Download Outline15 Spinal Cord

Biology 218 – Human Anatomy
Clemens
Nervous System 2 – Spinal Cord and Spinal Nerves
A. Spinal Cord
1. Meninges
a. dura mater
b. arachnoid mater
c. pia mater
Text: Chapter 17
spaces
epidural space
subdural space
subarachnoid space
denticulate ligaments
filum terminale
2. External Anatomy of the Spinal Cord
- adult spinal cord extends from foramen magnum to vertebra L2
cervical enlargement
lumbar enlargement
conus medullaris
cauda equina
3. Internal Anatomy of the Spinal Cord
anterior median fissure
posterior median sulcus
central canal
gray matter
posterior (dorsal) gray horn - sensory
anterior (ventral) gray horn - somatic motor
lateral gray horn - autonomic motor
gray commissure
white matter
posterior white columns - sensory (ascending) tracts
lateral white columns - sensory (ascending) and motor (descending) tracts
anterior white columns - ascending and descending tracts
roots of spinal nerves
dorsal root - sensory
ventral root - motor
B. Spinal Nerves
31 pairs: cervical
C1-C8
(exit above the same-numbered vertebrae)
thoracic
T1-T12 (exit below the same-numbered vertebrae)
lumbar
L1-L5
(exit below
"
"
)
sacral
S1-S5
(exit through the sacral foramina)
coccygeal
Co1
1. Connective tissue coverings
epineurium - surrounds the nerve
perineurium - surrounds fascicles
endoneurium - surrounds individual axons
2. Branches of spinal nerves
anterior ramus
posterior ramus
rami communicantes
3. Dermatomes
4. Plexuses
Nerve examples:
cervical plexus (C1-C5)
phrenic nerve
brachial plexus (C5-T1)
median nerve, radial nerve, ulnar nerve
lumbar plexus (L1-L4)
femoral nerve
sacral plexus (L4-S4)
sciatic nerve
Biology 218 – Human Anatomy
Clemens
Study Questions
1.
2.
Describe the major anatomical features of the spinal cord as seen in a cross-section.
Name and describe the meninges of the spinal cord. What are the names of the
spaces between the meninges, and what is contained in these spaces?
What is contained in the epidural space?
3. Diagram the arrangement of the gray matter and the white matter of the spinal cord.
4. Distinguish between the anterior (ventral) and posterior (dorsal) gray horns in terms
of function and what types of neurons are located within them.
5. What type of information is carried by ascending tracts? What type of information is
carried by descending tracts? Are these tracts in the gray matter or the white matter?
Indicate which of the following are ascending tracts and which are descending tracts:
lateral corticospinal tracts • posterior white columns • anterior corticospinal tracts
6. Describe the general structure of spinal nerves and their connective tissue coverings.
7. What type of information is carried by the dorsal (posterior) roots of spinal nerves?
What type of information is carried by the ventral (anterior) roots of spinal nerves?
8. What effectors are innervated by somatic motor neurons?
What effectors are innervated by autonomic motor neurons?
9. What is a dermatome and what is its clinical significance?
10. List the four principal spinal nerve plexuses and name one major nerve that arises
from each plexus. Name three nerves that arise from the brachial plexus.
11. In the following table, identify the locations of the neural components of a reflex arc
in relation to specific structures in the CNS (spinal cord) and PNS. Refer to Fig.
17.12 in your textbook. (The first two lines are filled in as examples.)
CNS or PNS
Specific location
sensory neurons:
dendrites
PNS
at sensory receptors
axons
PNS
in spinal nerves
cell bodies
_____
axon terminals
_____
integrating center:
interneurons
_____
motor neurons:
cell bodies
_____
axons
_____
axon terminals
_____