Anantomy and Physiology 1 Chapter 13

Spiinal cord, spinal nerves, and spinal reflexes

List the four spinal cord regions from superior to inferior?

cervical, thoratic, lumbar, sacral

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

cerebrospinal fluid

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

shoulder and upper limbs

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

pelvis and lower limbs

What do dorsal root ganglia contain?

cell bodies of sensory neurons

What is the function of the dorsal roots?

carry sensory information into the spinal cord

What is the function of the ventral roots?

carry motor commands out of the spinal cord

What is the function of rami communicantes?

they connect spinal nerves to the symphathetic nervous system and help innervate glands and smooth muscles

White ramus communicans contains what types of axons?

myelinated axons

Gray ramus communicans contains what types of axons?

uunmyelinated axons

Spinal nerves are mixed nerves. What does this mean?

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

In which location would a doctor perform a spinal tap?

subarachnoid space to withdraw cerebrospinal fluid

What is meningitis?

viral or bacterial infection of the meninges

What structures are mainly found in gray matter?

cell bodies of neurons, neuroglia, and unmyelinated axons

What structures are mainly found in white matter?

myelinated and unmyelinated axons

What are organized areas of spinal cord grey matter called?

nuclei

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

receive incoming sensory information from peripheral receptors

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

send motor commands to peripheral effectors

What are organized areas of spinal cord white matter called?

columns

What type of information is carried by ascending tracts?

sensory information up toward the brain

What type of information is carried by descending tracts?

motor commands down to the spinal cord

Where are the epineurium located on a typical peripheral nerve?

outermost; network of collagen fibers

Where are the perineurium located on a typical peripheral nerve?

middle layer; separates nerve into fasicles (bundles of axons)

Where are the endoneurium located on a typical peripheral nerve?

innermost; surrounds individual axons

What is a dermatome?

a specific bilateral region of skin monitored by a single pair opf spinal nerves

What is a nerve plexus?

complex, interwoven network of nerve fibers

List the four nerve plexuses.

cervical, brachial, lumbar, and sacral

Which cervical plexus nerve innervates the diaphragm?

phrenic

What would happen if the phrenic nerve were damaged?

the diaphragm can longer contract normally

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

brachial

The sciatic nerve belongs to which plexus?

sacral

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

Name the five neural circuits

divergence, convergence, serial processing, parallel processing, and reverberation

divergence

a circuit for spreading stimulation to mutiple neurons or neural pools in the CNS

convergance

a circuit for providing input to a single neuron from multiple sources

serial processing

a circuit in which neuorns or pools work sequentially

parallel processing

a circuit in which neurons or pools process the same information simultaneously

reverberation

a positive feedback circuit

Define neural reflex.

rapid, automatic response to specific stimuli

List five steps of a simple neural reflex arc.

1. arrival of a stimulus and activation of a receptor

2. activation of a sensory neuron

3. information processing in the CNS

4. activation of a motor neuron

5. response by a peripheral effector

innate reflexes

basic neural reflexes formed before birth

aquired reflexes

rapid, automatic learned motor patterns

monosynaptic reflex

involve a single synapse

polysynaptic reflex

involves multiple synapses with one or more interneurons

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

stretch flex; monosynaptic

Are withdrawal reflexes monosynaptic or polysynaptic?

polysynaptic

Are crossed extensor reflexes monosynaptic or polysynaptic?

polysynaptic

What kind of body movements occurs in an ipsilateral reflex?

occur on the same side of the body as the stimulus

What kind of body movements occurs in a contralateral reflex?

occur on the side opposite of the stimulus

plantar reflex

normal in adults; stroking the lateral sole, causes reflexive toe-curling

the babinski reflex

normal in infants; stroking the lateral sole, causes fanning of the toes; in an adult may indicate CNS damage