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131 Cards in this Set

  • Front
  • Back
What is the relevance of variations in spinal cord diameter?
Changes in diameter reflect a change in the number of motor neurons that innervate skeletal muscle
What are the two primary enlargements within the spinal cord called?
Cervical and lumbar enlargements - The enlargements correspond to upper and lower extremities
Describe the tissue composition of the spinal cord in cross section
- Outer region composed of ascending and descending nerve tracts which are myelinated, this region is called white matter.
- The inner region of gray region is composed of unmyelinated neurons
What are the five divisions of the spinal gray matter region?
- The gray matter is organized into the following:
-- Gray commissure
-- Central canal
-- Anterior, lateral, and posterior horns
Which horn do sensory neurons from the PNS synapse with?
Incoming sensory neurons from the peripheral nervous system (PNS) synapse
with interneurons located within the dorsal (posterior) horn.
Which horns contain the outgoing motor neurons?
The cell bodies of outgoing motor neurons are located in the lateral and ventral (anterior) horns.
How do the motor neurons of the lateral and ventral horns differ?
The horns are specific in their design; the lateral horn contains motor neurons
which are responsible for autonomic function, while the motor neurons of the
ventral horns innervate skeletal muscle (somatic function).
Where do incoming afferent sensory neurons enter the spinal cord?
Incoming afferent sensory neurons enter the spinal cord through the dorsal root.
What type of neuron are the afferent sensory neurons?
This sensory neuron is a unipolar neuron; it has a long peripheral process leading
to the cell body and a short central process entering the cord.
Where do efferent motor neurons exit the spinal cord?
Efferent motor neurons exit the spinal cord through the ventral root.
What happens to the dorsal and ventral roots in the vertebral canal?
Both dorsal and ventral roots will merge within the vertebral canal and form a single spinal nerve.
Name the three columns of white matter.
Organized into three distinct columns or funiculi:
o The anterior, lateral, and posterior columns.
Why is "white matter" white?
White matter is composed primarily of myelinated axons which form ascending, descending, and transverse fibers. Recall that myelination increases the rate of transmission of the action potential along the axon by 150x (salutatory conduction).
How many neurons compose ascending and descending tracts in the spinal cord?
Ascending sensory tracts contain three neurons and descending motor tracts contain two neurons.
Describe 1st order neurons in the spinothalmic tract.
1st order neuron relays sensory input from PNS to posterior horn. The cell body of this neuron is located within the dorsal root ganglia.
Describe 2nd order neurons in the spinothalmic tract.
The first synapse occurs within the posterior horn; the 2nd order in the posterior horn travels to the contralateral side and ascends toward thalamus within either the anterior or lateral spinothalamic pathway. The cell body of 2nd order neuron is located within the posterior horn.
Describe 3rd order neurons in the spinothalmic tract.
The second synapse occurs within the thalamus. A 3rd order neuron in thalamus projects to the postcentral gyrus. The cell body resides within the thalamus.
What sense types are relayed by the spinothalmic tract?
The spinothalamic pathway carries information for pain, temperature, light touch, pressure, tickle, and itch.
Receptors within the skin are also known as?
These receptors are located within the skin and are known as cutaneous receptors.
What sense types are relayed by the medial-lemniscal pathway/dorsal column?
This sensory pathway is very specific, sensations include: two-point discrimination, pressure, vibration, proprioception.
Describe 1st order neurons within the dorsal column/medial-lemniscal pathway
The 1st order neurons enter spinal cord and ascend within the dorsal column without synapsing.
Describe 2nd order neurons within the dorsal column/medial-lemniscal pathway
The first synapse occurs within the medulla oblongata. At this point the 2nd order neurons cross-over (in the brainstem) and continue through the brainstem within the medial lemniscus pathway.
Describe 3rd order neurons within the dorsal column/medial-lemniscal pathway
Within the thalamus the second synapse occurs and the 3rd order neurons are projected to the specific location within the postcentral gyrus.
What carries sensory information from structures below mid-thorax?
Within the dorsal column, a specific pathway exists called the Fasciculus gracilis
that carries the above mentioned sensory information from those structures
below mid-thorax.
What carries sensory information from structures above mid-thorax?
The pathway Fasciculus cuneatus carries sensory impulses from structures above mid-thorax.
What is different about the nerve cross-over in the dorsal pathway?
The 1st order neurons from both pathways synapse in the medulla oblongata within specific structures called nuclei (nucleus gracilis & nucleus cuneatus).
