Chapter 13 The Spinal Cord, Spinal Nerves, and Somatic Reflexes
|The upper motor neurons that control skeletal muscles begin with a soma in||the precentral gyrus of the cerebrum.|
|The signals that control your handwriting travel down the spinal cord in||the corticospinal tract.|
|Many upper motor neurons synapse with lower motor neurons in||the anterior horns.|
|Which of the following sensory functions involves neurons in the posterior root ganglia?||touch|
|The spinal cord is divided into all of the following regions except||pelvic.|
|The following are all functions associated with the spinal cord except||to protect neurons in both the ascending and descending tract.|
|Which of the following fractures would be the least likely to cause a spinal cord injury||a fracture of vertebra L4|
|This figure shows a detail of the spinal cord, meninges and spinal nerves. What does “1” represent?||posterior root of a spinal nerve|
|This figure shows a detail of the spinal cord, meninges and spinal nerves. What does “4” represent?||arachnoid mater|
|Epidural anesthesia is introduced in the epidural space between ___ to block pain signals during pregnancy.||dural sheath and vertebral bones|
|This figure shows a cross section of the spinal cord. What does “3” represent?||anterior horn|
|Cerebrospinal fluid fills in the space between||arachnoid mater and pia mater.|
|Which of the following structures is the richest in lipid content?||white matter|
|Gray matter contains||neurosomas, dendrites, and proximal parts of axons of neurons.|
|___ carry motor commands from the brain along the spinal cord||Descending tracts|
|Second-order neurons synapse with third-order neurons in the||thalamus.|
|___ keep(s) nerve fibers insulated from one another.||Endoneurium|
|___ fibers innervate eyes and ears.||Special|
|A ganglion is a||cluster of neurosomas in the PNS.|
|There are __ pairs of spinal nerves.||31|
|This figure shows the anatomy of a nerve. What does “3” represent?||perineurium|
|This figure shows the posterior aspect of spinal nerve roots and plexuses. What does “3” represent?||brachial plexus|
|This figure shows the posterior aspect of spinal nerve roots and plexuses. What does “2” represent?||the cervical enlargement|
|The ventral rami of the spinal nerves form nerve plexuses in all regions except||the thoracic region|
|The cervical plexus gives origin to the ___ nerve(s||phrenic|
|Which of the following nerves originates in the coccygeal plexus?||sciatic|
|This figure shows a dermatome map. A patient with no sensation in the left thumb would probably have a nerve damaged in||C6|
|Which of these is an ascending tract of the spinal cord?||the gracile fasciculus|
|A mixed nerve consists of both||afferent and efferent fibers|
|Which of the following branches of a spinal nerve have somas of solely sensory neurons?||posterior (dorsal) root|
|The bundle of nerve roots that occupy the vertebral canal from L2 to S5 is called the||cauda equina.|
|Somatosensory refers to these sensory signals except the sensory signals from||the viscera.|
|Neurosomas of the posterior root are located in the ___, whereas neurosomas of the anterior root are located in the ___.||posterior root ganglion; gray matter|
|A ___ is a cordlike organ composed of numerous ___.||nerve; axons|
|Which one of the following best describes the order of a somatic reflex?||somatic receptor afferent nerve fiber interneuron efferent nerve fiber skeletal muscle|
|Which of the following groups of muscles have the most muscle spindles?||muscles of the hand|
|These are all properties of reflexes except||reflexes are spontaneous actions of the nervous system.|
|A muscle spindle contains mostly||muscle fibers.|
|A nurse pricks your finger to type your blood. You flinch at the pain, pulling your hand back. This is called the||flexor (withdrawal) reflex.|
|The quickest reflex arcs involve only two neurons, thus forming __ reflex arcs.||monosynaptic|
|The flexor (withdrawal) reflex employs a ____, which maintains a sustained contraction.||parallel after-discharge circuit|
|If a bee sting on the right thigh causes a quick involuntary reaction of the right arm, this would be an example of||an intersegmental reflex.|
|The sensitivity of the muscle spindle is maintained by||gamma motor neurons.|
|The fibers that carry action potentials to cause skeletal muscle to contract are||alpha motor neurons.|
|You go to the movies after a long day and you begin to nod off as soon as the movie starts. Your head starts to lower a little but this reflex causes your head to rise. This is called the||stretch (myotatic) reflex.|
|In the patellar tendon reflex arc, the patellar ligament is stretched, which stretches the quadriceps femoris muscle of the thigh. This reflex will cause the quadriceps femoris to||contract and the antagonist muscles, the hamstrings, to relax.|
|A reflex where the sensory input and motor output are on opposite sides of the spinal cord is called a(n) _____ reflex arc.||contralateral|
|The tendon reflex||prevents overcontraction of a muscle.|
|This reflex shows the least synaptic delay.||tendon reflex|
|Tendon organs are||proprioceptors.|
|Light touch, tickle, itch, temperature, pain, and pressure are stimuli collected by which spinal tract?|
A) gracile fasciculus
B) lateral corticospinal
C) ventral spinocerebellar
|Balance and posture, regulation of awareness of pain are all signals of which motor spinal tract?|
A) ventral spinocerebellar
B) dorsal spinocerebellar
C) ventral corticospinal
D) lateral reticulospinal
|D) lateral reticulospinal|
|This segment of the spinal cord has 8 spinal nerves.|
|Muscle spindles are a type of proprioceptors that respond to stretching of the|
C) muscle fibers.
|C) muscle fibers.|
|An example of a polysynaptic reflex arc is a _______ reflex.|
C) stretch reflex
|This spinal cord tract carries information about position and movement of the lower extremities to the brain.|
B) cuneate fasciculus
D) gracile fasciculus
E) ventral corticospinal
|D) gracile fasciculus|
|This area of the meninges has many smaller blood vessels and closely adheres to the outer surface of the central nervous system.|
A) dura mater
B) subdural space
C) arachnoid membrane
D) subarachnoid space
E) pia mater
|E) pia mater|
|Sensory neurons enter the spinal nerve cord at the|
A) anterior root.
B) ventral root.
C) gray commissure.
D) lateral horns.
E) anterior median fissure.
|B) ventral root.|
|Which branch of each spinal nerve gives rise to the nerves of the extremities?|
A) posterior ramus
B) posterior root
C) anterior ramus
D) anterior root
|C) anterior ramus|
|The brachial plexus innervates|
A) arms and shoulders.
B) only the arm, but the whole arm.
C) the upper arm only.
D) the lower arm only.
|A) arms and shoulders.|
|When the patellar reflex is elicited, the quadriceps muscles contract, but the hamstrings, their antagonists, relax. This relaxation is called|
A) reciprocal inhibition.
C) crossed extension.
D) flexor withdrawal.
E) extrafusal inhibition.
|A) reciprocal inhibition.|