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

Epidurial

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

They are mixed nerves.

Which is true about spinal nerves?

Ganglion

A _____ is a cluster of neuron cell bodies found outside of the CNS.

Nerve

A ______ is a cordlike organ composed of numerous nerve fibers (fascicles) bound together by connective tissue.

Loose connective

Endoneurium is composed of what type of tissue?

Somatic

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

Thoracic, lumbar, cervical, sacral

What are the regions of the spinal cord?

Motor

What type of nerve is a nerve containing only fibers carrying outgoing nerve signals from the CNS?

Grey Matter

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

Below vertebra C7

Where does spinal nerve C8 exit the spinal cord?

Posterior

Which ramus of a spinal nerve innervates the local muscles, joints, and skin of the back?

Posterior

Which roots are the spinal nerve roots that carry sensory nerve signals?

Spinal cord

Which structure contains the gray commissure?

Medullary cone

Which structure is indicated by the arrow labeled A in the figure?

Anterior median fissure

A longitudinal groove on the ventral surface of the spinal cord is which fissure?

Mixed Nerve

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

Skin, skeletal muscles, bones, and joints

A somatic fiber innervates which of the following?

Intervertebral

All spinal nerves except C1 pass through a(n) ________ foramen to emerge from the vertebral column.

Intervertebral foramen

All spinal nerves except C1 pass through which structure to emerge from the vertebral column?

Mixed

Based on the presence of both efferent and afferent fibers, spinal nerves are classified as which of the following?

Lumbar Cervical Sacral Thoracic

Choose all the regions of the spinal cord.

Segment

Each pair of spinal nerves serves a part of the spinal cord called a spinal _____.

31

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

2

Each spinal nerve arises from how many points of attachment to the spinal cord?

Conduction, locomotion, reflexes

Functions of the spinal cord include which of the following?

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

How are the spinal cord regions named?

Three

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

Mixed

Most nerves are what type of nerve?

Roots

Moving peripherally from the spinal cord, which anterior and posterior structures form a spinal nerve?

Epidural

Pain during childbirth is often managed by injecting an anesthetic into which space?

1. Cervical 2. Thoracic 3. Lumbar 4. Sacral

Put the spinal cord regions in order.

Sympathetic nervous system

The communicating rami are part of which of the following?

Perineurium

The connective tissue layer of a nerve that is indicated by letter B is the ______.

Lumbosacral enlargement

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?

Anterior

The horns of the spinal cord that contain the cell bodies of outgoing somatic motor neurons are _____ horns.

T2

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

T2 to L1

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

Sympathetic motor

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

commissure

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

-Optic nerve -Olfactory nerve

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

That two points are on opposite sides of the body.

What does contralateral mean?

That two points are on the same side of the body.

What does ipsilateral mean?

Cerebrospinal fluid

What does the central canal of the spinal cord contain?

Cerebrospinal fluid (CSF)

What fills the subarachnoid space?

The area of the spinal cord that gives rise to the nerves of the upper limbs

What is the cervical enlargement of the spinal cord?

Dura mater

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

Dense irregular connective tissue

What is the dural sheath composed of?

Anterior root

Which nervous system structure is indicated by the line labeled A in the picture given?

Sensory

Which pathways are made up of three neurons?

Myelin

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

Perineurium

Within a nerve, each fascicle is wrapped in which layer?

Fascicles

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

First order

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

Second-order

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

L1

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

Rootlets

In each segment of the spinal cord, what structures emerge from the anterior surface and join to form an anterior root?

Schwann

In the PNS, the ______ cells form a neurilemma and the myelin sheath around an axon.

Central

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

Subarachnoid space

In which does cerebrospinal fluid circulate?

1. dura mater 2. arachnoid mater 3. pia mater

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

-Lateral funiculus -Posterior funiculus -Ventral funiculus

Select all that apply: What are the three funiculi of white matter found in the spinal cord?

-Anterior horn -Posterior horn -Gray commissure

Select all that apply: Which spinal cord areas are composed of gray matter?

Pia

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

motor

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

Anterior

The branch of the spinal nerve indicated by the arrow is the ______ ramus.

Posterior

The branch of the spinal nerve that is indicated by the arrow is the ______ ramus.

Communicating

The branches of the spinal nerve that are indicated by the arrow labeled A are called the ______ rami.

cauda equina

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

White Matter

The matter that is composed of myelinated and unmyelinated axons and is superficial to the gray matter of the spinal cord is called

Rootlets

The nervous structures indicated by the letter A in the illustration are called ______.

Subarachnoid

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

Conduction

The spinal cord contains ascending and descending nerve fibers that send information between the CNS and the periphery. This illustrates which function of the spinal cord?

Medullary cone

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

A cluster of nerve cell bodies

What is a ganglion?

A cord of nerve fiber bundles bound together by connective tissue

What is a nerve?

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

What is the cauda equina?

Endoneurium

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

Fascicle

What is the nerve structure between the arrows labeled A?

The longitudinal groove on the dorsal surface of the spinal cord

What is the posterior median sulcus of the spinal cord?

Gray matter

What is the site of synaptic integration in the spinal cord?

The space between the arachnoid mater and pia mater

What is the subarachnoid space?

Efferent

What type of fiber is a nerve fiber carrying nerve signals away from the central nervous system?

Above the sacrum

Where does the sacral region of the spinal cord end?

At the foramen magnum

Where does the spinal cord arise from the medulla oblongata?

Superficial to the gray matter

Where is the white matter in the spinal cord?

Meninges

Which are a series of fibrous connective tissue membranes covering the central nervous system?

Olfactory and optic nerves

Which are purely sensory nerves?

Schwann

Which cells form a neurilemma and the myelin sheath around axons in the PNS?

Epineurium

Which connective tissue layer is indicated by the letter A?

Pia mater

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?

Arachnoid mater

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?

Posterior root

Which nervous system structure is indicated by the black arrow in the given figure?

Posterior root ganglion

Which nervous system structure is indicated by the letter C?

Anterior

Which ramus of a spinal nerve innervates the anterior and lateral skin and muscles of the trunk?

Contralateral

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

Ipsilateral

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

Ascending

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

Descending

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