Anatomy Exam - Topic 14, Chapter 14 P2

Optic Nerve

a bundle of over one million nerve fibers that connects the eye to the brain, transmitting visual information to be interpreted as images

Lens

biconvex, flexible structure to help focus light on the retina, held by suspensory ligaments which attach to ciliary muscles

What are rods covered in and what do they react to?

proteins and light

What do cones sense?

color

How is vision processed?

right to left, upper and lower, and is inverted

Hyperopia

eyeball is short, light focuses after the retina (farsightedness)

Myopia

eyeball is long, light focuses before retina (near sidedness)

Diplopia

eyes do not focus on the same spot (double vision)

Outer Ear

auricle, external auditory meatus, external auditory canal with ceruminous gland, and tympanic membrane (ear drum)

Middle Ear

begins at the tympanic membrane, three ossicles (malleus, incus, and stapes), and ends at an oval window

What is the middle ear filled with?

air, unless there is an ear infection

Inner Passages in the Temporal Bone

vestibule, cochlea, and three semicircular ducts (equilibrium)

What is the Auditory Tube known as?

eustachian tube

Eustachian Tube

a narrow tube that connects the middle ear to the back of the throat, equalizing pressure in the ears

Pharynx

a membrane-lined cavity behind the nose and mouth, connecting them to the esophagus

How many ducts does the Cochlea have?

three ducts: scala vestibuli, scala media, and scala tympani

What are Vestibular and Tympanic Canals filled with?

perilymph

Organ of Corti

a structure in the cochlea of the inner ear which produces nerve impulses in response to sound vibrations

Stereocilia

tiny, hair-like projections on the surface of sensory cells in the inner ear that are essential for hearing and balance

Audition

a physical and mechanical sensation

Ossicle

a very small bone, especially one of those in the middle ear

What do ossicles amplify?

sound waves

Intensity

more hair cells move because of louder sounds

Cochlear Implant

should conduct sound to nerve and used if hairs are no longer working

How do both auditory and balance work by?

mechanoreceptors