It is at this point that cross-over occurs, recall that in the spinothalamic pathway cross-over occurred within the cord
What neurons carry voluntary muscle movements?
Voluntary (skeletal) muscle movements are carried by two motor neurons: the upper and lower.
How does the process of voluntary movement begin?
Voluntary movement begins within the premotor area; a region within the frontal lobe responsible for the planning of the action, while the precentral gyrus initiates the planned movement.
What tract caries motor impulses for precise movements?
The corticospinal tract carries motor impulses from the cerebral cortex for precise finely coordinated limb movements
Where do the upper motor neurons of the corticospinal tract originate?
The upper motor neurons of this tract originate within precentral gyrus, the axon
continues down the brainstem by way of the cerebral peduncles.
Within the medulla oblongata, what percentage (approximate) of the upper motor neurons cross-over (decussate) within the pyramids? The axons of these neurons travel down the spinal cord within which tract?
Within the medulla oblongata, 75% of upper motor neurons cross-over (decussate) within the pyramids. The axons of these neurons continue down the spinal cord in the lateral corticospinal tract.
What is the path utilized by upper motor neurons that do not cross over in the pyramids?
The remaining 25% continue down the spinal cord within the anterior corticospinal tract and cross at the level of innervation.
Where do all upper motor neurons eventually synapse?
All upper motor neurons regardless of which descending motor tract will
eventually synapse lower motor neurons within the anterior horn of the gray
matter.
What would be the functional impairment resulting from damage to the spinal cord between T1 and L1?
Damage to the spinal cord between T1 and L1 results in motor loss of the lower
limbs (paraplegia).
What would be the functional impairment resulting from damage to the spinal cord in the cervical region?
Damage in the cervical region results in loss or both upper and lower limbs (quadriplegia) and possibly even respiratory function, the cervical plexus is the origin of the phrenic nerve which innervates the diaphragm.
What damage is caused within the spinal cord by the polio virus? What is the eventual result?
Poliomyelitis caused by the polio virus damages ventral horn motor neurons resulting in paralysis and eventual muscle atrophy.
What is the definition of the PNS?
The PNS includes all neural structures outside the brain and spinal cord.
What is the purpose of the PNS?
The PNS links the outside environment either external or internal to the CNS. This connection allows for the process of integration (decision making) by the CNS (brain & spinal cord) to be carried out.
What are the divisions of the PNS?
Peripheral Nervous System (PNS)
o Afferent Division (all sensory)
o Efferent Division (all motor)
 Somatic (skeletal muscle)
 Visceral (cardiac & smooth muscle, and glands)
Sympathetic – excites of inhibits metabolic ac
Parasympathetic – restores normal function
What is the difference between sensation and perception?
Sensation is the awareness of the stimulus while perception is the interpretation of that stimulus and determines the course of action.
What are somatic and visceral senses sensitive to, respectively?
o Somatic senses respond to: touch, tickle, itch, weight discrimination, pressure,
vibration, temperature, pain and proprioception.
o Visceral senses, associated with internal organs and respond to pain and
pressure.
Where are special senses located?
Special senses are anatomically restricted to the head and are specialized. The sensory receptors are located within an organ and are responsible for: vision, taste, olfaction, hearing, and balance.
What are the five types of receptor classifications, based on stimulus type?
o Mechanoreceptors – respond to deformation of surrounding tissue (touch,
pressure, stretch).
o Chemoreceptors –
detect chemical changes
in body fluids such as
blood or interstitial
fluids.
o Thermoreceptors –
sensitive to temperature
changes.
o Photoreceptors –
respond to light energy
(photons).
o Nociceptors – pain,
respond to potentially
tissue damaging stimuli,
extreme heat/cold,
excessive pressures, or inflammatory signals.
What are the three basic locations for receptors, based on type?
Anatomical location:
o Exteroceptors are near or at the body surface, respond to stimuli originating
outside the body (touch, pressure, pain, temperature and special senses).
o Interoceptors located within the walls of viscera and blood vessels (pain,
pressure, stretch, and chemical).
o Proprioceptors located in muscle tissue, joints, tendons and ligaments, are
designed to detect changes in limb position.
What are the differences in structural complexity between simple and complex receptors?
o Simple receptors are the dendritic ends of sensory neurons. Respond to tactile
sensations (touch, pressure, or vibration), pain, and temperature.
