Reflexes & neural structures

The nerve crucial for breathing that originates within the cervical plexus is called the ________ nerve.

Phrenic

A complex, interwoven network of nerves is called a(n) ________.

Plexius.

The neural "wiring" of a single reflex is called a(n) ________.

Reflex arc

In ________, axon collaterals extend back toward the source of the impulse and further stimulate the earlier neurons.

Reverberation

________ reflexes activate skeletal muscles.

Somatic

Visceral reflexes provide a mechanism for control of the abdominal muscles. True/False?

False.

The dura mater tapers inferiorly to form the ________.

coccygeal ligament

The most complicated spinal reflexes are called ________.

intersegmental reflex arcs

Reflexes that activate muscles on the same side of the body as the stimulus are called ________.

ipsilateral

A(n) ________ reflex has at least one interneuron placed between the sensory and motor neurons.

polysynaptic

Blood vessels traveling within the ________ deliver oxygen and nutrients to the spinal cord.

subarachnoid space

What is a reflex arc? What components must be present to qualify?

A reflex arc is the wiring pattern of neurons that underlie a particular reflex. A reflex arc consists of three elements at the minimum: (1) a sensory receptor and neuron to carry afferent information to the CNS; (2) an excitatory synapse on a motor neuron; (3) the motor neuron to generate an action potential and conduct the impulse to an effector such as a skeletal muscle motor unit.

The spinal cord consists of five regions and ________ segments. A. 31 B. 25 C. 12 D. 5 E. number varies widely among individuals

A. 31

The spinal cord continues to elongate until about age A. 4 years. B. 10 years. C. 2 months. D. 6 months. E. 20 years.

A. 4 years.

Nerve tracts or fasciculi make up the A. anterior white columns. B. posterior gray horns. C. central canal. D. gray commissures. E. both B and C

A. anterior white columns.

Postganglionic fibers of the autonomic nervous system that innervate internal organs do not rejoin the spinal nerve but form A. autonomic nerves. B. ventral rami. C. dorsal rami. D. gray rami. E. white rami.

A. autonomic nerves.

The white matter of the spinal cord contains A. bundles of axons with common origins, destinations, and functions. B. bundles of dendrites with common origins, destinations, and functions. C. sensory and motor nuclei. D. interneurons. E. both axons and dendrites.

A. bundles of axons with common origins, destinations, and functions.

The dorsal root ganglia mainly contain A. cell bodies of sensory neurons. B. synapses. C. axons of sensory neurons. D. cell bodies of motor neurons. E. axons of motor neurons.

A. cell bodies of sensory neurons.

The postganglionic fibers that connect an autonomic ganglion in the thoracic or lumbar region with the spinal nerve are A. gray rami communicantes. B. dorsal ramus. C. white rami communicantes. D. ventral ramus. E. dermatomes.

A. gray rami communicantes.

Recognized neuronal circuit patterns include all of the following, except A. multipolar. B. reverberating. C. convergent. D. divergent. E. parallel processing.

A. multipolar.

The gray horns of the spinal cord contain mainly A. nerve cell bodies. B. columns. C. meninges. D. nerve tracts. E. funiculi.

A. nerve cell bodies.

The brachial plexus gives rise to all of the following nerves, except the A. phrenic. B. radial. C. median. D. ulnar. E. musculocutaneous.

A. phrenic.

Each of the following nerves originates in the lumbar plexus, except the ________ nerve. A. sciatic B. obturator C. femoral D. genitofemoral E. saphenous

A. sciatic

The posterior horns of the spinal cord contain mainly A. sensory nuclei. B. nerve tracts. C. autonomic motor nuclei. D. sympathetic nuclei. E. somatic motor nuclei.

A. sensory nuclei.

In the condition ________, a virus infects dorsal root ganglia, causing a painful rash whose distribution corresponds to that of the affected sensory nerves as seen in their dermatomes. A. shingles B. Hodgkin's disease C. myasthenia gravis D. neuronal damage E. chickenpox

A. shingles

The subdural space lies between A. the dura mater and the arachnoid mater. B. the arachnoid mater and the pia mater. C. the pia mater and the dura mater. D. the pia mater and the subarachnoid space. E. the endosteum and the periosteum.

