A&P CH13

Question 1

List the four spinal cord regions from superior to inferior?

Answer 1

1. cervical
2. thoracic
3. lumbar
4. sacral

Question 2

What fluid is in the central canal of the spinal cord and the subarachnoid space?

Answer 2

cerebrospinal fluid (CSF)- shock absorber and medium for diffusion of dissolved gases, nutrients, chemical messengers and waste

Question 3

What parts of the body are being served by the cervical and lumbar enlargements?

Answer 3

cervical enlargement- supplies nerves to the upper limbs and shoulders
lumbar enlargement- innervates structures of the pelvis and lower limbs

Question 4

What do dorsal root ganglia contain?
Note: dorsal root is synonymous with posterior root

Answer 4

spinal ganglia- contain cell bodies of sensory neurons

Question 5

What is the function of the dorsal roots? What is the function of the ventral roots?
Note: ventral root is synonymous with anterior root

Answer 5

posterior/dorsal root- bring sensory info to the spinal cord
anterior/ventral root- contains the axons of motor neurons that extend into the periphery to control somatic and visceral effectors

Question 6

What is the function of rami communicantes?

Answer 6

axon bundles that link the spinal nerves with the ganglia of the sympathetic chain

Question 7

White ramus communicans contains what types of axons? Gray ramus communicans contains what
types of axons?

Answer 7

white- myelinated axons
gray- unmyelinated fibers that innervate glands and smooth muscles

Question 8

Spinal nerves are mixed nerves. What does this mean?

Answer 8

they contain both afferent (sensory) and efferent (motor) fibers

Question 9

in which location would a doctor perform a spinal tap?

Answer 9

the arachnoid matter

Question 10

What is meningitis?

Answer 10

inflammation of the meningeal membranes caused by bacteria or viral infection- disrupts normal circulation of CSF, damaging or killing neurons and neuroglia in the affected areas

Question 11

What structures are mainly found in gray matter? What structures are mainly found in white matter?

Answer 11

gray- cell bodies of neurons, neuroglia and unmyelinated axons
white- myelinated and unmyelinated axons

Question 12

What are organized areas of spinal cord grey matter called?

Answer 12

Nuclei- masses of gray matter within the CNS

Question 13

What is the function of sensory nuclei in the spinal cord? What is the function of motor nuclei in the
spinal cord?

Answer 13

sensory nuclei- receive and relay sensory info. from peripheral receptors
motor nuclei- issue motor commands to peripheral effectors

Question 14

What are organized areas of spinal cord white matter called?

Answer 14

columns- posterior, anterior and lateral

Question 15

What type of information is carried by ascending tracts? What type of information is carried by
descending tracts?
Note: This makes sense-remember Figure 12-1. The afferent division of the PNS brings sensory
information to the CNS for processing. Ascending tracts in the CNS carry sensory signals (=sensory
information) to CNS areas for processing- The signal ascends which means they go upwards. Descending
tracts in the CNS carry motor commands (=motor information) downward through the CNS to be passed
into efferent PNS nerves. The motor commands descend which means they go down.

Answer 15

ascending- carry sensory info to the brain
descending- convey motor commands to the spinal cord

Question 16

Where are the epineurium, perineurium, and endoneurium located on a typical peripheral nerve?

Answer 16

epineurium-outermost layer
perineurium-middle layer
endoneurium-innermost layer

Question 17

What is a dermatome?

Answer 17

a sensory region monitored by the dorsal rami of a single spinal segment; specific bilateral region of the skin surface monitored by a single pair of spinal nerves

Question 18

What is a nerve plexus? List the four nerve plexuses

Answer 18

a complex interwoven network of nerves; anterior rami of adjacent spinal nerves blend their fibers to produce a series of compound nerve trunks
1. cervical plexus
2. brachial plexus
3. lumbar plexus
4. sacral plexus

Question 19

Which cervical plexus nerve innervates the diaphragm? What would happen if this nerve was
damaged?

Answer 19

the phrenic nerve
-couldn’t breathe

Question 20

Carpal tunnel syndrome is caused by compression of one or more nerves that innervate the wrist.
Which plexus do these nerves belong to?

Answer 20

the brachial plexus

Question 21

The sciatic nerve belongs to which plexus?

Answer 21

the sacral plexus

Question 22

What type of CNS neurons are organized into functional groups called neuronal pools?

Answer 22

interneurons
neuron pools: functional groups of interconnected neurons

Question 23

Name five neural circuits and states their functions (use Figure 13-13 Neural Circuits: The
Organization of Neuronal Pools for the information)

Answer 23

1. Divergence: spreads stimulation to multiple neurons or neuronal pools in the CNS
2. Convergence: provides input to a single neuron from multiple sources
3. Serial processing: neurons or pools work sequentially
4. Parallel processing: neurons or pools process the same information simultaneously
5. Reverberation: a positive feedback circuit

Question 24

Define neural reflex

Answer 24

sensory fibers deliver info. from peripheral receptors to an integration center in the CNS and motor fibers carry motor commands to peripheral effectors

Question 25

List five steps of a simple neural reflex arc.

Answer 25

1. arrival of a stimulus and activation of a receptor
   2.activation of a sensory neuron
2. information processing in the CNS
3. activation of a motor neuron
4. response by a peripheral effector

Question 26

Differentiate between innate and acquired reflexes.

Answer 26

innate: result from the connections that form between neurons during development
acquired- learned motor patterns

Question 27

Differentiate between monosynaptic vs polysynaptic reflex.

Answer 27

monosynaptic: a reflex in which the sensory afferent neuron synapses directly on the motor efferent neuron
polysynaptic: a reflex in which interneurons are interpreted between the sensory fiber and the motor neurons

Question 28

What type of reflex is a patellar reflex? Is it monosynaptic or polysynaptic?

Answer 28

monosynaptic

Question 29

Are withdrawal reflexes monosynaptic or polysynaptic?

Answer 29

polysynaptic

Question 30

Are crossed extensor reflexes monosynaptic or polysynaptic?

Answer 30

polysynaptic

Question 31

What kind of body movements occurs in an ipsilateral reflex? A contralateral reflex?

Answer 31

ipsilateral- the sensory stimulus and the motor response occur on the same side of the body
contralateral- the motor response occurs on the opposite side of the stimulus

Question 32

Compare and contrast the plantar reflex (negative Babinski reflex) and the Babinski sign (positive
Babinski reflex).

Answer 32

plantar reflex- stroking the lateral sole of the foot produces a curling of the toes: occurs in adults
Babinski reflex- stroking the lateral side of the foot produces a fanning of the toes: occurs in infants
-if the Babinski reflex occurs in adults it can be a sign of a CNS injury