Exam #2 Notes Flashcards
(137 cards)
1
Q
What type of information does the Anterolateral System (STT) covey?
A
Pain, Temperature and crude touch
2
Q
Are sensory pathways ascending or descending?
A
Ascending.
Motor pathways are descending
3
Q
In the STT and DCML the primary neurons are all located in the:
A
DRG
4
Q
Neuron #1 synapses in:
A
The spinal cord
5
Q
The STT and DCML pathways will synapse on:
A
The cortical sensory strip
6
Q
What are the two parts of the anterolateral (STT) tract:
A
Anterior spinothalamic tract: Crude touch
Neospinothalamic tract (classic LST): Pain (fast) and temp
7
Q
What type of fibers can be found in the ALS/STT?
A
Mostly Ad (myelinated) Some C fibers (unmyelinated)
8
Q
Describe the 3 neuron system in the ALS/STT:
A
- 1* neuron in DRG (is pseudonunipolar): Central process transmits into CNS
Peripheral process picks up Information from receptor - 2* neuron (Multipolar) in I (marginal zone; Rex laminal) and II (Substantial gelatinosa; Rex lamina 2)– Dorsal horn
- 3* neuron (Multipolar) in VPL of THALAMUS (central posterior lateral nucleus): The third neuron projects to sensory strip
9
Q
What types of receptors does the STT have?
A
Free nerve endings: Sense pain, temp touch
10
Q
Grey matter contains
A
Cell bodies
11
Q
White matter contains:
A
Nerve fibers
12
Q
What forms Lissauer’s tract?
A
Central process going into the spinal cord trying to get to grey matter forms the lissauer’s tract
13
Q
What is the central process?
A
Terminates in brainstem or spinal cord
14
Q
What is the peripheral process?
A
Receptive end (Muscle, join, skin, eat)
15
Q
Function of mechanoreceptors?
A
Touch, Pressure, Stretch
16
Q
Function of thermoreceptors
A
Temperature
17
Q
Function of Nociceptors
A
Noxious stimuli (pain)
18
Q
Function of Chemoreceptors:
A
Smell, Taste, pH ion concentration
19
Q
List and describe the Non-encapsulated receptors:
A
Hair Follicle receptor: Located in the follicle. Senses touch
Merkel Complex: Located on hairy and glabrous skin. Senses touch
Free Nerve Ending: Located on skin, muscle, tendons, joints. Senses pain (nociceptors)
20
Q
List and describe the Encapsulated receptors:
A
Meissner’s receptor: Senses light touch. Is made up of horizontal lamellae. Created by stacks of epithelial cells. 1* afferent goes into structure indigestion between the stacks of epithelial cells
Pacinian Receptos: Sense vibration and pressure. Concentric lamellae: Rings of CT lined by single layer of epithelial cells. 1* afferent in center
Ruffini Receptors: (look like free nerve endings) Sense stretch and proprioception. Ct capsule and 1* afferent
21
Q
What are the types of pain?
A
Skin (Cutaneous; dermis and epidermis)- somatic
Joint
Visceral
22
Q
What receptors are found in Gingiva?
A
Meissner’s Ruffini, Free nerve endings
23
Q
What receptors are found in Teeth?
A
Pulp, Dentin: Free nerve endings
PDL: Ruffini, Free nerve endings
24
Q
What are the types of fibers in the muscle spends that help to detect changes in length?
A
- Extrafusal fibers: Skeletal muscle fibers
- Intrafusal fibers: Nuclear bag fiber, Nuclear chain fiber
- Sensory fibers: Annulospiral and flower spray endings
Nuclear bag is associated with both annulospiral and flower spray endings.
Nuclear chain is only associated with flower spray endings.
wrap around nuclear chain and bag fibers
25
What does the Golgi Tendon Apparatus do?
Detects tension. It's found at the junction of tendon and muscle
26
Which nerve fibers is the fastest, slowest, smallest and largest?
