of MUSCLE TONE (posture)
  • maintenance of BALANCE

Receives vast amount of sensory info, but does not give rise to CONSCIOUS SENSORY perceptions

61
Q

External Cerebellum (superior surface)

Right and left hemispheres connected by …

Parallel surface folds called … are grey matter

A

External Cerebellum (superior surface)

Right and left hemispheres connected by VERMIS

Parallel surface folds called FOLIA are grey matter

62
Q

Cerebellar Lobes

Anterior & posterior lobes co-ordinate ….

A

Cerebellar Lobes

Anterior & posterior lobes co-ordinate MOVEMENT

63
Q

Flocculonodular lobe helps with ….

A

Flocculonodular lobe helps with BALANCE

64
Q

Cerebellum: Sagittal Sub-Divisions

What are the zones?

A

Cerebellum: Sagittal Sub-Divisions

What are the zones?

  • Lateral zone
  • Intermediate zone
65
Q

Spinocerebellum (vermis & intermediate zone):

Receives … information

Regulates … via …

A

Spinocerebellum (vermis & intermediate zone):

Receives PROPRIOCEPTIVE information

Regulates BODY MOVEMENTS via ERROR CORRECTION

66
Q

Cerebrocerebellum (lateral zone):

Receives input from the …. and … ….., outputs to the … and … …..

…. movements and motor learning

Coordination of …

Important in …… …. movements

A

Cerebrocerebellum (lateral zone):

Receives input from the PONS and CEREBRAL CORTEX, outputs to the THALAMUS and RED NUCLEUS

PLANNING movements and motor learning

Coordination of MUSCLES

Important in VISUALLY GUIDED movements

67
Q

Vestibullocerebellum (flocculonodular lobe):

Receives inputs from the …. system, sends outputs back to the …. ….

Controlling …

…. reflexes

A

Vestibullocerebellum (flocculonodular lobe):

Receives inputs from the VESTIBULAR system, sends outputs back to the VESTIBULAR NUCLEI

Controlling BALANCE

OCULAR (eye) reflexes

68
Q

Three major components:

A

Three major components:

  • Superficial gray matter (cortex)
  • White matter)
  • Deep nuclei (gray mattey)
69
Q

What makes up the Deep Cerebellar Nuclei?

A

What makes up the Deep Cerebellar Nuclei?

  • Fastigial
  • Interposed
  • Dentate
70
Q

Cerebellar Cortex - Circuity

Two main inputs:

…. from spinal cord or brainstem neurons conveying motor or sensory input

….. mainly from inf. olivary nucleus = proprioceptive input

…. … form excitatory synapses with … …. in the cerebellar cortex

The …. …. send their axon as a ‘parallel fibre’ to form exitatory synapses with the …. neurons

A

Cerebellar Cortex - Circuity

Two main inputs:

MOSSY FIBRES from spinal cord or brainstem neurons conveying motor or sensory input

CLIMBING FIBRES mainly from inf. olivary nucleus = proprioceptive input

MOSSY AXONS form excitatory synapses with GRANULE NEURONS in the cerebellar cortex

The GRANULE NEURONS send their axon as a ‘parallel fibre’ to form exitatory synapses with the PURKINJE neurons

71
Q

Cerebellar Cortex - Circuitry

Climbing axons form …. synapses directly with the …. …. in the …. ….

…. neurons are the sole output of the cerebellar cortex

  • Inhibitory - synapse in … …. ….
  • Work with input axons to regulate … …. and …. of the neurons in the deep cerebellar nuclei
A

Cerebellar Cortex - Circuitry

Climbing axons form EXCITATORY synapses directly with the PURKINJE NEURONS in the CEREBELLAR CORTEX

PURKINJE neurons are the sole output of the cerebellar cortex

  • Inhibitory - synapse in DEEP CEREBELLAR NUCLEI
  • Work with input axons to regulate FIRING FREQUENCY and AMPLITUDE of the neurons in the deep cerebellar nuclei
72
Q

Draw Cerebellar Cortex Circuity

  • L8, Page 29
A

xrctvybu

73
Q

Cerebellar Peduncles

Inferior Cerebellar Peduncle (Medulla)

Conveys …. information to the cerebellum

  • From ….. proprioceptors throughout the body
  • From the … …. of the brainstem (equilibrium & balance)

Contains both …. & … axons

A

Cerebellar Peduncles

Inferior Cerebellar Peduncle (Medulla)

Conveys SENSORY information to the cerebellum

  • From MUSCLE proprioceptors throughout the body
  • From the VESTIBULAR NUCLEI of the brainstem (equilibrium & balance)

Contains both AFFERENT & EFFERENT axons

74
Q

Cerebellar Peduncles

Middle Cerebellar Peduncle (Pons)

Contains only …. axons (crossed axons from …. …. ….)

