SPINAL CORD Flashcards
What are the two enlargements in the spinal cord
cervical enlargement
Lumbosacral enlargement
The ___ innervates the upper limb
brachial plexus
The ___ innervates the lower limb
lumbosacral plexus
At what vertebral level does the spinal cord end
L1/L2
Are vertebral level and spinal cord level the same
no
Spinal nerves exit the spinal cord at ___
their respective vertebral level
What tethers the spinal cord to the coccyx
cauda equina
What tethers the spinal cord at every level
denticular ligaments
What occurs to spinal cord in thoracic segment
anterior horns are much smaller - fewer motor neurons coming out here - only a few myotomes are only a couple core muscles
What synapses in the lateral horn
visceral motor fibres
What occurs to spinal cord in the lumbar segment
less white matter, because thoracic has motor and sensory tracts for whole body while lumbar is just lower body
3 main functions of the spinal cord
- Conduit (pathways to and from the brainstem and cortex-white matter tracts)
- Reflexes
- Locomotion - Central pattern generators
What is transmitted in fasciculus gracilis? where in the spinal cord is it?
Found in medial dorsal column. Transmits sensory - fine touch, proprioception) from ipsilateral lower limb
What is transmitted in fasciculus cuneatus? where in the spinal cord is it?
Found in lateral dorsal column. Transmits sensory (fine touch, proprioception) from ipsilateral upper limb
What is transmitted in spinocerebella tract? where in the spinal cord is it?
Found in posterior lateral column. Proprioception from limbs to cerebellum
What is transmitted in lateral corticospinal tract? where in the spinal cord is it?
Found in medial lateral column. Motor to ipsilateral ventral horn - mostly limb musculature
What is transmitted in Spinothalamic tract? where in the spinal cord is it?
Found in the anterior lateral horn. Transmits pain and temperature from contralateral side of the body
What is transmitted in anterior corticospinal tract? where in the spinal cord is it?
Found in ventral column. Transmits motor to ipsi- and contralateral ventral horn mostly axial musculature
Does the lateral or anterior corticospinal tract cross in the brainstem
lateral
Where does the lateral corticospinal tract cross? What % of the corticospinal tract is this
in the medulla (pyramidal decussation) 80%
Where does the anterior corticospinal tract cross? what % of the corticospinal tract is this
in spinal cord at anterior white commissure. 20% of fibres
The corticospinal tract originates in the…
primary motor cortex
Where in the brainstem do the corticospinal tract fibres travel
anterior brainstem
What tract is primarily responsible for compensating for balance
vestibulospinal tracts
How does the vestibulospinal tract compensatre for balance
It stabilizes neck musculature and innervates flexors and extensors of lower limb to withstand gravity
what is muscle tone
continuous contraction, readiness of a muscle
What determines muscle tone
activity of muscle spindles
What is the function of the vestibulospinal tract
maintaining balance, postural control, muscle tone
What is the function of the reticulospinal
postural control, muscle tone
What is the function of the tectospinal tract
directing eyes and head&neck to object of interest
What are central pattern generators
automated sequence of motor neuron activation to allow for locomotion: generation of repetitive cycles of flexor and extensor activation
What are 2 ways that CPGs can respond to environmental cues
- Proprioceptors regulate timing to stepping patterns
2. Skin receptors allow for adaptation to obstacles
Signals travel from bladder to where to signal that it is full
Cortex and Periaqueductal grey
What is the role of the cortex in bladder control
sample environment to ensure appropriate setting. if appropriate, activates pontine micturition centre
What does the pontine micturition centre do once activated by the cortex
inhibits sympathetics and somatic motor
Activates parasympathetic
What is the result of the pontine micturition centre inhibiting sympathetics
Internal sphincter relaxation (in males)
What is the result of the pontine micturition centre inhibiting somatic motor
relaxation of external sphincter
What is the result of the pontine micturition centre activating parasympathetics
contraction of the detrusor muscle
Is there cortical control of the bladder in infants
no
What is the sacral reflex of bladder control
when the bladder is full to a certain point it will just contract the detrusor
What is the problem encountered with the sacral reflex of bladder control
you are contracting against a closed sphincter - does not fully empty bladder
At what level does the spinal cord end
L1-L2
What is the epidural space filled with
Fat and venous plexus
The denticulate ligaments separate…
the posterior and anterior roots
What is the entry point for posterior roots carrying sensory information
posterolateral sulcus
What is the exit point for anterior roots carrying motor information
Anterolateral sulcus
Why do the cervical and lumbar regions have more gray matter
these regions innervate the limbs, motor neurons for all limb muscles are located at the levels as are snesory nerves
Segmental arteries branch to form…
posterior/anterior radicular arteries and segmental medullary arteries
Radicular arteries supply…
anterior/posterior spinal roots at each level
Anterior spinal artery supplies the _____
Posterior spinal artery supplies the ____
anterior 2/3
posterior 1/3
Visceral motor neurons of the sympathetic nervous system are located within ___ segments
T1-L2
Visceral motor neurons of the parasympathetic nervous system are located within ___ segments
S2-S4 s