Fastest: Aalpha (Ia/b): Largest and faster found in annulospiral endings and golgi tendons--- Myelinated
Slowest: C (IV): the smaller and slowest nerve fiber. Functions in pain and temp. Is the only unmyelinated fiber
The slowest myelinated fiber is the Alphadelta (III) It functions in crude touch, temp and pain
27
Describe the pathway of STT:
Neuron #1: Peripheral process picks up sensory information to dorsal horn. The cell body is located in DRG
Neuron #2: Will decussate in anterior white commissure. Will either travel to RL I (Marginal zone) or RL II (Substantial gelatinous)
It will ascend in contralateral lateral functions. The same pattern occurs in cervical, thoracic, and lumbar regions. Pathway gets larger as it ascends.
Neuron #3 is located in the VPL in the Thalamus. Axons of neuron #3 will ascend to the cortex, from thalamus out to the posterior limb of the internal capsule then make way up to the post central gyrus.
28
What is the internal capsule?
Structure composed of lots of different types of fibers
29
How does the neurons from #3 in the STT get to the post central gyrus
Through the posterior limb of the internal capsule
30
Sensation to the face will exit the somatosensory cortex near the:
Lateral sulcus
31
The central process creates sewers tract from:
Cell body #1 the pseudonunipolar neuron
32
What are the descending pathways?
- Periaqueductal gray (PAG) in midbrain
- Rostroventral medulla (RVM)
- Nucleus raphe magnus (NRM)
These are off shoots of STT, Important for pain modulation
33
Describe the PAG-NRM pathway:
STT sends fibers to PAG: (Some ascending afferent fibers will change course: will leave tract and project to PAG)
PAG fibers project to NRM in RVM
NRM fibers project to DH: Release serotonin and activate interneurons
Interneurons release endogenous opioids (ex. Enkephalins): bind opioid receptors on incoming Adelta and C fibers
Produce analgesia (block some pain)
34
Describe the Periaquaductal Grey (PAG):
1. Ascending fibers branch off to PAG
2. From PAG other axons project down to NMR
3. Will descend to dorsal horn.
For pain modulation
35
How do the descending pathways block pain?
Fibers originating from STT activate neurons in NMR. Serotonin is related from NRM neurons which activates interneurons.
Interneurons release endogenous opioids (enkephalins) that bind to opioid receptors on incoming C and A-delta fibers
Blocks activation of 2nd order STT neuron
Produces analgesia
36
What is affected in Brown squared syndrome?
It's a hemisection of the spinal cord and will affect pain, temp, touch, proprioception and motor affected.
Specifically it will lead to contralateral loss of pain, temp and crude touch. (STT)
Loss of motor function and vibration, position, and deep touch sensation on same side as the damage. Ipsilateral loss. (DCML)
UMN axons cross at brinastem (medulla) so anything below is ipsilateral
37
What is a Cordotomy?
Surgical intervention for intractable pain. Cuts ascending tracts. Procedure done on opposite side
Dysesthesia (abnormal sensations) often develops
38
What types of sensation are carried in the DC-ML pathway?
- Proprioception (conscious)
- Kinesthesia (Perception of motion)
- Fine touch/ 2 point discrimination:
- Stereognosis: Ability to perceive/recognize forms w/o hearing and vision
- Vibration
39
Which cell bodies are pseudo unipolar and multipolar in DC-ML?
Cell body #1: Pseudounipolar
Cell body #2&3: Mutlipolar
*Same as STT
40
What types of nerve fibers are in the DC-ML?
ABeta: Flowerspray Myelinated: GTO, annulospiral
41
Does the DC-ML have few or many synapses?
Few synapses
42
What are the sensory receptors in the DC-ML?