A

Cerebellar Peduncles

Middle Cerebellar Peduncle (Pons)

Contains only AFFERENT axons (crossed axons from CONTRALATERAL PONTINE NUCLEI)

75
Q

Cerebellar Peduncles

Superior Cerebellar Peduncle (Midbrain)

Formed by axons that arise from … …. … (main …. pathway)
- Fibres decussate at various levels - either terminate in the … ….. or continue rostrally to end w/in the … (then to … … ….)

A

Cerebellar Peduncles

Superior Cerebellar Peduncle (Midbrain)

Formed by axons that arise from DEEP CEREBELLAR NUCLEI (main EFFERENT pathway)
- Fibres decussate at various levels - either terminate in the RED NUCLEUS or continue rostrally to end w/in the THALAMUS (then to CEREBRAL MOTOR CORTEX)

76
Q

Cerebrocerebellar Ciruit (Lateral Zone)

Dentate nucleus receives …. information from …. …. …., …. …. & …..
- Input to the … …. & … ….

Controls …. movements of …, And contributes to … ….

A

Cerebrocerebellar Ciruit (Lateral Zone)

Dentate nucleus receives SENSORIMOTOR information from LATERAL CEREBELLAR CORTEX, CEREBRAL CORTEX & PONS
- Input to the VENTROLATERAL THALAMUS & RED NUCLEUS

Controls MULTI-JOINTED movements of LIMBS, and contributes to MOTOR PLANNING

77
Q

Spinocerebellar Circuit

Fastigial nucleus receives …… information from … …. …. & …
- Input to … … & … ….

Controls … via influencing axial muscles in ….

A

Spinocerebellar Circuit

Fastigial nucleus receives SOMATOSENSORY information from VERMAL CEREBELLAR CORTEX & TRUNK
- Input to VESTIBULAR NUCLEI & RETICULAR FORMATION

Controls POSTURE via influencing axial muscles in TRUNK

78
Q

Spinocerebellar Circuit (Intermediate Zone)

Interposed nuclei receive ….. information from … … …. & ….
- Inputs to the … …

Controls … … … … (precision of movements at joints)

A

Spinocerebellar Circuit (Intermediate Zone)

Interposed nuclei receive SOMATOSENSORY information from INTERMEDIATE CEREBELLAR CORTEX & LIMBS
- Inputs to the RED NUCLEUS

Controls ACCURACY OF LIMB MOVEMENTS (precision of movements at joints)

79
Q

Vestibulocerebellar Circuit (Flocculonodular Lobe)

Flocculonodular lobe receives …. information
- Input to the ….

Controls ….

A

Vestibulocerebellar Circuit (Flocculonodular Lobe)

Flocculonodular lobe receives VESTIBULAR information
- Input to the VESTIBULAR NUCLEI

Controls BALANCE

80
Q

Match up the Cerebellar Structures

L8, page 39

A

drtfychvgh

81
Q

How is synergistic multijoint movement achieved?

At the same time, the cerebellum receives information from proprioceptors … … …, as well as … & ….. input

A

How is synergistic multijoint movement achieved?

At the same time, the cerebellum receives information from proprioceptors THROUGHOUT THE BODY, as well as VISUAL & VESTIBULAR input

82
Q

L9 Learning objectives

  • Identify cortical regions involved in processing special and general senses
  • Classify the different sensory receptors based on function, location & complexity
  • Explain the structure of different general sensory receptors
  • Identify and describe the ascending somatosensory pathways, their functions, and the consequence of damage to each pathway
A

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83
Q

Sensation
….. of sensory stimulus

Stimulus = change in the …. or …. environment

Perceptions
….. of the meanings of the sensory stimuli

Both sensation & perception occur in the ….

