NURS 203: Unit 5 - Neurological System: Sensory Response(Lab 5 Review)

2 Sensory Pathways of the Body

- Spinothalmic tract

- Posterior (dorsal) columns

Spinothalmic Tract

The sensory pathway that contains sensory fibres that transmit the sensations of pain, temperature, and crude or light touch

Posterior (Dorsal) Columns

The sensory pathway that contains the sensory fibres that conduct the sensations of position, vibration, and finely localized touch

Cranial Nerves

- 12 pairs of nerves that carry messages to and from the brain

- Considered as lower motor neurons

12 Cranial Nerves

1.) Olfactory

2.) Optic

3.) Oculomotor

4.) Trochlear

5.) Trigeminal

6.) Abducens

7.) Facial

8.) Acoustic (Vestibulocochlear)

9.) Glossopharyngeal

10.) Vagus

11.) Spinal Accessory

12.) Hypoglossal

(Oh Only Octopuses Try Taming Adventurous Foxes Admiring Gloomy Vampires Stalking Humans)

Some Say Marry Money But My Brother Says Big Brains Matter More

1. - Sensory (Olfactory nerve - CN I)

2. - Sensory (Optic nerve - CN II)

3. - Motor (Oculomotor nerve - CN III)

4. - Motor (Trochlear nerve - CN IV)

5. - Both (Trigeminal nerve - CN V)

6. - Motor (Abducens nerve - CN VI)

7. - Both (Facial nerve - CN VII)

8. - Sensory (Acoustic (vestibulocochlear) nerve - CN VIII)

9. - Both (Glossopharyngeal nerve CN IX)

10. - Both (Vagus nerve - CN X)

11. - Motor (Spinal accessory nerve - CN XI)

12. - Motor (Hypoglossal nerve - CN XII)

Function of the Olfactory Nerve (CN I)

Smell

What to Assess for the Olfactory Nerve

- Patency

- Sense of smell

Anosmia

Decrease or loss of smell

Function of the Optic Nerve (CN II)

Vision

What to Assess for the Optic Nerve

- Visual acuity

- Ocular fundus

Function of the Oculomotor Nerve (CN III)

- Controls most extraocular movement

- Opening of eyelids

- Pupil constriction

- Controls shape of lens

Function of the Trochlear Nerve (CN IV)

Downward/inward movement of the eye

Function of the Abducens Nerve (CN VI)

Lateral movement of the eye

What to Assess for the Oculomotor, Trochlear, and Abducens Nerve

- Palpebral fissures

- Pupils

- Extraoccular movements

Nystagmus

Back-and-forth oscillation of the eyes

Characteristics to Note for a Nystagmus

- Presence in one or both eyes

- Type of movement

- Amplitude

- Frequency

- Plane

Function of the Trigeminal Nerve (CN V)

- Muscles of mastication

- Sensation of face and scalp, cornea, and mucous membranes of the mouth and nose

What to Assess for the Trigeminal Nerve

- Motor function

- Sensory function

- Corneal reflex

3 Areas to Assess the Sensory Function of the Trigeminal Nerve

- Forehead (ophthalmic)

- Cheek (maxillary)

- Jaw (mandibular)

Corneal Reflex

- A reflex that makes someone blink in response to corneal stimulation by a cotton wisp

- Only tested if someone has an abnormal facial sensation or movements

Function of the Facial Nerve (CN VII)

- Facial muscles

- Closing of the eyes

- Labial speech

- Closing of the mouth

- Taste (anterior 2/3rds of the tongue)

- Saliva and tear secretin

What to Assess for the Facial Nerve

- Mobility

- Facial symmetry

- Sense of taste (only if there is facial nerve injury)

Function of the Acoustic (Vestibulocochlear) Nerve (CN VIII)

Hearing and equilibrium

What to Assess for the Acoustic Nerve

- Hearing acuity

- Whispered voice test

- Weber test

- Rinne test

Function of the Glossopharyngeal Nerve (CN IX)

- Phonation

- Swallowing

- Taste (posterior 1/3rds of the tongue)

- Gag reflex

- Parotid gland

- Carotid reflex

Function of the Vagus Nerve (CN X)