- Merkel's Receptors: Light pressure/texture
- Pancinian Corpuscles: Vibration and Pressure
- Meissners corpuscles: Light touch
- Proprioception:
- Neuromuscular: Annulospiral and Flower spray endings
- Neurotendinous: Golgi Tendon
43
Spinal Primary Affernets enter:
Cell body in DRG Enter post SC via Dorsal rootlets; Rootlets represent efferents.
Delta and C fibers come in leisseurs tract
Larger fibers enter more medially through the large fiber entry zone.
44
In DC-ML; Sensation from the lower extremities will travel through the:
Fasciculus gracilis
45
In DC-ML; Sensation from the upper extremities will travel through:
Fasciculus cuneatus
46
What is the posterior column/funiculus?
Formed by afferent fibers carrying touch and proprioception
Fibers going in the posterior column, part of dorsal column medial leminscus: Efferents carrying fine touch and proprioception go in through the posterolateral sulcus or Posterolateral tract.
This as opposed to STT which is synapsing in dorsal horn.
47
What is the relationship of F. Cuneatus and F. Gracilis to the vertebral column?
F. cuneatus is rostral to T6 (is T6 and above)
f. Gracilis is caudal to T^ ( is T7 and below)
48
If there's a lesion below T6 what will it affect in the DC-ML pathway?
It will only effect info coming from the legs
49
The somatic organization of the spinal cord fibers will enter?
Medially and be added laterally
50
Describe the pathway in DC-ML:
Neuron #1: Cell body in DRG. CP enters (medially to STT) spinal cord and ascends
Neuron #2: Cell body is in nucleus gracilis (legs) or cuneatus (trunk, UE). (In the medulla) Axon of CB#2 will decussate as internal arcuate fibers. Forms the medial meniscus and projects to the thalamus.
As fibers are decussating they are called internal arcuate fibers. As they ascend they are called medial meniscus.
Neuron #3: In the VPL of the thalamus. Never fibers from CB#3 (VPL) ascend (exit) thru posterior limb of internal capsule on way to cortex (SAME as STT). Will terminate in post central gyrus
51
Spinal cord lesion in DC-ML pathway:
Will lead to ipsilateral loss of modalities below lesion:
- Inferior to decussation (decussation occur in medulla
- axons haven't crossed
52
Medial meniscus/medulla lesion in DC-ML pathway:
Will lead to contralateral loss of modalities below lesion:
- Superior to decussation
- Axons have crossed
53
Lesions in the DC-ML will lead to:
Impairment of tactile perception: Because you still have the STT in tract, Still have crude touch but won't have fine touch
- Loss of proprioception and kinesthesia
- Ataxia
54
What is Tabes Dorsalis?
Neurosyphilis (posterior column damage)- Stage 4
- Chronic inflammation of dorsal roots and ganglia. Degeneration of posterior column
- Loss of 2 point discrimination
- movement and position impairment
- difficulty walking
- Positive rhomberg's sign: Identifies sensory ataxia
55
What is the Rhomberg's sign?
- Identifies sensory ataxia
- Problems with proprioception causes loss of balance.
- Positive test is loss of balance
- Negative test could indicate cerebrally lesion
56
Describe an overview of the GSA Trigeminal system:
- GSA's on face carried by trigeminal Nerve
- It is a Homologue to STT and DC-ML
1* Neuron: Cell body in sensory ganglia, CP projects into CNS
2* Neuron: Cell body in CNS, Projects to thalamus
3* Neuron: Cell body in thalamus, Projects to cortex. From #3 it goes to lateral aspect of parietal lobe towards central sulcus
57
Where does the sensory and motor roots of CN V exit?
Exits the brainstem at midpons
58
What are the components of CN V
GAS (skin): Anterior 2/3 of head
SVE (Muscles from 1st arch):
- Muscles of mastication: Master, pterygoids (2), temporalis
- Other muscles innervated by CN V: Tensor tympani, Tensor Veli palatini, Mylohyoid, Ant belly digastric
59
What types of sensory does CN V supply?