A

Sensation
DETECTION of sensory stimulus

Stimulus = change in the EXTERNAL or INTERNAL environment

Perceptions
INTERPRETATION of the meanings of the sensory stimuli

Both sensation & perception occur in the BRAIN

84
Q

Special Senses

Each special sense organ projects to a specialized region of the brain. In the cerebrum, specialized region is called a .. … …

Taste - lower end of … ….

Smell - medial …. & ….. lobes

Vision ….. lobe

Hearing - ….. temporal gyri/ ….. temporal gyri

Equilibrium - mainly to the …

A

Special Senses

Each special sense organ projects to a specialized region of the brain. In the cerebrum, specialized region is called a PRIMARY SENSORY CORTEX

Taste - lower end of POSTCENTRAL GYRUS

Smell - medial TEMPORAL & ORBITOFRONTAL lobes

Vision OCCIPITAL lobe

Hearing - SUPERIOR temporal gyri/ TRANSVERSE temporal gyri

Equilibrium - mainly to the CEREBELLUM

85
Q

Sensory Receptors
- Are specialized to respond to …. in their ….

Classified by:

  • the type of …. they detect
  • their body ….
  • their structural ….
A

Sensory Receptors
- Are specialized to respond to CHANGES in their ENVIRONMENT

Classified by:

  • the type of STIMULUS they detect
  • their body LOCATION
  • their structural COMPLEXITY
86
Q

Classification of Sensory Receptors by Stimulus Type

1) Mechanoreceptors
- Are sensitive to a …. ….
(eg touch, pressure, vibration, stretch, itch)

2) Thermoreceptors
- Are sensitive to ….. changes

3) Photoreceptors
- Respond to …. …. (the retina of the eye)

4) Chemoreceptors
- Respond to …. in solution (molecules smelt or tasted, or changes in blood chemistry)

5) Nociceptors (noci = harm)
- Respond to potentially …. …. that result in pain

A

Classification of Sensory Receptors by Stimulus Type

1) Mechanoreceptors
- Are sensitive to a MECHANICAL FORCE
(eg touch, pressure, vibration, stretch, itch)

2) Thermoreceptors
- Are sensitive to TEMPERATURE changes

3) Photoreceptors
- Respond to LIGHT ENERGY (the retina of the eye)

4) Chemoreceptors
- Respond to CHEMICALS in solution (molecules smelt or tasted, or changes in blood chemistry)

5) Nociceptors (noci = harm)
- Respond to potentially DAMAGING STIMULI that result in pain

87
Q

Classification of Sensory Receptors by Location

1) Exteroceptors
- are sensitive to stimuli arising …. the body
- are located …. or … the body surface
- include:
- touch, pressure, pain & temperature receptors
- receptors of special senses (VIsion, hearing)

2) Interoceptors or Visceroceptors
- are sensitive to stimuli ….. the body
- are located in the …. …. & … ….
(eg chemical changes, tissue stretch, temperature)

A

Classification of Sensory Receptors by Location

1) Exteroceptors
- are sensitive to stimuli arising OUTSIDE the body
- are located NEAR or AT the body surface
- include:
- touch, pressure, pain & temperature receptors
- receptors of special senses (VIsion, hearing)

2) Interoceptors or Visceroceptors
- are sensitive to stimuli WITHIN the body
- are located in the VISCERAL ORGANS & BLOOD VESSELS
(eg chemical changes, tissue stretch, temperature)

88
Q

Proprioceptors

  • Are sensitive to …. stimuli
  • Located in … ….., …., …., …… & in ….. …. coverings of bones & muscles
  • …… receptors of the inner ear are sometimes included in this class
  • Constantly advise the brain of the body’s …. & …. in ….
A

Proprioceptors

  • Are sensitive to …. stimuli
  • Located in SKELETAL MUSCLES, TENDONS, JOINTS, LIGAMENTS & in CONNECTIVE TISSUE coverings of bones & muscles
  • EQUILIBRIUM receptors of the inner ear are sometimes included in this class
  • Constantly advise the brain of the body’s MOVEMENT & LOCATION in SPACE
89
Q

Classification of Sensory Receptors by Structural Complexity

Complex Receptors of the special senses are located in …. …. …. (eg rods & cones of retina)

