Chapter 13 lecture Flashcards

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The peripheral nervous system
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Which of the following nerves does not arise from the brachial plexus?

  • Median
  • Phrenic
  • Radial
  • Ulnar



Which of the following is not a way that sensory receptors are classified?

  • type of stimulus detected
  • location in the body
  • structural complexity
  • sensitivity to a stimulus

Sensitivity to a stimulus


Which of the following is not a main level of neural integration in the somatosensory system?

  • receptor
  • circuit
  • segmental
  • perceptual



Starting at the spinal cord, the subdivisions of the brachial plexus are (in order):

  • roots, trunks, divisions, and cords
  • roots, divisions, cords and trunks
  • divisions, roots, trunks and cords
  • trunks, divisions, cords, and roots

Roots, trunks, divisions, and cords


The cranial nerve with a cervical origin (spinal cord) is the _______.

  • hypoglossal
  • accesory
  • vagus
  • glossopharyngeal



A major nerve of the lumbar plexus is the ____.

  • femoral
  • iliohypogastric
  • sciatic
  • ilioinguinal



Spinal nerves exiting the cord from the Level of L4 to S4 form the ___.

  • lumbar plexus
  • femoral plexus
  • sacral plexus
  • thoracic plexus

Sacral plexus


Striking the "funny bone" is actually stimulation of (or injury to) the ___.

  • radial nerve
  • sciatic nerve
  • ulnar nerve
  • median nerve

Ulnar nerve


Pressure, pain, and temperature receptors in the skin are___.

  • Interoceptors
  • exteroceptors
  • proprioceptors
  • mechanoreceptors



Potentially damaging stimuli that result in pain are selectively detected by ____.

  • interoceptors
  • photoreceptors
  • nociceptors
  • proprioceptors



_____ are stimulated when sound waves vibrate hair cells in the inner ear.

  • Mechanoreceptors
  • Thermoreceptors
  • Photoreceptors
  • Nociceptors



Which of the following pairs of receptors appear to play complementary roles in hairy and hairless skin?

  • tactile discs and lamellar corpuscles
  • bulbous corpuscles and hair follicle receptors
  • Tendon organs and tactile corpuscles
  • Tactile corpuscles and hair follicle receptors

Tactile corpuscles and hair follicle receptors


At which level of the somatosensory system are conscious decisions made about low-grade touch stimuli?

  • Receptor level
  • Circuit level
  • Perceptual level
  • Effector level

Perceptual level


Nerves that carry impulses toward the CNS only are ____.

  • afferent only
  • efferent only
  • motor nerves
  • mixed nerves

Afferent nerves


The posterior side of the thigh, leg, and foot is served by the ___nerve.

  • obturator
  • common fibular
  • tibial
  • femoral



Which cranial nerve is the largest?

Trigeminal nerve (V)


Which cranial nerve is the only one that exists in the "posterior" side of the brainstem?

Trochlear nerve (IV)


How many cranial nerves are responsible for eye movement?

3; Oculomotor nerve (III), Trochlear nerve (IV), and Abducens nerve (VI)


What does "abducens" refer to?

Moves the eye laterally causing abduction of the eye.


Which cranial nerves cary gustatory (taste) information?

Facial nerve (VII), glossopharyngeal nerve (IX), Vagus nerve (X)


Which cranial nerve is the longest?

Vagus nerve (X)


What 2 cranial nerves carry sensory information about blood pressure to the brain?

Glossopharyngeal neve (IX), and Vagus nerve (X)


Which cranial nerve is responsible for pupillary constriction?

Oculomotor nerve (III)


Which nerve innervates the superior oblique muscle?

Trochlear nerve (IV)


Which is the longest cranial nerve?

Vagus nerve (X)


Damage to this nerve would cause dizziness, nausea, and loss of balance.

Vestibulocochlear nerve (VIII)


This nerve is involved in movement of the digestive tract.

Vagus nerve (X)


Damage to this would would cause difficulty in speech and swallowing, but no effect on visceral organs.

Hypoglossal nerve (XII)


Damage to this nerve would keep the eye from rotation inferolaterally.

