Chapter 13 Concepts Flashcards
The eyeball transmits an external image to the brain via the ______ ______
optic nerve
What are the three layers of the eyeball
sclera, choroid, retina
Lighter enters the eyes through structures of the
sclera
light is focused onto the sensory receptor cells of the _____
retina
What do sensory receptor cells do
convert light to electric signals that travel via the optic nerve
What is the outermost layer of the eyeball
the sclera
The sclera is the ____ part of the eye
white
What is the anterior portion of the sclera
the cornea
what does the cornea do
refract light rays as they pass through and enter the eye
What is the middle layer of the eyeball
the choroid
What does the choroid do for the eye
distribute blood supply
What are the anterior parts of the choroid layer
iris, pupil, ciliary body
What connects the lens to the ciliary body
suspensory ligaments
What is the innermost layer of the eyeball
the retina
what are the two types of sensory receptor cells
rods and cones
what are rods responsible for
to be active in dim light and help the eye see gray tones
what do cones do
are active in bright light and are responsible for color vision
Light that passes through the lens strikes the ____ _____
macula lutea
What is the name for the depression on the macula lutea
fovea centralis
What does the fovea centralis contain
cones
what is the optic disk
spot where optic nerve leaves the eyeball, spot where retinal blood vessels enter and leave
True or false: the optic disk contains no rods or cones
true
the optic disk is also referred to as the ____ ____ in each eye
blind spot
What is the watery fluid that fills the spaces between the cornea and lens
aqueous humor
what is the semisolid gel that fills the large open area between the lens and retina
vitreous humor
How many muscle control the eye
6; four rectus, two oblique
Rectus muscles produce movement in a ___ ____
straight line
Oblique muscles produce ______ eye movement
diagonal
what can weakness in the external eye muscles cause
strabismus
What is the conjunctiva
a mucous membrane lining that provides protection by sealing off the eyeball in the socket
What are the structure apart of the lacrimal apparatus
lacrimal gland, lacrimal canals, nasolacrimal duct
What does the lacrimal gland do
produce tears to wash and lubricate the eye
what do the lacrimal canals do
drain tears into the nasolacrimal duct
what does the nasolacrimal duct do
carries the drainage to the nasal cavity
What is the order of light when it enters the eye
cornea –> pupil –> aqueous humor –> lens –> vitreous humor –> retina (rods and cones) –> optic nerve –> brain
What are the proper functions of the four mechanisms
external eye muscles coordinated, pupil admits correct amount of light, lens focus light onto retina, optic nerve transmits the sensory images to the brain
What is the ear responsible for
hearing, equilibrium
sensory information is carried from the ear to the brain by the _______ ______
vestibulocochlear nerve
what portions carries hearing information
cochlear
what portion carrier equilibrium information
vestibular
what does the external ear consist of
auricle, auditory canal, tympanic membrane
what does the auricle do?
functions like a funnel by capturing sound waves
what are the names of the ossicles
malleus, incus, stapes
What does the eustachian tube do
connect the nasopharynx and the middle ear, equalize pressure
what is the name of the fluid filled cavity in the inner ear
the labyrinth
what are the structures of the inner ear
vestibule, cochlea, semicircular canals, utricle, saccule
what are the hair cells within the cochlea called
the organ of Corti
what are the steps to hearing
- sound travels down the external auditory canal and strikes the tympanic membrane
- tympanic membrane vibrates the ossicles
- ossicles create vibrations across the middle ear to the oval window
- oval window vibrates the fluid in the cochlea
- fluid vibrations strike hair cells and stimulate nerve endings
- nerve endings send impulses to the brain
