Chapter 14 A&P and Extra Credit
The distribution of the sensory fibers within which of the following structures illustrates the segmental division of dermatomes supplied by the spinal cord?
Dorsal and ventral rami
Which nerve of the brachial plexus supplies the rhomboid and levator scapulae muscles
Dorsal scapular nerve
Which of the spinal meninges consist(s) of a layer of dense irregular connective tissue with an epithelial covering on both inner and outer surfaces?
Dura mater
Jim is a truck driver who often has to spend 10-15 hours each day completing long hauls. During these trips, he carries a large wallet in his back pocket at all times. He, therefore, has recently been complaining of lumbar pain and weakness in his leg muscles. Which peripheral neuropathy is indicated in Jim's case?
Sciatic compression
Which nerve of the sacral plexus is the largest nerve in the human body, innervates the semimembranosus and semitendinosus muscles, and branches into the tibial and fibular nerves?
Sciatic nerve
Which of the following is an example of a reflex classification based on the nature of the resulting motor response?
Somatic or visceral (autonomic) reflexes
The middle layer of the meninges, which consists of simple squamous epithelium, is called (the) ________.
arachnoid mater
Which of the following is a nerve of the cervical plexus?
lesser occipital nerve
Place in order the following steps of a stretch reflex. 1. Stimulus 2. Information processing at a motor neuron 3. Response 4. Activation of a sensory neuron 5. Activation of motor neuron
1, 4, 2, 5, 3
Place in order the following steps of a neural (withdrawal) reflex. 1. Activation of a motor neuron 2. Arrival of stimulus and activation of the receptor 3. Response by effector 4. Information processing in the CNS 5. Activation of a sensory neuron
2, 5, 4, 1, 3
How many pairs of spinal nerves are associated with the cervical vertebrae?
8
Which nerve of the cervical plexus innervates five extrinsic muscles of the larynx?
Ansa cervicalis
Which gray horns contain neurons concerned with somatic motor control?
Anterior gray horns
What do the cervical and brachial plexuses have in common?
Both plexuses contain ventral rami of C5 spinal nerves.
Which spinal segment of the cervical plexus innervates the skin of the upper chest, shoulder, neck, and ear?
C2-C3
The brachial plexus consists of which spinal nerve segments?
C5-T1
The __________ consists of the brain and spinal cord.
CNS
Regarding the gross anatomy of the spinal cord, which of the following structures supplies/supply nerves to the pectoral girdle?
Cervical enlargement
Which structure of the spinal cord contains axons crossing from one end of the cord to the other before reaching a destination within the gray matter?
Gray commissure
Which of the following is a structure of the rami communicantes that supplies postganglionic fibers to smooth muscles and glands of the body wall and limbs?
Gray ramus
What are the projections of gray matter toward the outer surface of the spinal cord called?
Horns
Which nerve of the lumbar plexus is responsible for supplying the abdominal muscles (external and internal obliques and transversus abdominis) and the skin over the inferior abdomen and buttocks?
Iliohypogastric nerve
Why are there 30 vertebrae but 31 pairs of spinal nerves?
In the cervical area, there are eight nerve pairs, with the first exiting above C1.
Where is cerebrospinal fluid found?
In the subarachnoid space
Which nerve of the sacral plexus innervates the large gluteus maximus muscle?
Inferior gluteal nerve
Which type of reflexes is genetically determined?
Innate reflexes
Which of the following describes the filum terminale?
It begins at the inferior tip of the conus medullaris. It extends from the conus medullaris along the length of the vertebral canal as far as the dorsum of the coccyx. It is a slender strand of fibrous tissue.
Which of the following statements regarding a stretch reflex is/are true?
It provides automatic regulation of skeletal muscle length. It responds to information provided by the stretch receptors of muscle spindles. It is a simple monosynaptic reflex.
The adult spinal cord extends from the foramen magnum to the inferior border of the __________.
L1 vertebra
Which structure of the spinal cord is only found between segments T1 and L2, and contains visceral motor neurons?
