Chapter 13 The Spinal Cord, Spinal Nerves, and Somatic Reflexes
The denticulate ligaments are extensions of which meninx?
Pia mater.
Which meninx forms the terminal filum?
Pia mater.
Which meninx is closely associated with the contours of the spinal cord?
Pia mater.
What is a reflex involving one or more interneurons called?
Polysynaptic.
What reflexes are important in stabilizing joints?
Stretch.
regions of the spinal cord
cervical, thoracic, lumbar, sacral
What is the subarachnoid space?
space between arachnoid and pia mater
Place the meninges in order from superficial to deep.
1. Dura mater 2. Arachnoid mater 3. Pia mater.
Place the components of a reflex arc in order.
1. Receptor 2. Afferent nerve fiber 3. Integration center 4. Efferent nerve fiber 5. Effector
What are the four components of a monosynaptic somatic reflex arc?
1. Skeletal muscle 2. Afferent nerve fiber 3. Efferent nerve fiber 4. Receptor in skin, muscle or tendon
How many spinal nerves are there and in order from superior to inferior?
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
What is a region of the spinal cord supplied by a pair of spinal nerves called?
A segment.
The first cervical spinal nerve emerges above vertebrae _____________.
C1.
Within a nerve, nerve fibers are gathered into bundles called __________.
Fascicles.
What is an afferent fiber?
Sensory nerve fiber.
Where are the receptors for somatic reflexes found?
Skin, muscle, and tendons.
The anterior horns of the spinal cord contain the somas of which neurons?
Somatic motor.
_________ nerve fibers innervate skin, skeletal muscles, bones, and joints.
Somatic.
__________ nerve fibers innervate skin, skeletal muscles, bones, and joints.
Somatic.
In the spinal cord, where is the white matter in relation to the gray matter?
Superficial.
The lateral horns of the spinal cord contain somas of which neurons?
Sympathetic motor.
The lateral horns of the spinal cord contain somas of ___________ motor neurons.
Sympathetic.
T or F: The neural pathway of a flexor reflex is more complex than that for the tendon reflex.
True.
There are ______ pairs of spinal nerves.
31
What is gray commissure of 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 caudal equina?
A bundle of nerve roots occupying the vertebral canal from L2 to S5.
At the end of the spinal cord is the ____________ ____________, a bundle of nerve roots occupying the vertebral canal that resemble a horse's tail.
Cauda equina.
In the spinal cord, what is the space within the gray commissure that contains CSF?
Central canal.
In the spinal cord, the _______ canal is lined with ependymal cells and contains cerebrospinal fluid.
Central.
The anterior rami of spinal nerves from which nerve plexuses?
Cervical, lumbar, sacral.
Place the spinal cord regions in order from superior to inferior.
Cervical, thoracic, lumbar, and sacral.
Which rami connects the anterior rami to the sympathetic chain?
Communicating.
Within the spinal cord, which tracts carry motor signals down from the brain?
Descending.
What is the dural sheath around the spinal cord made of?
Dura mater.
External to the neurilemma of a nerve fiber is the layer of loose connective tissue that surrounds a nerve fiber called an _______________.
Endoneurium.
The crossed _________ reflex is contralateral.
Extensor.
T or F: Severing a sensory nerve root will completely deaden sensation from a dermatome.
False.
What muscles are the effectors in a patellar reflex?
Quadriceps.
The intercostal nerves arise from the anterior rami of the ___________ spinal nerves.
Thoracic.
What is a nerve?
A cord of nerve fiber bundles bound together by connective tissue.
In an adult, the spinal cord ends at vertebra _________.
L1
What is hemiplegia?
Paralysis on one side of the body.
What is paralysis of both lower limbs called?
Paraplegia.
Within a nerve, each fascicle is wrapped in a layer called a ________
Perineurium.
Which are considered a distal branch of a spinal nerve?
Posterior and Anterior ramus.
What are the three columns of white matter found in the spinal cord?
Posterior column, Anterior column, and Lateral column.
Which is a tangle of nerve endings entwined in collagen fibers?
Tendon organ.
Which reflex occurs in response to excessive tension on a tendon?