 Unencapsulated dendritic nerve ending or naked nerve endings are
simply exposed dendrites (pain or temperature).
 Encapsulated dentritic nerve endings are enclosed in a connective tissue capsule. Typically all mechanoreceptors (touch, pressure, vibration) are
of this type.
o Complex receptors are associated with the special senses, the receptor are
specialized and located within an organ (vision, taste, hearing, olfaction, and balance).
Describe sense processing at the first level (Receptor level)
Processing at the Receptor Level
The first level is the receptor level. Each sensory receptor responds to a specific stimulus for example temperature or pain.
The energy of the stimulus (temperature variation or pain) must be converted into a form recognized by the cell, which is a graded potential or receptor potential. The stronger the stimulus the greater the chances of the graded potential reaching threshold. Once threshold is reached, then an action potential will be generated and continue towards the CNS.
What types of receptors exhibit adaptation? What types do not?
o Phasic receptors are fast adapting, giving information at the beginning and at the end of a stimulus (pressure and touch).
o Tonic receptors provide a sustained response within little or no adaptation (pain and proprioception).
Describe sense processing at the circuit level (2nd level)
The second level is the circuit level and corresponds to the various ascending pathways leading to the appropriate location within the cerebral cortex (postcentral gyrus). These ascending pathways are represented by three neurons; 1storder, 2nd order, and 3rd order.
1st order neuron (spinal nerve) enter the spinal cord within the posterior horn and may synapse immediately with a motor neuron (spinal reflex) or synapse with a 2nd order neuron on the contralateral side.
Eventually the 2nd order neuron will synapse with a 3rd order neuron located within the thalamus. The 3rd order neuron then projects to the appropriate location within the cerebral cortex.
Describe processing at the perceptual level
The third level is perceptual level which involves the cerebral cortex. The cerebral cortex has the ability to interpret incoming information, that is, what type of information is coming in and where it is coming from.
Describe the physical structure of the nerve
Each nerve contains numerous axons arranged in parallel bundles; some may be myelinated or unmyelinated.
Most nerves contain both motor and sensory neurons. These mixed nerves may also carry both somatic and autonomic nervous system fibers.
Ganglia are collections of neuron cell bodies associated with the nerves of the PNS.
Nuclei are cell bodies associated with the CNS.
Packaging with the connective tissue is similar to muscle tissue.
o Endoneurium - the connective tissue around each individual axon
o Perineurium - surrounds and defines the fascicle. Blood vessels located between each fascicle.
o Epineurium –surrounds all nerve fascicles and encloses the entire nerve.
By which aperatures do each of the 12 cranial nerves exit the skull?
Olfactory (I) cribriform plate
Optic (II) optic canal
Oculomotor (III) superior orbital fissure
Trochlear (IV) s.o.f
Trigeminal (V) s.o.f., f.r., f.o.
Abducens (VI) s.o.f
Facial (VII) stylomastoid foramen
Vestibularcochlear (VIII) internal auditory meatus
Glossopharyngeal (IX) jugular foramen
Vagus (X) j.f.
Accessory (XI) j.f.
Hypoglossal (XII) hypoglossal canal
The spine has 31 nerve pairs. List the proportions of nerves found in each spinal location.
There are 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal spinal nerves.
Describe the relevance of the dorsal and ventral ramus with regard to spinal nerves
Dorsal and Ventral Ramus
Spinal nerve is short, after emerging from intervertebral foramen divides into a dorsal and ventral ramus.
The rami are mixed containing both sensory and motor neurons.
The spinal nerve rami will innervate both skeletal muscle and the skin from the neck down.
The dorsal rami innervate structures associated with the posterior trunk.
The ventral rami innervate the anterior trunk and the upper and lower extremities (plexuses).
Describe the location and general structures innervated by the 5 spinal plexuses
Cervical (C1-C4)
o Phrenic nerve, damage to this nerve or
spinal cord regions above result in
paralysis of the diaphragm.
Brachial (C5-T1)
o Upper extremity with smaller branches
serving the muscles and skin of the
shoulder and upper thorax.
o Axillary, musculocutaneous, median,
radial, and ulnar nerves
Lumbar (L1-L4)
o Lower extremity
o Femoral, anterior thigh muscles (quadriceps)
Sacral (L4-S4)
o Lower extremity
o Sciatic, posterior thigh muscles (hamstrings)
Coccygeal (S5 & Co)
What is a dermatome?
