Flashcards in Motor and sensory innervation of muscle Deck (76)
What are the main functions of the brain in the motor system? (3)
What are the main functions of the spinal cord in the motor system? (2)
What is the function of the basal ganglia in the motor system?
Coordination of movement.
-proper initiation and dampens down movement
What is the function of the cerebellum in the motor system?
Sensory motor coordination and recognises error.
What are the main collections of UMNs in the brain involved in the motor system? (2)
What is the role of the motor cortex?
Planning, initiating and directing voluntary movements.
What is the role of the brainstem centres?
Basic movements and postural control.
How is information from UMNs passed to LMNs?
Most goes via interneurons in the spinal cord.
-5% go directly to LMNs
Where is the 1* motor cortex located?
What is the role of the precentral gyrus?
Planning and initiating voluntary movement.
What are the main Brodmann's area associated with the motor cortex?
Brodmann's areas 4 and 6.
Where is Brodmann's area 4 located?
1* motor cortex.
Where is Brodmann's area 6 located?
What are BETZ cells?
Pyramidal cells in 5th layer of the 1* motor cortex.
What is the main function of BETZ cells?
Provide indirect connection to spinal cord via corticospinal tract.
What is the main function of non-BETZ cells?
Provide direct connection from UMNs to LMNS.
What tracts to axons descend in from the motor cortex to the spinal cord?
-to brainstem centres
-to spinal cord
How are the corticospinal and corticobulbar tracts arrange in the primary motor cortex?
Corticospinal tract = MEDIAL.
Corticobulbar tract = LATERAL.
What is another name for the corticospinal tract?
How do the axons of the corticospinal tract descend?
*95% cross the midline in the MEDULLA >> descend contralaterally
*5% descend ipsilaterally and cross in the SPINAL CORD
Where in the spinal cord are the contralateral and ipsilateral corticospinal tract axons located?
CONTRALATERAL - posterior / lateral cord
IPSILATERAL - ventral cord
Where do the axons of the corticospinal tract terminate?
Onto lower motor neurons in the ventral horn.
-directly / indirectly (through interneurons)
Where are lower motor neurons localised?
Lamina IX of ventral horn.
-dorsal horn = sensory
Where do efferent motor axons exit the spinal cord?
Via the ventral root and spinal nerve.
What are the 2 main types of LMNs?
Which LMNs are directly responsible for the generation of force by muscle?
Alpha motor neurons.
What are gamma motor neruons mainly responsible for?
How many axons is each fibre within a muscle innervated by?
Who introduced 'the final common pathway concept'?
-defined motor neurons and units
-motor neuron = last ste