Spinal Cord Flashcards
Which layers cover the spinal cord?
Dura, subarachnoid, pia
Which layer contains CSF?
Subarachnoid. Central canal contains CSF.
What is the function of the spinal cord?
Provides autonomic innervation of most viscera.
Where does the spinal cord end?
Between first and second lumbar vertebrae. Ends as filum terminale.
What structure forms as the spinal cord tapers off?
Conus medullaris
What name is given to the spinal nerves that arise from the end of the spinal cord?
Cauda equina
Name the 4 columns of the spinal cord.
Dorsal horn
Ventral horn
Intermediate column
Lateral horn
What is the function of the dorsal horn?
- Contains neurones that receive somatosensory information from the body.
- Transmits information via ascending pathways to the brain
What is the function of the ventral horn?
Contains motor neurones that exit the spinal cord to innervate skeletal muscle.
What are the functions of the intermediate column and lateral horn?
Contain neurones that innervate visceral and pelvic organs.
What does the spinal nerve divide into when it leaves the vertebral canal?
Posterior and anterior rami
What are the 31 paired spinal nerves?
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
Is the dorsal root sensory or motor?
Sensory
Is the ventral root sensory or motor?
Motor
Which arteries supply the spinal cord?
Anterior spinal artery > Paired posterior spinal arteries > Anterior and posterior segmental medullary arteries
Which veins drain the spinal cord?
Anterior and posterior spinal veins > Internal and external vertebral plexuses
Which stain is used to stain white matter black?
Osmium. Stains myelin.
Which stain is used to stain grey matter black?
Silver stain. Stains cell body.
How many laminae are in grey matter?
10
Is the fasciculus gracilis an ascending or descending tract?
Ascending.
Carries proprioception and vibration information from the lower body to gracile tubercle in medulla.
Is the fasciculus cuneatus an ascending or descending tract?
Ascending.
Carries proprioception and vibration information from upper body to cuneate tubercle in medulla.
Is the spinothalamic tract ascending or descending?
Ascending.
Lateral side carries pain & temperature information. Medial side carries crude touch information. Both sides ascend on the same side for 1/2 segment, decussate and join at the medulla. Cell bodies are in dorsal root ganglion.
Is the lateral corticospinal tract ascending or descending?
Descending.
Begins in primary motor cortex. Medulla decussation. Transmits control of voluntary limb muscles.
Is the ventral corticospinal tract ascending or descending?
Descending.
Begins in primary motor cortex. Decussates as it leaves the anterior white commissure. Transmits control of voluntary axial muscles.
What are fasiculi?
Nerve axons running up and down the spinal cord in bundles.
What are upper motor neurones and what do they do?
Neurones that originate in the cerebral cortex and brainstem. They control movement, muscle tone, spinal reflexes.
What are lower motor neurones and what do they do?
Neurones that originate in the anterior grey column, cell bodies in brainstem. They receive signals from UMN and transmit these to muscle fibres.
Upper motor neurones are divided into two types. Give these.
Pyramidal and extrapyramidal.
What are pyramidal UMN?
2 neurone pathway that originates in the cerebral cortex. Decussate in the medulla and descend contralaterally. Synapse with cell bodies of the ventral horn of the spinal grey matter.
What are extrapyramidal UMN?
Originate in brainstem. Carry motor fibres to spinal cord. Responsible for involuntary autonomic control of all musculature.
Name the 4 sensory nerve endings that can sense fine touch.
- Meissner’s corpuscle
- Pacinian corpuscle
- Ruffini endings
- Merkel endings
What is Brown-Sequard syndrome?
A hemi-section of the spinal cord.
What occurs as a result of Brown-Sequard syndrome?
Ipsilateral loss of: proprioception, motor & fine touch a few segments below the level of damage. Descending corticospinal tract is damaged.
Contralateral loss of: pain, temperature & crude touch a few segments below the level of damage.
