Chapter 13: The Spinal Cord, Spinal Nerves and Somatic Reflexes
A ___ nerve is a peripheral nerve carrying nerve signals to the CNS.
Afferent
What are the regions of the spinal cord?
Cervical Thoracic Lumbar Sacral
What are the spinal cord regions in order from superior to inferior?
Cervical Thoracic Lumbar Sacral
The left and right sides of the gray matter in the spinal cord are connected by the gray ___.
Commissure
Which rami connect the anterior rami to the sympathetic chain?
Communicating
Which rami of spinal nerve T1-L2 connect to the sympathetic chain ganglia?
Communicating
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?
Conduction
What are the functions of the spinal cord?
Conduction Neural Integration, Locomotion Reflexes
What is the epineurium composed of?
Dense irregular connective tissue
What are the extensions of the pia mater that anchors the spinal cord?
Denticulate ligaments
What is an area of skin innervated by a spinal nerve called?
Dermatome
The dural sheath around the spinal cord is formed from the ___ mater.
Dura
What is the order of the meninges from superficial to deep?
Dura Mater Arachnoid Mater Pia Mater
Which structure is indicated by the arrow in the figure?
Medullary Cone (Conus medullaris)
The ___ branch of the spinal nerve innervates the meninges.
Meningeal
The ___ are a series of fibrous connective tissue membranes covering the central nervous system.
Meninges
Spinal nerves are described as ___ nerves because they carry both afferent and efferent signals.
Mixed
An anterior roots of a spinal nerve contains axons of ___ neurons.
Motor
The anterior root of a spinal nerve contain axons of which neuron?
Motor
Within the spinal cord, what type of information do the descending tracts carry?
Motor
How many neurons are found in the descending tract?
2
It takes ___ neurons for a somatic response sensation nerve signal to complete the sensory pathway.
3
How many pairs of spinal nerves are there?
31
How many spinal nerve are there in order from superior to inferior?
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
Which describes a mixed nerve?
A nerve containing both sensory and motor nerve fibers
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
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 larger ___ ramus of a spinal nerve innervates the anterior and lateral skin and muscles of the trunk and gives rise to the nerves of the limbs.
Anterior
Which horns of the spinal cord contain the cell bodies of outgoing somatic motor neurons?
Anterior
The distal branches of a spinal nerve include which of the following?
Anterior and Posterior Rami
Which are made of gray matter?
Anterior, posterior, and lateral horns
The ___ mater is just below (deep to) the dura mater.
Arachnoid
The ___ mater that consists of layers of squamous to cuboidal cells with a loose mesh of fibers in the space below.
Arachnoid
The middle layer of the meninges is the ___ mater.
Arachnoid
The neural pathway that mediates a reflex is called a reflex ___.
Arc
Where does the spinal cord arise from the medulla oblongata?
At the Foramen Magnum
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
Where is the epidural space around the spinal cord?
Between the vertebral bones and dural sheath
Which are the names of a plexus?
Brachial Cervical Coccygeal Lumbar Sacral
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 vertebra ___.
C1
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 connective tissue layer indicated by the arrow is the ___.
Epineurium
What is the dense irregular connective tissue layer enclosing an entire nerve called?
Epineurium
T/F: Severing a sensory nerve root will completely deaden sensation from a dermatome?
False
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
What structure marks the superior end of the spinal cord?
Foramen magnum
A ___ is a cluster of neuron cell bodies found outside of the CNS.
Ganglion
Where are the neuron cell bodies, dendrites, and synapses found in the CNS?
Gray matter
All spinal nerves except C1 pass through a(n) ___ foramen to emerge from the vertebral column.
Invertebral
Some nerve tracts do not decussate and have their origin and destination on the same side of the body. These tracts are considered ___.
Ipsilateral
Which tract will have its origin and destination on the same side of the body?
Ipsilateral
In an adult, where does the spinal cord end? (At what vertebra)
L1
Which are purely sensory nerves?
Olfactory and optic nerves
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 ___ median sulcus is a longitudinal groove on the dorsal surface of the spinal cord.
Posterior
The ___ roots are the spinal nerve roots that carry sensory nerve signals.
Posterior
Which ramus of a spinal nerve innervates the local muscles, joints, and skin of the back?
Posterior
What are the three pairs of funiculi in the spinal cord?
Posterior Lateral Anterior
What are some somatosensory stimulus's?
Pressure Touch Pain Temperature Stretch
What are the components of a reflex arc in order?
Receptor Afferent Nerve Fiber Integration Center Efferent Nerve Fiber Effector
Which are properties of a reflex?
Require stimulation Quick Involuntary Stereotyped
Which are closest to the spinal cord?
Rootlets
Moving peripherally from the spinal cord, which anterior and posterior structures for a spinal nerve?
Roots
Nerve fibers of peripheral nerves are encased in ___ cells.
Schwann
___ cells form a neurilemma and the myelin sheath around axons in the PNS.
Schwann
The posterior root of a spinal nerve carries ___ nerve fibers.
Sensory
The somas of ___ neurons are found within the posterior root ganglion.
Sensory
Within the spinal cord, which tracts carry information up to the brain?
Sensory
Which disease results from herpes virus residing in a posterior root ganglion?
Shingles
The first cervical spinal nerve emerges between which two structures?
Skull and vertebra C1
What are the possible effectors of a reflex response?
Smooth, cardiac, and skeletal muscle as well as glands
___ reflexes use receptors located in the skin, muscle, and tendons.
Somatic
In which does cerebrospinal fluid circulate?
Subarachnoid space
Where is the white matter in the spinal cord?
Superficial to the gray matter
The coccygeal ligament is formed from the fusion of which two structures?
Terminal filum and dura mater
What is the anterior median fissure of the spinal cord?
The longitudinal groove on the ventral surface of the spinal cord
What is the subarachnoid space?
The space between the arachnoid mater and pia mater. (cerebrospinal fluid is here)
The intercostal nerves arise from the anterior rami of the ___ spinal nerves.
Thoracic
In the CNS, bundles of axons that make up white matter are called ___.
Tracts
In the descending pathways, which motor neurons have their somas in the cerebral cortex or brain stem?
Upper
___ matter is composed of myelinated and unmyelinated axons and is superficial to the gray matter of the spinal cord.
White
In the spinal cord, the ___ canal is lined with ependymal cells and contains spinal fluid.
central
