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N5315 Advanced Pathophysiology
Neurologic System
Module 7
Examine the anatomy and physiology of the Central Nervous System.
1. Discuss the anatomy and physiology of the brain and brain stem.
a. Explain the function of the twelve cranial nerves
I – Olfactory (Smell)
Function: Sensory, carries impulses for sense and smell
Sign of Dysfunction: Loss or disturbance in the sense of smell.
II – Optic (Sight)
Function: Sensory, carries impulses for vision
Sign of Dysfunction: decreased visual acuity and contrast sensitivity, impaired color vision,
and an afferent pupillary defect. (blindness)
III – Oculomotor
Function: Contains motor fibers to interior oblique and to superior, inferior, ad medial rectus
extraocular muscles that direct eye ball; levator muscles of eyelid; smooth muscles of iris and
ciliary body; and proprioception (sensory) to brain from extraocular muscles
Sign of Dysfunction: Drooping of the eyelid, eyeball moves outward, dilation of the pupil,
double vision.
IV – Trochlear
Function: Propioceptor and motor fibers for superior oblique muscle of eye (extraocular
muscles)
Sign of Dysfunction:
Rotation of eyeball upward and outward, double vision
V Trigeminal
(facial muscles including chewing, facial sensation)
This is the largest cranial nerve
Function: Both motor and sensory for face; conducts sensory impulses from mouth, nose,
surface of eye, and dura mater; also contains motor fibers that stimulate chewing muscles
Sign of Dysfunction: Sensory root – Pain or loss of sensation in the face, forehead, temple
and eyes. Motor root – affecting the jaw, trouble chewing
VI Abducens (moves eyeballs)
Function: Moves the eyeballs outwards by sending nerve impulses to the lateral rectus
muscles
Sign of Dysfunction: Deviation of the eyes outward; double vision
, 2
VII Facial
(taste, tears, saliva and facial expressions)
Function: Mixed: 1. Supplies motor fibers to muscles of facial expression and to the lacrimal
and salivary glands. 2. Carries sensory fibers from taste buds of anterior part of tongue
Sign of Dysfunction: Paralysis of all the muscles in one side of the face, inability to wrinkle the
forehead, close the eye, whistle, deviation of the mouth. Bell’s Palsy
VIII Vestibulocochlear (acoustic) auditory
Function: Purely sensory; vestibular branch transmits impulses for sense of equilibrium,
cochlear branch transmits impulses for sense of hearing
Sign of Dysfunction: Deafness or ringing in the ears, dizziness, nausea and vomiting
IX Glossopharyngeal (swallowing, saliva, taste)
Function: Mixed: 1. Motor fibers serve pharynx and salivary glands. 2. Sensory fibers carry
impulses from, pharynx, posterior tongue, and pressure receptor of carotid artery (blood
pressure)
Sign of Dysfunction: Disturbance of taste; Difficulty in swallowing
X Vagus (control of PNS: smooth muscles of GI tract)
Function: Sensory and motor impulses for pharynx; a large part of this nerve is
parasympathetic motor fibers, which supply smooth muscles of abdominal organs
Sign of Dysfunction: Hoarseness and difficulty swallowing and talking.
This nerve also regulates the heart, blood vessels and digestion resulting in irregular
heartbeat and lowered blood pressure. It regulates the stomach telling it to move food
through the digestive system, thus damage can result in decreased digestion and thus
nausea, bloating and vomiting.
XI Spinal accessory (moving of head and shoulders, swallowing)
Function: Provides sensory and motor fibers for sternocleidomastoid and trapezius muscles
(movement of head and shoulders) and muscles of soft palate, pharynx, and larynx (swallowing)
Sign of Dysfunction: Dropping of the shoulder; inability to rotate the head away from affected
area.
XII Hypoglossal (tongue muscles, speech and swallowing)
Function: Carries motor fibers to muscles of tongue and sensory impulses from tongue to
brain.
Sign of Dysfunction: Paralysis of one side of the tongue; deviation of tongue toward paralyzed
side; thick speech.
, 3
b. Explain the function of the cerebrum, cerebellum, parietal lobe, frontal lobe,
occipital lobe, temporal lobe, brain stem, reticular formation reticular activating system,
and limbic system.
Cerebrum
Location: forebrain
Largest part of the bain. Derived from the telencephalon, characterized by numerous
convolutions called gyri. Comprised of two hemispheres
Contain- cerebral cortex, basal ganglia, epithalamus, thalamus, hypothalamus, subthalamus.
Prefrontal lobe- goal-oriented behavior/concentration, short-term memory, elaboration of thought
and inhibition on the limbic areas of the CNS. Prefrontal (Brodmann 6) programming motor
movements. Basal ganglia system- extrapyramidal system- efferent pathways outside the
pyramids of the medulla. Frontal eye fields (lower portion of Brodmann 8) controlling eye
movement in the middle frontal gyrus.