Touch
Proprioception
Pain
Temperature
60
What is the origin of the Trigeminal Ganglion?
Cleft of petrous bone. Lateral to cavernous sinus
| contains GSA cell body #1
Except unconscious proprioception of jaw- Will have different cell body
61
What all exits at the midpoint?
```
Ophthalmic nerve
Trigeminal ganglion
Maxillary Nerve
Mandibular Nerve
Motor roots
```
62
What is larger? The sensory portion nucleus or the motor nucleus of the trigeminal nerve?
Sensory is larger; Motor is small
63
Where does V1 (Ophthalmic) exit?
V1: Superior orbital fissure
64
Where does V2 (maxillary) exits?
V2: Foramen rotunda
65
Where does V3 (mandibular) Exit?
V3: Foramen Ovale
66
Where does the Mesencephalic nuclei go?
| Describe it:
- Rostroally (towards Midbrain)
- It is a Pseudounipolar neuron
- Is involved in unconscious proprioception
- M. of Mastication, PDL, Gingiva, Palate, Teeth, TMJ, Extraocular m.
67
Where does the spinal nuclei go and what sensations does it have??
Caudally (towards medulla): Can extend all the way down to the cervical area. It is a multipolar neuron
Has Pain, temperature and crude touch
68
Describe the Main sensory Nuclei:
Located at Mid-pons
Is multipolar neurons #2
Has touch and conscious proprioception
Can be divided into two parts:
1. Ventral aspect: Mechanosensation and position sense from face
2. Dorsal aspect: Mechanosensation from oral cavity
69
What types of Neurons does the trigeminal ganglion have?
Heavily myelinated neurons with large diameter: Alpha Beta's
70
What are the ascending pathways of the Mina sensory Nucleus:
Ventral 2/3: Make up bulk of nucleus
- Discriminative touch (mechanosensation) and proprioception of face (V1, V2, V3)
- Projects to VPM of thalamus along with medial meniscus
- Crosses midline
Dorsal 1/3:
- Mechanosensation from teeth and oral cavity (V2, V3)
- Projects to VPM (Ventral posterior medial)- Nucleus of the thalamus for the trigeminal system
- Is uncrossed does not decussate
71
What is the Ventral Trigeminal Tract?
The sensory for the face but not the oral cavity
Cell body #1: Located on Trigeminal nerve: Contains ABeta fibers
Cell body #2: Principal sensory nucleus (midpons area)
Cell body #3: Ventral posterior medial nucleus of thalamus (VPM)
Cell body #4 goes to face
72
Describe the dorsal Trigeminal Tract:
Mechanosensation from teeth and oral cavity
Cell body #1: pseudo unipolar.
#2 Cell bodies of CP located on dorsal aspect
73
What are the similarities between the VTT and DTT? Differences?
Both originate in trigeminal ganglion
Both synapse in main sensory nucleus
VTT: Intro from face: will have decussation and it goes to contralateral VPM; Contains Touch, proprioception and face.
DTT: Dorsal will synapse on #2 then ascends ipsilateral; Contains mechanosensation- OC #1 is pseudo unipolar
74
What types of fibers does the Spinal Trigeminal tract contain?
What sensations are carried?
ADelta, and C
Extends inferiorly down to medulla and possibly into cervical area
Carries Pain and Temperature from body.
75
What are the three divisions of nuclie of the Spinal trigeminal tract that carry pain and temperature?
Caudal nucleus: Face
Oral nucleus: Teeth and other oral structures
interpolar: Teeth
76
What is the only thing that runs in the dorsal tract?
Mechanosensation and proprioception from the oral cavity
77
What is the Ventral Trigeminothalamic Tract (VTTT)?
Carries fibers from spinal n. and principal n. = fine touch, conscious proprioception, fast pain and temp
Not info from oral cavity (Dorsal Trigeminothalamic tract DTTT)
78
What is the Corneal Reflex?