Abducens nerve (VI)


On occasion our trusty truck acts funny - very good vehicle anyhow.

Olfactory Optic Oculomotor Trochlear Trigeminal Abducens Facial Vestibulocochlear Glossopharyngeal Vagus Hypoglossal


What is the PNS?

provides links from and to the world outside our bodies. Outside the CNS.


What does the PNS consist of?

All neural structures outside the brain and spinal cord.


List the neural structures outside the body:

Sensory receptors

Peripheral nerves

Efferent motor endings


***What are 3 ways to classify sensory receptors?

  1. Type of stimulus they detect
  2. Location in body
  3. Structural complexity


***List the sensory receptors that are classified by stimulus type:

  • Mechanoreceptors
  • Thermoreceptors
  • Photoreceptors
  • Chemoreceptors
  • Nociceptors


What stimulus does the mechanoreceptor respond to?

Touch, mechanical force, pressure (BP), vibration, and stretch


What stimulus does a thermoreceptor respond to?

Sensitive to changes in temperature.


What stimulus does photoreceptors respond to?

Respond to light energy (retina)


What stimulus does chemoreceptors respond to?

chemicals, (ie...smell, taste, changes in blood chemistry) interstitial fluid chemistry


What stimulus do Nociceptors respond to?

Noci = harm

Potentially damaging stimuli, sensitive to pain causing stimuli (i.e. extreme heat or cold, excessive pressure, inflammatory chemicals) can also trigger subtypes of previous receptors (i.e. thermoreceptors, mechanreceptors, and chemoreceptors.)


***List the receptors that are classified by location:

  • Exteroceptors
  • Interoceptors
  • Proprioceptors


Describe exteroceptors:

  • Near or at body surface
  • Respond to stimuli arising outside the body
  • Receptors in skin for touch, pressure, pain, and temp.
  • Most special sense organs (i.e. vision, hearing, equilibrium, taste, smell)


Describe Interoceptors (visceroceptors):

  • Respond to stimuli arising in internal viscera and blood vessels
  • Sensitive to chemical changes, tissue stretch, and temperature changes
  • Sometimes cause discomfort but usually unaware of their workings
  • Damaged stimuli can result in pain and is processed by interoceptors


Describe Propioceptors (one's own):

  • Respond to stretch in skeletal muscles, tendons, joints, ligaments, and connective tissue coverings of bones and muscles.
  • Informs brain of ones movements


List the sensory receptors that are classified by structures:

  • Simple receptors for general senses
  • Receptors for special senses
  • Non-encapsulated
  • Encapsulated


Describe the simple receptors for general senses:

  • Tactile sensations (touch, pressure, stretch, vibration) temp., pain, and muscle sense
  • Modified dendritic endings of sensory neurons


Describe the receptors for special senses:

  • Vision, hearing, equilibrium, smell and taste
  • Survival depends upon sensation and perception
  • Sensation-the awareness of changes the internal and external environment
  • Perception- the conscious interpretation of those stimuli


What does Non-encapsulated mean?

(Free)- located nearly everywhere in the body, abundant in epithelia and connective tissue. Respond primarily to temp, painful stimuli and itch. (Tactile (Merkel discs), Hair follicle receptors)


What does Encapsulated mean?

(enclosed)- in a connective tissue capsule. Virtually all are mechanoreceptors but vary greatly in shape, size, and distribution in the body.


Give examples of sensory receptors that are classified by structures:

  • Tactile (Meissner's) corpuscles- discriminative touch
  • Lamellar (Pacinian) corpuscles- deep pressure and vibration
  • Bulbous corpuscles (Ruffini endings)- deep continuous pressure
  • Muscle spindles- muscle stretch
  • Tendon organs- stretch in tendons


What sensory organization serves the body wall and limbs?



