ANA300Y1 Lecture : ANA300 - SPINAL CORD & NERVES
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SPINAL CORD & SPINAL NERVES
CNS = Brain + Spinal Cord
- cranium encloses the brain
o cerebrum â bilaterally paired, anatomically symmetrical
cerebral
hemispheres
o brainstem â contains nuclei (grey matter), white matter tracts, vital
centers and is continuous with the spinal cord
o cerebellum â bilaterally paired
cerebellar hemispheres
, and
coordinates movement
- spinal cord â elongated continuation of brainstem enclosed in the vertebral
column
PNS = Cranial Nerves, Spinal Nerves & Ganglia
- everything outside of the CNS
Cranial Nerves
- 12 pairs arise from the brain and brainstem
- special senses: vision, hearing, smell, balance, taste
- general sensations from the face (touch, pain)
- voluntary motor control of striated muscle in the face
- parasympathetic outflow to targets in face (constrict pupil) and thoracic and
abdominal viscera
Spinal Nerves
- arise from spinal cord
- general sensation from body and back of head
- voluntary motor control of striated muscle in the body
- sympathetic outflow (thoracic and abdominopelvic viscera, skin and targets in
face â pupil dilate)
- parasympathetic outflow to visceral organs of pelvis
Ganglia
- collection of neuronal cell bodies
- associated with cranial and spinal Ns
Dermatomes & Myotomes
- dermatome â area of skin innervated by a given spinal level to provide
sensation
- myotome â group of muscles supplied by the spinal cord to provide
movement
- lesions in spinal nerves results in predictable loss of sensory input and
motor output
Meninges
- membrane covering the CNS
- composed of: dura mater (outer), arachnoid mater, pia mater (delicate and close
to spinal cord)
- subarachnoid space (deep to arachnoid) contains CSF
Rostro caudal Subdivisions of the Spinal Cord
- bilaterally paired spinal nerves are named according to vertebra they emerge
from
o C1 spinal nerve emerges above the atlas, ï cervical spinal nerves are
named according to the vertebra below them
âȘ 8 cervical nerves and cervical spinal segments, but only 7
vertebra segments
Derma: skin
Tone: cut