Involuntary blinking of eyelids (CN VII) by stimulating cornea (CNV)
- Afferent: V1 and V2
- Efferent: CN VII
- Direct response
- consensual response
* This is an easy way to determine the integrity of both cranial nerve 5 and 7
79
Describe the neural circuit of the eye:
1* afferent: Free nerve endings in cornea, cell body #1 in CN V ganglion
2* afferent: spinal trigeminal nucleus
Collaterals synapse on CN VII motor neurons (bilaterally)
Orbicularis oculi contracts (both)
80
Describe the Mesencephalic Nucleus of CN V:
- Contains cell bodies of muscle spindle receptors for jaw muscles
- Part of trigeminal ganglion
- Pseudounipolar neurons
- Processes collect into mesencephalic trigeminal tract
- Unconscious proprioception for muscles of mastication
- Unconscious proprioception for gingiva, palate, TMJ, PDL and maxillary and mandibular teeth
-Not in trigeminal ganglion: Contains A alpha fibers
Many CP will synapse on motor n. of V
Some CP will go to main sensory n of V
Some CP will go to cerebellum
81
What does the Jaw Jerk Reflex do?
Tests integrity of CN V
Afferent: Mesencephalic neuron
Effent: Trigeminal motor neuron
82
What is Trigeminal Neuralgia?
Brief attacks of severe pain
Trigger zones
Distributes along divisions of CN V
No sensory abnormalities between attacks
Often attributed to vascular compression
83
Ophthalmic Zoster:
Herpes zoster V1 Pattern
84
What is Wallenberg's Syndrome?
Ipsilateral sensory alteration of pain and temperature (5th CN)
Contralateral alteration of pain and temperature (spinothalamic tract)
85
What are other GSA components of the Face:
| What are the 1* cell body's location?
CN VII: Skin behind ear and ext auditor canal.
- 1* cell body in geniculate ganglion
CN IX: Tympanic membrane and auditory canal
- 1* cell body in superior/jugular ganglion
CN X: Skin behind ear and ext auditory canal
- 1* cell body in superior/jugular ganglion
All will utilize spinal trigeminal nucleus
Will all ascend in spinal trigeminal tract
Will all go to VPM
86
What is Glossopharyngeal Neuralgia?
Pain in posterior pharynx that radiates to ear
Can be triggered by swallowing or talking
Can be treated by drugs or surgery
- Cut torso-medial spinal trigeminal tract in caudal medulla
87
What are the motor systems?
Pyramidal: Direct activation pathway. Directly innervates target (muscle)
Monosynaptic: UMN -> LMN
( UMN= in cortex) (LMN= In nuclei)
Controls voluntary movement: head neck and limbs.
- Corticobulbar & corticospinal tracts
Extrapyramidal: Doesn't run in pyramids. Indirect- modulates/ regulates
Polysynaptic: multiple synapses
Impacts voluntary movement: modifies neural impulses, dampens erratic motion, maintains muscle tone, facilitates trunk stability
88
Describe the Pyramidal System:
- 2 Neuron system
- UMN: Pyramidal cell of cortex (Multipolar) 1-3 ft.
- LMN: Alpha motor neuron in VH or CN motor n. (brain stem)- (Multipolar) 4-5 ft.
89
Descending pathways of the Motor systems joins:
Internal capsule (along with sensory fibers)
Post limb= motor and sensory
90
What is the target of UMN?
LMN. (ventral horn)
UMN will project down to brainstem. LMN is controlled by UMN. Cell bodies are located in spinal cord and CN nuclei
CN motor nuclei= bulbar tract.
91
What Nuclei are apart of the Motor system?
```
Oculomotor Nucleus
trochlear Nucleus
Motor Nucleus of the Trigeminal nerve
Abducens Nucleus
Facial nucleus
Hypoglossal Nucleus
Nucleus Ambiguus
```
92
What is the origin of the pyramidal tract? What are the secondary areas?