Tendon.
Stretch reflexes are mediated primarily by which of the following?
The brain.
What is the posterior median sulcus of the spinal cord?
The longitudinal groove on the dorsal surface of the spinal cord.
Into what cavity is an epidural anesthetic delivered?
The space between the vertebral bones and dural sheath.
A general fiber innervates which of the following?
Widespread organs such as muscles, skin, glands, viscera, and blood vessels.
Which of the following describes a sensory nerve?
A nerve containing on fibers carrying incoming nerve signals to the CNS.
What is a reflex?
A stereotyped, involuntary response to a stimulus.
A ___________ peripheral fiber is a nerve fiber carrying nerve signals toward the central nervous system.
Afferent.
During a crossed extension reflex, which nerve fibers cross the contralateral side?
Afferent.
The _________ median fissure is a longitudinal groove on the ventral surface of the spinal cord.
Anterior.
The larger __________ ramps 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 ramus of the spinal nerve innervates the anterior and lateral skin and muscles of the trunk?
Anterior.
Which meninx consists of simple squamous epithelium with a mesh of fibers in the adjoining space?
Arachnoid mater.
The _____ mater is just below (deep to) the dura mater.
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.
the term "nerve fiber" refers to the ____ of a neuron.
Axon.
Which is a name of a plexus?
Brachial, Lumbar, Cervical, and Sacral.
What is the white matter of the spinal cord?
Bundles of myelinated and unmyelinated axons found superficial to the gray matter.
A spinal cord injury above which segment will lead to respiratory failure?
C4.
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.
Which reflex is contralateral?
Crossed extension reflex.
What are extensions of the pia mater that anchor the spinal cord?
Denticulate ligaments.
The _______ matter of the CNS is where the neuron cell bodies, dendrites, and synapse are found.
Gray.
Both somatic and automatic reflexes are exaggerated in which of the following?
Hyperreflexia.
In which reflex arc do the input and output occur at different levels of the spinal cord?
Intersegmental.
All spinal nerves except C1 pass through an _______________ foramen to emerge from the vertebral column.
Intervertebral.
The subarachnoid space inferior to the medullary cone is called the _____________ _________________.
Lumbar cistern.
What is the name of the hollow space that contains the caudal equina and cerebrospinal fluid?
Lumbar cistern.
Which branch of spinal nerve innervates the meninges?
Meningeal.
The _________ are a series of fibrous connective tissue membranes covering the central nervous system.
Meninges.
The anterior horns of the spinal cord contain somas of the somatic _____________ neurons.
Motor.
The anterior root of a spinal nerve contain axons of which neurons?
Motor.
Which spinal cord areas are composed of gray matter?
Posterior horn, Anterior horn, and Lateral horn.
The ___________ roots are the spinal nerve roots that carry sensory nerve signals.
Posterior.
Which ramps of the spinal cord innervates the local muscles, joints, and skin of the back?
Posterior.
Which spinal nerve roots carry sensory nerve signals?
Posterior.
What is the neural pathway that mediates a reflex called?
Reflex arc.
Functions of the spinal cord
Reflexes Conduction Locomotion
Properties of a reflex:
Requires stimulation, involuntary, quick, and stereotyped.
Moving peripherally from the spinal cord, which anterior and posterior structures form an spinal nerve?
Roots.
A ____________ nerve is a peripheral nerve carrying nerve signals to the CNS.
Sensory.
The somas of which neurons are found within the posterior root ganglion?
Sensory.
Within the spinal cord, which tracts carry information up to the brain?
Sensory.
The disease called _____________ 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.
___________ fibers are nerve fibers that innervate more localized organs in the head (eyes, ears, taste receptors, etc).
Special.
Which is responsible for the inhibition of antagonistic contraction during a reflex response?
Spinal cord interneurons inhibit alpha neurons to the antagonists.
The patellar reflex is an example of ____________ reflex.
Stretch.
The patellar reflex is an example of which type of reflex?
Stretch.
Which reflex is mediated by the brain?
Stretch.
The communicating rami connect the anterior rami to which of the following?
The sympathetic chain.