Notes
Spinal Cord & PNS
Sections
Summary
Spinal Cord
- Passes information in between the brain and the periphery
Segments of the spinal cord from top to bottom
- Cervical
- Thoracic
- Lumbosacral and coccygeal
Peripheral Nervous System
- Roots
- Dorsal: sensory
- Ventral: motor
- Plexuses
- Cervical
- Brachial
- Lumbosacral
- Nerves descend through the lumbar cistern as the cauda equina and exit the spinal canal to form the lumbosacral plexus.
- Thoracic nerves
- Remain unmixed.
- Nerve transmissions pass across neuromuscular junctions to stimulate muscle.
- Peripheral nerve sensory receptors are present to detect sensory impulses from the periphery.
Full Text
SPINAL CORD
- Next, we will draw the spinal cord and peripheral nervous system
- Draw the spinal cord.
- Indicate that it passes information in between the brain and the periphery.
- Label the segments of the spinal cord from top to bottom as: cervical, thoracic, lumbosacral and coccygeal; these segments innervate the superior to inferior periphery, respectively.
NERVE ROOTS
- Next draw a representative nerve root.
- Denote that dorsal or posterior nerve roots receive sensory fibers.
- Whereas ventral or anterior nerve roots emit the motor fibers.
PLEXUSES
- Now, indicate that the cervical nerves interweave to form cervical and brachial plexuses.
- Show that the nerves emerge from these plexuses as peripheral nerves and extend through the periphery.
- Then, show that the lower lumbosacral nerve roots descend through the lumbar cistern as the cauda equina and exit the spinal canal to form the lumbosacral plexus.
NERVES, NEUROMUSCLE JUNCTION, & RECEPTORS
- Next, show that the majority of thoracic nerves remain unmixed.
- Then, show that nerve transmissions pass across neuromuscular junctions to stimulate muscle, and indicate that peripheral nerve sensory receptors are present to detect sensory impulses from the periphery.