Precentral gyrus (1* motor strip)
Secondary areas:
- Postcentral Gyrus (sensory strip)
- Premotor cortex
- Supplemental motor cortex
93
What do secondary areas influence in the pyramidal tract?
Sequencing
Planning
filtering
Position
94
What is the function of the Corticospinal tract of the pyramidal system??
Controls motor neurons in SC
- Lateral corticospinal tract: Forms 90% (90% will decussate) of pyramids, control distal musculature and forms the decussation of pyramids at the FORAMEN MAGNUM
- Anterior corticospinal tract: Uncrossed (10%) Controls upper extremity and neck
95
What is the function of the corticobulbar tract of the pyramidal system?
Controls brainstem nuclei
96
The axons of the UMN exit the cortex and converge to form:
Post limb of internal capsule. These fibers will descend through the lower cerebral peduncle (midbrain) and enter lower brainstem and pyramids
97
What makes up the pyramidal decussation?
Corticospinal nerve fibers that are traveling to the medulla.
98
What happens to the pyramidal tract as it goes inferior to the decussation?
Continue caudally
Will synapse on LMN in VH
fibers exit via ventral root
99
What happens in a UMN lesion in the corticospinal tract?
Rostral to decussation: Contralateral spastic paralysis ( increase in muscle tone)
Caudal to decussation: Ipsilateral spastic paralysis
*!!!!! Spastic = UMN !!!!!*
100
what happens in a LMN lesion in the corticospinal tract?
Inferior to lesion: Ipsilateral at or below level of lesion.
- Flaccid paralysis (decrease in muscle tone)
101
What are the symptoms of UMN Lesion?
- Loss of voluntary movement
- Spasticity
- Increased deep tendon reflex ( hyperreflexia)
- Loss of superficial reflex (Hyporeflexia)
- Clonus (repetitive movements of foot)
- Babinski's sign
- Little muscle atrophy
102
What are the symptoms of LMN lesion?
Loss of muscle tone (flaccid)
Muscle atrophy
Loss of reflex and voluntary movement
103
Hemiplegia:
One side
104
Monoplegia:
Single limb
105
Paraplegia:
Both limbs (legs)
106
Quadriplegia:
All 4 limbs
107
Corticospinal Pearls:
- CST is crossed
- Lesions rostral to decussation = contralateral deficits (below lesion)
- Lesions in spinal cord (caudal to decussation) = Ipsialteral deficits (below level of lesion)
- Cortical neurons are UMN: Death = minimal muscle atrophy
- LMN are alpha motor neurons: located in the VH of the spinal cord (corticospinal) or cranial motor nucleus (Corticobulbar)
Death = Muscle atrophy
108
Corticobulbar Pearls:
- Origin: Lateral aspect of primary motor cortex (UMN)
- Project to brainstem CN nuclei (LMN)
- Follows corticospinal tract
- Fn: vol control of m. of facial expression, eye movements, jaw opening and closing, tongue movements
- Most innervated bilaterally (R and L cortex)
- Exceptions: certain muscles innervated by CN VII, IX, XII
109
Explain Bilateral vs Unilateral innervation related to the CN VII:
Bilateral controls the upper muscles of facial expression (temporal and zygomatic branches of facial nerve)
Unilateral controls the lower muscles of facial expression (mandibular and buccal branches of facial nerve)
110
Contralateral mild weakness (bilateral innervation) above the eyes and contralateral paralysis (unilateral innervation) below eyes would be a:
Supranuclear (UMN) Lesion
111
Total loss of function, Ipsilateral loss above and below eyes would be:
Lesion at the level of nucleus/nerve (LMN)
112
How to determine lesion of CN XII:
Muscle atrophy: LMN
No atrophy: UMN
UMN: R: tongue deviates to contralateral side (L) due to unopposed genioglossus
LMN: L: tongue deviates ipsilaterally (L) due to unopposed genioglossus
113
What provides innervation to the palatal arches and uvula?
