TutorW1 Flashcards
UMN cell bodies where ?
brain
LMN cell bodies where ?
Ventral horn of spinal cord
Somatotopy of spinal gray matter
Truncal muscles medial to the extremity muscles, and flexor muscles are more central to the extensor muscles
Lateral corticospinal tract innervates
LMN of the extremity muscles
Anterior corticospinal tract innervates
LMN of truncal muscles
Area 4
Motor coltex housing UMN cell bodies
Area 6
Integration of sensation and movement
Areas 5,7
Posterior Parietal lobe - the where pathway
Supplemental Motor Area (SMA)
Will-driven movements, intention
Motor unit
One motor neuron with a cell body in the ventral horn of the spinal cord, and all of the muscle fibers it innervates.
Smallest unit of functional control, increment of tension?
The Motor Unit
Type of motion yielded by healthy random distribution of slow and fast fibers ?
Smooth graded
Clustering of slow and fast fibers, which is pathological will result in ?
Jerky movements
Spontaeous AP, quivering muscles is indicative of ?
LMN lesion
Signs of UPN lesion are ?
Increased motor WEAKNESS
Increased reflexes
Increased Tone
Signs of LMN include
Increased motor WEAKNESS Atrophy Fasciculations Increased reflexes Increased tone
Characteristics of Type1 Fibers
1) Slow contraction speed
2) Fatigue resistance
3) Low force production
4) High use of aerobic enzymes
5) Low use of anaerobic enzymes
6) Small fiber diameter
7) Major storage fuel Triglycerides
Characteristics of Type 2a Fibers
1) Fast contraction speed
2) Intermediate/low fatigue resistance
3) Intermediate force production
4) Intermediate/low aerobic enzymes
5) High anearobic enzymes
6) Intermediate fiber diameter
7) Major storage fuel: Creatine phosphate, glycogen
Characteristics Type 2b fibers
1) Fast contraction speed
2) Low fatigue resistance
3) High force production
4) Low aerobic enzyme use
5) High anearobic enzymes
6) Large fiber diameter
7) Major storage fuel: Creatine phosphate, glycogen
Force of muscle contraction depends on:
1) Rate code -temporal summation; speed faster = more force
2) Recruitment -spatial summation; recruitment of more units = more force due to stronger contraction
3) Size principal- the smaller units get recruited first and stop firing last as they have the lowest threshold.
Dynamic nuclear bag fibers-
Sense change in length of muscle (velocity of muscle contraction), will change firing patter based on movement
Static nuclear bag/chain fibers
Sense static length of muscle when muscle is not moving.
Is it dynamic or static nuclear bag/chain fibers that are important for proprioception
Both are important for proprioception or the sense of the limbs in space
Do static or dynamic discharge more when the muscle is stretched ?
They both discharge more when the muscle is stretched and not contracting.