Lateral (intermediate) gray horns
Which nerve of the brachial plexus innervates the serratus anterior muscle?
Long thoracic nerve
What is the correct description of a spinal injury called paraplegia?
Loss of motor control of the lower limbs
A college freshman admitted at a hospital presents with a high fever, severe headache, a stiff neck, nausea, and confusion. The attending resident suspects a case of spinal meningitis, an inflammation of the CNS membranes (meninges) surrounding the brain and spinal cord, usually due to the spread of an infection. Which procedure will most likely confirm this diagnosis?
Lumbar puncture
Which of the meninges is punctured when a woman in labor receives an epidural injection of anesthesia?
None of the meninges is punctured, because the injection is in the epidural space.
Which nerve of the lumbar plexus innervates the adductor muscles of the hip, gracilis muscle, and skin over the medial surface of the thigh?
Obturator nerve
Which connective tissue covering of a peripheral nerve is a central layer composed of collagenous fibers, elastic fibers, and fibrocytes, and divides the nerve into a series of fascicles?
Perineurium
Which nerve of the cervical plexus is extremely important, in that it innervates the diaphragm?
Phrenic nerve
Where are the denticulate ligaments located?
Pia mater
Which layer of the spinal meninges is the innermost layer, and is firmly bound to the underlying neural tissue?
Pia mater
Which structure of the spinal cord contains somatic and visceral sensory nuclei?
Posterior (dorsal) gray horn
Which nerve of the sacral plexus innervates the skin of the perineum and posterior surface of the thigh and leg?
Posterior femoral cutaneous nerve
Which white matter columns are between the posterior gray horns and the posterior median sulcus?
Posterior white columns
The arachnoid mater consists of simple squamous epithelium and is separated from the pia mater by which of the following?
Subarachnoid space
If Abby goes to the doctor complaining of numbness in her third, fourth, and fifth phalanges on her hand, what spinal nerve will the doctor know has been affected?
T1
Which of the following correctly describes a feature of the cervical plexus?
The cervical plexus controls breathing by innervating the diaphragm with the phrenic nerve
What is true of all of the axons within a particular tract?
They carry either sensory or motor information. They are of approximately the same diameter. They carry information to approximately the same location.
Which of the following statements regarding nerve plexuses is FALSE?
They exist where dorsal rami are converging and branching to form compound nerves.
Which of the following is not a spinal nerve plexus?
Thoracic
The cervical enlargement supplies nerves to the pectoral girdle and upper limbs.
True
The ventral root of a spinal nerve contains ________.
axons of motor neurons
To avoid damaging the spinal cord during a spinal tap, the needle should be inserted _____.
below L1- L2
Epidural anesthesia:
blocks pain but preserves some motor function.
The ulnar nerve is found in the ________ plexus.
brachial
Which nerve plexus innervates the pectoral girdle and upper limbs?
brachial plexus
The ulnar nerve, which we refer to as our "funny bone" when we strike it, comes from what structure?
brachial plexus, medial cord
Damage to the cervical plexus could interfere with what important process?
breathing
The ventral ramus of each spinal nerve receives motor information from a specific segment of the skin and muscles of the neck and back.
false
All of the axons within a particular tract __________.
carry information to approximately the same location carry either sensory or motor information are of approximately the same diameter
The filum terminale and ventral and dorsal spinal cord roots extending distal to the conus medullaris are collectively referred to as the ________.
cauda equina
The lateral gray horns __________.
contain the nuclei for visceral motor nerves
The spinal cord __________.
contains enlarged areas for nerves supplying the upper and lower limbs
The ventral root of a spinal nerve __________.
contains visceral and somatic motor nerve axons
The spinal cord ends at the _____.
conus medullaris
The spinal cord is continuous with the brain and ends at the__________.
conus medullaris
Which of the following terms identifies the most inferior part of the spinal cord?
conus medullaris
The body surface region monitored by a specific pair of spinal nerves is called (a) ________.
