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Chapter 7: Spinal Cord. Anatomy & Physiology Kasprowicz. Quick Review. Gray matter vs. white matter - location - composition Terminology: CNS neurons - nuclei; tracts PNS neurons - ganglia; nerves. Location & Appearance. cylindrical; ~ 17 inches (42 cm) long
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Chapter 7: Spinal Cord Anatomy & Physiology Kasprowicz
Quick Review • Gray matter vs. white matter - location - composition Terminology: CNS neurons - nuclei; tracts PNS 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 caudaequina
General Functions • 2 way impulse conduction pathway to and from the brain from the body • Major reflex center
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 & Physiology Kasprowicz
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 • 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 • Optic sensory; sense of sight (vision)
Cranial Nerves: Function • Oculomotor midbrain eye; motor control of the eyeball, eyelid, lens shape & pupil size IV. Trochlear midbrain eye; motor control of eye muscle
Cranial Nerves: Function V. Trigeminal pons face - sensory impulses from skin on face; inside nose & mouth - activate chewing (motor)
Cranial Nerves: Function VI. Abducens pons eye; motor control of eye muscle
Cranial Nerves: Function • Facial pons face; - motor control of facial muscles, lacrimal & salivary glands - sensory impulses from taste buds
Cranial Nerves: Function • Vestibulocochlear inner ear brainstem; sensory information - vestibular (balance) - cochlear (hearing)
Cranial Nerves: Function • Glossopharyngeal medulla throat; - motor control of swallowing - sensory input from taste buds & pressure receptors in carotid artery
Cranial Nerves: Function X. Vagus medulla thorax & abdomen sensory/motor impulses from & to throat, voicebox, viscera of chest & abdominal cavities (parasympathetic motor neurons)
Cranial Nerves: Function XI. Accessory medulla & superior spinal cord muscles of neck/back motor control of sternocleidomastoid & trapezius muscles
Cranial Nerves: Function XII. 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 & Physiology Kasprowicz
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 • 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
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