Area of skin innervated by the cutaneous receptors of spinal nerves (except C1) is called a dermatome.
Dermatomes of the body trunk are uniformed in size, nearly horizontal, and correspond with the thoracic nerve.
Describe the basic reflex arc
The neural arc represents the basic neural pathway representing the three basic functions of the nervous system: sensory, integration, and motor.
Reflexes are rapid, unlearned, involuntary & protective responses, no higher brain input is required.
Reflexes are divided into somatic and visceral reflexes.
The basic components of all reflexes include: sensory receptor, sensory neuron, motor neuron, and the effector organ (muscle or gland).
Describe a monosynaptic reflex
The monosynaptic reflex is the simplest neural pathway with eespect to design. Requires no cerebral influence.
The afferent sensory neuron synapses directly to an efferent motor neuron within either the lateral or anterior horn of gray matter.
The stretch or knee-jerk reflex is the simplest reflex. As the muscles within the anterior thigh (quadriceps) begin to stretch, sensory receptor (muscle spindle) relays this information towards the CNS through an afferent sensory neuron. This neuron synapse with the appropriate efferent motor neurons causing the quadriceps group to contract and counter-act the potentially harmful stretching force.
Inhibition of the hamstring muscle group also occurs, allowing the lower leg to be extended.
Describe a polysynaptic reflex
Polysynaptic reflexes contains an interneuron located between the sensory and motor neurons e.g., the withdraw reflex has three neurons.
The addition of the interneuron allows for communication with the brain and innervation of skeletal muscle on the contralateral (opposite) side.
How does a chemical synapse function?
Neurons do not make physical contact with adjacent neurons or muscle tissue.
Information from the motor neuron is transferred across the synapse through a neurotransmitter released from the synaptic bulb of the motor neuron.
Chemical receptors associated with the ion channels of effector organs (muscle tissue or glands) will bind the neurotransmitter and initiate the events associated with
depolarization by opening sodium ion channels.
The action of the neurotransmitter is short-lived due to the action of destructive enzymes within the synaptic cleft.
Describe the process of neurotransmitter release
Within each synaptic bulb of the axon terminal are numerous membrane-bound sacks
containing neurotransmitters called synaptic vesicles.
Neurotransmitter release results from the depolarization of the axon terminal; this opens voltage gated Ca++ channels, entrance of extra-cellular Ca++ initiates exocytosis.
The membrane of the synaptic vesicle will fuse with the cell membrane of the axon
terminal. Recall that cell membranes and membrane bound structures both share the same phospholipid bilayer design.
Neurotransmitters cross the synaptic cleft & bind to ion channel receptors on the effector organ, in most situations resulting in depolarization.
What are ganglia?
Ganglia are collections of neuron cell bodies associated with nerves in the PNS.
The large onion-shaped receptors that are found deep in the dermis and in subcutaneous tissue and that respond to deep pressure are:
A) Merkel discs
B) Pacinian corpuscles
C) Free nerve endings
D) muscle spindles
B) Pacinian corpuscles
Proprioceptors include all of the following except:
A) muscle spindles
B) Golgi tendon organs
C) Merkel discs
D) joint kinesthetic receptors
C) Merkel discs
The aspect of sensory perception by which the cerebral cortex identifies the site or pattern of stimulation is:
A) perceptual detection
B) feature abstraction
C) pattern recognition
D) spatial discrimination
D) spatial discrimination
The neural machinery of the spinal cord is at the:
A) precommand level
B) projection level
C) segmental level
C) segmental level
Dorsal root ganglia contain:
A) cell bodies of somatic motor neurons
B) axon terminals of somatic motor neurons
C) cell bodies of autonomic motor neurons
D) axon terminals of sensory neurons
E) cell bodies of sensory neurons
C) cell bodies of autonomic motor neurons
The connective tissue sheath that surrounds a fascicle of nerve fibers is the:
A) epineurium
B) endoneurium
C) perineurium
D) neurilemma
C) perineurium
A reflex that causes reciprocal activation of the antagonist muscle is the:
A) crossed-extensor
B) flexor
C) Gogli tendon
D) muscle stretch
C) Golgi tendon
In what way are dermatomes clinically significant in patients with spinal cord injury?
The distribution of dermatomes affected can help the physician determine which nerves are damaged and localize the injured region of the spinal cord.
There is a major difference in the functions of the intrafusal and extrafusal muscle fibers. What is it?