A. the dura mater and the arachnoid mater.

Which of the following is not true about a positive Babinski reflex? A. why you close your eyes when you sneeze B. a sign of injury to descending spinal tracts C. flaring of the toes when the sole is stroked D. abnormal in adults E. normal in newborns

A. why you close your eyes when you sneeze

Which of the following associations is incorrect? A. 1 coccygeal spinal nerve B. 11 thoracic spinal nerves C. 8 cervical spinal nerves D. 5 lumbar spinal nerves E. 5 sacral spinal nerves

B. 11 thoracic spinal nerves

Tina falls while climbing a tree and lands on her back. Her frightened parents take her to the emergency room, where she is examined. Her knee-jerk reflex is normal and she exhibits a plantar reflex (negative Babinski reflex). These results suggest that A. Tina has a spinal injury in the cervical region. B. Tina suffered no damage to her spinal cord. C. Tina has injured one of her ascending nerve tracts. D. Tina has a spinal injury in the lumbar region. E. Tina has injured one of her descending nerve tracts.

B. Tina suffered no damage to her spinal cord.

In which of the following would the delay between stimulus and response be greater? A. a monosynaptic reflex B. a polysynaptic reflex

B. a polysynaptic reflex

Identify the structure labeled "10." A. anterior median fissure B. anterior gray commissure C. anterior white column D. anterior white commissure E. anterior white horn

B. anterior gray commissure

The dorsal root of a spinal nerve contains A. interneurons. B. axons of sensory neurons. C. cell bodies of sensory neurons. D. cell bodies of motor neurons. E. axons of motor neurons.

B. axons of sensory neurons.

In which plexus does the ulnar nerve arise? A. cranial B. brachial C. sacral D. lumbar E. cervical

B. brachial

The ________ reflex complements the flexor reflex by activating contralateral muscles. A. tendon B. crossed extensor C. reciprocal D. stretch E. flexor

B. crossed extensor

Enlargements of the spinal cord occur A. in the sacral region. B. in those spinal segments that control the limbs. C. in the thoracic region. D. adjacent to the anterior median fissure. E. near the posterior median sulcus.

B. in those spinal segments that control the limbs.

Reflexes based on synapses formed during development are ________ reflexes. A. visceral B. innate C. acquired D. vegetative E. somatic

B. innate

The ventral rami form four major plexuses, including all of the following, except the ________ plexus. A. cervical B. nuchal C. brachial D. sacral E. lumbar

B. nuchal

Identify the structure labeled "1." A. anterior white column B. posterior white column C. lateral white horn D. median commissure E. lateral white column

B. posterior white column

Identify the structure labeled "8." A. ventral root B. spinal nerve C. dorsal root D. peripheral nerve E. dorsal ramus

B. spinal nerve

A dorsal and ventral root of each spinal segment unite to form a A. lumbar enlargement. B. spinal nerve. C. cervical enlargement. D. spinal ganglion. E. spinal meninx.

B. spinal nerve.

Cerebrospinal fluid flows within the A. filum terminale. B. subarachnoid space. C. pia mater. D. arachnoid mater. E. dura mater.

B. subarachnoid space.

Identify the structure labeled "2." A. ventral root B. ventral ramus C. spinal nerve D. white ramus E. dorsal ramus

B. ventral ramus

The preganglionic fibers that connect a spinal nerve with an autonomic ganglion in the thoracic and lumbar region of the spinal cord form the A. ventral ramus. B. white rami communicantes. C. dermatomes. D. gray rami communicantes. E. dorsal ramus.

B. white rami communicantes.

After age ________ the vertebral column continues to elongate, but the spinal cord itself does not. A. 8 B. 18 C. 4 D. 12 E. none of the above

C. 4

The ventral root of a spinal nerve contains A. axons of sensory neurons. B. interneurons. C. axons of motor neurons. D. cell bodies of sensory neurons. E. cell bodies of motor neurons.

