Chapter 12 HW

Regarding reflexes in normal adults:

a negative Babinski reflex occurs

Which of the following reflexes involves a contralateral reflex arc?

crossed extensor reflex

Motor commands are conveyed to the spinal cord by which of the following?

descending tracts

Which structure lies between the pedicles of the adjacent vertebrae?

dorsal root ganglion

Which is the innermost connective tissue layer of the spinal nerve that surrounds each axon?

endoneurium

Which of the following is a nerve of the lumbar plexus?

genitofemoral nerve

Which nerve of the sacral plexus supplies an extensor of the hip?

inferior gluteal nerve

The dorsal ramus:

innervates the muscles, joints, and skin of the back

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

ipsilateral

The stretch reflex

is important in regulating muscle length

The white matter of the spinal cord is/are

myelinated axons and unmyelinated axons

Look up...

page 430; spinal cord page 432; spinal cord surrounding structures page 436; connective tissues and rami page 438 & 439; motor commands and sensory info page 445; leg nerves page 447; neuronal pools page 448; reflex arc page 447; neural circuits page 448; reflex arc

The ________ nerve, which arises in the cervical plexus, innervates the diaphragm

phrenic

Which efferent nerve is involved in the anal reflex?

pudendal nerve

Which nerve of the brachial plexus arises from the posterior cord?

radial nerve

Which neuronal circuit pattern is similar to a positive feedback loop involving neurons?

reverberation

Which structure contains preganglionic and postganglionic fibers innervating structures in the thoracic cavity?

sympathetic nerve

Which efferent nerve is involved in the plantar reflex?

tibial nerve

Sweat glands receive instructions through the ventral and dorsal rami of spinal nerves. The neurons carrying these messages are _____ motor fibers, and their cell bodies are found in the __________

visceral; sympathetic ganglion Sweat glands are part of autonomic/visceral control, not somatic. All visceral motor fibers pass through the sympathetic ganglion after leaving the spinal cord. Many of them synapse at the sympathetic ganglion, and post-ganglionic visceral motor fiber axons pass through the dorsal and ventral rami. Others continue through without synapsing; all of these follow the sympathetic nerve.

Define gray matter in the spinal cord

It is neural tissue that is dominated by the cell bodies of neurons, neuroglia, and unmyelinated axons, and it surrounds the narrow central canal

Which is correct regarding the spinal cord? -The amount of gray matter is greatest in segments of the spinal cord dedicated to the sensory and motor control of the head and neck. -The cord itself is as long as the vertebral column. -The dorsal and ventral roots gradually shorten with age. -The adult spinal cord ends between vertebrae L1 and L2.

The adult spinal cord ends between vertebrae L1 and L2

Which of the following correctly describes a difference between the gray and white rami communicantes of a spinal nerve?

The white ramus contains myelinated fibers, and the gray ramus does not Myelination of the preganglionic axons makes the white ramus communicans appear white. This difference is found throughout the nervous system.

When does the activation of a motor neuron occur in a stretch reflex?

after information processing in the CNS

Jim was in a car accident and suffered damage to the dorsal ramus of several spinal nerves in his lumbar region. What problems might he experience as a result? -muscle weakness or paralysis -loss of sensation from affected areas -decreased sympathetic response -all of the above

all the above

The dorsal and ventral roots of spinal segments L2 to S5 and the filum terminale together form a complex called the:

cauda equina

The epidural space contains

connective tissue and blood vessels