Describe somatosensory:

Receives inputs from

  • Exteroceptors, proprioceptors, and interoceptors
  • Input relayed toward head, but processed along the way


List the levels of neural integration in sensory systems:

  1. Receptor level- sensory receptors
  2. Circuit level- processing in ascending pathways
  3. Perceptual level- processing in cortical sensory areas


***What are the 2 categories of reflexes?

  1. Inborn (intrinsic) reflex- rapid, involuntary, predictable motor response to stimulus (ex: maintain posture, control visceral activities) Can be modified by learning and conscious effort.
  2. Learned (acquired)- reflexes result from practice or repitition, (Ex: driving skills)


***What are the 5 components of a reflex arc (neural path)?

  1. Receptor
  2. Sensory neuron
  3. Integration center
  4. Motor neuron
  5. Effector


What is a nerve?

A cordlike organ of the PNS.


What are nerves composed of?

  • Numerous nerve fibers that are organized into bundles known as fascicles.
  • Bundle of myelinated and non-myelinated peripheral axons enclosed by connective tissue


List the layers of the connective tissue covering around nerve fibers and their descriptions:

  • Endoneurium- loose connective tissue that encloses axons and their myelin sheaths
  • Perineurium- coarse connective tissue that bundles fibers into fascicles
  • Epineurim- tough fibrous sheath around a nerve


In general, how are nerves classified throughout the PNS?

  1. Most nerves are mixtures of afferent and efferent fibers and somatic and autonomic (visceral) fibers
  2. Classified according to direction the impulse transmits to


***Name the nerves that are classified according to the direction of impulse:

  • Mixed nerves-both sensory and motor fibers; impulses both to and from CNS
  • Sensory (afferent) nerves- impulses only toward CNS
  • Motor (efferent)- impulses only away from CNS
  • Peripheral nerves classified as cranial or spinal nerves


What is the ganglia?

  • Neuron cell bodies associated with nerves in PNS
  • Those associated with afferent nerve fibers contain cell bodies of sensory neurons
  • Those associated with efferent nerve fibers contain autonomic motor neurons


How many cranial nerves are associated with the brain?

12 pairs. Only 2 pairs are attached to the forebrain. The rest are found on the brain stem.


**What nerve is a major nerve of the lumbar plexus?

The Femoral nerve L2-L4


***What are the major roots of the Brachial plexus?

  1. Roots
  2. Trunks
  3. Divisions
  4. Cords


Olfactory Nerve I

Sensory organ that carries impulses for smell to the brain


Optic Nerve II

Sensory organ that carries impulses for vision to the brain


Oculomotor Nerve III

Motor nerve that carries impulses to the extrinsic eye muscles which help direct the position of the eyeball. This nerve also carries impulses to the muscles that regulate the size of the pupil.


Trochlear Nerve IV

Motor nerve that carries impulses to one extrinsic eye muscle (the superior oblique muscle). This muscle helps regulate the position of the eyeball.


Trigeminal Nerve V

A mixed nerve. The sensory fibers of this nerve carry impulses for touch, temp and pain associated with the face, teeth, lips, and eyelids. The motor fibers of this nerve carry impulses to some of the mastication muscles of the face.


Abducens Nerve VI

A mixed nerve, but primarily a motor nerve. This nerve carries impulses to the lateral rectus muscle of the eye. This muscle is an extrinsic eye muscle which is involved in positioning the eyeball.


Facial Nerve VII

A mixed nerve.The sensory fibers of this nerve carry touch, temp, pressure and pain sensations from the face to the brain. The motor fibers of this nerve carry impulses to many of the muscles of the face and they carry impulses to the lacrimal glands.


Vestibulocochlear Nerve VIII

A sensory nerve that carries impulses for hearing and equilibrium from the ear to the brain.


Glossopharyngeal Nerve IX

A mixed nerve. The sensory fibers of this nerve carry basic sensory info and taste sensations from the pharynx and tongue to the brain. The motor fibers of this nerve carry impulses associated with swallowing to the tongue and pharynx.


Vagus Nerve X

A mixed nerve. The sensory fibers of this nerve carry impulses from the pharynx , larynx, and some internal organs to the brain. The motor fibers of this nerve carry impulses to some internal organs and to the skeletal muscles of the larynx and pharynx.


Accessory Nerve XI

A mixed nerve, but primarily a motor nerve. Carries impulses to muscles of the larynx, pharynx, and neck.


Hypoglossal Nerve XII

Primarily a motor nerve. This nerve carries impulses to the muscles that move and position the tongue.