Cranial nerves and parts of the brain

CN I

Olfactory: Smell

CN II

Optic: Vision

Snellen —> visual acuity

Pupil response

CN III

Oculomotor: extraocular muscle movement, opening of eyelids, pupil constriction, lens shape

Accommodation, eye movements (up, down, medial)

CN IV

Trochlear: Eye movement

smooth movements (down, inward)

CN V

Trigeminal: Sensation and chewing, muscle of mastication

sensory of the mucous membranes of mouth and nose

clenching of jaw, strength of masseter muscle

CN VI

Abducens: Lateral eye movements

Eyes follwoing an object side to side without head movement

CN VII

Facial: facial expressions and taste (anterior two thirds), close eyes, close mouth, labial speech

saliva and tear secretion

close eyes tight, raise eyebrows, puff cheeks

CN VIII

Acoustic: Hearing and balance

CN IX

Glossopharyngeal: Gag reflex, swallowing, taste (posterior one third)

parotid and carotid reflex

phonation of ahhh, swallow

CN X

Vagus:Regulates rest and digest

CN XI

Accessory: trapezius and sternomastoid muscle

shrug shoulders and head turn

CN XII

Hypoglossal: tounge movement

Cerebral cortex

thought, memory, reasoning, sensation, voluntary movement

Cerebral cortex: frontal lobe

personality, behavior, emotions, intellectual function

Broca’s area: medicates motor speech

Cerebral cortex: Parietal lobe

Postcentral gyrus —> primary center for sensation

Cerebral cortex: Occipital lobe

primary visual receptor center

Cerebral cortex: Temporal lobe

primary auditory reception center, taste, and smell

Wernicke’s area: language comprehension

Damage to cerebral cortex

• motor weakness

• paralysis

• loss of sensation

• impaired ability to understand and process language

happens when there is an occlusion in cerebral artery

Cerebellum

Concerned with motor coordination and muscle tone of voluntary movements

Nervous system two parts

Central and Peripheral

Sensory (Afferent)

to CNS from sensory receptors

Motor (efferent)

to muscle and glands from CNS

Cerebral cortex is cerebrum’s _____

outer layer of nerve cells (grey matter)

Brainstem

central core of the brain

• midbrain

• pons

• medulla

Thalamus

main relay station where sensory pathways of spinal cord, cerebellum, and brainstem from synapses and an integrating center

hypothalamus

respiratory center with basic function and control and coordination of vital functions: temp, appetite, sex drive, heart rate, blood pressure, sleep center, anterior and posterior pituitary gland regular and coordinator of the autonomic nervous system and stress response

pathway of CNS

Left cerebral cortex receives sensory and controls motor function for right side

Anterolateral (spinothalamic tract)

contains sensory fibers that transmit sensations of pain, temo, and crude or light touch

Posterior (dorsal) columns

Conduct sensations of position, vibration, and localized touch

stereognosis

localized touch

Pyramidal tract

fibers mediate voluntary movement, particularly very skilled, discrete, purposeful movements

Extrapyramidal tracts

maintain muscle tone and control body movements, esp gross automatic movements (like walking)

Cerebellar system

coordinates movements, maintains equilibrium and posture

Upper motor neurons

Located completely in CNS

• convey impulses from motor areas of cerebral cortex to lower motor neurons

Lower motor neurons

ex. cranial nerves, and spinal nerves of peripheral nervous system

• located in brainstem and spinal cord, when they get signal from upper motor neurons they send signal to muscle to make them contract

Three types of reflexes

• stretch on/ deep tendon (myotatic)

  • knee jerk

• superficial

  • plantar reflex

• visceral (organ)

  • pupillary response to light and accommodation

CN that are attached to brain

CN I, II,III, XII

Segments of the spine

8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

peripheral nervous system two parts:

Somatic

Autonomic

CN I testing

test sense of smell

• head trauma

• abnormal mental status

• presence of intracranial lesion

• those that report altered smell

CN II testing

Visual acuity and visual fields by confrontation

• use ophthalmoscope and examine ocuar fundus to determine color, size, shape of optic disc

CN III, IV, and VI testing

• pupils are 3mm, direct and consensual w/ accommodation

• assess for extraocular movements by cardinal positions of gaze

• assess for nystagmus

CN V testing

• motor function: clench ur jaw and palpate temporal muscle, test strength of muscle of mastication

• sensory function: light touch sensation

• Corneal reflex if pt has abnormal facial sensation or abnormalities of facial movement

• test all three divisions: ophthalmic, maxillary, and mandibular

CN VII testing

• facial symmetry

• puff cheeks

• test sensory only if suspected facial nerve injury

  • sense of taste

CN VIII testing

whispered voice test

hearing acuity

CN IX and X testing

• rises midline on the phonation of ahhh

• tonsillar pillars move medial

• gag reflex

CN XI testing

• shrug shoulders against resistance

• rotate head w resistance

CN XII testing

• no tremors on tongue

• tongue moves midline

• light tight dynamite (for clear lingual speech)

Cerebellar function test

• Gait, tandem walking, romberg

Balance

Tactile discrimination

Fine touch

• tests also measure discrimination ability of sensory cortex

Graphethesia

ability to read a number having it traced on skin

Clonus

test when refleces hyperactive

Plantar

normal response is plantar flexion of toes and inversion and flecion of the toes

Parkinsonism

resting tremor, flat fascial expressipn, staring, excessive salivation, reduced eye blink, stooped posture, impaired equilibrium, loss of balance, shuffling gate

Cerebellar

ataxia, lurching to affected side while walking, slow, finger to nose, tremor and over or undershoot, involuntary eye movement moving rapidly from side to side, up and down

Paraplegia

LMN damage, extensor spasms, leading to prevailing extensor tone, DTR reappear and become increased, flexor spasms of legs

multiple sclerosis

chronic, progressive, immenuemediated disease, axons are inflammed, nystagmus spasticity, loss of balance, hyperreflexia, babinski sign

abnormal postures: decorticate rigidity

upper:

• Flexion of arm, wrist, and fingers

• adduction of arm: tight against thorax

lower

• extension, internal rotation, plantar flexion, inhicates hemispheric lesion of cerebral cortex

Decerebrate rigidity

Upper extremities: stiffly extended, adducted, internal rotation, palms pronated

lower: stiffly extended, plantar flexion; teeth clentch; hyperextended back

ominous