Transcript Nerve activates contraction

Spinal Cord & Nerves
Spinal Cord
 Extends from the base of the skull to the first
or second lumbar vertebra
 31 pairs of spinal nerves arise from the
spinal cord
Spinal Cord Anatomy
Figure 7.20 (1 of 2)
Spinal Cord Anatomy
Figure 7.20 (2 of 2)
Spinal Cord Anatomy
Figure 7.21
Spinal Cord Anatomy
 Meninges cover the spinal cord
 Spinal nerves leave at the level of each
vertebrae
Dorsal root
 Ventral root

Pathways Between Brain and Spinal Cord
Figure 7.22
Peripheral Nervous System (PNS)
 Nerves outside the central nervous system
 Nerve = bundle of neuron fibers
 Neuron fibers are bundled by connective tissue
PNS: Structure of a Nerve
endoneurium
perineurium
epineurium
fascicle
Figure 7.23
PNS: Classification of Nerves
 Mixed nerves
 Both
sensory and motor fibers
 SENSORY (afferent) nerves
 Carry
impulses toward the CNS
 MOTOR (efferent) nerves
 Carry
impulses away from the CNS
Cranial Nerves
PNS: Cranial Nerves
 12 pairs of nerves that mostly serve the head and
neck
 Only the pair of vagus nerves extend to thoracic
and abdominal cavities
 3 are SENSORY only
 5 are MOTOR only
 4 are MIXED
Diagram & Chart
Open up your notebook to
next empty page. You
will be using both
pages on either side of
spiral.
LEFT: (refer to p. 260)
Color code CRANIAL
NERVES diagram and
paste it into your
notebook.
RIGHT:
Draw chart
#
Nerve
S
Function
or
M?
I
OLFACTORY
II
OPTIC
III
OCULOMOTOR
IV
TROCHLEAR
V
TRIGEMINAL
VI
ABDUCENS
VII
FACIAL
VIII
VESTIBULOCOCHLEAR
IX
GLOSSOPHARYNGEAL
X
VAGUS
XI
ACCESSORY
XII
HYPOGLOSSAL
2 lines each row
PNS: Cranial Nerves

I Olfactory nerve — SENSORY for smell
 II Optic nerve — SENSORY for vision
 III Oculomotor nerve — MOTOR fibers to eye
muscles
 IV Trochlear — MOTOR fiber to eye muscles
PNS: Cranial Nerves
 V Trigeminal nerve — SENSORY for the face;
MOTOR fibers to chewing
muscles
 VI Abducens nerve — MOTOR fibers to eye muscles
 VII Facial nerve —
SENSORY for taste;
MOTOR fibers to the face
 VIII Vestibulocochlear nerve — SENSORY for balance
and hearing
PNS: Cranial Nerves
 IX Glossopharyngeal nerve — SENSORY for taste;
MOTOR fibers to the
pharynx
 X Vagus nerves — SENSORY and MOTOR fibers for
pharynx, larynx, thoracic
and abdominal areas
 XI Accessory nerve — MOTOR fibers to neck and
upper back
 XII Hypoglossal nerve — MOTOR fibers to tongue
CRANIAL NERVES function
Figure 7.24
Olfactory
II. Optic
III. Oculomotor
IV. Trochlear
V. Trigeminal
VI. Abducens
VII. Facial
VIII.Vestibulocochlear
IX. Glossopharyngeal
X. Vagus
XI. Accessory
XII.Hypoglossal
I.
PNS:
Cranial
Nerves
PNS: Cranial Nerves Device
Oh
Oh
Oh
To
Touch
And
Feel
Very
Green
Vegetables
A
H
Olfactory
II. Optic
III. Oculomotor
IV. Trochlear
V. Trigeminal
VI. Abducens
VII. Facial
VIII.Vestibulocochlear
IX. Glossopharyngeal
X. Vagus
XI. Accessory
XII.Hypoglossal
I.
PNS:
Cranial
Nerves
PNS: Spinal Nerves
 There is a pair of spinal nerves at the level of each
vertebrae for a total of 31 pairs
 Formed by the combination of the ventral and dorsal
roots of the spinal cord
 Named for the region from which they arise
Cervical
nerves
Thoracic
nerves
Lumbar
nerves
Sacral
nerves
C1
2
3
4
5
6
7
8
T1
2
3
4
5
6
7
8
9
10
11
Ventral rami form
cervical plexus
(C1 – C5)
Ventral rami form
brachial plexus
(C5 – C8; T1)
No plexus
formed
(intercostal
nerves)
(T1 – T12)
12
L1
2
3
4
Ventral rami form
lumbar plexus
(L1 – L4)
5
(a)
S1
2
3
4
Ventral rami form
sacral plexus
(L4 – L5; S1 – S4)
Figure 7.25a
PNS: Spinal Nerve Plexuses
 Plexus–networks of nerves serving motor and
sensory needs of the limbs
 Form from ventral rami of spinal nerves in the
cervical, lumbar, and sacral regions
Four plexuses:
•
•
•
•
Cervical
Brachial
Lumbar
Sacral
Axillary nerve
These
nerves
arise from
the
BRACHIAL
PLEXUS
Humerus
Ulna
Radius
Ulnar nerve
Radial nerve
(a) The major nerves
of the upper limb
Figure 7.26a
These
nerves
arise from
the
LUMBAR
PLEXUS
Femoral
Lateral
femoral
Obturator
Anterior
femoral
Saphenous
(b) Lumbar plexus,
anterior view
Figure 7.26b
These
nerves
arise
from the
SACRAL
PLEXUS
Superior
gluteal
Inferior
gluteal
Sciatic
Posterior
femoral
cutaneous
Common
fibular
Tibial
Sural (cut)
Deep
fibular
Superficial
fibular
Plantar
branches
(c) Sacral plexus, posterior view
Figure 7.26c
Summary
On a half sheet of paper, use today’s
notes to write a summary on the
spinal cord.
Then, answer these…
Which cranial nerves are mixed?
Which ones control the eye?
Taste & chewing?