Function:
Divided into numerous smaller areas which are each dedicated to specific areas of function.
These areas include frontal lobe, parietal lobe, temporal lobe and occipital lobe
Basal ganglia- fine tuning of motor movement. Cerebral cortex has contralateral control of the
body.
Sign of Injury/Lesion/Disorder:
Dependent on location, see below
Parkinson’s, Huntington disease- basal ganglia
Cerebral cortex has contralateral (opposite side) control of the body.
Frontal
Location:
Anterior portion of the brain encompassing from the frontal part of the skull to the central sulcus
of the brain
Function:
Include prefrontal which is responsible for goal oriented behavior, short term memory,
elaboration of thought and inhibition of limbic system. Includes the premotor area which is
involved in movements, includes the neurons contributing to the extrapyramidal system or basal
ganglia. Frontal lobe also includes primary motor area which forms a somatic organization
referred to as a homunculus (little man). Also includes Broca’s area, responsible for speech
Sign of Injury/Lesion/Disorder:
Damage to the frontal will manifest itself significant to the area of the injury. For example,
damage to the Broca area from CVA will cause difficulty in forming words
, 4
Temporal
Location:
Makes up the lower portion of the brain, just above the pons/cerebellum and spans L and R
hemispheres. Lies inferior to the lateral sulcus, composed of superior, middle, and inferior
temporal gyri.
Function:
Primary auditory cortex (Brodmann area 42 and associated area 42) lie deep within the lateral
sulcus of the superior temporal gyrus. Wernicke area (posterior portion of Brodmann area 22) –
superior temporal gyrus- interpretation of speech, dysfunction = receptive aphasia or dysphasia.
Major area for long-term memory and balance, taste, smell. Epileptic loci often found in the
temporal lobe.
Sign of Injury/Lesion/Disorder:
Parietal
Location: Forebrain: Lies within border of the central, parietooccipital and lateral sulci
Function: Somatic sensory input.
Communication between motor and sensory areas
Sign of Injury/Lesion/Disorder:
Occipital
Location: Forebrain: Caudal to the pareitococcipital sulci and superior to the cerebellum
Function: Visual cortex
Sign of Injury/Lesion/Disorder:
Cerebellum
Location: Hindbrain:
Function: Responsible for conscious and unconscious muscle synergy .
Maintaining balance and posture
Sign of Injury/Lesion/Disorder:
Damage causes ipsilateral loss of equilibrium, balance, motor coordination. (has ipsilateral
control of the body).
N5315 Advanced Pathophysiology
Neurologic System
Module 7
Examine the anatomy and physiology of the Central Nervous System.
1. Discuss the anatomy and physiology of the brain and brain stem.
a. Explain the function of the twelve cranial nerves
I – Olfactory (Smell)
Function: Sensory, carries impulses for sense and smell
Sign of Dysfunction: Loss or disturbance in the sense of smell.
II – Optic (Sight)
Function: Sensory, carries impulses for vision
Sign of Dysfunction: decreased visual acuity and contrast sensitivity, impaired color vision,
and an afferent pupillary defect. (blindness)
III – Oculomotor
Function: Contains motor fibers to interior oblique and to superior, inferior, ad medial rectus
extraocular muscles that direct eye ball; levator muscles of eyelid; smooth muscles of iris and
ciliary body; and proprioception (sensory) to brain from extraocular muscles
Sign of Dysfunction: Drooping of the eyelid, eyeball moves outward, dilation of the pupil,
double vision.
IV – Trochlear
Function: Propioceptor and motor fibers for superior oblique muscle of eye (extraocular
muscles)
Sign of Dysfunction:
Rotation of eyeball upward and outward, double vision
V Trigeminal
(facial muscles including chewing, facial sensation)
This is the largest cranial nerve
Function: Both motor and sensory for face; conducts sensory impulses from mouth, nose,
surface of eye, and dura mater; also contains motor fibers that stimulate chewing muscles
Sign of Dysfunction: Sensory root – Pain or loss of sensation in the face, forehead, temple
and eyes. Motor root – affecting the jaw, trouble chewing
VI Abducens (moves eyeballs)
Function: Moves the eyeballs outwards by sending nerve impulses to the lateral rectus
muscles
Sign of Dysfunction: Deviation of the eyes outward; double vision
, 2
VII Facial
(taste, tears, saliva and facial expressions)
Function: Mixed: 1. Supplies motor fibers to muscles of facial expression and to the lacrimal
and salivary glands. 2. Carries sensory fibers from taste buds of anterior part of tongue
Sign of Dysfunction: Paralysis of all the muscles in one side of the face, inability to wrinkle the
forehead, close the eye, whistle, deviation of the mouth. Bell’s Palsy
VIII Vestibulocochlear (acoustic) auditory
Function: Purely sensory; vestibular branch transmits impulses for sense of equilibrium,
cochlear branch transmits impulses for sense of hearing
Sign of Dysfunction: Deafness or ringing in the ears, dizziness, nausea and vomiting
IX Glossopharyngeal (swallowing, saliva, taste)
Function: Mixed: 1. Motor fibers serve pharynx and salivary glands. 2. Sensory fibers carry
impulses from, pharynx, posterior tongue, and pressure receptor of carotid artery (blood
pressure)
Sign of Dysfunction: Disturbance of taste; Difficulty in swallowing
X Vagus (control of PNS: smooth muscles of GI tract)
Function: Sensory and motor impulses for pharynx; a large part of this nerve is
parasympathetic motor fibers, which supply smooth muscles of abdominal organs
Sign of Dysfunction: Hoarseness and difficulty swallowing and talking.
