NEURO: Exam 2

cranial nerves,

CN I

Olfactory

Location: inferior aspect of the frontal lobes;

Sensory function: Smell; Lesion results in anosmia or hyposmia

CN II

Optic;

Location:

Visible on the inferior aspect of the cerebrum; Sensory function:

Vision; Lesion results in visual field cuts

CN III

Occulomotor;

Location: Exits at the top of the brainstem/midbrain;

Motor function: Constricts pupil, opens eyelids, eye movement; Lesion results in ptosis, dilated pupils, strabismus

CN IV

Trochlear

Location: Exits via the dorsal brainstem (midbrain);

Motor function: Eye movements; Lesion results in weakness of downward eye movement, diplopia

CN V

Trigeminal;

Location: Exits from the lateral aspect ventral pons of brainstem;

Motor function: Biting, chewing; Sensory function:

Sensation to face and mouth; Lesion results in trigeminal neuralgia, chewing problems

CN VI

Abducens;

Location: Originates abducens nucleus of the pons;

Motor function: Lateral eye movement; Lesion results in strabismus, diplopia

CN VII

Facial;

Location: Pons; Motor function: Innervates facial muscles;

Sensory function: Taste sensation, sensation from ear canal; Lesion results in facial palsy, loss of taste, inability to close eyelids

CN VIII

Vestibulocochlear;

Location: Exits inferior to the facial nerve;

Sensory function: Cochlear branch controls hearing, Vestibular branch maintains balance; Lesion results in hearing or balance reduction, vertigo

CN IX

Glossopharyngeal;

Location: Exits medulla inferior to auditory-vestibular nerve;

Motor function: Supply muscles of pharynx, tonsils;

Sensory function: Pain, touch, taste sensations; Lesion results in loss of taste, swallowing problems, glossopharyngeal neuralgia

CN X

Vagus;

Location: Exits medulla inferior to glossopharyngeal nerve;

Motor function: Movement within neck, thorax, abdomen;

Sensory function: Sensation in thoracic, abdominal regions; Lesion results in loss of reflexes, paralysis of soft palate, voice disorders

CN XI

Spinal Accessory;

Location: Exits medulla inferior to vagus nerve;

Motor function: Supplies neck muscles; Lesion results in failure to hold head up

CN XII

Hypoglossal;

Location: Exits medulla between pyramids and olives;

Motor function: Supplies tongue muscles; Lesion results in paralysis of tongue, dysarthria

Neurons

Cells in the CNS generating and conducting nerve impulses

Neuroglia

Supporting and protecting nerve cells, active in tissue repair

Cell Body

One of the three primary elements of a neuron

Dendrites

Receive impulses in a neuron

Axon

Conducts impulses in a neuron

Myelin Sheath

Determines nerve conduction speed, formed by oligodendroglial cells in the CNS and Schwann cells in the PNS

Synapse

Space between the axon terminal and a neighboring cell where neurotransmitters are released

Multipolar Neurons

Most common neuron type in the CNS with many processes arising from the cell body

Bipolar Neurons

Found in the retina and inner ear, with two processes arising from the cell body

Unipolar Neurons

Found in the spinal dorsal root ganglia, with a single process arising from the cell body

Astrocytes

Glial cells that act as scaffolding and skeletal support, also involved in engulfing cellular debris

Oligodendrocytes

Glial cells that form the myelin sheath in the CNS

Ependymal Cells

Glial cells lining the inner surface of the ventricles

Microglia

Glial cells that act as scavengers in the CNS, activated during brain injury

Endoneurium

Fibrous connective tissue covering for axons in the PNS

Embryogenesis

Process reaching full complement of nerve cells by the 25th week of gestation, involving neuronal migration and differentiation

Neuroplasticity

Brain's ability to reorganize and optimize functioning, more flexible in developing brains

Axonal Regeneration

Process of nerve fiber regrowth, more successful in the PNS than in the CNS

Acetylcholine

Neurotransmitter regulating muscular activities

Dopamine

Neurotransmitter regulating basal ganglia motor functions

Norepinephrine

Neurotransmitter regulating sleep, attention, and mood

Serotonin

Neurotransmitter regulating arousal, emotions, and pain perception

Brain Tumors

Abnormal growths in the brain, categorized as primary or metastatic, malignant or benign

CN 5 Examinations

Trigeminal

• “Bite down hard.” Palpate temporalis and masseter muscles.

