Special Senses: Eye and Ear

By: Anne CozziBiology 120

The ear is much more than the flexible soft tissue that attaches to the side of your head.

The ear is actually very complex. It is divided into 3 parts called the outer, middle, & inner ear.

Each part performs an important function for the process of hearing.

The outer ear consists of an auricle and ear canal.The eardrum is a very thin membrane that separates the outer ear from the middle ear.

The middle ear is an air filled chamber containing 3 small bones called ossicles.They connect the eardrum to the inner ear and are named individually the malleus (hammer), incus (anvil) and stapes (stirrup).

The last part of the ear is called the inner ear. It contains a structure called the cochlea that is shaped much like a snail's shell. This organ contains small hair cells bathed in fluid.

Ear tubes are known by several names: tympanostomy tubes, ventilating tubes, pressure equalizing tubes or most frequently, PE tubes. They are tiny hollow tubes made of a soft material.

PE tubes decrease the frequency of ear infections by allowing air in and helping fluid to drain into the throat. Preventing fluid from staying in the middle ear can help to restore and preserve normal hearing. The small tubes that are used do not cause hearing loss or long term damage to the eardrum.

Pressure Equalizer (PE) Tube

Pressure Equalizer (PE) Tube

abbreviation for eyes, ears, nose, and throat

EENT

Bone conduction is the conduction of sound to the inner ear through the bones of the skull.

Bone conduction is the reason why a person's voice sounds different to him/her when it is recorded and played back. Since the skull transmits high frequencies with less attenuation than does air , most people perceive their own voice as being of a higher pitch than others hear it.

Bone Conduction

Emmetropia:a state of proper correlation between the refractive system of the eye and the axial length of the eyeball, rays of light entering the eye parallel to the optic axis being brought to focus exactly on the retina.

Emmetropia

Exotropia is a type of strabimus or eye misalignment. Exotropia refers to an outward deviation of the eyes. Although Exotropia commonly begins around age 2 to 4 years, it can appear at any age.

Exotropia

Left Eye

OS is the abbreviation for left eye. OS stands for the Latin term, oculus sinister

Right Eye

The medical abbreviation for the right eye is o.d., which stands for "oculus dexter". In Latin, "dexter" means right, fortunate, or favorable

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An ear infection is an inflammation of the middle ear, usually caused by bacteria, that occurs when fluid builds up behind the eardrum. Anyone can get an ear infection, but children get them more often than adults. Three out of four children will have at least one ear infection by their third birthday. In fact, ear infections are the most common reason parents bring their child to a doctor. The scientific name for an ear infection is otitis media (OM

Otitis media

Eye movements are controlled by muscles innervated by cranial nerves III, IV and VI. The most common symptom of damage to these nerves is double vision. The oculomotor nerve has the additional function of control of the pupil .

Extraocular movement

Visual acuity is the spatial resolving capacity of the visual system. This may be thought of as the ability of the eye to see fine detail. There are various ways to measure and specify visual acuity, depending on the type of acuity task used. Visual acuity is limited by diffraction, aberrations and photoreceptor density in the eye . Apart from these limitations, a number of factors also affect visual acuity such as refractive error, illumination, contrast and the location of the retina being stimulated.