C. axons of motor neurons.

Muscles of the neck and shoulder are innervated by spinal nerves from the ________ region. A. sacral B. thoracic C. cervical D. coccygeal E. lumbar

C. cervical

In the spinal cord, white matter is separated into ascending and descending tracts organized as a. horns. B. nuclei. C. columns. D. nerves. E. ganglia.

C. columns.

The epidural space contains A. lymph. B. blood. C. connective tissue and blood vessels. D. denticulate ligaments. E. cerebrospinal fluid.

C. connective tissue and blood vessels.

The outermost connective-tissue covering of nerves is the A. endomysium. B. perineurium. C. epineurium. D. epimysium. E. endoneurium.

C. epineurium.

The ________ is a strand of fibrous tissue that provides longitudinal support as a component of the coccygeal ligament. A. conus medullaris B. dorsal root C. filum terminale D. ventral root E. cauda equina

C. filum terminale

The outward projections from the central gray matter of the spinal cord are called A. wings. B. pyramids. C. horns. D. tracts. E. fibers.

C. horns.

Spinal nerves from the sacral region of the cord innervate the ________ muscles. A. shoulder B. intercostal C. leg D. facial E. abdominal

C. leg

The layer of connective tissue that surrounds a fascicle within a peripheral nerve is the A. epineurium. B. endosteum. C. perineurium. D. epimysium. E. endoneurium.

C. perineurium.

Identify the structure labeled "5." A. autonomic ganglion B. dorsal root ganglion C. rami communicantes D. autonomic nerve E. ventral root

C. rami communicantes

Compared to the vertebral column, the spinal cord is A. the same length. B. longer. C. shorter. D. A, B, or C, depending on age E. A or C, depending on age

C. shorter.

Reflexes can be classified according to all of the following, except A. their development. B. the complexity of the neural circuit. C. whether they are sensory or motor. D. where information processing occurs. E. the motor response.

C. whether they are sensory or motor.

The ________ plexus supplies innervation to the diaphragm.

Cervical.

Reflexes that activate muscles on the opposite side of the body as the stimulus are called ________.

Contralateral.

In which structure are sensory cell bodies located? A. 4 B. 6 C. 5 D. 10 E. 12

D. 10

The obturator nerve is distributed to the A. skin over buttocks. B. skin over the perineum. C. biceps femoris. D. adductors of the hip. E. extensors of the hip.

D. adductors of the hip.

Mary is in an automobile accident and suffers a spinal cord injury. She has lost feeling in her lower body. Her doctor tells her that swelling is compressing a portion of her spinal cord. Which part of her cord is likely to be compressed? A. the anterior gray commissures B. the anterior gray horns C. the anterior white commissures D. ascending tracts E. descending tracts

D. ascending tracts

Spinal nerves are A. involuntary. B. purely sensory. C. purely motor. D. both sensory and motor. E. interneuronal.

D. both sensory and motor.

What is the function of the structure labeled "14"? A. control of skeletal muscle B. somatic motor control C. somatic sensory processing D. control of visceral effectors E. visceral sensory processing

D. control of visceral effectors

The ________ of each spinal nerve innervates the skin and muscles of the back. A. ventral ramus B. gray ramus communicantes C. white ramus communicantes D. dorsal ramus E. dermatome

D. dorsal ramus

The tough, fibrous, outermost covering of the spinal cord is the A. pia mater. B. epidural block. C. periosteum. D. dura mater. E. arachnoid.

D. dura mater.

Axons crossing from one side of the spinal cord to the other within the gray matter are found in the A. white commissures. B. anterior gray horns. C. posterior gray horns. D. gray commissures. E. lateral gray horns.

D. gray commissures.

A viral disease that destroys the cells of the anterior gray horn will A. block autonomic regulation. B. interfere with position sense. C. mainly interfere with crude touch and temperature sense. D. lead to muscle weakness or paralysis. E. all of the above

D. lead to muscle weakness or paralysis.

Bill contracts a viral disease that destroys cells in the posterior gray horns in his spinal cord. As a result, which of the following would you expect? A. uncontrollable sweating of his feet B. inability to breathe C. problems with moving his legs D. loss of sensation in his torso E. problems with moving his arms

D. loss of sensation in his torso

If a person has a crush injury to the C3-C5 spinal segments, you would expect that he A. would have full range of motion in all extremities. B. could walk without difficulty. C. would be in a coma. D. might be unable to breathe on his own. E. would exhibit none of the above.

