Eye, Nose, & Nasal senses

ID/Describe this muscle

Levator Palpebrae Superioris

Origin - Greater wing of sphenoid in orbit

Insertion - Components of upper eyelid

Innervation - Oculomotor N (dmg = drooping eyelid)

Fxn - Elevate upper eyelid

What are the movements of the eye

Elevation - Superiorly

Depression - Inferiorly

Adduction - Medially

Abduction - Laterally

External/Internal rotation

ID/Describe this muscle

Superior Rectus (deep to levator palpebrae superioris)

Origin - Sup part common tendinous ring

Insertion - Sclera of eye / Ant .5 superiorly

Innervation - Oculomotor N

Fxn - Elevation* / Adduction / Medial rotate eyeball

ID/Describe this muscle

Inferior Rectus

Origin - Inferior part common tendinous ring

Insertion - Sclera of eye / Ant .5 inferiorly

Innervation - Oculomotor N

Fxn - Depress* / Adduct / Lat rotate eyeball

ID/Describe the muscle

Medial Rectus

Origin - Medial part common tendinous ring

Insertion - Sclera of eye / Ant .5 medially

Innervation - Oculomotor N

Fxn - Adduct eyeball

ID/Describe this muscle

Lateral Rectus

Origin - Lateral part common tendinous ring

Insertion - Sclera of eye / Ant .5 laterally

Innervation - Abducens N

Fxn - Abduct eyeball

ID/Describe this muscle

Superior Oblique (goes through tendinous loop - trochlea + 90 degree bend in muscle)

Origin - Sphenoid bone

Insertion - Superior surface eye, posteriorly

Innervation - Trochlear N

Fxn - Depress / Abduct / Medially rotate eyeball

ID/Describe this muscle

Inferior Oblique (“Cradles” eyeball)

Origin - Medial floor bony orbit

Insertion - Sclera of eye, laterally

Innervation - Oculomotor N

Fxn - Elevate / Abduct / Laterally rotate eyeball

How to clinically test the muscles of the eyeball

Superior + Inferior Rectus

1: “look laterally”, reset or prep muscle so that second movement allows for testing of a specific muscle

Aligns axis of eyeball to long axes of muscles

2: movement in BOLD is what you are looking for the pt to do

Superior + Inferior oblique 

Same but “look medially”

Follow finger to follow for all movement

What is the lacrimal apparatus responsible for

Production, Movement, Drainage of fluid from surface of eyeball (tears)

What composes the Lacrimal Apparatus

Lacrimal gland, Lacrimal ducts, Puncta, Lacrimal canalciculi, Lacrimal sac, Nasolacrimal duct

Describe the Lacrimal Gland

Located in superolateral region of orbit

Produces tears/fluids

Fluid moves from gland to eye via ducts

Fluid continually secreted/moved across eye when blink

What is most medial on the eye

fluid moves over eye towards medial side of orbit to Lacrimal Puncta

Medial side of orbit + Opening fluid enters to reach lacrimal canaliculi

What are the small tubs associated with upper/lower eyelid

Lacrimal canaliculi (carry fluid to lacrimal sac)

Where is the Lacrimal Sac located

Medial to orbit + Lateral to nose

Where does the lacrimal sac drain

It drains into the Nasolacrimal Duct

Duct runs along maxilla and dumps tears into nasal cavity (why your nose runs when u cry)

Describe the Optic N

CN 2, Large N, Post wall of eyeball, Runs through Optic Canal

Describe the Oculomotor N

Enters orbit via Superior Orbital Fissure

Divides into a sup/inf division

Describe Trochlear N

Innervates: Superior Oblique

Enters orbit via Superior Orbital Fissure

Describe the Abducens N

Innervates: Lateral Rectus

Enters orbit via Superior Orbital Fissure

Describe the walls of the eyeball

3 layers:

Outer Fibrous Layer → Sclera + Cornea

Middle Vascular Layer → Choroid + Cilliary Body + Iris

Inner Layer → Optic part of retina + Nonvisual part of retina

Describe the Sclera of the Eye (outer)

“Whites” of your eye

Fibrous CT

Post placed

Protects and shapes eye

Describe the Cornea of the Eye (outer)

Transparent ant portion

Allows light to enter eye

Describe the Choroid of the Eye (middle)

Supplies blood to all layers

Brown pigment to absorb light, prevent scatter, & visual confusion

Firmly attached to retina / Loosely attached to sclera

Describe the Cillary Body of the Eye (middle)

Thickened ring of tissue surrounding lens

Contains: Ciliary Muscles + Processes

Suspensory ligament

Describe the Iris of the Eye (middle)

Colored portion of eye, surrounds the pupil

Projects outward from ciliary body

Contains 2 muscles that control size of pupil: Sphincter pupillae + Dilator pupillae

Describe the Optic part of the retina of the Eye (inner)

Delicate 2-layered membrane

Outer pigmented layer → No photoreceptors

Inner neural layer → Photoreceptors / Sensitive to light

Describe the Pigmented Layer of Retina (optic part)

One cell thick, firmly attached to choroid

No photoreceptors

Absorbs light and prevents scattering

Stores Vit A

Describe the Neural Layer of Retina (optic part)

Contains: Photoreceptors, Rods/Cones, Other neurons involved in transmitting impulses to optic N

Only attached to pigmented layer around optic N and Ora Serrata (what detaches in detached retina)

Describe Rods and Cones (optic part)

Photoreceptor Cells

Rods → Responsible for detecting Black and White

Cones → Responsible for detecting Colors

Describe the Optic N and Optic Disc (optic part)