- Talking

- Swallowing

- General sensation from carotid body, carotid sinus, pharynx, and viscera

- Carotid reflex

What to Assess for the Glossopharyngeal and Vagus Nerve

- Tongue

- Gag reflex

Function of Accessory Nerve (CN XI)

Movement of trapezius and sternocleidomastoid muscles

What to Assess for the Accessory Nerve

- Muscle symmetry

- Muscle strength

Function of the Hypoglossal Nerve (CN XII)

Movement of tongue

What to Assess for the Hypoglossal Nerve

- Tongue

- "Light, light, dynamite"

Objective Data to Assess for the Sensory System

- Spinothalmic tract

- Posterior column tract

What to Assess for the Spinothalmic Tract

- Pain

- Temperature

- Light touch

What to Assess for the Posterior Column Tract

- Vibration

- Kinaesthesia

- Fine touch

What to Assess for Fine Touch

- Stereognosis

- Graphaesthesia

- Two-point discrimination

- Extinction

- Point location

Stereognosis

The ability to recognize objects by feeling their forms, sizes, and weights, with the eyes closed

Graphaesthesia

The ability to "read" a number by having it traced on the skin

Two-Point Discrimination

The ability to distinguish the separation of two simultaneous pinpoints on the skin

Major External Anatomy of the Eyes

- Eyelids

- Palpebral fissure

- Limbus

- Canthus

- Caruncle

- Tarsal plates

- Meibomian glands

- Conjunctiva

- Lacrimal apparatus

(Mnemonic Here)

Eyelids

Two movable flaps of skin that further protect the eye from injury, strong light, and dust

Palpebral Fissure

The elliptical open space between the eyelids

Limbus

The border between cornea and sclera

Canthus

The corner of the eye; the angle where the eyelids meet

Caruncle

A small fleshy mass containing sebaceous glands

Tarsal Plates

Connective tissue within the upper eyelids that gives it shape

Meibomian Glands

Modified sebaceous glands in the tarsal plates that secrete an oily lubricating material onto the eyelids

Conjunctiva

A transparent protective covering of the eye

Palpebral Conjunctiva

The conjunctiva that lines the eyelids and is clear, with many small blood vessels

Bulbar Conjunctiva

The conjunctiva that overlies the opeyeball, with the white sclera showing through

Lacrimal Apparatus

The structures in the eye that provides constant irrigation to keep the conjunctiva and cornea moist and lubricated

4 Straight Muscles of the Eye

- Superior rectus

- Inferior rectus

- Lateral rectus

- Medial rectus

2 Oblique Muscles of the Eye

- Superior oblique

- Inferior oblique

3 Cranial Nerves the Stimulates the Extraocular Muscles

- Abducens

- Trochlear

- Oculomotor

3 Layers/Coats of the Eye

- Outer fibrous sclera

- Middle vascular choroid

- Inner nervous retina

Sclera

A tough, protective, white covering of the eye that makes up its outer layer; the white part of the eye

Major Structures in the Outer Fibrous Sclera

Cornea

Cornea

The clear tissue that covers the front of the eye

Choroid

The middle, vascular layer of the eye, between the retina and the sclera

Major Structures in the Middle Vascular Choroid

- Ciliary body

- Iris

- Pupil

- Lens

- Anterior chamber

- Posterior Chamber

Ciliary Body

Structure surrounding the lens that connects the choroid and iris. It contains ciliary muscles, which control the shape of the lens, and it secretes aqueous humor.

Iris

A ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening

Pupil

The opening through which light enters the eye; round and regular

Lens

A transparent biconvex disc located just behind the pupil and serves as a refracting medium that keeps viewed objects in continual focus on the retina

Anterior Chamber

- The chamber located posterior to the cornea and anterior to the iris and lens

- Contains clear, watery aqueous humor produced by the ciliary body which delivers nutrients to the surrounding tissues drain metabolic wastes

Posterior Chamber

The chamber located behind the iris to the sides of the lens

Major Structures of the Inner Nervous Retina

- Optic disc

- Retina vessels

- Macula

- Fovea centralis

Retina

The visual receptive layer of the eye in which light waves are changed into nerve impulses

