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?
