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37 Cards in this Set
- Front
- Back
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Structure of a Nerve
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Cordlike organ of PNS
Bundle of Myelinated and nonmyelinated peripheral axons enclosed by connective tissue |
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Endoneurium
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loose connective tissue that encloses axons and their myelin sheaths
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Perineurium
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coarse connective tissue that bundles fibers into fasicles
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Epineurium
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tough fibrous sheath around a nerve
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Mixed nerves
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both sensory and motor fibers; impulses both to and from CNS
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Sensory (afferent) nerves
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impulses only away from CNS
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Motor (efferent) nerves
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impulses only aways from CNS
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Peripheral nerves classified as
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Cranial nerves
Spinal nerves |
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Cranial nerves
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originate from the brain
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Spinal nerves
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originate from the spinal
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spinal nerves
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31 pairs of mixed nerves fro the spinal cord and supply all parts of the body except the head and part of neck
-named according to their point of tissue |
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spinal nerve pairs
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-8 cervivcal (c1-c8)
-12 thoracic (t1-t12) -5 lumbar (l1-l5) -5 sacral (s1-s5) -1 coccygeal (c0) |
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Roots
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Each spinal nerve connects to spinal cord via 2 roots
-ventral roots (anterior) -dorsal roots (posterior) Dorsal and Ventral roots unite to form spinal nerves which emerge from vertebral column via intervertebral foramina |
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Ventral roots (anterior)
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contain motor (efferent) fibers from ventral horn motor neurons
-fibers innervate skeletal muscles |
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dorsal roots (posterior)
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contain sensory (afferent) fibers from sensory neurons in dorsal root ganglia and conduct impulses from peripheral receptors
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Rami
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distal branches of spinal nerves
spinal nerves are short Each branches into mixed Rami |
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dorsal ramus
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innervates the muscles and joints in that region of the spine and the skin of the back
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ventral ramus
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larger, innervates the anterior and lateral skin and muscles of the trunk and givers rise to nerves of the limbs
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meningeal branch
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tiny, reenters vertebral canal innervates meninges and blood vessels
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rami communicantes
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(automatic pathways) join ventral rami in thoracic region
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ventral rami
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all ventral rami except T2-T12 form interlacing nervier networks called plexuses
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plexuses
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are found in the cervical, brachial, lumbar, and sacral regions
each branch of a plexus contains fibers from several spinal nerves |
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cervical plexus in the neck C1-C5
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supplies neck and phrenic
formed by ventral rami of C1-C4 most branches are cutaneous nerves of the neck ear back of head and shoulders most important nerve is the phrenic nerve |
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brachial plexus near the shoulder C5-T1
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supplies upper limb and some of shoulder and neck
divides into five major peripheral nerves |
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lumbar plexus in the lower back L1-L4
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supplies abdominal wal anterior thigh and genitalia
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sacral plexus in the pelvis L4 L5 and S1-S4
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supplies remainder of lower trunk and lower limb
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coccygeal plexus S4 S5 and C0
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I dont know
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five major nerves of bracchial plexus
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axillary
musculocutaneous median ulnar radial |
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axiallry
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innervates the muscles and skin of shoulders
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musculocutaneous
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sends fibers to the biceps brachia and brachialis
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median
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passes down the anterolateral surface of arm
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ulnar
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supplies posteriomedial surface of arm
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radial
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passes down posterolateral surface of arm and forearm
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major nerve of lumbar plexus
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femoral
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poliomyelitis
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destruction of the anterior horn motor neurons by the poliovirus
early symptoms fever headache muscle pain and weakness and loss of somatic reflexes |
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radial nerve injury
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passes through axilla
crutch paralysis wrist drop |
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sciatic nerve injury
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sciatica- sharp pain that travels from gluteal region along the posterior side of the thigh and leg to ankle
90% comes from herniated intervertebral disc or osteoporosis |
