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Flashcards in SPINAL CORD Deck (9)
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1. Which of the following reflexes is a monosynaptic reflex?
(A). Achilles reflex
(B). Babinski reflex
(C). Corneal reflex
(D). Extensor plantar reflex
(E). Papillary light reflex

1.-A. The Achilles reflex or ankle jerk reflex, is a myotatic monosynaptic reflex that is mediated by cord segmnet S1

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2. All of the following statements concerning the spinal cord are correct EXCEPT
(A). It represents 2% of brain weight
(B). It terminates in the adult at VL1-VL2
(C). It is closely applied to the piamater
(D). It terminates at VS2 in the newborn
(E). It contains 31 pairs of spinal nerves

2.-D. In the newborn, the spinal cord ends at the level of the third lumbar vertebra (VL3). In the adult, the spinal cord ends at the level of the interspace between the first and second lumbar vertebra (VL1-VL2), and the dural cul-de-sac ends at the level of the second sacral vertebra (VS2). The piamater is the innermost meningeal layer of the spinal cord;spinal cord, piamater, arachnoid, duramater, ligamenta flava, periosteum.

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3. All of the following statements concerning spinal nerves are correct EXCEPT
(A). Dorsal root contain sensory input
(B). Ventral roots contain motor output
(C). All spinal nerves have gray communicating rami
(D). All spinal nerves have white communicating rami
(E). The first cervical nerves frequently have no dorsal roots

3.-D. White communicating rami are found only at thoracolumbal levels of the spinal cord(T1-L3); they contain myelinated preganglionic sympathetic fibers and myelinated general visceral afferent (GVA) fibers (from splanchnic nerves). Gray communicating rami contain unmyelinated postganglionic sympathetuic fibers and contribute to all spinal nerves. The first cervical nerve and the coccygeal nerve usually have no dorsal (sensory) roots

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4. All of the following statements concerning the myotatuc reflex are correct EXCEPT
(A). It is a monosynaptic and ipsilateral reflex
(B). It is a muscle stretch reflex (MSR)
(C). It includes a muscle spindle
(D). It includes a ventral horn motor neuron
(E). The cell body of the sfferent nerve fiber is found in the dorsal horn

4.-E. The myotatic reflex is a monosynaptic and ipsilateral muscle stretch reflex (MSR;incorrectly called a deep tendon reflex). The afferent llimb consists of a muscle spindle (receptor) and a 1a fiber (axon) of a dorsal root ganglion neuron;the efferent limb consists of the axon of a ventral horn alpha motor neuron and the innervated striated muscle fibers (effector). The quadriceps (patellar) and triceps surae (ankle) MSRs are myotatic reflex.

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(A). Cervical cord
(B). Upper thoracic cord
(C). Lumbar cord
(D). Lower thoracic cord
(E). Sacral cord

5. Contains preganglionic parasympathetic neurons

5.-E. The sacral cord contains the sacral arasympathetic nucleus (S2-S4); this gives rise to proganglionic fibers that synapse in the intramural ganglia of the pelvic viscera.

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(A). Cervical cord
(B). Upper thoracic cord
(C). Lumbar cord
(D). Lower thoracic cord
(E). Sacral cord

6. Contains massive ventral horns and dorsal intermediate sulcus

6.-A. The cervical cord contains massive ventral horns, which give rise to the brachial plexus (C5-C8). The dorsal intermediate sulcus and septum are also indicative of cervical cord levels.

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(A). Cervical cord
(B). Upper thoracic cord
(C). Lumbar cord
(D). Lower thoracic cord
(E). Sacral cord

7. Has a Ciliospinal center of Budge

7. –B. The ciliospinal center of Budge is found in the lateral horn at T1. This sympathetic nucleus innervates the radial muscle of the iris (dilatator papillae) and the nonstriated superior and inferior tarsal (Muller) muscle.

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(A). Cervical cord
(B). Upper thoracic cord
(C). Lumbar cord
(D). Lower thoracic cord
(E). Sacral cord

8. Contains the spinal acessory nucleus (CN XI)

8.-A. The spinal accesory nucleus extends from C1-C6 and gives rise to the spinal root of the spinal accesory nerve, it innervates the sternocleidomastoid and trapezius muscle.

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(A). Cervical cord
(B). Upper thoracic cord
(C). Lumbar cord
(D). Lower thoracic cord
(E). Sacral cord

9. Contains the phrenic nucleus.

9.-A. The phrenic nucleus extends from C3-C6 and innervates the diaphragm