Done by CN IX and X
- Motor is provided by CN X
- Sensory is done by IX
114
What happens in a contralateral and ipsilateral lesion of CNX
Contralateral: Weakened but not lost due to bilateral innervation
LMN Ipsilateral: Sagging of palatal arches; uvula de vitas toward unaffected side in LMN lesion.
115
What are the functions of the Extrapyramidal Systems?
Dampen erratic motion
Maintain muscle tone
Trunk stability
116
What is the role of the basal ganglia?
Role in fluid movement
117
What nuclei is involved in Parkinson's disease?
Substantia nigra (compact and reticular part)
118
What is the motor loop of the extrapyramidal?
Motor loop: (Cortex-Thalamus-Cortex) Learned movements
119
What is the cognitive loop of the extrapyramidal?
```
Cognitive loop (prefrontal cortex)
Motor intention
```
120
What is the Limbic loop of the extrapyramidal?
(limbic cortex- ventral striatum)
Emotional aspects of movement
Control and reinforcement of behavior
121
What is the Oculomotor loop?
(superior colliculus)
Eye movement control
voluntary saccades (both eyes move in same direction)
Damage = weird eye movements
122
What is the function of the Basal Ganglia?
```
Processing information of movement
Maintenance of stored movements
Postural control
Muscle tone
Emotional motor expression
Automatic associated movements
```
123
What are the Basal Ganaglia diseases?
Involuntary movements during rest
Parkinson's disease
Chorea (Huntington's disease)
Tourrette's syndrome
124
What is Dyskinesia?
Increased voluntary/decreased involuntary movement
125
What is Bradykinesia?
Slow movement
126
What is Akinesia?
Loss of normal motor function
127
What is Parkinson's Disease?
```
Loss of stratal dopamine (BG nuclei)
Hypokinesis (Partial or complete loss)
- Projound akinesia (loss)
- Bradykinesia (slow)
Resting tremors
rigidity
```
128
What is Huntington's Chorea?
Hyperkinetic signs (frenetic)
Chorea: Dancing
Demetia
Genetic: Autosomal dominant
129
What is Tourett's Syndrome?
Motor and vocal tics
Possible genetic basis
Associated with other disorders (ADHD, OCD)
Dysfunction of caudate n. (BG) and its link to prefrontal cortex
130
Describe the Reticulosoinal Tract:
1. Begins in reticular formation
2. Synapse on LMN in VH
3. Modifies voluntary and reflex activity
131
Describe the Rubrospinal tract:
1. Starts in red nucleus of midbrain
2. Synapses on VH neurons
3. Facilities flexors and inhibits extensors
132
Describe the Tectospinal tract:
1. begins in superior colliculus of midbrain
2. Synapse in VH
3. Involved with reflex postural movements in response to visual stimuli: Jumping due to noise
133
Describe the Vestibulospinal tract:
1. Nuclei in pons and medulla
2. Receives afferents from inner ear and cerebellum
3. Synapse in VH
4. Facilitates extensors and inhibit flexors
134
What is the function of the cerebellum?
Regulation of motor function
| Receives sensory input regarding status of muscles
135
Describe the function spinocerebellar tract:
Unconscious proprioception carries info from muscle spindles and golgi tendon organs to cerebellum:
Ventral: Trunk and lower body; Whole limb movements
Dorsal: Trunk and lower body; Individual muscles
136
What is the function of the cuneocerebellar tract?
Unconscious proprioception
Form the upper body (C8-C2)
Upper limb equivalent to DST (individual muscles)
Does individual muscles of the upper limb
137
Describe some Cerebellar Disorders:
```
Ataxia:
- Asynergy: Loss of coordination
- Decomposition of movement
- Dysmetria: Over/Undershooting
- Past pointing
Hypotonia: Decreased muscle tone
Nystagmus: Involuntary eye movement
Gait ataxia
```
