Spinal Cord

The word "poliomyelitis" translates as:

"Inflammation of the gray matter of the spinal cord"

The term "cauda equina" translates as:

"horse's tail"

The term "filum terminale" translates as:

"terminal filament"

Where would the ventral horns be largest in the spinal cord?

The ventral horns would be largest in the limb-innervating cervical and lumbar enlargements.

How does the poliovirus cause flaccid paralysis?

The virus destroys the ventral horn motor neurons.

In humans, how many pairs of spinal nerves are there?

31 pairs

The spinal cord is about 17 inches long and _____ thick.

3/4 inches

During the course of _________ , the sufferer loses the ability to speak, swallow, and breathe. Death typically occurs within five years.

ALS

What part of the core of the spinal cord is filled with cerebrospinal fluid?

Central canal

In what parts of the spinal cord would you find the lateral horns?

Cervical and lumbar enlargements

For most of its length, the spinal cord is about the width of a thumb. However, where the nerves serving the the upper limbs arise, the diameter of the spinal cord is greater and is known as the:

Cervical enlargement

In 3-D, the dorsal and ventral horns form ______ of gray matter that run the entire length of the spinal cord.

Columns

Inferiorly, the spinal cord terminates in a tapering cone-shape structure called the:

Conus medullaris

Throughout the length of the spinal cord, saw-toothed shelves of pia mater called _______ secure the spinal cord to the tough spinal dura mater.

Denticulate ligaments

The two dorsal projections of gray matter in the spinal cord cross section are called the:

Dorsal horns

Name the vertical groove on dorsal side of the spinal cord that runs the length of the spinal cord and partially divides the cord into right and left halves.

Dorsal median sulcus

The cell bodies of the associated sensory neurons are found in an enlarged region of the dorsal root called the:

Dorsal root ganglion or spinal ganglion

Afferent fibers carrying impulses from peripheral sensory receptors form the ______ of the spinal cord that fan out as dorsal rootlets before they enter the spinal cord.

Dorsal roots

Between the bony vertebrae and the spinal dura mater is an _______ filled with a soft padding of fat and a network of veins.

Epidural space

What are the early symptoms of poliomyelitis?

Fever, headache, muscle pain and weakness, and loss of certain somatic reflexes

The ______ is a fibrous extension of the conus medullaris covered by pia mater, that extends inferiorly from the conus medullaris to the coccyx, where it anchors the spinal cord so it is not jostled by body movements.

Filum terminale

How can poliomyelitis be prevented?

Fortunately, vaccines have nearly eliminated polio.

What connects the spinal cord gray matter on either side of the central canal?

Gray commissure

In cross section the gray matter of the spinal cord looks like the letter ______ or like a butterfly.

H

Amyotrophic lateral sclerosis (ALS) is also called:

Lou Gehrig's disease

The spinal cord, for most of its length, is about the width of a thumb. However, the diameter of the spinal cord is larger at the point where the nerves serving the lower limbs emerge called the:

Lumbar enlargement

Since the spinal cord ends between L1 and L2, the subarachnoid space within the meningeal sac inferior to that point provides an ideal spot for removing cerebral spinal fluid for testing, a procedure called:

Lumbar puncture

Are spinal nerves part of the CNS or PNS?

PNS

What is the causative agent of poliomyelitis?

Poliovirus

Which is closer to the gray matter of a spinal cord: roots or rootlets?

Rootlets

Inferiorly, the spinal dura and arachnoid maters extend to the level of ______, well beyond the end of the spinal cord.

S2

Spinal reflexes are initiated and completed by the:

Spinal cord

The _____, enclosed in the vertebral column, extends from the foramen magnum of the skull to the first or second lumbar vertebra, just inferior to the ribs.

Spinal cord

The meningeal layer within the vertebral canal is called the:

Spinal dura mater

What external meninx covers the spinal cord but is not attached to the bony walls of the vertebral column?

Spinal dura mater

The dorsal and ventral roots of the spinal cord are very short and fuse laterally to form the:

Spinal nerves

In the spinal cord, cerebrospinal fluid fills the _______ between the arachnoid and pia mater meninges.

Subarachnoid space

Each spinal nerve exits from the vertebral column by passing _______ to its corresponding vertebra via the intervertebral foramen, and travels to the body region it serves.

Superior

What is the cauda equina?

The collection of spinal nerve roots arising from the conus medullaris and extend down through the vertebral canal.

In a cross section of the spinal cord, where is the gray matter?

The gray matter of the spinal cord is located at its core, with the white matter outside.

Since the spinal cord proper ends at L1 and L2, how do the rest of the spinal nerves exit (lumbar and sacral)?

The lumbar and sacral spinal nerve roots angle sharply downward and travel inferiorly through the vertebral canal for some distance before reaching their intervertebral foramina.

How do you get infected by the poliovirus?

The poliovirus typically enters the body in feces-contaminated water.

Why is a lumbar puncture relatively safe?

The spinal cord is absent there and the delicate nerve roots drift away from the point of needle insertion, there is little or no danger of damaging the cord (or spinal roots) below L3.

How did many polio victims die?

They asphyxiated due to paralyzed respiratory muscles.

All neurons who cell bodies are in the spinal cord gray matter are multipolar. True or False?

True

The dorsal horns of the spinal cord gray matter are entirely interneurons. True or False?

True

The spinal cord is a major reflex center. True or False?

True

The spinal cord provides a two-way conduction pathway to and from the brain. True or False?

True

The ventral horns of the gray matter of the spinal cord are mostly cell bodies of motor neurons with some interneurons. True or False?

True

ALS is a devastating neuromuscular condition that progressively destroys __________ motor neurons and fibers of the pyramidal tracts (a major motor pathway).

Ventral horn

The motor neurons that arise from the ______ of the spinal cord send their axons out to the skeletal muscles.

Ventral horns

The two ventral projections of gray matter in the spinal cord cross section are known as the:

Ventral horns

Name the deep groove that runs the length of the spinal cord on the ventral side partially dividing the cord into right and left halves.

Ventral median fissure

Rootlets from the ventral horns fuse to form the ______ of the spinal cord.

Ventral roots

The ______ of the spinal cord is composed of myelinated and nonmyelinated nerve fibers that allow communication between different parts of the spinal cord and the between the cord and the brain.

White matter