Simple Receptors of the general senses:

  • Tactile sensation
  • Temperature
  • Pain
  • Muscle sense

Anatomically, these receptors are either ….. …. endings or ….. ….. endings

A

Classification of Sensory Receptors by Structural Complexity

Complex Receptors of the special senses are located in SPECIAL SENSE ORGANS (eg rods & cones of retina)

Simple Receptors of the general senses:

  • Tactile sensation
  • Temperature
  • Pain
  • Muscle sense

Anatomically, these receptors are either FREE NERVE endings or ENCAPSULATED NERVE endings

90
Q

Free (Unencapsulated) Nerve Endings

Widely present dendrites forming small knoblike swellings, respond mainly to .. & …. (also overt pressure)

Modified free nerve endings, respond to …. ….

A

Free (Unencapsulated) Nerve Endings

Widely present dendrites forming small knoblike swellings, respond mainly to PAIN & TEMPERATURE (also overt pressure)

Modified free nerve endings, respond to …. ….

91
Q

Tactile Corpuscles (Meissners Corpuscles)

  • Numerous in …., …. & soles of the …
  • …. …. & …..
A

Tactile Corpuscles (Meissners Corpuscles)

  • Numerous in NIPPLES, FINGERTIPS & soles of the FEET
  • LIGHT TOUCH & TEXTURE
92
Q

Lamellated Corpuscles (pacinian Corpuscles)

  • …. tissue of the skin
  • … …., …., …. & ….
A

Lamellated Corpuscles (pacinian Corpuscles)

  • SUBCUTANEOUS tissue of the skin
  • DEEP PRESSURE, STRETCH, TICKLE & VIBRATION
93
Q

Ruffini Corpuscles

  • …, …. tissue & … capsules
  • …. ….. & ….
A

Ruffini Corpuscles

  • DERMIS, SUBCUTANEOUS tissue & JOINT capsules
  • DEEP PRESSURE & STRETCH
94
Q

Muscle Spindles

  • W/in … ….
  • Each consist of a bundle of … skeletal muscle fibres in a … …. ….
  • … …. (proprioception)
A

Muscle Spindles

  • W/in SKELETAL MUSCLES
  • Each consist of a bundle of MODIFIED skeletal muscle fibres in a CONNECTIVE TISSUE CAPSULE
  • MUSCLE STRETCH (proprioception)
95
Q

Encapsulated nerves Endings: Joint Kinesthetic Receptors

  • Are …… that monitor stretch in the articular capsules that enclose synovial joints
  • Contribute to … …..
A

Encapsulated nerves Endings: Joint Kinesthetic Receptors

  • Are PROPRIOCEPTORS that monitor stretch in the articular capsules that enclose synovial joints
  • Contribute to CONSCIOUS PROPRIOCEPTION
96
Q

Ascending Somatosensory Exteroception & Proprioception Systems

Recieves input from ….. & ……

….. …. - …. ….. Pathway
- fine touch, vibration & conscious proproiception = fin discrimination

……. Pathways

  • Pain, temperature, crude touch & pressure
  • … & …. Pathways

…. Pathways
- unconscious proprioception

A

Ascending Somatosensory Exteroception & Proprioception Systems

Recieves input from EXTEROCEPTORS & PROPRIOCEPTORS

DORSAL COLUMNS - MEDIAL LEMNISCUS PATHWAY Pathway
- fine touch, vibration & conscious proproiception = fin discrimination

SPINOTHALAMIC Pathways

  • Pain, temperature, crude touch & pressure
  • ANTERIOR & LATERAL Pathways

SPINOCEREBELLAR Pathways
- unconscious proprioception

97
Q

General Organzation of Somatosensory Systems

3) Cerebral neural circuits
- – order neurons

2) Ascending pathways
…. order neurons

1) Sensory receptors
…. order neurons

A

General Organzation of Somatosensory Systems

3) Cerebral neural circuits THIRD order neurons

2) Ascending pathways
SECOND order neurons

1) Sensory receptors
FIRST order neurons

98
Q

1) Processing at the Receptor Level

Propagation
- generating … … to the …. …./ …..

Transduction
- Converting …. …. into changes in membrane potential in … axons

Receptors
- Detecting ….

