A&P Chapter 13 Concepts

Which meninx is closely associated with the contours of the spinal cord?

Pia mater

Which viral disease results in the destruction of motor neurons?

Poliomyelitis

What are the regions of the spinal cord?

Thoracic, lumbar, cervical, sacral

The bundle of nerves inferior to the medullary cone of the spinal cord is called the

cauda equina

The left and right sides of the gray matter in the spinal cord are connected by the gray

commisure

An ______ fiber is a nerve fiber carrying nerve signals away from the central nervous system.

efferent

External to the neurilemma of a nerve fiber is the layer of loose connective tissue that surrounds a nerve fiber called a(n)

endoneurium

The cerebrospinal fluid circulates in the _____space between the meninges.

subarachanoid

The cerebrospinal fluid circulates in the ____ space between the meninges.

subarachnoid

The number of neurons in a descending pathway is

two

____ matter is composed of myelinated and unmyelinated axons and is superficial to the gray matter of the spinal cord.

white

somatic motor

"voluntary" nervous system: innervates skeletal muscle

How many spinal nerves are in each region of the spinal cord in order from superior to inferior?

8,12,5,5,1

What is the gray commissure of the spinal cord?

A band of gray matter connecting the gray matter of the left side with the gray matter of the right side

What is the loose connective tissue surrounding an individual nerve fiber called?

Endoneurium

Which pathways are made up of three neurons?

Sensory

A somatic fiber innervates which of the following?

Skin, skeletal muscles, bones, and joints

Where is the white matter in the spinal cord?

Superficial to the gray matter

The lateral horns of the spinal cord contain somas of which neurons?

Sympathetic motor

What is a bundle of nerve fibers within the white matter of the spinal cord called?

Tract

The ____ horns of the spinal cord contain the cell bodies of outgoing somatic motor neurons.

anterior

The ______ median fissure is a longitudinal groove on the ventral surface of the spinal cord.

anterior

The _____ space is located between the vertebrae and the dural sheath around the spinal cord.

epidural

What is the cauda equina?

A bundle of nerve roots occupying the vertebral canal from L2 to S5

What is a nerve?

A cord of nerve fiber bundles bound together by connective tissue

Which describes a mixed nerve?

A nerve containing both sensory and motor nerve fibers

Which of the following describes a sensory nerve?

A nerve containing only fibers carrying incoming nerve signals to the CNS

What is a fasciculus in the spinal cord?

A tract of nerve fibers within a funiculus

In which disease does sclerosis of the lateral spinal cord occur, with destruction of motor neurons?

Amyotrophic lateral sclerosis

Which horns of the spinal cord contain the cell bodies of outgoing somatic motor neurons?

Anterior

Which meninx consists of several layers of squamous epithelial cells with a mesh of fibers in the adjoining space?

Arachnoid mater

Which meninx is just below (deep to) the dura mater?

Arachnoid mater`

Where does the spinal cord arise from the medulla oblongata?

At the foramen magnum

A nerve fiber refers to which part of a neuron?

Axon

Where is the epidural space around the spinal cord?

Between the vertebral bones and the dural sheath

What is the white matter of the spinal cord?

Bundles of myelinated and unmyelinated axons found superficial to the gray matter

What is the tail-like bundle of nerves indicated by the arrow labeled A in the figure called?

Cauda equina

In the spinal cord, what is the space within the gray commissure that contains CSF?

Central canal

What does the central canal of the spinal cord contain?

Cerebrospinal fluid

Functions of the spinal cord include which of the following?

Conduction, locomotion, reflexes

What factor accounts for the fact that the right side of the brain communicates with the left side of the body, and vice versa?

Decussation

What is the epineurium composed of?

Dense irregular connective tissue

Within the spinal cord, which tracts carry motor signals down from the brain?

Descending

What is the order of the meninges from superficial to deep?

Dura mater, arachnoid mater, pia mater

What is the dense irregular connective tissue layer enclosing an entire nerve called?

Epineurium

Which connective tissue layer is indicated by the arrow?

Epineurium

Which is composed of dense irregular connective tissue?

Epineurium

In a sensory pathway, which neuron detects the stimulus and transmits the signal to the spinal cord or brainstem?

First order

How are the spinal cord regions named?

