Test 2 SG

Nervous System

Central Nervous System (CNS)

• CNS = Brain + Spinal Cord

• Brain:

  • Cerebrum: Higher thinking, movement, sensation.

  • Cerebellum: Balance, coordination.

  • Brainstem: Vital functions (breathing, heart rate).

• Spinal Cord: Connects brain to peripheral nerves.

Brainstem Breakdown

• Midbrain

• Pons

• Medulla Oblongata

  • Controls HR, breathing, vasomotor response.

  • Origin of cranial nerves III to XII.

• Controls: Sneezing, coughing, swallowing

• Reticular Formation: Filters sensory input, coordinates motor control.

Reticular Activating System (RAS)

• Brainstem + Reticular Formation + Cerebral Cortex

• Keeps you awake and alert

• Injury here can lead to coma or sleep-wake disruptions.

Autonomic Nervous System (ANS) Integration

• Sympathetic (Fight or Flight):

  • Increases HR, BP, dilates pupils.

• Parasympathetic (Rest & Digest):

  • Decreases HR, increases digestion and salivation.

• Located in:

  • Reticular formation

  • Hypothalamus

  • Brainstem and spinal cord

Peripheral Nervous System (PNS)

• PNS = Cranial + Spinal Nerves

• Components

  • Cranial Nerves (12 pairs)

  • Spinal Nerves (31 pairs)

  • Ganglia + branches

• Nerve Fiber Types

  • Afferent = Toward CNS (sensory)

  • Efferent = Away from CNS (motor)

• Functional Divisions

  • Somatic Nervous System: Voluntary movement

  • Autonomic Nervous System: Involuntary responses

Cranial Nerves Overview

• I Olfactory – Smell

• II Optic – Vision

• VII Facial – Expression & Taste

• Mnemonic for all 12 nerves? “Oh Oh Oh To Touch And Feel Very Green Vegetables, AH!”

Peripheral Nerve Anatomy

• Axons → wrapped in myelin → grouped into fascicles → surrounded by connective tissue.

• Myelin helps speed up nerve signals (like insulation on wires).

• CNS is the boss of all body functions—when it misfires, everyone suffers the consequences!

Neurologic Problems

• Stroke = Brain Attack – Time = Brain!

• Increased ICP (Intracranial Pressure) is a life-threatening emergency.

• Seizures ≠ Epilepsy unless they are recurring without cause.

• TIA is a warning sign – treat it seriously!

Stroke (Cerebrovascular Accident – CVA)

• Sudden interruption of blood flow to the brain

  • Ischemic (block) – 87%

  • Hemorrhagic (bleed)

Types of Strokes

• Ischemic: Blocked artery, Thrombus or embolus

• Hemorrhagic: Bleeding in brain tissue, Ruptured aneurysm or trauma

• TIA (Transient Ischemic Attack): Mini-stroke, resolves in <24 hr, Warning of future stroke

Key Symptoms (FAST)

• Face drooping

• Arm weakness

• Speech difficulty

• Time to call 911

Treatment & Nursing Priorities

• CT scan STAT to rule out bleeding.

• Ischemic → tPA within 3–4.5 hours.

• Hemorrhagic → control BP, surgery if needed.

• Monitor for ICP

• Prevent aspiration (NPO until swallow eval)

Intracranial Pressure (ICP)

• Skull Components:

  • Brain (80%) + CSF (10%) + Blood (10%)

• Monro-Kellie Doctrine: If one increases, the others must decrease to prevent pressure.

Early Signs of ↑ ICP

• Headache

• Nausea/vomiting

• Restlessness

• Blurred vision

Late Signs (Neuro Emergency)

• Cushing's Triad:

  • ↑ Systolic BP (widened pulse pressure)

  • ↓ HR (bradycardia)

  • ↓ RR (irregular breathing)

• Pupillary changes

• Posturing (decorticate, decerebrate)

• Coma

Nursing Care

• Keep head midline

• Elevate HOB 30°

• No coughing, straining

• Monitor neuro status frequently

• Avoid hypotonic fluids! (can worsen cerebral edema)

Seizure Disorders

• Sudden, uncontrolled electrical activity in the brain.

