Lp 7 Flashcards
(26 cards)
Sensory & motor branches meet at 2 junctions?
-SC: reflexive movement (involuntary)
-Cerebral cortex: invitation of voluntary movement
-Voluntary movement?
-Helps plan movements; involved in complex motor tasks; supplies~15% of pyramidal fibres
1* motor cortex
&
Premotor cortex
-activates mm dealing w/speech?
-voluntary eye movement?
-Broca’s area
-frontal eye field
-impulses from somatosensory cortex & thalamus
-voluntary control over skeletal m Fxn
Stimulation
-located on ventral surface of cerebral cortex
-thick region ++ layers of pyramidal cells (cell bodies of UMNs)
1* motor cortex
-association neurons
-origin= frontal lobes
-long myelinated axons from pyramidal (corticospinal) tracts that project to brain stem & SC
-80% decussate at medulla
-synapse on LMNs in ventral horn
UMNs
Pyramidal cells also link to?
-somatosensory area
-thalamus
-premotor cortex
-basal nuclei
-innervation of many m fibres by same UMN (gross movement)?
-allows fro precision & fine motor coordination?
-polysynaptic
-monosynaptic
Body areas map on specific motor cortex sites
- (homunculus)
Somatotopy
-damage to areas of motor cortex
-leads to paralysis of specific mm
UMNL
R & L side of motor cortex=
Contralateral hemiplegia
?= weakness of distal flexor m groups & decrease fine motor coordination
Posterior aspect
?= weakness f larger limb & girdle mm
Anterior aspect
Only voluntary control is lost- mm still contract reflexively
-leads to spasticity
Lesions
-increase in motor tone
-leads to tetany & awkward movement
Spasticity
Temporary or permanent loss of voluntary motor Fxn
Paralysis
-several large gray masses on both sides of thalamus
-contralteral control
-links circuits to premotor & primary motor cortices, & thalamus
-highly skilled behaviours
Fxn: grace movement (highly skilled motor performance) & repetitive motion patterns
Basal nuclei
Damage to the basal nuclei leads to ABN movement patterns & lack of coordination.
Examples are?
-Parkinson’s disease
-Huntington’s chorea
-cerebral palsy (some forms)
-located on posterior fossa of cranium
-unpaired central mass; 2 large cerebellum jemipheres
-composed of outer grey matter & inner white matter
-communicates w/cerebellum via thalamus
1* Fxn:
-coordinates skilled voluntary movements
-controls balance & m tone
-(with cerebrum) smoothies out movements of limbs, trunk, head & eyes
-provides constant adjustment of m contraction required of highly skilled movement
Cerebellum
Cerebellum receives?
-proprioception input
-sensory input from ears & eyes
-coordination of specific body parts w/signals to & from cerebellum
-enables assessment of status of given body parts
Somatotopy
-checks what is suppose to happen w/what is actually happening & corrects via 1* motor cortex
-inhibits movement, overcoming momentum 7 stopping motion at intended point
Cerebellar monitoring
Source of pyramidal cells, which are the origin of corticospinal (pyramidal) tracts; inmates contralateral voluntary movement
Primary motor cortex
-helps plan movements
-selects & sequence basic motor movements into more complex task
Premotor cortex
