Chapter 17 Special Senses

which cranial nerve innervates the lacrimal gland

#7 facial nerve

what are the functions of the choroid

1. 2.

name 3 intrinsic eye muscles

1. 2. 3.

name the 3 types of cones

1. 2. 3.

3 tissue layers or tunics of the eye

1. Fibrous tunic 2. vascular tunic (uvea) 3. nervous tunic

2 types of interior eye spaces

1. anterior cavity 2. posterior cavity

what are the 2 chambers in the anterior cavity

1. anterior chamber 2. posterior chamber

the ciliary body contains two important structures called

1. ciliary muscle 2. ciliary process

which 2 intrinsic eye muscles are located in the iris

1. dilator pupillae 2. constrictor pupillae

4 layers that make up the retina

1. pigmented epithelium 2. photoreceptors 3. bipolar neurons 4. ganglion cells

4 errors of refraction

1. presbyopia 2. myopia 3. hyperopia 4. astigmatism

what are the 2 types of photoreceptors

1. rods 2. cones

name the 6 extrinsic eye muscles

1. superior rectus 2. inferior rectus 3. medial rectus 4. inferior oblique 5. superior oblique 6. lateral rectus

what does the anterior cavity include

2 chambers

if more aqueous humor is produced than is absorbed in the canal of Schlemm, which condition results?

Glaucoma

what nerve is innervated by the cornea

Trigeminal nerve

the lens divides into what type of cavities

anterior and posterior cavities

the anterior cavity is subdivided into

anterior and posterior chamber

what are the anterior chamber and posterior chamber filled with

aqueous humor

what type of fluid does the ciliary process contain

aqueous humor

what is the function of the ciliary muscle

attaches to the lens via "suspensory ligaments"

why is the dilator pupillae an intrinsic eye muscle

because it is located inside the eye.

what is the function of the lens

bend light and focus image onto the retina *suspensory ligament

what is refraction

bending of light one medium to the next

where is the anterior chamber located

between the iris and cornea

where is the posterior chamber located

between the lens and iris

what is the choroid

brown pigment layer

when suspensory ligaments are lax the lens will

bulge

define accommodation

bulging and flattening of the lens

what does the vascular tunic consist of

choroid, ciliary body, and iris

what is conjuctiva

clear thin tissue that lays on the sclera

what is a catatract

clouding of the lens proteins in lens are no longer clear

what does the fibrous tunic contain

collagen

the oculomotor nerve also innervates 2 intrinsic eye muscles called

constrictor pupillae and ciliary muscle

what is the cornea

covers the opening of the eye

when looking at an object close up, ___ light rays enter the eye that must be refracted onto the retina of the eye

divergent

what are the 6 layers of the eyelid from superficial to deep

epidermis, dermis, hypodermis, skeletal muscle, tarsal play and tarsal glands, conjuctiva

where is the lacrimal gland located

eye lid

what is myopia

eyeball too long

what is hyperopia

eyeball too short

name the type of tissue that is found in the sclera

fibrous tissue

discuss the flow of tears.

from lacrimal gland through the lacrimal ducts to the nasal

what is the function of the vitreous humor

helps push the retina onto the choroid (vascular layer)

where does the aqueous humor flow

into the canal of Schlemm (scleral venous sinus)

what is unique about its synthesis

it never replaces itself

when does light bend

it passes through the structures of the eye as it travels to the retina

what is unique concerning the cornea

lacks blood vessels but contains a lot of nerves

which muscle is innervated by the abducens nerve

lateral rectus

how does the lens change its shape?

lens elasticity makes it round and allows it to change shape. sensory ligaments pull on lens making it flat. when suspensory ligaments are lax the lens will bulge

what happens in hyperopia

light rays will be refracted to a point behind the retina. the lens will try to adjust so that light rays are refracted onto the retina.

what happens in myopia

light rays will be refracted to a point in front of the retina. the lens will try to adjust so that the light rays are refracted onto the retina.

what would work for myopia near or distant vision

near

name the nerve that innervates the ciliary muscle

oculomotor #3

which never innervates the other four muscles

oculomotor nerve

when looking at an object far away, _____ light rays enter the eye that must be refracted onto the retina of the eye

parallel

what does the nervous tunic contain

photoreceptors

what is another name for conjuctiva

pink eye

name 2 functions of the fibrous sclera

protection and attachment of muscles

what is the function of the suspensory ligaments

pull on lens to make it flatter

what does the nervous tunic consist of

retina

what chemicals are in tears

salt, lysozyme, mucus, ion

what does the fibrous tunic consist of

sclera and cornea

what is the nervous tunic

sits around posterior cavity of the eye

an infection of the tarsal glands is called

sty

which muscle is innervated by the trochlear nerve

superior oblique

what is the aqueous humor made by

the choroid plexus of the ciliary process

what happens in prebyopia

the lens loses the ability to change its shape

what is the purpose of the tarsal plate and tarsal glands

to give the shape of the eye

what is the posterior cavity filled with

vitreous humor (gel-like substance)

what is the sclera

white part of the eye

why does the lens lose its ability to accommodate in older people

without the elastic nature the lens cannot bulge