The extrafusal muscle fibers are effectors, when adequately stimulated, they contract, shortening the muscle. The intrafusal fibers are part of a receptor apparatus that provides input for regulation of the activity of the muscle.
The spinal cord begins at the foramen magnum and terminates at the:
Terminates caudally as the conus medullaris, while the filum terminale
represented by the pia mater continues through the sacral canal and anchors the
spinal cord to the coccyx.
Which menigeal layer forms the filium terminale?
Represented by the pia mater
Cell bodies of visceral motor neurons are located within the:
The cell bodies of outgoing motor neurons are located in the lateral and ventral (anterior) horns.
The spinothalamic tract transmits what type of sensory stimuli?
Ascending Pathway (Spinothalamic)
Three neurons: 1st order, 2nd order, and 3rd order.
1st order neuron relays sensory input from PNS to posterior horn. The cell body of this neuron is located within the dorsal root ganglia. The first synapse occurs within the posterior horn; the 2nd
order in the posterior horn travels to the contralateral side and ascends toward thalamus within either the anterior or lateral spinothalamic pathway. The cell body of 2nd order neuron is located within the posterior horn.
The second synapse occurs within the thalamus. A 3rd order neuron in thalamus projects to the postcentral gyrus. The cell body resides within the thalamus.
Each pathway carries different sensory information, each sensory neuron has a unique sensory receptor. The spinothalamic pathway carries information for pain, temperature, light touch, pressure, tickle, and itch.
These receptors are located within the skin and are known as cutaneous receptors.
3rd order neurons of the spinothalamic tract terminate within the:
A 3rd order neuron in thalamus projects to the postcentral gyrus. The cell body resides within the thalamus.
Upper motor neurons of the corticospinal tract cross-over within the
Within the medulla oblongata, 75% of upper motor neurons cross-over (decussate) within the pyramids. The axons of these neurons continue down the
spinal cord in the lateral corticospinal tract.
The remaining 25% continue down the spinal cord within the anterior corticospinal tract and cross at the level of innervation.
The nerve plexuses are formed by the:
The spinal nerves of the ventral rami with the exception to those within the thoracic
region (T2-T12) will intertwine forming a web-like structure called a plexus.
Which anatomical region of the body is not served by a nerve plexus?
The thoracic region
Which five spinal nerves form the brachial plexus?
Axillary, musculocutaneous, median, radial, and ulnar nerves
Define the peripheral nervous system (PNS)?
The PNS includes all neural structures outside the brain and spinal cord.
Sensory neurons associated with joints and tendons are called:
Proprioceptors located in muscle tissue, joints, tendons and ligaments, are
designed to detect changes in limb position.
Sensory receptors located within the walls of viscera are called:
Interoceptors located within the walls of viscera and blood vessels (pain,
pressure, stretch, and chemical).
All spinal nerves exit the vertebral canal through the intervertebral foramen except:
The exception is the Vagus (X) which innervates the
viscera of the chest and abdomen.
Interoceptors located within the walls of viscera and blood vessels respond to:
(pain, pressure, stretch, and chemical).
This nerve of the lumbar plexus will innervate muscles of the anterior thigh (quads)
Femoral nerve
The dendritic end of sensory receptors are designed to respond to specific stimuli and generate:
Simple receptors are the dendritic ends of sensory neurons. Respond to tactile
sensations (touch, pressure, or vibration), pain, and temperature.
 Unencapsulated dendritic nerve ending or naked nerve endings are
simply exposed dendrites (pain or temperature).
 Encapsulated dentritic nerve endings are enclosed in a connective tissue
capsule. Typically all mechanoreceptors (touch, pressure, vibration) are
of this type.
This type of sensory receptor responds to physical deformation.
Mechanoreceptors – respond to deformation of surrounding tissue (touch,
pressure, stretch).
Unencapsulated or naked nerve endings respond to this type of stimulus.
pain or temperature
Those cranial nerves which innervate the extrinsic eye muscles pass through the:
Optic canal
Afferent sensory neurons enter the spinal cord through the:
A) Anterior horn
B) Dorsal root
C) Lateral horn
D) Ventral root
B) Dorsal root
What type of neuron is located within the ventral horns?
A) Autonomic motor neuron
B) Multipolar interneuron
C) Afferent sensory neuron
D) Somatic motor neuron
D) Somatic motor neuron
Ascending and descending neural pathways are located within the:
A) Posterior horns of spinal cord
B) Gray matter of the spinal cord
C) Cerebral cortex
D) The outer white matter of spinal cord
B) Gray matter of the spinal cord
This neural pathway carries sensory information for pain.