D. might be unable to breathe on his own.

The white matter of the spinal cord is mainly A. nodes of Ranvier. B. unmyelinated axons. C. neuroglia. D. myelinated axons. E. Schwann cells.

D. myelinated axons.

Blood vessels that supply the spinal cord run along the surface of the A. dura mater. B. epidural space. C. subdural space. D. pia mater. E. subarachnoid space.

D. pia mater.

The anterior horns of the spinal cord contain mainly A. autonomic motor nuclei. B. sympathetic nuclei. C. nerve tracts. D. somatic motor nuclei. E. sensory nuclei.

D. somatic motor nuclei.

What is the function of the structure labeled "12"? A. control of visceral effectors B. ascending pathway C. visceral sensory receiving D. somatic sensory receiving E. control of skeletal muscle

D. somatic sensory receiving

Samples of CSF for diagnostic purposes are normally obtained by placing the tip of a needle in the A. dura mater. B. epidural space. C. arachnoid mater. D. subarachnoid space. E. cerebral ventricles.

D. subarachnoid space.

Identify the structure labeled "6." A. rami communicantes B. dorsal root ganglion C. ventral root D. sympathetic ganglion E. autonomic nerve

D. sympathetic ganglion

The reflex that prevents a muscle from exerting too much tension is the ________ reflex. A. stretch B. crossed extensor C. flexor D. tendon E. reciprocal

D. tendon

Sometimes, when it is difficult to initiate a knee-jerk reflex by tapping the patellar tendon, a patient will be asked to voluntarily make a fist. Then the reflex will be easily evoked. What does this illustrate about the relation between voluntary and involuntary reflex movement?

Descending motor tracts that excite the motor neurons that activate forearm and hand muscles also send excitatory impulses to motor neurons lower down the spinal cord. These EPSPs spatially summate with the excitatory inputs from the muscle spindles to quadriceps motor neurons, bringing the quadriceps neurons to threshold, and thus generate a brisk "knee jerk" response.

Where do somatic motor neurons reside? A. 10 B. 12 C. 13 D. 14 E. 15

E. 15

In an adult, the conus medullaris is found at about A. T10. B. T6. C. Co1. D. L5. E. L1.

E. L1.

In meningitis, A. viruses can be the cause. B. bacteria can be the cause. C. CSF flow can be disrupted. D. inflammation of the meninges occurs. E. all of the above

E. all of the above

Which of the following is true regarding an epidural block? A. It is commonly used as a method of pain control during labor and delivery. B. It can be difficult to achieve in the upper cervical and midthoracic region. C. It provides mainly sensory anesthesia. D. It affects only the spinal nerves in the immediate area of the injection. E. all of the above

E. all of the above

All of the following are true of polysynaptic reflexes, except that they A. have reverberating circuits that prolong the reflexive motor response. B. involve pools of interneurons. C. are intersegmental in distribution. D. involve reciprocal innervation. E. are arranged according to dermatomes.

E. are arranged according to dermatomes.

All of the following are true of muscle spindles, except that they A. consist of specialized fibers called intrafusal fibers. B. are the receptor for the stretch reflex. C. are found within skeletal muscle. D. are innervated by gamma motor neurons. E. are found in tendons.

E. are found in tendons.

The stretch reflex A. involves a receptor called the Golgi tendon organ. B. is important in regulating muscle length. C. is an example of a polysynaptic reflex. D. is activated when a skeletal muscle lengthens. E. both B and D

E. both B and D

Each peripheral nerve provides ________ innervation to peripheral structures. A. motor B. sensory C. motor AND sensory D. motor OR sensory E. both C and D

E. both C and D

The ventral rami of spinal nerves C5 to T1 contribute fibers to the ________ plexus. A. sacral B. cervical C. lumbar D. thoracic E. brachial

E. brachial

All of the following are true of neural reflexes, except that they A. help preserve homeostasis. B. are automatic motor responses. C. involve at least two neurons. D. are the simplest form of behavior. E. cannot be modified by the brain.

