A&P Lecture Chpt. 13
Identify the regions of the spinal cord.
cervical, thoracic, lumbar, sacral
Place the spinal cord regions in order from superior to inferior
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
External to the neurilemma of a nerve fiber is the layer of loose connective tissue that surrounds a nerve fiber called a(n) __________
endoneurium
A __________ nerve fiber innervates widespread organs such as muscles, skin, glands, viscera, and blood vessels.
general
Unlike visceral fibers that innervate blood vessels, glands, and viscera, ______ nerve fibers innervate skin, skeletal muscles, bones, and joints.
somatic
The anterior horns of the spinal cord contain the somas of which neurons?
somatic motor
What is the subarachnoid space?
space between arachnoid and pia mater
How many neurons are typically found in an ascending pathway between the receptor and the brain?
three
The number of neurons in a descending pathway is __________
two
Consider the two motor neurons that form descending pathways. The neurons called the __________ motor neurons have their somas in the cerebral cortex or brainstem.
upper
In descending pathways, which motor neurons have their somas in the cerebral cortex or brainstem?
upper
______ fibers are nerve fibers that innervate blood vessels, glands, and internal organs.
visceral
__________ matter is composed of myelinated and unmyelinated axons and is superficial to the gray matter of the spinal cord.
white
Which are functions of the spinal cord?
-Conduction -Locomotion -Reflexes
Place the meninges in order from superficial to deep.
1. dura mater 2. arachnoid mater 3. pia mater
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
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
The ______ median fissure is a longitudinal groove on the ventral surface of the spinal cord.
anterior
The __________ horns of the spinal cord contain the cell bodies of outgoing somatic motor neurons
anterior
Which horns of the spinal cord contain the cell bodies of outgoing somatic motor neurons?
anterior
Pain during childbirth is often managed by injecting an anesthetic into which space?
epidural
In descending tracts, which motor neuron innervates the target organ?
lower
The ______ motor neurons (which are the motor neurons connecting the brainstem and spinal cord to muscle fibers) of the descending pathway innervate skeletal muscle.
lower
The ______ is the tapered end of the spinal cord.
medullary cone
Each pair of spinal nerves serves a part of the spinal cord called a spinal __________
segment
Each pair of spinal nerves serves a part of the spinal cord called a spinal ____________
segment
A ______ nerve is a peripheral nerve carrying nerve signals to the CNS.
sensory
Which pathways are made up of three neurons?
sensory
What is the cauda equina?
A bundle of nerve roots that occupy 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 motor nerve?
A nerve containing only fibers carrying outgoing nerve signals from the CNS
What is a fasciculus in the spinal cord?
A tract of nerve fibers within a funiculus
Where does the spinal cord arise from the medulla oblongata?
At the foramen magnum
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
The first cervical spinal nerve emerges above vertebrae ______.
C1
Which connective tissue layer is indicated by the arrow?
Epineurium
How are the spinal cord regions named?
For the level of vertebral column from which its spinal nerves emerge
Which spinal cord areas are composed of gray matter?
Gray commissure Anterior horn Posterior horn
What are the three funiculi of white matter found in the spinal cord?
Lateral funiculus Ventral funiculus Posterior funiculus
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
Which fibrous structure is indicated by the letter A in the figure?
Terminal filum
The coccygeal ligament is formed from the fusion of which two structures?
Terminal filum and dura mater
What does ipsilateral mean?
That two points are on the same side of the body
What is the cervical enlargement of the spinal cord?
The area of the spinal cord that gives rise to the nerves of the upper limbs
In a sensory pathway, which neurons run from the thalamus to the sensory cerebral cortex?
Third in order
A general fiber innervates which of the following?
Widespread organs such as muscles, skin, glands, viscera, and blood vessels
A(n) ______ fiber is a nerve fiber carrying nerve signals toward the central nervous system.
afferent
The __________ mater is just below (deep to) the dura mater.
arachnoid
The middle layer of the meninges is the ______ mater.
arachnoid
Which meninx is just below (deep to) the dura mater?
arachnoid mater
Within the spinal cord, which tracts carry information up to the brain?
ascending
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
The superior most region of the spinal cord is the ______ region.
cervical
Functions of the spinal cord include which of the following?
conduction, locomotion, reflexes
The end of the spinal cord indicated by the arrow labeled A in the figure is the medullary __________
cone
Which tract will have its origin and destination of opposite sides of the body?
contralateral
What is the epineurium composed of?
dense irregular connective tissue
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
What is the order of the meninges from superficial to deep?
dura mater, arachnoid mater, pia mater
What is the loose connective tissue surrounding an individual nerve fiber called?
endoneurium
The connective tissue layer indicated by the arrow is the __________
epineurium
What is the dense irregular connective tissue layer enclosing an entire nerve called?
epineurium
Which is composed of dense irregular connective tissue?
epineurium
The bundle between the arrows labeled A is a(n) _________ and contains several nerve fibers.
fascicle
What is the structure between the arrows labeled A?
fascicle
Within a nerve, nerve fibers are gathered into bundles called what?
fascicles
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
What structure marks the superior end of the spinal cord?
foramen magnum
The __________ matter of the spinal cord contains the synapses and therefore is the site of synaptic integration.
gray
Where are the neuron cell bodies, dendrites, and synapses found in the CNS?
gray matter
Which nerve tracts do not decussate?
ipsilateral
The ______ enlargement is the area of spinal cord that gives rise to the nerves of the lower limbs and pelvis.
lumbosacral
A nerve containing both sensory and motor nerve fibers is called a(n) __________ nerve.
mixed
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
A __________ is a cordlike organ composed of numerous nerve fibers (fascicles) bound together by connective tissue
nerve
A __________ is a cordlike organ composed of numerous nerve fibers (fascicles) bound together by connective tissue.
nerve
Which are purely sensory nerves?
olfactory and optic nerves
What does contralateral mean?
on the opposite side of the body
What are two examples of nerves that carry only sensory information?
optic nerve, olfactory nerve
Within a nerve, each fascicle is wrapped in which layer?
perineurium
The __________ mater is the meningeal layer that is closely associated with the contours of the spinal cord
pia
The denticulate ligaments are extensions of which meninx?
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?
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 cerebrospinal fluid circulates in the __________ space between the meninges.
subarachnoid
In which does cerebrospinal fluid circulate?
subarachnoid space
In the spinal cord, where is the white matter in relation to the gray matter?
superficial
How many neurons are found in a descending tract?
two
