COM 1 Physiology week 3 Flashcards
(73 cards)
1
Q
Why is the cerebellum sometimes called the silent area
A
- As electrical stimulation does not cause conscious sensation
2
Q
What is the role of cerebellum in movement- what is it crucial for + e.g
A
- Crucial for rapid,skilled and coordinated muscle activites such as :
- Running
3
Q
Name the 2 key inputs the cerebellum recieves
A
- Motor signals from the brains motor conrol areas
-Sensory feedback from the body
4
Q
What does the cerebellum help plan
A
The next movement in advance
5
Q
The cerebellum is divided into what 3 lobes
A
-Anterior lobe
-Posterior lobe
-Flocculondular lobe
6
Q
What is the flocculondular lobe responsible for
A
- Body equillibirum
7
Q
What are the three longitudinal function divisions w/n the the Anterior and Posterior lobe
A
- Vermis
-Intermediate zone
-Lateral Zone
8
Q
WHere is the vermis located + what does it control
A
- Located along the midline of the cerebellum
-Controls axial body movements : trunk,neck shoulders
9
Q
Where is the intermediate zone found +what does it control+ E.G
A
- On either side of the vermis
- Controls movements of distal limbs : hands, fingers,feet
10
Q
What are the Topographical represenations of :
-Vermis
-Intermediate zone in the cerebellum- what does it represent
A
Vermis- Represents Axial body parts
Intermediate zone- Represents limbs and facial regions
11
Q
Where does the vermis and itermediate zone recieve afferent signals from
A
- Corresponding body parts
-Topographical motor areas in the cerebral cortex and brainstem
12
Q
The intermediate zone and vermis send effernet motor signals to what
A
- Cerebral motor cortex
-Red nucleus
-The reticular formation in the brainstem
13
Q
What is the lateral cerebellar hemisphers involved in
A
Involved in planning and coordinating raoid sequential movements
14
Q
What does the lateral cerebellar hemisphere recieve input mainly from
A
- Premotor areas of the frontal
-Somatosensory and association areas of the pariteal cortex
15
Q
What is the structure of the cerebellar cortex
A
A folded sheet
16
Q
What are the folds in the cerebellar cortex called
A
Folia
17
Q
Wht is beneath the cerebellar cortex?
A
Deep cerebellar nuclei
18
Q
Name the INPUT AFFERENT pathway from the cerebrum to the CEREBELLUM
- Where it orginates
-Passes through
-Projects
A
- Corticopontocerebellar pathway
-Originaes in the motor,premotor and somatosensory cortices
-Passes through the pontine nuclei and pontocerebellar tracts
-Projects to the lateral cerebellar hemispheres
19
Q
Where does the olivocerebellar tract :
-originates from
-Carries signals from
-projects to where
A
- From inferior olive
-Carries signals from :
motor cortex, basal ganglia,reticular formation and spinal cord
-Projects to all parts of the cerebellum
20
Q
Explain where the vestibulocerebellar fiber pathway from the Brainstem is:
-From
-WHere it terminates
-Importanr for what
A
- From the vestibular apparatus and vestibular nuclei
-Terminates in the flocculondular lobe and fastigial nucleus
-Important for balance and equilibirum
21
Q
Explain the reticulocerebellar fiber pathway from the Brainstem :
- Where its from
-Where it terminates
-What is it involved in
A
- From reticular formation
-Terminate in the vermis
-Involved in postural and axial control
22
Q
Name the inut afferent pathways from the Brainstem to the cerebellum
A
-Olivocerebellar tract
-Vestibulocerebellar fibers
-Reticulocerebellar fibers
23
Q
Name the 2 afferent pathways from the PERIPHERY to the cerebellum
A
-Dorsal spinocerebellar tract
-Ventral spinocerebellar tract
24
Q
In the Dorsal spinocerebellar tract from the periohery:
- What does it enter via
-Where does it terminate
-Where does the signals originate from
A
Pathway: Enters via the inferior cerebellar peduncle.
Termination: Ipsilateral vermis and intermediate zones of the cerebellum.
Origin of Signals: Mainly from muscle spindles, also:
Golgi tendon organs
Large tactile receptors in the skin
Joint receptors
25
What is the function of Dorsal spinocerebellar tract - what does it provide informaiton on
- Tendon tension
-Muscle contraction status
-Forces on body surfaces
26
Explain the ventro spinocerebellar tract from the periphery:
-Where it enters via
-Where it terminates
-Where the signals originate from
Pathway: Enters via the superior cerebellar peduncle.
