W19-L9: Functional Organisation of Spinal Cord Flashcards Preview

Matt's Block 06 - Neuro block > W19-L9: Functional Organisation of Spinal Cord > Flashcards

Flashcards in W19-L9: Functional Organisation of Spinal Cord Deck (24):

Where do spinal nerve exit the spinal cord, above or below their corresponding vertebral body?

Above for cervical, below for thoracic, lumbar and sacral


As you head more rostral in the spinal cord the amount of white matter



T/F: There are local intra-spinal communication as well as ascending/descending tracts



What are the two groups of ventral motor neurones?

Medial and Lateral groups


Where do lateral ventral motor neurones innervate?

More distal muscle, medial is more proximal, ventral is more ventral muscles and dorsal more dorsal


motor neurone pool

cluster of motor neurone cell bodies relating to a single muscle in the spinal cord (column of cells)


How much does a motor neurone innervate?

motor neurone does a collection of muscle fibres, from 2-100


motor unit

collective term for muscle fibres and the motor neurone that innervates them


Muscle Spindle

also called intra-fugal fibres, can contract but main job is to detect stretch, in parallel with muscle fibres and transmits by group I and II axons


What motor neurone innervates muscle spindles

gamma motor neurones (so it can contract to respond to muscle position)


Tendon Organ

responds to how much force is going through the tendon,
in series with the fibres, transmitted by I b afferent neurone


Monosynaptic stretch reflex complexity

Simple as it involves a single central synapse, is the most important sign in neurology


Monosynaptic stretch reflex function

Reflex maintains posture, when a load is applied


Monosynaptic stretch reflex mechanism

signal travels through dorsal root and makes an excitatory synapse with the motor neurone that innervates the same muscle, and also with an interneurone which is inhibitory to the motor neurone innervating opposing muscle


Golgi tendon organ reflex

Too much force through a muscle causes stimulation of an inhibitory interneurone which synapses with the motor neurone of the same muscle, and stimulation of an excitatory interneurone which synapses with the motor neurone of the antagonistic muscle


Golgi tendon organ reflex function

When load is too much protects the muscle and causes the load to be dropped


multi-segmental reflex

ipsilateral to painful stimulus you want to activate flexor to withdraw foot and extensor muscles are inhibited to allow flexion to occur, also to support the body the contralateral leg's extensor is excited
and the flexor is inhibited


Short propriospinal neurones

Lateral ipsilateral neurones that tend to be shorter and are involved in smaller finer muscle reflexes


Long propriospinal neurones

Medial bilateral interneurones that are longer and deal with larger postural muscles


T/F: A limb can direct itself to the stimulus without the brain, all within the spinal cord



lower motor neurone

neurone that innervates muscle


upper motor neurone

neurone that effects the excitability of the LMN (functional term)


upper motor neurone clinical sign

increased muscular response and therefore
larger reflex


upper motor neurone injury mechanism

most of descending motor control is inhibitory so loss causes increased excitability beneath the region of the lesion

Decks in Matt's Block 06 - Neuro block Class (48):