Chapter 7: Spinal CordAnatomy & PhysiologyKasprowicz
Quick Review• Gray matter vs. white matter - location - composition
Terminology:CNS neurons - nuclei; tractsPNS neurons - ganglia; nerves
Location & Appearance• cylindrical; ~ 17 inches (42 cm)
long• Glistening white appearance• Protected by the vertebrae & the
meninges• ~ size of thumb in diameter;
enlargements in the cervical and lumbar regions (near limbs)
Location & Appearance• Continuous with the medulla
oblongata; extends to the first or second lumbar vertebrae
(just below the ribs)• Ends in a collection of spinal
nerves called the cauda equina
General Functions• 2 way impulse conduction
pathway to and from the brain from the body
• Major reflex center
Video Preview of Spinal Cord
Spinal Cord Anatomy· Internal gray matter (mostly cell
bodies); resembles a butterfly or the letter H
· Surrounds the central canal containing cerebrospinal fluid
Spinal Cord Anatomy·Dorsal (posterior) horns – contain interneurons and cell bodies of sensory neurons· If damaged, sensation from the body will be lost
·Anterior (ventral) horns – contain cell bodies of motor neurons
Spinal Cord Anatomy· Exterior white matter
conduction tracts·Sensory tracts – (afferent); tracts conducting sensory impulses to the brain·Motor tracts – (efferent); carry impulses from the brain to skeletal muscles· one side to the other
Chapter 7: Peripheral Nervous System
Anatomy & PhysiologyKasprowicz
Peripheral Nervous System• Contains nerves (bundles of
neuron axons) & ganglia (groups of neuron cell bodies) found outside the CNS
• Includes both sensory (afferent) and motor (efferent) nerves
Structure of a Nerve in the PNS• Similar “packaging” to a muscle
fiber
• Neuron fibers (axons) are bundled by connective tissue
Structure of a Nerve in the PNS
Structure of a Nerve in the PNS• Individual nerve cell process is
covered by the endoneurium.• Groups of nerve cell processes
are bundled together into a fascicle, surrounded by the perineurium.
• Fascicles are bound together by the epineurium = NERVE
Cranial Nerves• 12 pairs that innervate the head and neck; the vagus nerves travel to the thoracic and abdominal cavities
Cranial Nerves: Function
I. Olfactory (bulb & tract) sensory; sense of smell
II. Optic sensory; sense of sight
(vision)
Cranial Nerves: FunctionIII. Oculomotor midbrain eye; motor
control of the eyeball, eyelid, lens shape & pupil size
IV. Trochlear midbrain eye; motor
control of eye muscle
Cranial Nerves: FunctionV. Trigeminal pons face - sensory impulses from
skin on face; inside nose & mouth
- activate chewing (motor)
Cranial Nerves: FunctionVI. Abducens pons eye; motor control
of eye muscle
Cranial Nerves: FunctionVII. Facial pons face; - motor control of facial
muscles, lacrimal & salivary glands
- sensory impulses from taste buds
Cranial Nerves: FunctionVIII. Vestibulocochlear inner ear brainstem; sensory information - vestibular (balance) - cochlear (hearing)
Cranial Nerves: FunctionIX. Glossopharyngeal medulla throat; - motor control of swallowing - sensory input from taste
buds & pressure receptors in carotid artery
Cranial Nerves: FunctionX. Vagus medulla thorax & abdomen sensory/motor impulses from &
to throat, voicebox, viscera of chest & abdominal cavities
(parasympathetic motor neurons)
Cranial Nerves: FunctionXI. Accessory medulla & superior spinal cord
muscles of neck/back motor control of sternocleidomastoid & trapezius muscles
Cranial Nerves: FunctionXII. Hypoglossal medulla tongue sensory & motor impulses
from/to the tongue
Mnemonic Device
•Oh, oh, oh, to touch and feel very good velvet, ahhh.
PNS: Spinal Nerves & Nerve Plexuses
Anatomy & PhysiologyKasprowicz
Spinal Nerves • 31 pairs consisting of the
ventral & dorsal roots of the spinal cord
• ½ long• Divide into the dorsal rami &
ventral rami
Spinal Nerves
Spinal Nerves • Dorsal rami skin/muscles of
posterior body trunk• Ventral rami - T1-T12 (rib muscles, skin/muscles of anterior & lateral trunk) - form plexuses
Plexuses• Complex networks of nerves
serving the sensory & motor needs of the limbs
1) cervical plexus diaphragm, shoulder & neck
Plexuses 2) brachial plexus shoulder, upper thorax, arm & hand 3) lumbar plexus lower abdomen, hip & thigh 4) sacral plexus lower trunk, glutes, leg & foot
Lumbar
Plexus
Sacral Plexus
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CD
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front
back
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