Spinal Cord (I) Flashcards
vertebral foramen
Hole in vertebra. multiple stacked creates VERTEBRAL CANAL
name regions of the spine superior to inferior
cervical
thoracic
lumbar
sacral and coccygeal
intervertebral foramina
openings between vertebrae where spinal nerves exit the spinal canal
why is spinal cord longer than vertebral column?
- difference in growth speed during development (spinal cord continues to develop into adulthood)
purpose of spinal cord
- communication link between brain and PNS (below head)
- integrate info and produce responses
start and end of spinal cord
extends from foramen magnum to L2 (@ about most inferior rib)
how many pairs of spinal nerves are there?
31
What are the 2 spinal cord enlargements and why do they occur?
- CERVICAL ENLARGEMENT (C4-T1)
- LUMBOSACRAL ENGLARGEMENT (T9-T12)
provides extra nervous tissue to supply upper and lower limbs
conus medullaris
Inferior end of the spinal cord. Nerves supplying the lower limbs
cauda equina
nerves coming out of the bottom of the spinal cord
where do nerves exit past the conus medullaris?
They continue down vertebral canal, exiting through respective foramina or through SACRAL FORAMINA (holes in sacrum)
Filum terminale
extension of pia mater that anchors spinal cord to end of vertebral column (COCCYX)
meninges of spinal cord
continuous of brain
DURA MATER
- dense irregular CT
- EPIDURAL SPACE: between tissue and bone (periosteum only connected to bone, not dura). Helps protect and hold spinal cord in place.
ARACHMOID MATER
- avascular, simple squamous, colagen and elastin fibres
- SUBDURAL SPACE: between arachnoid and dura mater
PIA MATER
- tight to spinal cord
- DENTICULATE LIGAMENTS: small extensions that connect to dura mater. Prevent lateral movement.
- FILUM TERMINALE: anchors spinal cord to coccyx
- SUBARACHNOID SPACE: contains CSF
what are denticulate ligaments?
- extensions of pia mater that connect it to dura mater
- prevent lateral movement of spinal cord
What structures prevent movement in spinal cord?
- fiium terminale prevents longitudinal movement
- denticulate ligaments prevent lateral movement
anatomy of a spinal cord cross section (draw it out)
internal anatomy of the spinal cord (draw it out)
structure and function of grey matter in spinal cord
butterfly shaped
DORSAL HORN (posterior)
- where sensory neurons enter spinal cord
LATERAL HORN
- found only in thoracic and lumbar
- ANS
VENTRAL HORN (anterior)
- “motor horn”
- somatic motor neurons that go to skeletal
GREY COMMISURES
- connects R and L side
- in centre is CENTRAL CANAL
structure and function of white matter in horn
- 2 halves, 3 columns in each half
- columns subdivided into ascending and descending nerve tracts (FASCICULI) that are grouped based on function
- connected by WHITE COMMISSURES that allow signals to move from one side to the other
what structure connects R and L sides of spinal cord in grey matter?
grey commissures
rootlets
- located at each spinal level
- leave or enter spinal cord
- a part of PNS
what is the inferior end of the spinal cord called?
conus medullaris
dorsal and ventral regions of spinal cord
dorsal: posterior median sulcus
ventral: anterior median fissure
structure of grey matter in spinal cord
- butterfly shape in centre
- contains posterior, lateral and anterior horns
- grey commissures connect each side
- in the centre is the CENTRAL CANAL (continuum of ventricles in brain, contains CSF)
function of grey matter horns
POSTERIOR: sensory
- sensory neurons enter and synapse in spinal cord
- contains only interneuron cell bodies because sensory cell bodies are in dorsal root ganglion
LATERAL: ANS
VENTRAL: motor
- contains somatic motor neurons that go to skeletal muscles
lateral horns are only found in…
thoracic and lumbar regions
when dorsal and ventral roots merge we get the…
spinal nerve
where do neurons from lateral horn exit? What tissues do they target?
- ventral root
- 2 neuron system
- target cardiac muscle, smooth muscle or glands
diseases asscociated with anterior spinal cord injury
polio
ALS
What happens after sensory neurons enter spinal cord
- synapse with interneurons or enter white matter and ascend or descend cord
where are the cell bodies of motor and sensory neurons located?
sensory: dorsal root ganglion
motor: ventral horn