This nerve also regulates the heart, blood vessels and digestion resulting in irregular
heartbeat and lowered blood pressure. It regulates the stomach telling it to move food
through the digestive system, thus damage can result in decreased digestion and thus
nausea, bloating and vomiting.
XI Spinal accessory (moving of head and shoulders, swallowing)
Function: Provides sensory and motor fibers for sternocleidomastoid and trapezius muscles
(movement of head and shoulders) and muscles of soft palate, pharynx, and larynx (swallowing)
Sign of Dysfunction: Dropping of the shoulder; inability to rotate the head away from affected
area.
XII Hypoglossal (tongue muscles, speech and swallowing)
Function: Carries motor fibers to muscles of tongue and sensory impulses from tongue to
brain.
Sign of Dysfunction: Paralysis of one side of the tongue; deviation of tongue toward paralyzed
side; thick speech.
, 3
b. Explain the function of the cerebrum, cerebellum, parietal lobe, frontal lobe,
occipital lobe, temporal lobe, brain stem, reticular formation reticular activating system,
and limbic system.
Cerebrum
Location: forebrain
Largest part of the bain. Derived from the telencephalon, characterized by numerous
convolutions called gyri. Comprised of two hemispheres
Contain- cerebral cortex, basal ganglia, epithalamus, thalamus, hypothalamus, subthalamus.
Prefrontal lobe- goal-oriented behavior/concentration, short-term memory, elaboration of thought
and inhibition on the limbic areas of the CNS. Prefrontal (Brodmann 6) programming motor
movements. Basal ganglia system- extrapyramidal system- efferent pathways outside the
pyramids of the medulla. Frontal eye fields (lower portion of Brodmann 8) controlling eye
movement in the middle frontal gyrus.
Function:
Divided into numerous smaller areas which are each dedicated to specific areas of function.
These areas include frontal lobe, parietal lobe, temporal lobe and occipital lobe
Basal ganglia- fine tuning of motor movement. Cerebral cortex has contralateral control of the
body.
Sign of Injury/Lesion/Disorder:
Dependent on location, see below
Parkinson’s, Huntington disease- basal ganglia
Cerebral cortex has contralateral (opposite side) control of the body.
Frontal
Location:
Anterior portion of the brain encompassing from the frontal part of the skull to the central sulcus
of the brain
Function:
Include prefrontal which is responsible for goal oriented behavior, short term memory,
elaboration of thought and inhibition of limbic system. Includes the premotor area which is
involved in movements, includes the neurons contributing to the extrapyramidal system or basal
ganglia. Frontal lobe also includes primary motor area which forms a somatic organization
referred to as a homunculus (little man). Also includes Broca’s area, responsible for speech
Sign of Injury/Lesion/Disorder:
Damage to the frontal will manifest itself significant to the area of the injury. For example,
damage to the Broca area from CVA will cause difficulty in forming words
, 4
Temporal
Location:
Makes up the lower portion of the brain, just above the pons/cerebellum and spans L and R
hemispheres. Lies inferior to the lateral sulcus, composed of superior, middle, and inferior
temporal gyri.
Function:
Primary auditory cortex (Brodmann area 42 and associated area 42) lie deep within the lateral
sulcus of the superior temporal gyrus. Wernicke area (posterior portion of Brodmann area 22) –
superior temporal gyrus- interpretation of speech, dysfunction = receptive aphasia or dysphasia.
Major area for long-term memory and balance, taste, smell. Epileptic loci often found in the
temporal lobe.
Sign of Injury/Lesion/Disorder:
Parietal
Location: Forebrain: Lies within border of the central, parietooccipital and lateral sulci
Function: Somatic sensory input.
Communication between motor and sensory areas
Sign of Injury/Lesion/Disorder:
Occipital
Location: Forebrain: Caudal to the pareitococcipital sulci and superior to the cerebellum
Function: Visual cortex
Sign of Injury/Lesion/Disorder:
Cerebellum
Location: Hindbrain:
Function: Responsible for conscious and unconscious muscle synergy .
Maintaining balance and posture
Sign of Injury/Lesion/Disorder:
Damage causes ipsilateral loss of equilibrium, balance, motor coordination. (has ipsilateral
control of the body).