A

1) Processing at the Receptor Level

Propagation
- generating NERVE IMPULSES to the SPINAL CORD/ MEDULLA

Transduction
- Converting STIMULUS ENERGY into changes in membrane potential in SENSORY axons

Receptors
- Detecting STIMULI

99
Q

Processing at the Circuit level

Ascending Sensory Pathways
- Impulses delivered to the appropriate regions of the ….

  • OR impulses delivered to the ……
A

Processing at the Circuit level

Ascending Sensory Pathways
- Impulses delivered to the appropriate regions of the THALAMUS

  • OR impulses delivered to the CEREBRUM
100
Q

3) Processing at the Perceptual Level

- ….. of sensory input

A

3) Processing at the Perceptual Level

- INTERPRETATION of sensory input

101
Q

Dorsal Column - Medial Lemniscus Pathway

…. carries impulses from lower limbs & inferior body trunk

…. transmits afferent impulses from upper limbs, trunk & neck

A

Dorsal Column - Medial Lemniscus Pathway

GRACILE TRACT carries impulses from lower limbs & inferior body trunk

CUNEATE TRACT transmits afferent impulses from upper limbs, trunk & neck

102
Q

Comparing Cross-section of Spinal Cord

….. …. increases in dorsal columns from lumbar to cervical regions
- reflects increasing addition of …. fibres from caudal to rostral truck regions

A

Comparing Cross-section of Spinal Cord

WHITE MATTER increases in dorsal columns from lumbar to cervical regions
- reflects increasing addition of SENSORY fibres from caudal to rostral truck regions

103
Q

Cuneate & Gracile tubercles (in closed medulla) receive …… information from ….. ….. & ….. ….. spinal tracts, from the upper and lower body respectively

A

Cuneate & Gracile tubercles (in closed medulla) receive SOMATOSENSORY information from CUNEATE FASCICULUS & GRACILE FASCICULUS spinal tracts, from the upper and lower body respectively

104
Q

Spinothalamic Pathways

Lateral Spinothalamic Pathway
- Transmits impulses with … & … to opposite somatosensory cortex

Anterior Spinothalamic Pathway
- Transmits impulses concerned with … … & …. to opposite somatosensory cortex

A

Spinothalamic Pathways

Lateral Spinothalamic Pathway
- Transmits impulses with PAIN & TEMPERATURE to opposite somatosensory cortex

Anterior Spinothalamic Pathway
- Transmits impulses concerned with CRUDE TOUCH & PRESSURE to opposite somatosensory cortex

105
Q

Spinocerebellar Pathways

Transmit information about muscle or tendon stretch to the ….. ….., which use this information to coordinate skeletal muscle activity

Responsible for …. …..

A

Spinocerebellar Pathways

Transmit information about muscle or tendon stretch to the IPSILATERAL CEREBELLUM, which use this information to coordinate skeletal muscle activity

Responsible for UNCONSCIOUS PROPRIOCEPTION

106
Q

Somatosensory pathways

Fill in the table
- L9, page 45

A

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107
Q

L10 objectives

  • Explain the hierarchy of motor control
  • Describe the descending motor tracts (pyramidal and extrapyramidal) and their functions
  • Explain the consequences of pyramidal tract damage
A

srvdt

108
Q

Hierarchy of Motor Control

Highest:
…, …. & …..
- …. level
- ….. level

Middle
…. & ….
- ….. level

Lowest
….
- ….. level

A

Hierarchy of Motor Control

Highest:
PRE-MOTOR CORTEX, BASAL GANGLIA & CEREBELLUM
- PRECOMMAND level
- PRE-ACTION level

Middle
PRIMARY MOTOR CORTEX & BRAINSTEM
- PROJECTION level

Lowest
SPINAL CORD
- SEGMENTAL level

109
Q

General organisation of the Motor System

  • L10, page 5
A

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110
Q

1) Precommand Level - Programs & Instructions

Includes the … …., …. & … ….