dermatome
Motor fibers travel in the ________ of the spinal cord.
descending tracts
Every spinal cord segment is associated with a pair of ________, which contain the cell bodies of sensory neurons.
dorsal root ganglia
If a mosquito lands upon Tyrone's arm, the electrical message conveying the detection of the mosquito would travel through which structure?
dorsal root ganglion
If a motor impulse travels to a sweat gland located on the upper limb, which structure would the impulse NOT pass through?
dorsal root of the spinal nerve
The __________ is the outermost covering of the spinal cord and brain.
dura mater
What is the last layer of connective tissue that blood vessels must penetrate in order to supply individual axons in a spinal nerve?
endoneurium
The connective tissue wrapping that surrounds an entire spinal nerve is called the __________.
epineurium
The brachial plexus is composed of cutaneous and muscular branches of the ventral rami of spinal nerves C1-C4.
false
The subarachnoid space is ________.
filled with cerebrospinal fluid
The median nerve _____.
gets a branch from the medial and lateral cords
The gray matter of the spinal cord is organized into anterior, posterior, and lateral ________.
horns
The term for a reflex that is genetically determined is a(n) ________ reflex.
innate
A newborn baby's suckling reflex could be classified as __________.
innate and cranial
A dermatome __________.
is a region of skin supplied by a specific spinal nerve
The patellar reflex __________
is a stretch reflex that prevents damage to the quadriceps
A nerve plexus _________
is a tangled bundle of spinal nerves formed by the fusion of multiple ventral rami
The spinal meninges __________.
isolate the spinal cord from surrounding tissue absorb shock transmitted up the body when walking, running, or other vigorous motions occur protect the cord from injury that would be caused by rubbing against a vertebral foramen
Injuries in the _________________ spine can cause some impairment in the hips, lower extremities, bowel, and bladder, and may impair sexual functions.
lumbar
Which of the following is correctly matched?
lumbar—5 pair of spinal nerves
Inferior to the ________, the spinal cord tapers to the conus medullaris.
lumbosacral enlargement
Which of the following INCORRECTLY represents the contribution for each of the peripheral nerves?
median Nerve—C5, C6, C8, T1
If Adam is walking through his yard barefoot and steps on a nail, he will withdraw his injured foot yet also extend his other leg so as not to fall. This kind of reflex could be called __________.
polysynaptic
If Adam is walking through his yard barefoot and steps on a nail, he will withdraw his injured foot, yet also extend his other leg so as not to fall. This kind of reflex could be called __________.
polysynaptic
What do the spinal meninges do?
protect the cord from injury that would be caused by rubbing against a vertebral foramen absorb shock transmitted up the body when walking, running, or other vigorous motions occur isolate the spinal cord from surrounding tissue
The denticulate ligaments of the pia mater __________.
protect the spinal cord from side-to-side motion that might damage the cord
The brachial plexus is more complex than the cervical plexus. How is the brachial plexus organized from the spinal nerve to the periphery?
rami → trunks → divisions → cords → nerves
From medial to lateral, brachial plexus structures are organized as which of the following?
roots,trunks,divisions,cords,nerves
The largest nerve in the body that is formed from L4-S3 is the ________.
sciatic nerve
Visceral (autonomic) reflexes control the actions of all of the following, except:
skeletal muscle.
The cervical enlargement _____.
supplies nerves to the upper extremity
Which of the following does not arise from the posterior cord?
suprascapular
All of the following are true of the spinal cord and associated structures, except:
the dorsal roots associated with the spinal segments contain the axons of motor neurons.
All of the following statements are true of the sectional anatomy of the spinal cord, except:
the gray matter contains many myelinated and unmyelinated axons organized in tracts or columns.
In a reflex arc, which step follows the activation of a motor neuron?
the response by the effector
Stretch reflexes provide automatic regulation of skeletal muscle length.
true
The regional order from the spinal cord roots is _____.
trunks, divisions, cords, and peripheral nerves