Termination: Both sides of the cerebellum.
Origin of Signals: Mainly from:
Corticospinal tract
Rubrospinal tract
Internal motor pattern generators
27
What is the function of the ventral spinocerebellar tract
-What does it send
Sends an efference copy of motor commands , informing the cerebellum about the motor output being sent
28
Name the 4 deeper cerebellar nuclei + indicate which is the interposed nucleus
-Fatigial nucleus
- Globose nucleus
-Emboliform nucleus
-Dentate nuclues
Interposed nucleus is Globose + emboliform
29
Where does the deep cerebellar nuclei recieve signals from
- The cerebellar cortex
-Sensory afferent tracts entering the cerebellum
30
Explain what the input signals to the deep cerebellar nucleis split into and where Each of them go + THE RESULT
A direct excitatory signal to the deep nucleus
An indirect inhibitory signal via the cerebellar cortex (arrives a moment later)
➡️ This results in excitation followed by inhibition at the deep nucleus level.
31
Name the major efferny pathways of the cerebellum
-- Fastigial Nucleus Pathway
-Interposed nucleus pathway
-Dentate nucleus pathway
32
Explain the fastigial nucleus pathway :
- Origin
-The deep nucleus involved
-What are the Targets/ what recieves the signals from the Fastigial nucleus
Origin: Vermis
Deep nucleus : Fastigial
Targets:
-Medullary & pontine regions of brainstem
-Vestibular nuclei (equilibrium control)
-Reticular formation
33
What is the function of the fastigial nucleus pathway- what it controls
It contols
balance, equilibrium and postural adjustments
34
Explain the interposed nucleus pathway:
-Origin
-Deep nucleus involved
+ function, what does it coordinate + examples
Origin: Intermediate zome
Deep nucleus : interposed
- It coordinates reciprocal movemnts of limbs e.g hands, fingers, thumbs
35
Explain the Dentate nucles pathway:
-Origin
-Deep nucleus involved
-Targets- where the signals go
Origin: Lateral cerebellar hemisphere
Deep nucleus: Dentate
Targets:
Ventrolateral & ventroanterior thalamic nuclei
→ Cerebral cortex
36
What is the function of the dentate nucleus pathway- what does it coordinate
- It coordinates complex sequential motor activites
37
Name the afferent inputs to the cerebellu(not pathways)
- Climbing fibers
-Mossy fibers
38
Where do climbing fibers originate from
Inferior olivary nucleus
39
1 climbing fiber contacts
-how many purkinje cells ,
-makes what with each purkinje cell and
- sends what to where
- contacts 5-10 purkinje cells
-Makes 300 synapses with each purkinje cellls soma
-Sends collaterals to deep nuclear cells
40
What do mossy fibers originate form
Spinal cord, brainstem , higher brain centers
41
Explain the function of mossy fibers :
- What they send and why
- What do they synapse with and where
- Send collaterals to excite deep nuclear cels
-Synapse with granule cells in the granule layer
-
42
Name the layers of the cerebellar
- Molecular cell layer
-Purkinje cell layer
-Granule cell layer
43
What does the molecular layer of the cerebellar cortex contain
Parallel fibers, stellate cells and basket cells
44
What does purkinje cell layer contain
- Purkinje cell neurons
45
What does the granule cell layer contain
Granule cells and mossy fiber terminals
46
Where does the deep nuclear cells receive excitatory or inhibitory input from
- Excitatory input from afferent fibers
-Inhibitory input from purkinje cells
47
When granule cell axons enter the molecular layer what do they split into and what does the contents excite
Splits into parallel fibers and excites :
-Purkinje cell
-Basket cells
-Stellate cells
48
Where are basket cells and stellate cells located
-Where do they recieve input from
- In the molecular layer
- Recieve input from parallel fibers
49
What is the function of the basket and stellate cells
- What do they inhibit
-+ Enhance
-Inhibit neigbouring purkinje cells via lateral inhibition
- Enhance contrast and precision of signals
50
What are the 3 levels the cerebellum coordinates motor control at
- Vestibulocerebellum
-Spinocerebellum
-Cerebrocerebellum
51
Explain the vestibulocerebellm level of cerebellar motor control
-Where it is
- Function - what it maintains + coordinates
- Location- Flocculondular lobe and vermis
-Maintains balance and posture
-Cordinates equilibrium -related movements
52
Explain the spinocerebellum level of cerebellar motor control :
