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If I only had a brain!... And cranial nerves!

Terms in this set (75)

Cerebrum
Composed of right & left hemisphere & divided into 4 lobes.
4 lobes of the cerebrum
1. Frontal
2. Parietal
3. Temporal
4. Occipital
Pre-Frontal Lobe
Area of concentration, motivation. Ability to formulate goals & plan. Ability to initiate, maintain or terminate actions. Ability to self monitor. Ability to use feedback.
Frontal Lobe
Primary motor area, provides conscious control of skeletal muscle. Memory retention, voluntary eye movement. Also contains Broca area.
Broca Area of Frontal lobe
Coordinates the complex muscular activity that makes speech possible.
Temporal Lobe
Integrates somatic, visual & auditory data. Left temporal - Spoken language memories (Wernicke's Speech Area ) Right temporal - Other sound memories.
Wernicke Area
Comprehension - integrates auditory language/understanding of spoken words.
Parietal lobe
Interprets spatial information - Concept formation & abstract thinkings. Proprioception. Right & Left orientation. Mathematics
Contains the sensory cortex - impulses from skin (touch), Pain, Temperature.
Occipital Lobe
Processing of sight. Interprets impulses from retina. Visual memories stored here. Registers visual images.
Brain Stem
Composed of Midbrain, pons, medulla oblongata. Ascending & Descending fibers pass through. Contains centers for sneezing, coughing, hiccuping, vomiting, sucking & swallowing. Reflexes involving the eyes.
Pons
Links cerebellum & rest of the nervous system. Cranial Nerve V & VIII originate from.
Medulla Oblongata
Contains vital centers: Respiratory, Vasomotor, Cardiac Function. Cranial nerves IX & XII arise from medulla.
Basal Ganglia
Near lateral ventricles of both cerebral hemispheres. Controls & facilitates learned & automatic movements.
Thalamus
Below Basal ganglia. Relays sensory & motor input to and from the cerebrum. Cranial nerve II arises from thalamus. Combines with hypothalamus to form the diencephalon.
Hypothalamus
Below thalamus. Regulates endocrine & autonomic functions: blood pressure, temperature, fluid & electrolyte balance, body weight. Combines with thalamus to form the diencephalon.
Limbic system
Located near the inner surfaces of the cerebral hemispheres. Concerned with emotion, aggression, feeding behavior, sexual responses.
Reticular formation
Located in brainstem. Is a group of neurons and axons from medulla to thalamus & hypothalamus the relay sensory information & influence excitatory and inhibitory control of spinal motor neurons. Controls vasomotor & respiratory activity.
Reticular Activating System RAS
Responsible for regulation of arousal & sleep/wake cycle.
Cerebellum
In the posterior part of cranial fossa, inferior to occipital lobe. Coordinates voluntary movement & maintains trunk stability & equilibrium. Receives information from cerebral cortex, muscles, joints, ears. Maintains muscle tone.
Meninges
Protective structure with 3 layers: Dura Mater, Arachnoid, Pia mater.
Dura Mater
Outer layer with connective tissue affixing to skull.
Arachnoid
delicate middle membrane
Subarachnoid space
Area between the arachnoid & pia mater that is filled with CSF. Arteries, veins, etc. pass through.
Pia Mater
Thin fibrous tissue that is impermeable to fluid & is firmly attached to the brain. Works with the other meningeal layers to protect and cushion the brain. Allows blood vessels to pass through and nourish the brain. Functions as a lymphatic system for the brain. When the pia mater becomes irritated and inflamed the result is meningitis.
Falx Cerebri
fold of the dura that separates the two cerebral hemispheres and slows expansion of brain tissue in conditions such as rapidly growing tumor or acute hemorrhage.
Tentorium cerebelli
fold of dura that separates the cerebral hemispheres from the posterior fossa.
Posterior Fossa
Contains the brainstem & cerebellum
Circle of Willis
Acts as a safety valve. When pressure changes are present or possible thrombus - can regulate cerebral blood flow.
Cerebrospinal Fluid
Supports tissue, cushions shock, carries nutrients. 500 ml. produced daily. 100 to 160 ml. normally present at all times. RBS should not be present.
Normal pH of CSF
7.35
Normal glucose of CSF
45 to 74
ICP
Intracranial Pressure - the presure exerted in the cranium by its contents. WNL: 5 to 15.
MAP
Mean arterial Pressure: SBP+(2XDBP)/3
CPP
Cranial Perfusion Pressure: Map-ICP CPP of 50 is lowest adequate cerebral perfusion. CPP 30 or < is not compatible with life.
#1 sign and symptom of increased ICP?
Change in level of consciousness.
Cushing Triad
1. Increased blood pressure.
2. widening pulse pressure - slow, bounding & bradycardic.
3. Irregular breathing pattern.
* Stupor
Cheyne-Stokes Respirations
Pattern of breathing that alternates period of apnea and deep rapid breathing.
Kussmaul Respirations
Deep-rapid breathing - trying to metabolize (blow off) acidosis (elevated CO2).
infratentorial herniation
Expansion of mass lesions in the cerebrum that forces brain to herniate through the opening created by the brainstem.
Babinski Sign
Firmly storking sole of foot. Big toe moves upward or toward the top of surface of foot while other toes fan out. Normal in children up to 2 years. Abnormal finding after. Notes change in CNS function. Present on one side denotes damage on opposite side of brain.
