Chapter 13 The Spinal Cord, Spinal Nerves, and Somatic Reflexes

In the spinothalamic tract, the which order neurons decussate from the posterior horn of the spinal cord?

2nd order

Sensory tracts normally travel across ---- neurons from their origin in receptors to the brain

3

Each spinal cord segment gives rise to a pair of spinal nerves. How many pairs of spinal nerves are typically present in an adult?

31

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 cauda equina?

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

Which spinal cord areas are composed of gray matter?

Anterior horn Posterior horn Gray commissure

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

Choose all that are functions of the spinal cord.

Conduction Locomotion Reflexes

Functions of the spinal cord include which of the following?

Conduction, locomotion, reflexes

Which tract carries signals for precise, finely coordinated limb movements?

Corticospinal

Which type of tract usually involves two neurons called upper and lower motor neurons

Descending tracts

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

Dura mater, arachnoid mater, pia mater

How are the spinal cord regions named?

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

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

L1

In which column of the spinal cord is the anterior spinocerebellar tract found?

Lateral

Which funiculus of the spinal cord is the posterior spinocerebellar tract located?

Lateral

In descending pathways, the upper motor neurons synapse with which motor neurons in the brainstem or spinal cord?

Lower

In descending tracts, which motor neuron innervates the target organ?

Lower

Which type of neuron directly innervates a muscle?

Lower motor neuron

Where do the first-order neurons of the spinocerebellar tract originate?

Muscles and tendons

Where are the pyramids of the brainstem?

On the anterior surface of the medulla oblongata

Where is the gracile fasciculus located in the spinal cord?

Posterior fasciculus

Where do first-order neurons of the spinocerebellar tract end?

Posterior horn of the spinal cord

Choose all the regions of the spinal cord.

Sacral Cervical Thoracic Lumbar

In which does cerebrospinal fluid circulate?

Subarachnoid space

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

Superficial

Where is the white matter in the spinal cord?

Superficial to the gray matter

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-L1

The coccygeal ligament is formed from the fusion of which two structures?

Terminal filum and dura mater

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 descending pathways, which motor neurons have their somas in the cerebral cortex or brainstem?

Upper

What is a region of the spinal cord supplied by a pair of spinal nerves called?

a segment

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

anterior

The spinoreticular tract is found in which columns of the spinal cord?

anterior and lateral

The spinothalamic tract is part of the which system in the anterior and lateral columns?

anterolateral

The system that passes up the anterior and lateral funiculi of the spinal cord and is composed of the spinothalamic tract and some smaller tracts is the ---system.

anterolateral

The system that passes up the anterior and lateral funiculi of the spinal cord and is composed of the spinothalamic tract and some smaller tracts is the ______________system.

anterolateral

The --- mater is just below (deep to) the dura mater.

arachnoid

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

arachnoid

Within the spinal cord, which tracts carry information up to the brain?

ascending

The lumbar cistern is the name of the hollow space that contains the---- equina and cerebrospinal fluid.

cauda

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

cauda equina

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

central

Where do signals ascending through the spinocerebellar tract terminate?

cerebellum

What does the central canal of the spinal cord contain?

cerebrospinal fluid

What fills the subarachnoid space?

cerebrospinal fluid

The---- enlargement of the spinal cord gives rise to the nerves of the upper limbs.

cervical

What is the most superior region of the spinal cord?

cervical

Place the spinal cord regions in order from superior (at the top) to inferior (at the bottom).

cervical thoracic lumbar sacral

Which ligament is formed by the fusion of the lumbar cistern and dura mater?

coccygeal

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

commissure

A tract that has its origin and destination on opposite sides of the spinal cord are called ---tracts.

contralateral

Which tract will have its origin and destination of opposite sides of the body?

contralateral

In the spinoreticular tract, the second order neurons decussate to where?

contralateral anterolateral system

The tract that carries signals for precise, finely coordinated limb movements is the ____________tract.

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

decussation

Extensions of the pia mater that extend through the arachnoid mater to the dura mater and anchors the cord and limits side-to-side movements of the cord are called---- ligaments.

denticulate

Which are extensions of the pia mater that anchor the spinal cord?

denticulate ligaments

The dural sheath around the spinal cord is formed from the----mater

dura

What is the dural sheath around the spinal cord made of?

dura mater

Place the meninges in order from superficial (at the top) to deep (at the bottom).

dura, arachnoid, pia

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

epidural

Within a nerve, nerve fibers are gathered into bundles called what?

fascicles

Which order neuron of the spinothalamic tract ends in the posterior horn at the point of entry to the spinal cord?

first

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

first order

Where does the spinal cord arise from the medulla oblongata?

foramen magnum

Where is the origin of sensory signals carried by the cuneate fasciculus?

from T6 and up

Nerve signals carried from the midthoracic and lower parts of the body are carried by which ascending tract?

gracile fasiculus

The matter of the spinal cord that contains the synapses and therefore is the site of synaptic integration is called ----matter.

gray

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

grey matter

Fibers from the cuneate fasciculus end on the which side of the medulla oblongata?

ipsilateral

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

ipsilateral

Which funiculus of the spinal cord is the posterior spinocerebellar tract located?

lateral

The gracile fasciculus carries sensory signals from the:

lower trunk and lower limbs.

What is the name of the hollow space that contains the cauda equina and cerebrospinal fluid?

lumbar cistern

The enlargement that is the area of spinal cord that gives rise to the nerves of the lower limbs and pelvis is which of the following?

lumbosacral

The structure that is the tapered end of the spinal cord is called which of the following?

medullary cone

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

motor

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

motor information

White matter has a pearly white appearance due to the presence of which of the following?

myelin

The spinoreticular tract carries what type of signals?

pain

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

pia

Which layer of the meninges is the most delicate and is composed of one or two layers of squamous to cuboidal cells and delicate collagenous and elastic fibers?

pia mater

Which meninx forms the terminal filum?

pia mater

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

posterior

The cuneate fasciculus is located in which fasciculus of the spinal cord?

posterior

What type of signal does the spinocerebellar tract carry?

proprioception

The second-order neurons of the spinoreticular tract terminate in the ----formation of the brainstem.

reticular

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

second order

Which pathways are made up of three neurons?

sensory

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

somatic motor

Which structure contains the gray commissure?

spinal cord

The anterolateral system is formed from some smaller tracts and the---- tract.

spinothalamic

The space between the arachnoid mater and pia mater is called the---- space.

subarachnoid

The number of neurons in a descending pathway is

two

What does ipsilateral mean?

two points are on the same side of the body