-Where it is
-What it coordinates
Location:Vermis and intermediate zones -
Function:
-Coordinates ongoing limb movements especially distal limbs
53
Explain the cerebrocerebellum level of cerebellar motor control
-Where it is
-ITS INPUTS
-What it plans to+ develops
- Locatioj: In large lateral zones of cerebellar hemispheres
-Inputs: cerebral motor, pre motor and somatosensory vortices
Function:
-It plans and initiates voluntary movements
-Develops motor imagery
54
Name the 5 structures the spinocerebellum works with / involved with
-Intermediate zone
-Interposed nucleus
-Cerebral motor cortex
-Red nucleus
-Rubrospinal and corticospinal tracts
55
Name the 2 types inputs the intermediate zone of the spincerbellum recieves when a movement is happening + explain where each comes from and what they both tell the cerebellum
- Motor plan input
-Sensory Feedback
(a) Motor Plan Input:
From the cerebral motor cortex and the red nucleus
Tells the cerebellum the intended movement for the next fraction of a second
(b) Sensory Feedback:
From proprioceptors (especially in distal limbs)
Tells the cerebellum what movement actually occurred
56
Name the 2 main output pathways the interposed nucleus sends corrective signals to 1. Via what and what does it refine
2. What does it send
-The cerebral motor cortex:
- Via the thalamus, it refines future movement commands
-The red nucleus :
-Sends corrections down the rubrospinal tract
57
What do both the outpir pathways from the interposed nucleus ( where the corrective signals go to ) help with
Help fine tune movements
58
What do the rubrospinal and corticospinal tracts target
Lateral motor neurons in the spinal cord
59
What is the cerebrocerebellum specialised for
- Intricate sequential movements
-Speech planning and execution
60
The cerebrocerebellum involves 2 way communicstion between what 3 structures
| Distinct level the cerebellum coordiantes motor control functions
- Cerebral cortex
- Basal ganglia
- Laterall cerebellar zones
61
What does the dentate nucleus neurons in the cerebellum suggest
- Suggest cerebellum is involved in anticipating and planning future actions
62
What is the function of the lateral cerebellar zones in the timing of sequential movements-what does it ensure
- It ensures proper timing of movemens
63
What happens without the laterall cerebellar zones which function in the timing of sequential movements
- The perosn cannot predict how far body parts will move
-poor timing leads to disorder sewuences and movements starting too early or late
64
What happens when the lateral cerebellar zones are damaged
-Incordination
-lack of smooth transition between movement phases
-Failure of smooth progression
65
Name the 6 Cerebellar signs( signs of dysfunction)
- DANISH!!
-Dysdiadochokinesia
-Ataxia
-Nystagmus
-Intention Tremor
-Slurred speech
-Hypotonia
66
What is dysdiadochokinesia+
- cause
-+ what it impacts
-+ How it is tested
Inability to perform rapid alternating movements
-Cause: Failure in cerebellar motor prediction and timing
Impact: Affects speech, upper and lowe limbs
-Test: Aking patients to rapidly turn their palm up and down
67
What is Ataxia
- Name the types + cause
-+ Symptoms
Uncoordinated clumsy voluntary movement
- types:
-Cerebellar ataxia: due to cerebellar damage
-Sensiry ataxia: due to distrupted proprioception
-Vestibular ataxia: due to inner ear dysfunction
-Symptoms: poor balance, lack of muscle control + staggering gait
68
What is Nystagmus
+ direction
+ what does it suggeest
Involuntary repetitive eye movements
- Direction: Horizontal or rotatory
-Significance: Suggests cerebellar or vestibular dysfunction
69
What is intention tremor
+ cause
A tremor that worsens during purposeful, targeted movement
- CAUSE: Inaccurate motor output from the cerebellum
70
What is slurred speech( Dysarthria)+ cause + symptoms
- Slow uneven articulaed speech
- cause: poor coordination of speech muscles
- symptoms: irregular rhythm
71
What is hypotonia
+ effect
+cause
- Decreased muscle tone
-effect: floppy msucles
cause- cerebellum reduced excitatiry influence on musce tone
72
What id Dysmetria+ symptom
Inability to control range, speed and direction of movement
-Difficulty touching a target
73
What is past pointing+ due to what
Moving beyond intended target due to lack of cerebellar inhibition