Types

• Generalized: Entire brain; loss of consciousness

  • Tonic-clonic (grand mal): Stiffening + jerking

  • Absence (petit mal): Brief stare, mostly in kids

• Focal: One hemisphere; may remain conscious

• Status Epilepticus

  • Seizure >5 minutes or 2+ without recovery

  • Medical emergency – can cause brain damage

Treatment

• Benzodiazepines (Ativan) for active seizures

• Anticonvulsants (phenytoin, levetiracetam) long-term

• Seizure precautions: padded side rails, O2, suction ready

Nursing Tips

• Turn patient on their side

• Don’t restrain

• Nothing in the mouth

• Time the seizure

• Document postictal (recovery) phase

Headaches

• Migraine

  • Throbbing, unilateral, often with aura

  • Triggers: stress, chocolate, hormones

  • Treatment: triptans, NSAIDs, rest in dark room

• Tension Headache

  • Band-like pressure, bilateral

  • Common with stress and poor posture

• Cluster Headache

  • Intense stabbing pain, often around one eye

  • Occurs in “clusters” over weeks

CUSHING’S TRIAD Mnemonic

• Chewing slower (↓ HR)

• Uncontrolled BP (↑ systolic)

• Slow RR

• It’s your brain’s last-ditch effort to survive pressure!

Ears and Sensory System

• The ear = hearing + balance

• Hearing loss can be conductive or sensorineural — know the difference!

• Vertigo often comes from inner ear issues.

• Safety is key with dizziness, tinnitus, or balance disorders.

Ear Anatomy & Function

3 Major Parts

• Outer Ear: Auricle, auditory canal, Collects sound

• Middle Ear: Tympanic membrane, ossicles (malleus, incus, stapes), Transmits sound via vibration

• Inner Ear: Cochlea, semicircular canals, Hearing + balance

Key Structures

• Cochlea = hearing (hair cells pick up sound waves)

• Semicircular Canals = balance and spatial orientation

• Eustachian Tube: connects middle ear to throat; equalizes pressure

Hearing Loss

Types of Hearing Loss

• Conductive: Problem in outer/middle ear; sound can't reach cochlea, Earwax, fluid, otitis media

• Sensorineural: Damage to inner ear or nerve pathways, Noise exposure, aging, ototoxic meds

Tests

• Weber Test: tuning fork on forehead

  • Conductive: sound louder in affected ear

  • Sensorineural: sound louder in good ear

• Rinne Test: compare bone vs. air conduction

  • Normal: air > bone

  • Conductive: bone > air

Balance & Dizziness

• Vertigo = spinning sensation

  • Often inner ear cause (like Benign Paroxysmal Positional Vertigo – BPPV)

• Dizziness = general unsteadiness

Meniere’s Disease

• Inner ear disorder → excess fluid buildup

• Triad: Vertigo, tinnitus, hearing loss

• Risk for falls and injury!

Treatment

• Diuretics, low-sodium diet, vestibular suppressants (meclizine)

• Fall precautions!

Tinnitus

• Ringing, buzzing, or roaring in the ears

• Often from loud noise exposure or ototoxic meds

• Can be permanent – protect your hearing!

Quick Look at Visual Connections

• CN VIII (Vestibulocochlear): Hearing and balance

• CN II (Optic): Vision

• CN III, IV, VI: Eye movement

• These nerves all help integrate sensory experiences—when damaged, you can get diplopia, nystagmus, or poor balance.

Memory Tips

• Tinnitus Tip: “TINnitus sounds like a tin can buzzing in your ear !”

• Weber/Rinne Quick Trick:

  • Weber = “W” is for Where does the sound go?

  • Rinne = “R” is for Right way (air > bone)

Nursing Priorities for Ear & Balance Disorders

• Fall risk assessment

• Turn head slowly

• Dim lights if photophobia present

• Hearing aids? Check batteries and fit

• Speak clearly, don’t shout

Vision & Eye Disorders

• CN II (Optic Nerve) = Vision

• CN III, IV, VI = Eye movement

• Eye disorders can affect sight, safety, and independence.

• Sudden vision loss = emergency!

