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
