Sense organs

sense organs consist of the:

eye, ear, nose, and tongue

Eyebrows prevents ___ from entering the eye and shades from _____

sweat, sunlight

What is another name for the eyelids?

Palpebrae

What part of the eye do the eyelids protect?

Anterior

Where do the upper and lower eyelids meet?

Medial & lateral canthi

What is the fleshy structure next to the medial canthus called?

lacrimal caruncle

medial canthus, Lacrimal caruncle

What glands are found in the lacrimal caruncle?

Sebaceous & sweat glands

What supports the eyelids internally?

Tarsal plates

Which muscle opens the eye?

Levator palpebrae superioris (green)

Which muscle closes the eye?

Orbicularis oculi

Why do we blink?

Prevent dehydration

What glands are located in the tarsal plates?

Tarsal glands

What do the tarsal (Meibomian) glands produce?

Meibum

What is the conjunctiva?

Transparent mucous membrane

What does the conjunctiva line?

Eyelids, anterior eyeball

What is the main function of the conjunctiva?

Produces lubricating mucus

What does the lubricating mucus prevent?

Dry eyes

What does the lacrimal apparatus consist of?

Lacrimal gland, ducts

What does the lacrimal gland produce?

Tears

Where do tears drain?

Nasal cavity

What three substances are found in lacrimal fluid?

Mucus, Antibodies, Lysozyme

What enzyme in tears destroys bacteria?

Lysozyme

Besides lubricating the eye, what else do tears do?

CLEAN

Where do the extrinsic eye muscles originate?

Walls of the orbit

Where do the extrinsic eye muscles insert?

Outer eyeball

What are the three main functions of the extrinsic eye muscles?

Follow moving objects, Maintain eye shape, Hold eye in orbit

How many extrinsic eye muscles are there?

6

What are the four rectus muscles?

Superior, Inferior, Medial, Lateral

Yellow

Superior

green

medial

blue

lateral

pink

inferior

What are the two oblique muscles?

Superior, Inferior

Which muscle moves the eye laterally?

Lateral Rectus

Which cranial nerve controls the lateral rectus?

Abducens (CN VI)

Which muscle moves the eye medially?

Medial Rectus

Which cranial nerve controls the medial rectus?

Oculomotor (CN III)

Which muscle rotates the eye medially and elevates it?

Superior Rectus

Which cranial nerve controls the superior rectus?

Oculomotor (CN III)

Which muscle rotates the eye medially and depresses it?

Inferior Rectus

Which cranial nerve controls the inferior rectus?

Oculomotor (CN III)

Which muscle rotates the eye laterally and elevates it?

Inferior oblique

Which cranial nerve controls the inferior oblique?

Oculomotor (CN III)

Which muscle rotates the eye laterally and depresses it?

Superior oblique

Which cranial nerve controls the superior oblique?

Trochlear (CN IV)

Which cranial nerves control the extrinsic eye muscles?

CN III, IV, VI

Abducens

VI

Oculomotor

III

Trochlear

IV

Which structure protects the eye and helps focus light?

Cornea

Which part of the eye gives it its color?

Iris

What does the iris control?

Pupil size

What is the pupil?

Hole in the eye

Which structure focuses light onto the retina?

Lens

What holds the lens in place?

Suspensory ligaments

What is the white part of the eye called?

Sclera

Which layer supplies nutrients to the retina?

Choroid

Which layer contains the photoreceptors?

Retina

Which photoreceptors detect light?

rods

Which photoreceptors detect color?

cones

Which photoreceptors are responsible for night vision?

rods

Which photoreceptors provide peripheral vision?

Rods

Which nerve carries visual information to the brain?

Optic nerve

Which structure is known as the "blind spot"?

Optic nerve

Which lobe of the brain processes visual input?

Occipital lobe

Why do images appear right-side up even though they are upside down on the retina?

Brain compensation

Which photoreceptors become more sensitive in the dark?

Rods

What does the iris do in bright light?

Constricts

Which colors of visible light can the human eye detect?

Red to violet

Can humans see infrared light?

no

Can humans see ultraviolet light?

no

Is the human eye sensitive to polarized light?

no

red

lens

orange

pupil

yellow

conjunctiva

green

cornea

teal

iris

light blue

ciliary muscle

dark blue

suspensory ligament

purple

sclera

sage green

retina

black

fovea

white

optic nerve

What are the three layers of the eyeball?

Fibrous, Vascular, Retinal

Which layer is the outermost layer of the eyeball?

Fibrous

What tissues make up the fibrous layer?

Sclera & cornea

Which layer forms the middle coat of the eyeball?

Vascular

What three structures make up the vascular layer?

Choroid, Ciliary processes and muscles

What do the ciliary processes produce?

Aqueous humor

What do the ciliary muscles control?

Lens shape

Which layer develops from an extension of the brain?

Retinal layer

What does the retinal layer contain?

Photoreceptors

What do photoreceptors do?

Convert light energy

What are the three main structures of the retina?

optic disk, macula, fovea

Which retinal structure is the blind spot?

Optic disk

Which retinal structure contains many rods?

Macula

What is the macula used for?

Reading & faces

Which retinal structure contains only cones?

Fovea

What do cones detect?

Light wavelengths