Below L2, the vertebral canal is occupied by a bundle of spinal nerve roots called

a. the terminal filum

b. the descending tracts

c. the gracile fasciculus

d. the medullary cone

e. the cauda equina

the cauda equina

The brachial plexus gives rise to all of the following nerves except.

a. the axillary nerve.

b. the radial nerve

c. the obturator nerve

d. the median nerve

e. the ulnar nerve

the obturator nerve

Nerve fibers adjust the tension in a muscle spindle are called

a. intrafusal fibers

b. extrafusal fibers

c. alpha motor neurons

d. gamma motor neurons

e. anulospiral fibers

gamma motor neurons

A stretch reflex requires the action of ______ to prevent an antagonistic muscle from interfering with the agonist

a. gamma motor neurons

b. a withdrawal reflex

c. a crossed extension reflex

d. reciprocal inhibition

e. a contralateral reflex

reciprocal inhibition

A patient has a gunshot wound that caused a bone fragment to nick the spinal cord. The patient now feels no pain or temperature sensations from that level of the body down. Most likely, the ------- was damaged.

a. gracile fasciculus

b. medial lemniscus

c. tectospinal tract

d. lateral corticospinal tract

e. spinothalamic tract

spinothalamic tract

Which of these is not a region of the spinal cord?

a. cervical

b. thoracic

c. pelvic

d. lumbar

e. sacral

pelvic

In the spinal cord, the somas of the lower motor neurons are found in

a. the cauda equine

b. the posterior horns

c. the anterior horns.

d. the posterior root ganglia

e. the fasciculi

the anterior horns

The outermost connective tissue wrapping of a nerve is called the

a. epineurium

b. perineurium

c. endoneurium

d. arachnoid mater

e. dura mater

epineurium

The intercostal nerves between the ribs arise from which spinal nerve plexus?

a. cervical

b. brachial

c. lumbar

d. sacral

e. none of them

none of them

All somatic reflexes share all of the following properties except

a. they are quick

b. they are monosynaptic

c. the require stimulation

d. the are involuntary

e. they are stereotyped

they are monosynaptic

Outside the CNS, the somas of neurons are clustered in swellings called-------.

ganglia

Distal to the intervertebral foramen, a spinal nerve branches into an anterior and posterior ----.

ramus

The cerebellum receives feedback from the muscles and joints by way of the ----- tracts of the spinal cord.

spinocerbellar

In the ----- reflex, contraction of flexor muscles in one limb is accompanied by the contraction of extensor muscles in the contralateral limb.

crossed extension

Modified muscle fibers serving primarily to detect stretch are called -----.

intrafusal fibers

The ----- nerves arise from the cervical plexus and innervate the diaphragm

phrenic

The crossing of a nerve fiber or tract from the right side of the CNS to the left, or vice versa, is called -----.

decussation

The nonvisual awareness of the body's position an movements is called ------.

proprioception

The ----- ganglion contains the somas of neurons that carry sensory signals to the spinal cord.

posterior root

The sciatic nerve is composite of two nerves, the ----- and -----.

tibial and common fibular

Where does the spinal cord end?

Region of L1 and slightly beyond

Cervical Enlargement

inferior cervical region, gives rise to nerves of the upper limbs

Lumbar enlargement

the lumbosacral region, where nerves to the pelvic region and lower limbs arise

Comus medullaris

inferior to the lumbar enlargement, the cord tapers to a point

Filum termindale

Within the lumbar cistern, at the level of vertebra S2, it exits the lower end of the cistern, fuses with the dura mater, and the two form a coccygeal ligament that anchors the cord and meninges to vertebrae column

Cauda equina

a bundle of nerve roots that occupy the vertebral canal from L2 to S5; resembles a horse's tail, innervates the pelvic organs and lower limbs.

Gray matter - Horns

(posterior or anterior horn) has a relatively dull color because it contains little myelin somas, dendrites and proximal parts of the axons of neurons

White matter

(posterior, later, and anterior column) has a bright pearly with appearance, which it gets from an abundance of myelin

What is the central canal

Located in the middle of the commissure which is collapsed in most area of the adult spinal cord, but in some places (and in young children) remains open, lined with ependymal cells, and filled with CSF)