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18 Cards in this Set
- Front
- Back
2 functions of spinal cord:
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1. serve as pathway for impulses between body and brain.
2. center of spinal reflexes. |
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Pathway of a spinal reflex:
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stimuli -------> receptor -------> nerve impulses -------> dendrite of sensory neuron ----> dorsal root ganglion -------> axon of sensory neuron -------> spinal cord ----> interneuron -------> motor neuron -------> axon of motor neuron -------> effector
------> reflex occurs. |
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4 features common to all spinal reflexes:
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1. Never more than 1 sensory neuron involved.
2. Cell body of sensory neuron lies outside the spinal cord in the dorsal root ganglion{spinal ganglion}. 3. Axon of sensory neuron always enters the spinal cord dorsally{posteriorly}. 4. Axon of motor neurons always leave the spinal cord ventrally{anteriorly}. |
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The peripheral nervous system{PNS} is composed of :
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12 pairs of cranial nerves
31 pairs of spinal nerves |
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a. List the name and numbers of the 5 types of spinal nerves:
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cervical - 8 pairs
thoracic - 12 pairs lumbar - 5 pairs sacral - 5 pairs coccygeal - 1 pair |
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b. Type of nerve?
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All are mixed nerves.
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c. Where are the cell bodies of their motor fibers located?
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They are located in gray matter of spinal cord.
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d. Where are the cell bodies of their sensory fibers located?
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They are located in the dorsal root ganglion { spinal ganglion }.
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e. Define plexus.
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A network of interlacing nerve fibers from several spinal nerves.
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f. 4 main plexuses
Hint: CBLS |
Cervical Plexus
Brachial Plexus Lumbar Plexus Sacral Plexus |
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formed from nerve fibers from the 1st 4 cervical spinal nerves - nerves from this plexus supply the skin and muscles of neck and shoulders
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cervical plexus
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formed from nerve fibers of the last 4 cervical spinal nerves and the 1st thoracic spinal nerve - nerves from this plexus supply the skin and muscles of the upper limbs
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brachial plexus
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formed from nerve fibers from the last thoracic spinal nerve and the 1st 4 lumbar spinal nerves - nerves from this plexus supply the lower abdominopelvic region, buttocks, and anterior part of thighs
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lumbar plexus
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formed from nerve fibers of the last 2 lumbar nerves and the 1st 4 sacral nerves - nerves from this plexus supply the lower trunk, posterior surface of legs, and the feet
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sacral plexus
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one of the main nerves arising from the plexus is the phrenic nerve.
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Cervical Plexus
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one of the main nerves arising from the plexus is the axillary plexus.
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Brachial Plexus
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main nerve arising from the plexus is the femoral nerve.
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Lumbar Plexus
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main nerve arising from the plexus is the sciatic nerve.
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Sacral Plexus
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