…… responsible for initiating plan for next intended movement

  • Innervates … …. to release brake to start a specific movement
  • Innervates … which precisely calculates the best way to achieve coordinated synergistic movements across multiple limb joints - also monitors muscle … & ….
A

1) Precommand Level - Programs & Instructions

Includes the PREMOTOR CORTEX, CEREBELLUM & BASAL GANGLIA

PREMOTOR CORTEX responsible for initiating plan for next intended movement

  • Innervates BASAL GANGLIA to release brake to start a specific movement
  • Innervates CEREBELLUM which precisely calculates the best way to achieve coordinated synergistic movements across multiple limb joints - also monitors muscle TONE & BALANCE
111
Q

2) the Projection Level

Made up of the …. … … (precentral gyrus) & ….

A

2) the Projection Level

Made up of the PRIMARY MOTOR CORTEX (precentral gyrus) & BRAINSTEM

112
Q

The Projecttion Level

… … … in the primary cortical motor areas & brainstem:
- synapse with … … …., which are motor neurons of the cranial nerves (brainstem) or spinal nerves

Upper motor neurons from cortical motor areas produce the direct (…..) system, eg:

  • Corticospinal tracts:
    - Regulates … & skilled movement
    - Plays some role in modulating …. input
  • Corticobulbar tracts:
    • …. expression, … movements, movements of …..
A

The Projecttion Level

UPPER MOTOR NEURONS in the primary cortical motor areas & brainstem:
- synapse with LOWER MOTOR NEURONS, which are motor neurons of the cranial nerves (brainstem) or spinal nerves

Upper motor neurons from cortical motor areas produce the direct (PYRAMIDAL) system, eg:

  • Corticospinal tracts:
    - Regulates FAST & skilled movement
    - Plays some role in modulating SENSORY input
  • Corticobulbar tracts:
    • FACIAL expression, TOUNGE movements, movements of MASTICATION
113
Q

The Projection Level

Upper motor neurons from the brainstem motor areas form the indirect (….., ……) system

  • …… tracts
    • Head, neck & eye movements
  • …. tracts
    • Flexor tone, large muscle movements & fine motor control
  • ….. tracts
    • Maintains skeletal muscle tone and initiates the central pattern generator in the spinal cord
  • …. tracts
    • Maintains balance & muscle tone
A

The Projection Level

Upper motor neurons from the brainstem motor areas form the indirect (MULTINEURONAL, EXTRAPYRAMIDAL) system

  • TECTOSPINAL tracts
    • Head, neck & eye movements
  • RUBRROSPINAL tracts
    • Flexor tone, large muscle movements & fine motor control
  • RETICULOSPINAL tracts
    • Maintains skeletal muscle tone and initiates the central pattern generator in the spinal cord
  • VESTIBULOSPINAL tracts
    • Maintains balance & muscle tone
114
Q

Corticospinal tract: Direct (Pyramidal) Tract

Origin is from the … …. ….

A

Corticospinal tract: Direct (Pyramidal) Tract

Origin is from the PRIMARY MOTOR CORTEX

115
Q

Corticospinal Tract Decussation

…. (… ….) formed by the large pyramidal (corticospinal) tracts descending from the motor cortex

…. …. (…. ….) axons of the pyramidal tracts cross over to the opposite side at the medulla - spinal cord junction

A

Corticospinal Tract Decussation

PYRAMIDS (OPEN MEDULLA) formed by the large pyramidal (corticospinal) tracts descending from the motor cortex

PYRAMIDAL DECUSSATION (CLOSED MEDULLA) axons of the pyramidal tracts cross over to the opposite side at the medulla - spinal cord junction

116
Q

Corticospinal Tracts - Summary

… … : “… … …”
- Precentral gyrus of the cerebral cortex

… ….
- Internal capsule, through midbrain (cerebral peduncle) and pons, passing into the pyramidal tract in the medulla

…..
- Most fibres decussate at the medulla-spinal cord junction

… ….
- Lateral corticospinal tracts (crossed & uncrossed), some fibres stay in ipsilateral anterior (ventral) corticospinal tract

…..: “… … …”
- Cell bodies in ventral horn of spinal gray matter

A

Corticospinal Tracts - Summary

CELL BODIES : “UPPER MOTOR NEURONS”
- Precentral gyrus of the cerebral cortex

BRAIN PATHWAY
- Internal capsule, through midbrain (cerebral peduncle) and pons, passing into the pyramidal tract in the medulla

DECUSSATION
- Most fibres decussate at the medulla-spinal cord junction

SPINAL PATHWAYS
- Lateral corticospinal tracts (crossed & uncrossed), some fibres stay in ipsilateral anterior (ventral) corticospinal tract

ENDPOINT: “LOWER MOTOR NEURONS”
- Cell bodies in ventral horn of spinal gray matter

117
Q

Corticospinal Tracts - Summary

Most corticospinal neurons synapse on ….
- regulate overall excitability

In … …. of grey matter, some corticospinal neurons synapse … with motor neurons

….. … … …. ….