A) Corticospinal
B) Spinothalamic
C) Cerebrospinal
D) Cerebovesalius
B) Spinothalamic
How many motor neurons are found in the corticospinal pathway?
A) One
B) Two
C) Three
D) Four
B) Two
The cell body for the first order neuron in an ascending sensory pathway is located in:
A) Anterior column
B) Anterior horn
C) Dorsal root ganglia
D) Gray commissure
C) Dorsal root ganglia
The decussation (crossover) of motor neurons occurs:
A) within the medullary pyramids
B) Cerebral peduncles
C) Central canal
D) Posterior horn
A) Within the medullary pyramids
The crossing-over of sensory neurons of the dorsal column-medial lemniscus pathway occurs:
A) Immediately as this neuron enters the spinal cord
B) In the thalamus
C) Within specific nuclei of the brainstem (nucleus gracilis)
D) Does not occur, as this is a motor pathway
C) Within specific nuclei of the brainstem (nucleus gracilis)
Which statement is false regarding the organization of the nervous system?
A) The peripheral nervous system (PNS) is represented by cranial and spinal nerves
B) The afferent division of the PNS is entirely sensory
C) The efferent division is divided into somatic and visceral systems
D) The somatic system is divided into the sympathetic and parasympathetic branches
A) The peripheral nervous system (PNS) is represented by cranial and spinal nerves
Which statement is false regarding efferent motor neurons?
A) Innervate skeletal muscle
B) Cell bodies located within the dorsal root ganglion
C) May be divided into somatic and visceral motor neurons
D) Are classified as multipolar neurons
B) Cell bodies located within the dorsal root ganglion
Sensory receptors can be classified according to:
A) Anatomical location
B) Response to stimulus (temperature, touch)
C) Structural design
D) All of the above
D) All of the above
This type of sensory receptor is located within joints, tendons and ligaments.
A) Mechanoreceptors
B) Nociceptors
C) Proprioceptors
D) Tactile receptors
C) Proprioceptors
Sensory receptors located in organs and highly specialized are associated with the:
A) Visceral senses
B) Somatic senses
C) Special senses
D) General senses
C) Special senses
An intereceptor will respond to all of the following stimuli except:
A) Pain
B) Pressure
C) Touch
D) Chemical
C) Touch
Which statement is false regarding sensory receptors:
A) Are designed to respond to changes in their environment
B) The stimulus detected by a sensory receptor will generate an action potential
C) A sensory receptor must first generate a graded potential
D) Are associated with general and special senses
B) The stimulus detected by a sensory receptor will generate an action potential
Nociceptors respond to:
A) Vibration
B) Light touch
C) Pain
D) Temperature
C) Pain
The interpretation of a stimulus is called:
A) Perception
B) Sensation
C) Cognitive function
D) Integration
A) Perception
In terms of structure, the simple receptor of a sensory neuron is the:
A) Synaptic bulb
B) Axon terminal
C) Dendritic end
D) Axon hillock
C) Dendritic end
The perceptual level of neural integration occurs within the:
A) Ascending tract
B) Post-central gyrus
C) Sensory receptor
D) Thalamus
B) Post-central gyrus
The perineurium will surround:
A) Each individual axon
B) Individual nerve fasciles
C) The dendritic ends (encapsulated dentrites)
D) Multiple nerve fasciles
B) Individual nerve fasciles
Which cranial nerve enters both the thoracic and abdominal cavities?
A) Trigeminal (V)
B) Vagus (X)
C) Glossopharangeal (IX)
D) Facial (VII)
B) Vagus (X)
Which cranial nerve will exit through the hypoglossal canal?
A) V
B) IX
C) X
D) XII
D) XII
Which statement is false regarding cranial nerves?
A) The 12 pairs of cranial nerves are located on the ventral surface of the brain.
B) Each cranial nerve will pass through a fissure or foramen to innervate it's organ
C) All cranial nerves possess both sensory and motor neurons
D) The majority of cranial nerves are located along the brainstem
C) All cranial nerves possess both sensory and motor neurons
Which statement is false regarding efferent motor neurons?
