Motor Cortex & Voluntary Movement
This gyrus contains the primary motor cortex.
What is the precentral gyrus?
This descending tract is especially important for voluntary movement of the hands and fingers.
Lateral Cortico spinal tract
Lesion to this causes spasticity
Upper motor neuron lesion
Type of nerve fibres that carry afferent information about length and velocity of muscle contraction
Type 1a afferents
This muscle protien is mutated in muscular dystrophy
Dystrophin
3 percent of the 1 million cells descending from each lobe of the motor cortex originate from these large neuronal cells
What are Betz Cells
These tracts help regulate axial musculature
Medial cortico spinal tract
Lesion to this causes fasiculations and fibrillations
LMN
They cause contraction of the ends of the muscle spindle (nuclear bag and nuclear chain fibres), keeping the muscle spindle constantly firing to maintain muscle tone
Gamma motor neurons
What ion cause the sliding of tropomyosin to reveal the actin binding heads?
Calcium
Rupture to this artery can cause severe hemiplegia on the contralateral side
What is the Lenticulo Striatal Artery
Decussation or cross of descending motor fibres happen at this level
Lower medulla
Twitching of a single muscle fibre not visible to naked eye
Fibrillation
Simultaneous contraction of agonists and antagonists
Cocontraction
Preventing GABA and Gycine from their inhibitory action on the extensor muscles.
The anterior part of the brainstem where the descending fibres go through
Crux Cerebri
This tract helps with balance and posture by influencing extensor muscles.
Vestibulo Spinal Tract
Positive Babinski Sign occurs in
UMN lesion
When the agonists are stimulated to contract the antagonists are relaxed through inhibititory signals
Reciprocal inhibition
The distance between two z discs
Sarcomere
This part of the brain controls planning of movements
Premotor cortex
This descending tract is involved in maintaining muscle synergies
Reticulo Spinal tract
Muscle loss happens primarily in
LMN lesions
Thin filament and thick filament
Actin and Myosin
The resting membrane potential of a skeletal muscle cell
-90mV