Optic N: Exits eyeball at back of eyeball

Optic Disc: Where Optic N extis retina, No photoreceptor cells, “Blind Spot”

Describe the Macula Lutea (optic part)

Lat to Optic Disc, Small area, Yellowish color

Central depression → Fovea Centralis

Describe the Fovea Centralis (optic part)

Depression in back of eye → Thinnest portion of Retina

HIGH visual sensitivity

High concentration of cones, color and bright light

Describe the Nonvisual part of retina 

Covers internal surface of ciliary body and iris

No light sensitivecells

Junction B/T nonvisual and optic part (Ora serrata)

Describe this chamber

Anterior Chamber

Space directly behind cornea

Ant to iris

Filled with liquid → Aqueous humor

Describe this chamber

Posterior Chamber, post to iris / ant to lens

SMALL

Filled with liquid → Aqueous humor / Secreted here

Continuous w/ anterior chamber via pupil (Aqueous humor exits posterior chamber to enter anterior chamber)

What is Aqueous Humor

Found in Ant/Post chambers of eye

Supplies nutrients to cornea and lens

Maintains intra-ocular pressure

Absorbed via Scleral Venous Sinus in ant chamber

Problems w/ production or absorption of aqueous humor can cause intraocular pressure to increase → Glaucoma

Rise in pressure - compression of retina and blood supply to retina

Describe this chamber

Vitreous chamber, post to lens

Filled w/ gelatinous vitreous body (humor) / gives shape to eyeball

What are the general fxns of the interal eye structures

Amount of light entering into the eye

Changes in the shape of lens to focus light onto the retina

ID/Describe

Pupil - central opening in the iris

Can change shape as muscels in iris contract or relax → Dilate & Constrict

ID/Describe

Sphincter Pupillae

Smooth muscle fibers in circular pattern

PNS control

Contraction constricts pupil

ID/Describe

Dilater Pupillae

Smooth muscle fibers in circular pattern

PNS control

Contraction dilates pupil

ID/Describe

Lens, attached cirumferentially to muscles associated w/ outer wall of eye

fxn: focus light entering eye

Distance focus - Ovoid shaped lens

Nearby focus - Round shaped lens

ID/Describe

Ciliary Body, contains ciliary muscle (Triangle shape extension of choroid)

Attach to lens via suspensory lig

Work to change shape of lens

Leads to changes in how light entering eye is focused

ID/Describe

Ciliary Muscles

Smooth muscle fibers, longitudinally, circular, and radial in orientation

PNS control

When they contract, decrease size of ring formed by ciliary body

ID/Describe

Ciliary Processes

Ridges that project from inner surface of ciliary body

Zonular fibers extend off processes → Collectively form Suspensory Ligament that attach to lens

What are the fxns of the ciliary body

Describe the Nasal Cavity

Uppermost part of resp tract

House olfactory receptors

Held open by bone & cartilage

Small ant region (External nose)

Large post region (Within skull)

What are the general fxns of the Nasal Cavity

House Olfactory receptors

Adjust temp & humidity of respired air (rich blood supply)

Filter air through hair

Capture foreign materialy in mucus (moved by ciliated epithelial cells

What is the green region

Nasal Vestible

Internal to nares, skin, hair follicles

What is the blue region

Respiratory Region

Largest, rich neurovascular supply, respiratory epithelium, ciliated cells, mucous cells

What is the pink region

Olfactory Region

Small, superior most, olfactory epithelium & receptors

What are the Nasal Cavity Boundaries

In half - Nasal Septum

Oral Cavity - Hard palate

Cranial Cavity - Frontal, Ethmoid, Sphenoid bones

Lateral Wall

Conchae - increased SA, Divide nasal cavity into 4 air channels

Skeletal Framework of the Nasal Cavity

Unpaired: Ethmoid, Sphenoid, Frontal, Vomer

Paired: Nasal, Maxillary, Palatine, Lacrimal, Inf nasal concha

What makes up the Lat wall of the Nasal Cavity

Superior, Middle, Inferior nasal concha of ethmoid

What openings are found in the Lat wall of Nasal Cavity

Nasolacrimal Duct + Paranasal Sinuses

Describe a normal + abnormal paranasal sinuses

Norm - Ciliated, respiratory mucus secreting / open into nasal cavities

Infected - Inflammed respiratory mucosa / blockage and fluid / bacteria, fungi, etc grow

PND can happen

Describe the Nasal Septum

Medial wall, bone + cartilage

Posteriorly: Perp plate of ethmoid, vomer, small contributions from nasal/frontal bone

Anterioly: Septal nasal cartilage

What is the floor of the Nasal Cavity

Soft tissue of external nose

Hard palate → Maxilla + Palatine bone

What is the roof of the Nasal Cavity

Superiorly - Ethmoid Bone (cribiform plate)

Anteriorly - Frontal + Nasal bone, Lateral process septal cartilage, Major alar cartilage

Posteriorly - Sphenoid, Medial pterygoid plate, Vomer

Describe the Ethmoid

Contributes towards → roof, lateral/medial walls, ethmoidal sinuses

Ethmoidal labyrinths → laterally, linked superiorly via cribifrom plate

Perp plate → vert, upper portion of nasal septum

What makes up the external nose

Bone: Nasal, Maxillary, Frontal

Cartilage: Single septal cartilage, Lateral processes of septal cart, Major + Minor alar

What is the Olfactory N

Formed from axons from olfactory sensory neurons

Through cribifom plate

Synapse w/ neurons in olfactory bulb

Sensory info sent to brain via olfactory tract

What is the pathway for the sense of smell