Ch 13 Dorsal and Ventral Roots and Gray Matter
sympathetic nervous system
What are the multipolar neurons in the lateral horn specific for?
thoracic and superior lumber segments (T1-L1)
Where are the lateral horns?
they contain both sensory axons and motor axons
Why are spinal nerves mixed?
These regions need a large number of myelinated axons because they are controlling upper and lower limbs.
Why are the cervical and lumber regions enlarged?
dorsal root
afferent neurons transmit signals from the rest of the body to the spinal cord and enter through the:
dorsal root ganglia
cluster of cell bodies of unipolar sensory neurons whose axons travel in the spinal cord via the dorsal roots
dorsal and ventral horns
columns of gray matter extending the entire length of the spinal cord
gray commissure
connects masses of gray matter; encloses central canal
ventral roots
consist of axons from motor neurons, which bring info to the periphery from cell bodies within the CNS
gray matter
consists of cell bodies of interneurons and motor neurons
dorsal horn
consists of many multipolar interneurons
ventral horn
consists of many multipolar somatic motor neurons
white matter
consists of myelinated motor and sensory axons
intervertebral foramina
dorsal roots and ventral roots come together and exit the ______________________ as they become spinal nerves
dorsal and ventral horns
each spinal nerve has two roots in the spinal cord:
ventral root
efferent neurons transmit signals from the spinal cord to the rest of the body and exit through the:
ventral median fissure
groove on the anterior side of the vertebrae and carries a lot of vascular structures that serve the spinal cod
ventral median fissure
large fissure in comparison to the dorsal median sulcus and can help when determining the orientation of the vertebrae
lateral horns
small lateral gray matter columns present only in the thoracic and superior lumbar segments (T1-L1)
effectors
spinal nerves extend from the spinal cord to _____________
cervical
the _________ region of the spinal cord has the largest amount of white matter
sacral
the __________ region of the spinal cord has the least amount of white matter
gray matter
the ___________ in the spinal cord is located internally
thoracic
the ___________ region of the spinal cord has the least amount of gray matter relative to the other regions
white matter
the _______________ in the spinal cord is located externally
upper limbs
the cervical region innervates the _________________
lower limbs
the lumbar region innervates the ______________
dorsal median sulcus
the posterior, shallower of the two grooves that partially divide the spinal cord into left and right halves
increases
the ratio of white matter to grey matter ______________ as you move up the spinal column
dorsal and ventral horns
these give off small axons that accumulates together to form a root
dorsal root ganglia
this gives the dorsal root a large bump, which is useful for distinguishing between the two roots
ventral horn
this horn sends its axons out to synapse on skeletal muscles