A) Are located in both cranial and spinal nerves
B) Will innervate skeletal muscle
C) Cell bodies are located within the dorsal root ganglion
D) May be divided into somatic and visceral motor neurons
E) Are classified as multi-polar neurons
C) Cell bodies are located within the dorsal root ganglion
This type of sensory receptor will detect stretch
A) Mechanoreceptor
B) Thermoceptor
C) Nociceptor
D) Proprioceptor
E) Chemoreceptor
A) Mechanoreceptor
Efferent somatic motor neurons emerge from the spinal cord through the:
A) Dorsal root ganglion
B) Posterior ramus
C) Lateral horn
D) Ventral horn
E) Dorsal column
D) Ventral horn
There are 31 pairs of spinal nerves, how many are located within the cervical region?
A) 8
B) 12
C) 5
D) 3
E) 1
A) 8
Which of the following structures is not a plexus?
A) Cervical
B) Brachial
C) Thoracic
D) Lumbar
E) Sacral
C) Thoracic
The phrenic nerve which innervates the diaphragm originates from which plexus?
A) Cervical
B) Brachial
C) Thoracic
D) Lumbar
E) Sacral
A) Cervical
The sciatic nerve will innervate:
A) Gluteal muscles
B) Anterior thigh muscles (quadriceps)
C) Lower leg muscles (gostrcnemius)
D) Posterior thigh muscles (biceps femoris)
E) Lateral compartments (fibularis group)
D) Posterior thigh muscles (biceps femoris)
Which spinal nerves contribute towards the formation of the brachial plexus?
A) C1-C4
B) C5-T1
C) T2-L2
D) L2-L5
E) S3-Co
B) C5-T1
The tenth cranial nerve, the Vagus (X) exits the skull through the:
A) Foramen magnum
B) Jugular foramen
C) Interal auditory meatus
D) Foramen ovale
E) Superior orbital fissure
B) Jugular foramen
Which of the following statements is false with respect to reflexes?
A) Are protective by design
B) Are learned responses
C) Happen rapidly following a stimulus
D) Are involuntary responses
E) Are associated with the viscera
B) Are learned responses
Which of the following statement is false regarding a monosynaptic stretch reflex?
A) The sensory neuron synapses directly to a motor neuron
B) Afferent sensory neuron will synapse with contralateral motor neurons
C) The muscle spindle is the sensory receptor
D) An interneuron is required for this reflex
E) The synapse occurs within the spinal cord
B) Afferent sensory neuron will synapse with contralateral motor neurons
AND
D) An interneuron is required for this reflex
Which neural component is unique to the polysynaptic reflex arc?
A) Sensory neuron
B) Afferent sensory neuron
C) Interneuron
D) Efferent motor neuron
E) Effector (muscle or gland)
C) Interneuron
The muscles of the upper and lower extremities are innervated from nerves originating from the:
A) Dorsal root ganglion
B) Ventral root
C) Ventral ramus
D) Dorsal ramus
E) Sympathetic chain ganglion
C) Ventral ramus
The spinal nerves of the sacral plexus exit through th:
A) Sacral foramina
B) Sacral hiatus
C) Superior sacral aperture
D) Intervertebral foramen
E) Transverse foramen
A) Sacral foramina
A polysynaptic reflex will:
A) Consists of at least three neurons
B) Possess an interneuron within the spinal cord
C) Can relay information towards the brain (withdraw reflex)
D) Only answer A is true
E) All statements are true
E) All statements are true
What are the respective functions of the dorsal and ventral rami?
The dorsal ramus contains nerves that serve the dorsal portions of the trunk carrying visceral motor, somatic motor, and sensory information to and from the skin and muscles of the back. The ventral ramus contains nerves that serve the remaining ventral parts of the trunk and the upper and lower limbs carrying visceral motor, somatic motor, and sensory information to and from the ventrolateral body surface, structures in the body wall, and the limbs
What are the respective functions of the dorsal (posterior), ventral (anterior), and lateral horns of the spinal cord?
Ventral (anterior) horn - contains some interneurons, but mostly cell bodies of somatic motor neurons.
Dorsal (posterior) horn - 1st order neurons for sensory input from the PNS; consists entirely of interneurons
Lateral horn - Cell bodies of outgoing motor neurons, only present in thoracic and superior lumbar sections
What composes the mass of the dorsal root ganglions?
The cell bodies of sensory neurons
What composes the dorsal roots of the spinal cord.
Formed from the fibers of peripheral sensory receptors. The cell bodies form an enlargement called the dorsal root ganglion.