Eye Anatomy Refresher

• Sclera: white part of the eye

• Cornea: clear, dome-shaped front layer

• Conjunctiva: thin membrane lining eyelids and eyeball

Internal Structures

• Lens: Focuses light on the retina

• Retina: Converts light to nerve impulses

• Macula: Center of retina – sharp vision

• Optic nerve (CN II): Carries vision signals to the brain

• Aqueous humor: Fluid in front of lens (drainage issues = glaucoma)

• Vitreous humor: Gel in eye that maintains shape

Cranial Nerves & the Eye

• CN II (Optic): Vision (test with Snellen chart)

• CN III (Oculomotor): Pupil constriction, eyelid elevation, most eye movement

• CN IV (Trochlear): Downward eye movement

• CN VI (Abducens): Lateral eye movement

• Mnemonic: “LR6 SO4, all the rest are 3!”

  • Lateral Rectus – CN VI

  • Superior Oblique – CN IV

  • All other eye movements – CN III

Common Eye Conditions

Refractive Disorders

• Myopia: Nearsighted

• Hyperopia: Farsighted

• Presbyopia: Age-related loss of near focus

• Astigmatism: Irregular cornea shape

• Corrected with glasses, contacts, or LASIK

Cataracts

• Cloudy lens = blurry vision

• Gradual onset, may see “halos” or glare

• Surgery = lens replacement

• Nursing Tip: Post-op: No straining, bending, lifting, or rubbing eye

Glaucoma

• ↑ Intraocular Pressure (IOP) damages optic nerve

• Types:

  • Open-angle (chronic) – slow, peripheral vision loss

  • Angle-closure (acute) – sudden pain, nausea, vision loss = emergency!

• Treated with eye drops (beta-blockers, prostaglandins)

• Check IOP regularly!

Macular Degeneration

• Loss of central vision

• Dry: Gradual; no cure

• Wet: Sudden; treated with injections (anti-VEGF)

• Leading cause of vision loss in older adults

Retinal Detachment

• Separation of retina = EMERGENCY

• Symptoms: floaters, flashes, curtain over vision

• Surgery needed to repair

Eye Tests & Assessments

• Snellen Chart: Visual acuity (distance)

• Tonometry: Intraocular pressure (for glaucoma)

• Pupil Reaction (PERRLA): CN III function

• Visual Fields: Peripheral vision

• Ophthalmoscope: Internal eye structures

• PERRLA: Pupils Equal, Round, Reactive to Light and Accommodation

Memory Tricks

• CN Eye Mnemonic: “Two, Three, Four, and Six see the tricks!”

  • CN II – See

  • CN III, IV, VI – Move the eyes

• Pupil Response: “The pupils are the windows to the brain. If they’re unequal, unreactive, or sluggish — something’s wrong!”

Nursing Priorities for Vision Issues

• Fall risk precautions

• Educate on med adherence (especially eye drops)

• Explain surgical prep/post-op (no rubbing, no lifting)

• Protect eyes from trauma or light if dilated

• Ensure accessibility tools for patients with low vision

Cranial Nerves

• 12 cranial nerves that come out of your brain and help you see, smell, chew, smile, hear, taste, and more.

• Think of them like magical wires that run from your brain to different parts of your head and neck.

Cranial Nerves Quick List

• 1 Olfactory: Smell like cookies! - Sensory

• 2 Optic: See the world like a superhero! - Sensory

• 3 Oculomotor: Move your eyeballs around - Motor

• 4 Trochlear: Look at your nose with your eyes - Motor

• 5 Trigeminal: Feel your face and chew your food - Both

• 6 Abducens: Look side to side like you're sneaking - Motor

• 7 Facial: Smile, cry, and taste ice cream! - Both

• 8 Vestibulocochlear: Hear music and balance like a gymnast - Sensory

• 9 Glossopharyngeal: Swallow your snacks and taste - Both

• 10 Vagus: Talk, digest food, and keep calm - Both

• 11 Accessory: Shrug your shoulders like “I don’t know!” - Motor

• 12 Hypoglossal: Stick out your tongue! - Motor

SUPER FUN MNEMONIC (to remember the NAMES)

"Oh Oh Oh To Touch And Feel Very Green Vegetables AH Heaven"

• Olfactory

• Optic

• Oculomotor

• Trochlear

• Trigeminal

• Abducens

• Facial

• Vestibulocochlear

• Glossopharyngeal

• Vagus

• Accessory

• Hypoglossal

HOW TO TELL IF IT’S SENSORY, MOTOR, OR BOTH?