  • 50% - cervical level
  • 20% - thoracic level
  • 30% lumbosacral level

Brain “commands” are integrated by spinal neural circuits to produce ….. …..

A

Corticospinal Tracts - Summary

Most corticospinal neurons synapse on INTERNEURONS
- regulate overall excitability

In CERVICAL ENLARGEMENT of grey matter, some corticospinal neurons synapse DIRECTLY with motor neurons

TERMINATION OF THE CORTICOSPINAL TRACT

  • 50% - cervical level
  • 20% - thoracic level
  • 30% lumbosacral level

Brain “commands” are integrated by spinal neural circuits to produce COMPLEX MOVEMENTS

118
Q

Corticobulbar Tract: Direct (Pyrimidal) Tract

Origin is from the … … …

… - Mainly contralateral

Terminates in ….

A

Corticobulbar Tract: Direct (Pyrimidal) Tract

Origin is from the PRIMARY MOTOR CORTEX

BILATERAL - Mainly contralateral

Terminates in BRAINSTEM

119
Q

Corticobulbar Tracts - Summary

Neurons arise from ventral part of … … …

Starts out in company with the corticospinal tract in … ….

Synapse in … … of …. … in the pons (V, VII) and medulla (X, XI & XII)

Provide … expression, … movement & movements of ….

A

Corticobulbar Tracts - Summary

Neurons arise from ventral part of PRIMARY MOTOR CORTEX

Starts out in company with the corticospinal tract in INTERNAL CAPSULE

Synapse in MOTOR NUCLEI of CRANIAL NERVES in the pons (V, VII) and medulla (X, XI & XII)

Provide FACIAL expression, TONGUE movement & movements of MASTICATION

120
Q

Clinical Notes - Corticospinal Tract Deficits:

Contralateral Deficit:
- If lesion … pyramidal decussation on right = left upper limb & lower limb muscles affects

Ipsilateral Deficit:
- If lesion … the pyramidal decussation on right = right limbs below the lesion affected

A

Clinical Notes - Corticospinal Tract Deficits:

Contralateral Deficit:
- If lesion ABOVE pyramidal decussation on right = left upper limb & lower limb muscles affects

Ipsilateral Deficit:
- If lesion BELOW the pyramidal decussation on right = right limbs below the lesion affected

121
Q

Indirect (Extrapyramidal) System

Upper motor axons arise from several … ….

Four major nuclei/regions are:

  • ….. …. located in tectum or roof of midbrain
  • … …. in the midbrain
  • … …. in pons & medulla
  • …. nuclei in medulla

Four major pathways

  • ….spinal tracts
  • ….spinal tracts
  • ….spinal tracts
  • ….spinal tracts
A

Indirect (Extrapyramidal) System

Upper motor axons arise from several BRAINSTEM NUCLEI

Four major nuclei/regions are:

  • SUPERIOR COLLICULUS located in tectum or roof of midbrain
  • RED NUCLEUS in the midbrain
  • RETICULAR FORMATION in pons & medulla
  • VESTIBULAR nuclei in medulla

Four major pathways

  • TECTOspinal tracts
  • RUBROspinal tracts
  • RETICULOspinal tracts
  • VESTIBULOspinal tracts
122
Q

Tectospinal Tracts

Axons arise from … ….