For the level of vertebral column from which its spinal nerves emerge

What structure marks the superior end of the spinal cord?

Foramen magnum

What is a cluster of neuron cell bodies located outside of the CNS called?

Ganglion

Where are the neuron cell bodies, dendrites, and synapses found in the CNS?

Gray Matter

Which spinal cord areas are composed of gray matter?

Gray commissure Posterior horn Anterior horn

Which tract will have its origin and destination on the same side of the body?

Ipsilateral

In an adult, the spinal cord ends at which vertebra?

L1

Which are functions of the spinal cord?

Locomotion Conduction Reflexes

Within the spinal cord, what type of information do the descending tracts carry?

Motor

Which are purely sensory nerves?

Olfactory and optic nerves

What are two examples of nerves that carry only sensory information?

Optic nerve Olfactory nerve

Nerve fibers of peripheral nerves are encased in which cells?

Schwann

______ cells form a neurilemma and the myelin sheath around axons in the PNS.

Schwann

In a sensory pathway, which neurons run from the spinal cord or brainstem to the thalamus?

Second-order

The first cervical spinal nerve emerges between which two structures?

Skull and vertebra C1

Unlike visceral fibers that innervate blood vessels, glands, and viscera, ______ nerve fibers innervate skin, skeletal muscles, bones, and joints.

Somatic

In which does cerebrospinal fluid circulate?

Subarachnoid space

The lateral gray horns of the spinal cord are found from segment _____ to segment L1 of the spinal cord.

T2

The lateral gray horns of the spinal cord are found in which segments of the spinal cord?

T2 to L1

What does contralateral mean?

That two points are on opposite sides of the body.

What is the posterior median sulcus of the spinal cord?

The longitudinal groove on the dorsal surface of the spinal cord

What is the subarachnoid space?

The space between the arachnoid mater and pia mater

In a sensory pathway, which neurons run from the thalamus to the sensory cerebral cortex?

Third-order

How many neurons are typically found in an ascending pathway between the receptor and the brain?

Three

visceral motor

To smooth muscle and glands from the lateral horn.

_____ matter is composed of myelinated and unmyelinated axons and is superficial to the gray matter of the spinal cord.

White

A(n) ______ fiber is a nerve fiber carrying nerve signals toward the central nervous system.

afferent

The middle layer of the meninges is the ______ mater.

arachnoid

In the spinal cord, the ______ canal is lined with ependymal cells and contains cerebrospinal fluid.

central

The superior most region of the spinal cord is the ______ region.

cervical

Place the spinal cord regions in order from superior to inferior.

cervical thoracic lumbar sacral

The _____ tract is also called the pyramidal tract.

corticospinal

The nerve fibers of which tract form ridges called pyramids on the anterior surface of the medulla?

corticospinal

Because the nerve tracts of the spinal cord undergo _____, the right side of the brain communicates with the left side of the body, and vice versa.

decussation

What is the structure between the arrows labeled A?

fascicle

A ______ is a tract of nerve fibers within a column of the spinal cord.

fasciculus

In a sensory pathway, the _____ order neuron detects the stimulus and transmits the signal to the spinal cord or brainstem.

first

The _____ matter of the spinal cord contains the synapses and therefore is the site of synaptic integration.

gray

The ______ are a series of fibrous connective tissue membranes covering the central nervous system.

meninges

A nerve containing both sensory and motor nerve fibers is called a(n) ____ nerve.

mixed

A ______ nerve is a nerve containing only fibers carrying outgoing nerve signals from the CNS.

motor

The anterior horns of the spinal cord contain somas of somatic ______ neurons.

motor

The connective tissue layer indicated by the arrow is the

perineurium

corticospinal

pertaining to the cerebral cortex and the spinal cord

The ___ mater is the meningeal layer that is closely associated with the contours of the spinal cord.

pia

The _____ median sulcus is a longitudinal groove on the dorsal surface of the spinal cord.

posterior

somatic sensory

receives sensory information from skin, fascia, joints, skeletal muscles, special senses

visceral sensory

receives sensory information from viscera

In the spinal cord, where is the white matter in relation to the gray matter?

superficial

In the CNS, bundles of axons that make up white matter are called ______.

tracts