corticospinal Flashcards
upper motor neurons originate in
corticospinal
corticobrainstem- vestibulospinal/ reiculospinal, rubrospinal, tectospinal
corticiospinal tract
origin- primary motor cortex
decends via the internal capsule
descends in mid brain/ pons/ pyrimids of medulla
terminates at lwer motor neurons in the anerior horn of spinal chords
corticospinal function
voluntary control of prescise movements distal muscle
control less presice movement of prox muscle of limb and trunk
corticobrainstem course
lateral primary motor cortex at face and head level decesends via internal capsule
termiantes at
V, VII, IX, XI, XII
bilateral info
function of corticobrainstem
serves as UMN to all motor cranial nerve
facilitates voluntary control of all aforementioned cranial nerve LMN
reticulospinal
reflexive head movement to visual and auditory info
vestibulospinal
vestibular - control neck and upper back muscles
rubrospinal
arise in red nucleus in mid brain minimal contribution to upper limb
LMN
transmit signals directly to skeletal muscle
alpha LMN
large myelin extrafussal muscle fibres
gamma LMN
medium myelin intrafussal muscle fibres
motor unit
alpha LMN all muscle fibres it inervates
when neurotransmitters released ACH- all muscle fibres contract
large motor unit
increased muscle fibre for control
small motor unit
decrease muscle fibres for precise control
larger cortical tissue
small motor unit
small cortical tissue
large motor unit b/c more UMN going to area
