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