Mnemonic for the FUNCTION:

“Some Say Money Matters But My Brother Says Big Brains Matter Most”

• 1 Sensory

• 2 Sensory

• 3 Motor

• 4 Motor

• 5 Both

• 6 Motor

• 7 Both

• 8 Sensory

• 9 Both

• 10 Both

• 11 Motor

• 12 Motor

BONUS ROUND – Let’s Pretend!

1. You just smelled a fresh-baked cookie… ➡ That’s Olfactory (I)!

2. You look at it to make sure it's chocolate chip… ➡ Optic (II)

3. Your eyes move to follow the cookie as Mom brings it… ➡ Oculomotor (III), Trochlear (IV), and Abducens (VI) all work together!

4. You feel the cookie in your hand and chew it up… ➡ Trigeminal (V)

5. You smile because it’s SO GOOD… ➡ Facial (VII)

6. You hear your brother asking for a bite… ➡ Vestibulocochlear (VIII)

7. You swallow the last bite and taste some frosting… ➡ Glossopharyngeal (IX)

8. You talk and say, “That was yummy!” ➡ Vagus (X)

9. You shrug when asked to share more… ➡ Accessory (XI)

10. You stick out your tongue to tease… ➡ Hypoglossal (XII)

PRACTICE ACTIVITY:

Match the nerve to the action:

1. Seeing stars

2. Tasting lemonade

3. Balancing on one foot

4. Smiling

5. Chewing a burger

6. Shrugging shoulders

7. Smelling flowers

ANSWERS:

1. Optic (II)

2. Glossopharyngeal (IX)

3. Vestibulocochlear (VIII)

4. Facial (VII)

5. Trigeminal (V)

6. Accessory (XI)

7. Olfactory (I)

Electrolyte Balance

Electrolytes = minerals that carry electrical charge. Functions include:

• Nerve conduction

• Muscle contraction ( especially the heart)

• Fluid balance

• Acid-base regulation

Major Electrolytes & Their Normal Ranges

• Sodium (Na): 135–145 mEq/L, Fluid balance, nerve impulses

• Potassium (K): 3.5–5.0 mEq/L, Cardiac & muscle contraction

• Calcium (Ca²): 8.6–10.2 mg/dL, Muscle contraction, blood clotting

• Magnesium (Mg²): 1.5–2.5 mEq/L, Nerve/muscle function, enzyme activity

• Chloride (Cl): 96–106 mEq/L, Works with sodium

• Phosphate (PO₄³): 2.5–4.5 mg/dL, Energy production, bone formation

• Bicarbonate (HCO₃): 22–26 mEq/L, Acid-base buffering

Fluid Balance Essentials

• ICF = Potassium

• ECF = Sodium

• Fluid loss = Electrolyte loss (e.g., vomiting, diarrhea)

• 1 Liter = 1 Kg (2.2 lbs) → Best measure: Daily weights

Electrolyte Imbalances: Mnemonics & Signs

Hyponatremia → SALT LOSS

• Stupor/coma

• Anorexia

• Lethargy

• Tendon reflexes ↓

• Limp muscles

• Orthostatic hypotension

• Seizures/headache

• Stomach cramping

Hyperkalemia → MURDER

• Muscle weakness

• Urine changes

• Respiratory distress

• Decreased cardiac contractility

• ECG changes

• Reflexes hyper/absent

Nursing Priorities:

• Monitor ECG

• Replace or restrict as needed

• Monitor labs & symptoms

• Educate about foods rich in K, Ca², etc.

Hormones That Regulate Fluids & Electrolytes

• ADH: Retains water

• Aldosterone: Retains Na, excretes K

• PTH: Increases Ca²

• Calcitonin: Decreases Ca²

• Vitamin D: Helps absorb Ca²

• ANP/BNP: Reduces fluid volume (opposes RAAS)

Quick Lab Clues

• ↑ Hematocrit, ↑ BUN = Dehydration

• ↓ Hematocrit, ↓ BUN = Fluid overload

• Urine output < 30 mL/hr = Kidney alert

Nursing Mnemonics

Hypovolemia → DRY

• Dehydration signs

• Reduced BP & urine

• You feel dizzy & confused

Hypervolemia → FLOOD

• Fluid overload

• Lung sounds (crackles)

• Overworked heart

• Output (monitor closely)

• Daily weights & diuretics