Receives projections from axons originating from the … tracts & the … & inferior …. lobes

Descending fibres innervate spinal nerve motor neurons of … …. … and motor neurons of …(…,…) & …. (…) cranial nerves

Mediates contralateral head and neck movements in response to …. stimuli

Specifically …, … & … movement to allow eyes to track a moving object

A

Tectospinal Tracts

Axons arise from SUPERIOR COLLICULUS
Receives projections from axons originating from the OPTIC tracts & the OCCIPITAL & inferior PARIETAL lobes

Descending fibres innervate spinal nerve motor neurons of CERVICAL SPINAL CORD and motor neurons of MIDBRAIN (III, IV) & PONS (VI) cranial nerves

Mediates contralateral head and neck movements in response to VISUAL stimuli

Specifically HEAD, NECK & EYE movement to allow eyes to track a moving object

123
Q

Rubrospinal Tracts

Axons arise from … ….

Descending fibres innervate spinal nerve motor neurons of … … …

Mediates … …, large … movements & … …. …. in the opposite upper body

A

Rubrospinal Tracts

Axons arise from RED NUCLEUS

Descending fibres innervate spinal nerve motor neurons of CERVICAL SPINAL CORD

Mediates FLEXOR TONE, large MUSCLE movements & FINE MOTOR CONTROL in the opposite upper body

124
Q

Retticulospinal Tracts

Axons arise from …. …. of the … & ….

Maintains …. … … & initiates the … … … in the … ….

A

Retticulospinal Tracts

Axons arise from RETICULAR FORMATION of the PONS & MEDULLA
Maintains SKELETAL MUSCLE TONE & initiates the CENTRAL PATTERN GENERATOR in the SPINAL CORD

125
Q

Vestibulospinal Tracts

Axons arise from the … … ….

Maintains … & …. via activation of axial (trunk) and limb extensor muscles

A

Vestibulospinal Tracts

Axons arise from the LATERAL VESTIBULAR NUCLEUS
Maintains BALANCE & MUSCLE TONEvia activation of axial (trunk) and limb extensor muscles

126
Q

the projection Level - Summary

The …. tracts

  • originate from the primary motor cortex
  • Synapse with lower motor neurons either in the brainstem or ventral horn of the spinal cord
  • Concerned with voluntary, discrete, skilled movements

The … tracts

  • originate from the brainstem
  • Synapse with lower motor neurons in the ventral horn of the spinal cord
  • Mediates vouluntary movement, muscle tone (posture), balance, and regulates the central pattern generator
A

the projection Level - Summary

The PYRAMIDAL tracts

  • originate from the primary motor cortex
  • Synapse with lower motor neurons either in the brainstem or ventral horn of the spinal cord
  • Concerned with voluntary, discrete, skilled movements

The EXTRAPYRAMIDAL tracts

  • originate from the brainstem
  • Synapse with lower motor neurons in the ventral horn of the spinal cord
  • Mediates vouluntary movement, muscle tone (posture), balance, and regulates the central pattern generator
127
Q

The Segmental Level - Spinal Cord

The … level of the motor hierarchy

Consist of the …. circuits of the … …

Activating .. … motor neurons of .a single spinal cord segment stimulates a specific group of muscle fibres

A

The Segmental Level - Spinal Cord

The LOWEST level of the motor hierarchy

Consist of the SEGMENTAL circuits of the SPINAL CORD

Activating VENTRAL HORN motor neurons of .a single spinal cord segment stimulates a specific group of muscle fibres

128
Q

Lower Motor Neurons

Receive input from upper motor neurons of the … and ….. pathways described earlier

A

Lower Motor Neurons

Receive input from upper motor neurons of the PYRAMIDAL and EXTRAPYRAMIDAL pathways described earlier

129
Q

Action potential —-> Events at NMJ

1) Voltage-sensitive … channels open
2) Influx of …. ions
3) Synaptic vesicles fuse to …. …..
4) release …. into …. ….
5) Diffusion across ..
6) Binds to … receptors on …. ….
8) AP in …. … & contraction of muscle
9) ….. broken down by ….

A

Action potential —-> Events at NMJ

1) Voltage-sensitive CALCIUM channels open
2) Influx of CALCIUM ions
3) Synaptic vesicles fuse to PRESYNAPTIC MEMBRANE
4) release ACETYLCHOLINE into SYNAPTIC CLEFT
5) Diffusion across CLEFT
6) Binds to NICOTINIC RECEPTORS receptors on POSTSYNAPTIC MEMBRANE
8) AP in MUSCLE CELL & contraction of muscle
9) NEUROTRANSMITTER broken down by ACETYLCHOLINESTERASE

ANAT242 (6 decks)

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