Optic Disc

The area in which fibres from the retina converge to form the optic nerve

Retinal Vessels

Vessels of the retina, which normally include a paired artery and extend to each quadrant, growing progressively smaller in caliber as they reach the periphery

Macula

Round darker area of the ocular fundus that mediates vision only from the central visual field

Fovea Centralis

Tiny pit or depression in the retina that is the region of clearest vision

Pupillary Light Reflex

The normal constriction of the pupils when bright light shines on the retina

Fixation

A reflex direction of the eye toward an object attracting a person's attention

Accomodation

The adaptation of the eye for near vision by increasing the curvature of the lens through movement of the ciliary muscles

Developmental Considerations Related to the Eyes for Infants and Children

- Peripheral vision is intact for newborns

- Can can fixate on a single image with both eyes simultaneously (binocularity) by 3-4 months

- Macula matures at 8 months

- Decrease in farsightedness by 7-8 years

- The eyeball reaches adult size by 8 years

Developmental Considerations Related to the Eyes for Adults

- Presbyopia

- Macular degeneration

- Cataracts

- Glaucoma

- Diabetic retinopathy

Myopia

Nearsightedness

Hyperopia

Farsightedness

Presbyopia

A condition in which the lens loses elasticity, becoming hard and glasslike, which decreases the lens's ability to change shape to accommodate for near vision

Cataracts

Clouding of the lens

Glaucoma

Increased intraocular pressure

Diabetic Retinopathy

A condition in which the blood vessels in the retina becomes blocked or damaged due to a high blood sugar level, eventually leading to loss of vision

Subjective Data to Assess for the Eyes

- Visual difficulty

- Pain

- Strabismus/diplopia

- Redness/swelling

- Watering/discharge

- History of ocular problems

- Glaucoma

- Use of glasses or contact lenses

- Self-care behaviours

- Medications

- Coping with vision changes/loss

Strabismus

A deviation in the anteroposterior axis of the eye

Diplopia

The perception of two images of a single object

Additional Health History Questions Related to the Eye for Infants/Children

- Mother's vaginal infection during delivery

- Developmental milestones

- Routine vision testing

- Safety measures

Additional Health History Questions Related to the Eye for Older Adults

- Movement and visual difficulty

- Glaucoma testing

- Cataracts

- Dryness of eyes

- Decreased activities

Equipment Needed for an Objective Physical Exam of the Eye

- Snellen eye chart

- Handheld visual screener

- Opaque card or occluder

- Penlight

- Applicator stick

- Opthalmascope

Objective Assessments for an Eye Exam

- External ocular structures

- Central visual acuity

- Visual fields

- Extraocular muscle function

- Anterior ocular structures

- Ocular fundus

What to Inspect for External Ocular Structures

- Eyebrows

- Eyelids

- Eyeballs

- Conjunctiva and sclera

- Lacrimal apparatus

Snellen Eye Chart

Eye chart used by eye care professionals and others to measure visual acuity

Confrontation Test

A gross measure of peripheral vision where the patient's peripheral vision is compared with your own, if yours is normal; tests visual fields

What to Inspect for Extraocular Muscle Function

- Corneal light reflex

- Cover-uncover test

- Diagnostic positions

Corneal Light Reflex (Hirschberg's Test)

A test in which you shine a light toward the patient's eyes and assess the reflection of the light on the corneas; they should be on the same spot on each eye

Cover-Uncover Test

- A test in which you cover one eye of the patient and ask them to stare straight ahead

- Detects small degrees of deviated alignment

- A normal response is a steady fixed gaze of the steady eye

Diagnostic Positions Test

- A test in which you move your fingers through the six cardinal positions of gaze and ask the patient to follow it

- Reveals any muscle weakness during movement

- A normal response is parallel tracking of the object with both eyes.

What to Inspect for Anterior Ocular Structures

- Cornea

- Lens

- Iris

- Pupil

PERRLA

- Pupils equal

- Round

- Reactive to light and accommodation

What to Inspect for the Occular Fundus

- Red reflex

- Optic disc

- Retinal vessels

- Fundus background

- Macula