Pronator Drift
Demonstrated by downward drifting of the arm or pronation of the palm
Strabismus
Crossed eyed: eyes don't look in exactly that same direction at the same time due to unequal pulling of eye muscles.
Anisocoria
Pupils that are unequal.
Papilledema
Edematous optic disc seen in retinal examination
Vasogenic Cerebral Edema
Most common type of cerebral edema. Occurs mainly in white mater and is characterized by leaking of macromolecules from the capillaries into the surrounding extracellular spaces.
Cytotoxic Cerebral Edema
Results from disruption of the integrity of the cell membranes, caused by destructive lesions or trauma with hypoxia, anoxia and syndrome of innappropriate SIADH secretion.
Interstitial Cerebral Edema
Usually a result of hydrocephalus - the build-up of fluid in the brain that is manifested by ventricular enlargement. Possible due to increased production, obstruction of outflow or inability to reabsorb CSF.
Decorticate (Flexor)
Flexion of arms, wrist & fingers - adduction in upper extremities. Extension, internal rotation & plantar flexion in lower extremities.
Decerebrate (extensor)
4 extremities in rigid extension. Hyperpronation of forearm & plantar flexion in feet.
Mediation treatment of ICP?
1. Mannitol (Osmitrol).
2. Hypertonic Saline Solution.
3. Corticosteroids (Dexamethasone)
Mannitol in treatment of ICP?
Osmotic diuretic given IV that reduces ICP 2 ways:
1. Plasma expansion - reduces hematocrit & blood viscosity. Causes increased cerebral blood flow & increased cerebral oxygen.
2. Osmotic effect - causes vascular osmotic gradient, which makes fluid move from tissue into blood vessels, which decreases ICP. (May be contraindicated with renal insufficiency.)
Hypertonic Saline Solutions in treatment of ICP?
Pulls fluid out of edematous swolen brain cells & into vessels. Requires close monitoring of blood pressure & seru electrolytes.
Corticosteroids in treatment of ICP?
Treats vasogenic edema.
When do you not use Corticosteroids?
In cases of head injury.
What are complications in relation of corticosteroid use?
Hyperglycemia, increased risk for infection, gastrointestinal bleeding. Make sure to monitor fluid intake & check blood glucose at least every 6 hours.
Concurrent treatment of corticosteroids & antacids?
H2 receptor blockers (Cimetidine), Proton pump inhbitors (Omeprazole) - to prevent GI ulcers & bleeding.
High doses of barbiturates?
Penobarbitol, Thiopenial - decreases cerebral metabolism which decreases ICP & decreases cerebral edema. Dosed per readings at bedside of EEG & ICP.
Nutritional therapy with ICP?
1. Patient is hypermetabolic & hyper catabolic with need for increased glucose.
2. Should be guided by fluid & electrolyte balance.
Why not use D5W?
Because it is a hypotonic solution - causes a shift from vascular to interstitial and may increase ICP.
Other treatment interventions with ICP?
1. Keep temperature at 36 - 37 degrees celcius. (Antipyretics, cooling blanket, etc.)
2. Do not let patient shiver - May need sedative.
3. Pain management without sedation.
4. Quiet, calm environment without noise and interruptions.
5. Decreased stimulation.
Compression of cranial nerve III
Dilated pupil on affected side. Slow or non-reactive to light, Not able to move eyes up, drooping eyelid(s). Neurological emergency - identifies herniation of the brain.
What other nerves may be involved?
Cranial nerves II (optic), IV (trochlear) and VI (abducens)
Other visual changes
Blurred vision, double vision, changes in extraoccular eye movement.
Cranial nerve I
Olfactory - arises from anterior ventral of cerebrum. Sense of smell.
Cranial Nerve II
Optic - arises from thalamus - vision.
Cranial Nerve III
Oculomotor - arises from midbrain - motor function: moves eyes, raises eyelids, constricts pupils, controls curvature of lens. Parasympathetic - smooth muscle of eyeball.
Cranial Nerve IV
Trochlear - arises from midbrain - moves eyes down & laterally
Cranial Nerve V
Trigeminal - arises from pons - sensory - forehead, eye, nasal cavity, face, teeth, surface of jaw, mucos of mouth, taste anterior tongue - motor - muscles of mastication.
Cranial Nerve VI
Abducens - arises from pons - lateral rectus of eyes - moves eyes laterally.
Cranial Nerve VII - 7
Facial - arises from junction of pons & medulla - sensory - taste from anterior 2/3 of tongue. motor - muscles of facial expression also hearing & pulling down of mandible.
Cranial Nerve VIII
Vestibulochlear (Auditory) - arises from junction of pons & medulla - hearing & balance.
Cranial Nerve IX
Glossopharyngeal - arises from medulla - parotid glans, carotid artery control, skin of external ear, inner tympanec membrane, taste posterior tongue & superior pharyngeal muscles.
Cranial Nerve X
Vagus - arises from medulla - sensory - much of visera of thorax & abdomen - motor - larynx & middle inferior pharyngeal muscles - parasympathetic - heart, lungs, most of digestive system.
Cranial Nerve XI
Spinal Accessory - arises from medula &superior spinal segments - sternodeidomastoid & Trapezus.
Cranial Nerve XII
Hypoglossal - arises from medulla - innervation of tongue muscle.
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