  • Weakness (limited contraction on: R, L, WNL Atrophy on R, L, WNL

• Don’t let me open your jaw.” Press down on the mandible at the midline.

CN 7 Examinations

Facial

• “Do you have any trouble controlling your emotions? Y N

• “Pucker up your lips.”

  • Weak on R, L, WNL Slowness on R, L, WNL

    Groping* Reduced range on R, L, WNL

    Other (explain)

CN 9/10 Examinations

• Glossopharyngel and Vagus

• “Say /ah/ for me.”

  • Palate lags on: R, L, WNL (symmetrical movement): Uvula deviates to: R, L: Slowness: Y, N WNL

• “Do you have trouble with?”:

  • Swallowing: Y, N: Drooling: Y, N: Choking: Y, N

CN 12 Examinations

• Hypoglossal

  • Have the patient sit with his mouth slightly open; observe the tongue at rest.

    Atrophy: R, L, WNL

    Fasiculations: Y, N

    Other (explain

  • “Wag your tongue back and forth as fast as you can.”

    Slowed and clumsy: Y, N, WNL

    Reduced in range on: R, L, WNL

    Groping: Y, N

Name nerve 1

Olfactory / I

Name Nerve 2

Trochlear / IV

Name Nerve 3

Auditory-Vestibular / VIII

Name Nerve 4

Vagus / X

Name Nerve 5

Spinal Accesory / XI

Name Nerve 6

Hypoglossal / XII

Name Nerve 7

Glossopharyngeal / IX

Name Nerve 8

Facial / VII

Name Nerve 9

Abducens / VI

Name Nerve 10

Trigeminal / V

Name Nerve 11

Oculomotor / III

Name Nerve 12

Optic / II

Thalamus

A major function of the ____ is to relay sensorimotor information to the cortex.

Thalamus

The thalamus also contributes to cortically mediated speech and language functions.

Hypothalamus

Regulates all endocrinic functions of the body by releasing hormones.

Hypothalamus

Maintaining body temperature, blood volume, food and water intake, body mass, reproduction, and the regulation of circadian rhythms.

Hypothalamus

Along with the limbic system, it contributes to drives and emotions.

Brainstem

Connects the diencephalon to the spinal cord.

Brainstem

Cranial nerve nuclei are found in the brainstem.

Brainstem

The reticular formation is interconnected with thalamus, spinal cord, and brain.

Brainstem

Forms the reticular activating system (RAS) which controls levels of cortical arousal and consciousness.

Midbrain

Forms a link between the cerebral hemispheres and peripheral and cranial sensory input systems.

Superior colliculus

Connected to the visual relay nucleus of the thalamus and participates in eye movement and visual reflexes.

Inferior colliculus

Part of the auditory pathway from the cochlea in the inner ear to primary auditory cortex in the temporal lobe.

Pons

All descending motor fibers and ascending sensory fibers pass through the pons.

Medulla oblongata

The most caudal part of the brainstem.

Pyramidal tract

Carries motor information from the motor cortex to the spinal cord for activation of skeletal muscles.

Cerebellum

Contributes to the maintenance of equilibrium and coordination of skilled motor activity.

Cerebellum

Does not initiate motor activity.

Cerebellum

Coordinates and modifies the tone, speed, and range of muscular excursions in the execution of skilled motor functions.

Spinal Cord

A bidirectional pathway that transmits motor impulses from brain to skeletal muscles.

Spinal Cord

Carries sensory information (pain, touch, temperature, proprioception) from the body to the brain.

Ventricles of the brain

The primary function of the ventricles is to circulate cerebrospinal fluid (CSF) which is secreted within the ventricles by the choroid plexus.

Hydrocephalus

A condition that arises when there is an interruption in the circulation of CSF within the ventricles.

Arcuate Fasciculus

Connects Wernicke's area to Broca's area in dominant hemisphere.

Corpus Callosum

Connects the right and left cerebral hemispheres.

Meninges

Consists of Dura mater, Arachnoid mater, and Pia mater.

Cranial Nerves

Includes I Olfactory, II Optic, III Oculomotor, IV Trochlear, V Trigeminal, VI Abducens, VII Facial, VIII Acoustic, IX Glossopharyngeal, X Vagus, XI Accessory, XII Hypoglossal.