E. cannot be modified by the brain.

The layer of connective tissue that surrounds individual axons within a peripheral nerve is termed the A. aponeurium. B. metaneurium. C. subneurium. D. perineurium. E. endoneurium.

E. endoneurium.

Somatic motor neurons in the spinal cord control all of the following muscles, except those that A. move the arm. B. position the pectoral girdle. C. move the forearm and hand. D. move the hand and fingers. E. move the neck.

E. move the neck.

The flexor reflex A. prevents a muscle from overstretching. B. usually depends on cranial neurons. C. is an example of a monosynaptic reflex. D. prevents a muscle from generating damaging tension. E. moves a limb away from a painful stimulus.

E. moves a limb away from a painful stimulus.

The ________ nerve, which arises in the cervical plexus, innervates the diaphragm. A. radial B. lesser occipital C. sciatic D. ansa cervicalis E. phrenic

E. phrenic

The layer of the meninges in direct contact with the spinal cord is the A. choroid plexus. B. dura mater. C. arachnoid. D. subarachnoid space. E. pia mater.

E. pia mater.

The complex, interwoven network formed by contributions from the ventral rami of neighboring spinal nerves is termed a(n) A. tract. B. autonomic nerve. C. dermatome. D. lateral nerve. E. plexus.

E. plexus.

As the ________ nerve approaches the knee, it divides into two branches, the fibular nerve and the tibial nerve. A. pudendal B. brachial C. perineal D. femoral E. sciatic

E. sciatic

If the dorsal root of a spinal nerve is severed, A. output to skeletal muscles would be blocked. B. the brain would not be able to communicate with that level of the spinal cord. C. output to visceral organs would be blocked. D. the spinal cord would not be able to process information at that level. E. sensory input would be blocked.

E. sensory input would be blocked.

The specialized membranes that surround the spinal cord are termed the A. epidural membranes. B. cranial mater. C. spinal mater. D. cranial meninges. E. spinal meninges.

E. spinal meninges.

The ________ innervates the ventrolateral body surface, structures in the body wall, and the limbs. A. dorsal ramus B. dermatomes C. white rami communicantes D. gray rami communicantes E. ventral ramus

E. ventral ramus

The ________ separates the dura mater from the walls of the vertebral canal.

Epidural space.

The loss of feeling and movement of the legs is termed ________.

Paraplegia.

The condition in which a person loses all feeling and movement of the arms and legs due to spinal cord injury is termed ________.

Quadriplegia

What would happen if the dorsal root of a spinal nerve were completely transected?

The dorsal roots contain axons of sensory neurons, so input from those afferents within the severed root would not be transmitted to the CNS and thus this lesion would result in a complete loss of feeling from the body region served by the afferent fibers in that dorsal root.

While playing football, a player is tackled hard, and as he tries to get up, he finds that he has difficulty flexing and adducting his left thigh and extending his left leg. Which nerve innervating the lower limb may be damaged, and how would the damage affect sensory perception in his left leg?

The player has a damaged left femoral nerve. This nerve also supplies sensory innervation to the skin on the anteromedial surface of the thigh and medial surfaces of the leg and foot, so she/he will also experience numbness in those regions.

In spinal reflexes, the synapses and neural processing are in the spinal cord. True/False?

True

After age 4 the vertebral column continues to elongate, but the spinal cord does not. True/False?

True.

The stretch reflex is monosynaptic. True/False?

True.

Suppose that you feel something brushing against your abdomen. The sensory information would be carried to the spinal cord over a ________ ramus.

Ventral

The specific strip of skin that is innervated by a specific spinal nerve is called a(n) ________.

dermatome

In ________, one neuron synapses on several postsynaptic neurons.

divergence

During the procedure known as a(n) ________, a needle is inserted into the subarachnoid space in the inferior lumbar region.

lumbar puncture (or spinal tap)

In a(n) ________ reflex, a sensory neuron synapses directly on a motor neuron.

monosynaptic