Spinal Cord and the Periphery Flashcards
Where is grey matter located?
Centrally
What enters through the dorsal horn and dorsal root of the grey matter?
Axons of sensory fibres
Where a motor neuron cell bodies?
Ventral horn
What is white matter made up of?
Tracts - axons transmitting information between higher centres in the brain and peripheral nerves
Are ascending pathways sensory or motor?
Sensory - descending pathways are motor
What columns are white matter arranged as?
Posterior, lateral and anterior
How many neurons are between the peripheral receptor and cortex in ascending tract pathways?
3 neurons
What does the posterior/dorsal column deal with?
Fine touch, tactile localisation, vibration sense and proprioception
What does the lateral spinothalamic tract deal with?
Pain and temperature from contralateral side of the body
Where do the descending tracts of the spinal cord originate?
Cerebral cortex and brainstem
What are the descending tracts concerned with?
Control of movement, muscle tone, spinal autonomic functions
How many neurons do the tracts coming from cerebral cortex have in their pathway?
2 neurons
Where do the motor/descending tracts decussate?
Brainstem
What are corticospinal/pyramidal tracts concerned with?
Control of voluntary skilled movements
Where do the corticospinal fibres mostly cross?
Decussation of pyramids
What is responsible for muscle tone and reflexes?
Lower motor neuron
What happens to reflex and tone if UMN is damaged but LMN is intact?
Exaggerated
What is a reflex?
Involuntary stereotyped pattern of response brought about by a sensory stimulus
Where are spinal reflexes mediated?
Level of the spinal cord
What sequence of events occurs with a stretch reflex?
Tendon stretched - intramural muscle fibres stimulated - sensory neuron activated
What is the stretch reflex important in control of?
Muscle tone and posture
What happens if you lose the LMN and the reflex?
Areflexia
What does the flexor reflex do?
Helps protect the body from painful stimuli