The Ear Change the graphics to symbolize different functions of the ear that are brought up on the next slide

Functions of the Ear Hearing Balance There are three parts to the Ear: The Outer Ear The Middle Ear The Inner Ear Upside down means????? Can add clips for each function…from movies, music, etc

Anatomy of Ear Auditory canal Tympanic membrane Pinna Ossicles Oval window Round window Cochlea Organ of Corti Semicircular canals Utricle Saccule Otoliths Auditory nerve Outer/middle/inner ear Switched “words like” with “terms”

Outer Ear Inner Middle Ear Ear Semicircular Canals Ossicles Tympanic Ear Anatomy… Outer Ear Inner Middle Ear Ear Semicircular Canals Ossicles Tympanic Membrane Auditory Nerve Auditory Canal Cochlea Pinna Eustachian Tube Ossicles

Anatomy of the Ear Outer Ear Outer Ear Function: To gather sound waves, causing the ear drum to vibrate. Made of skin and cartilage. The ear flap is called the pinna. Outer Ear Added waves to 2 and 5 Changed signals to impuses in second last

Outer Ear Pinna Auditory Canal Tympanic Membrane (aka. Ear Drum) Ear flap (cartilage) Funnels sound into auditory canal Auditory Canal Leads into the head Lined with wax secreting cells Tympanic Membrane (aka. Ear Drum) End of the auditory canal Separates outer ear from middle ear Do we need large?

Healthy Eardrum Eardrum with Pus Might need to clarify the portion of the picture that actually is the eardrum for the student centered presentation

Middle Ear

The Eardrum is connected to the three smallest bones in the body: -Malleus (hammer) - Incus (anvil) - Stapes (stirrup) Together these are known as the ossicles. Middle Ear Students able to naturally visualize and understand pharynx and eustachian tube link

Hammer Anvil Stirrup Tympanic Membrane

The bones are attached to each other by ligaments that allow them to move back and forth & AMPLIFY the sound! The last ossicle, the stirrup, is attached to the oval window. Middle Ear Students able to naturally visualize and understand pharynx and eustachian tube link

Sound Intensity and Pitch Sound intensity - depends on number of neurons and frequency of firing Pitch (hi or low note) - each hair cell responds to only one frequency.

Ear Test

The eustachian tube is located just after the eardrum, in the middle ear. The Eustachian tube connects to the throat and allows for pressure equalization on both sides of the tympanic membrane. How do we equalize pressure? Middle Ear

Size of tube compared to coin An Ear Tube Used To Drain Middle Ear Fluid Size of tube compared to coin

Inner Ear

Inner Ear Function#1: Hearing. Converts sound vibrations from the ossicles into nerve impulses!!! Function #2: Balance. The Cochlea is the organ that is responsible for hearing (this is the place where neurons attach). The Cochlea is coiled, like a snail shell. It is divided into scala vestibule and scala tympani by the cochlear duct. Again, for student centered, self guided tool may have to fill in more than one word points to clarify….but this could just be my lack of knowledge

Cochlea

Cochlea – Cross Section

Inner Ear

The cochlear duct contains the Organ of Corti where sound receptors (four rows of hair cells) are found. A fluid (called endolymph) surrounds the Organ of Corti. The scala vestibuli and the scala tympani contain another fluid called perilymph. The utricle, saccule, and semicircular canals are responsible for balance and body position

The Mechanics of Hearing Longitudinal sound waves travel down the auditory canal. Tympanic membrane vibrates. Ossicles (malleus, incus, & stapes) move. Stapes is connected to the oval window. When the stapes moves, it causes this window to bulge. The oval window bulging causes the fluid in the outer two parts of the cochlea to move. This puts pressure on the cochlear duct.

The Mechanics of Hearing The pressure waves cause the basilar membrane to move which causes the hairs in the organ of Corti to bend against the tectorial membrane. As the hairs bend, the small nerves that are connected to the base of the hairs are stimulated. These nerve impulses are carried to the brain along the auditory nerve. the temporal lobe of the cerebral cortex interprets the impulses as sound.

The Mechanics of Balance The utricle, saccule, and semicircular canals are important structures for balance & are filled with fluid and contain sensory hairs. The utricle & saccule contain small calcium carbonate particles called otoliths (ear stones). Movement of the head ( along one plane – horizontal/vertical), causes the otoliths to move in response to gravity. These particles cause sensory hairs to bend, triggering impulses which alert the brain as to the position of the head. The saccule contains sensory hairs as well

The Mechanics of Balance The semicircular canals contain sensory hairs which are bent by movement in the fluid surrounding them. One canal detects bending forward and backward, another detects bending left or right, and a third detects a turning motion. The brain then signals the appropriate muscles to maintain balance.

Semicircular Canals

Ear Safety Small muscles in your ears help protect your hearing When loud noises are around, Muscles attached to the hammer (malleus) contract and restrict intense movements. A second muscle contracts pulling the stirrup (stapes) away from the oval window limiting inner ear damage. Not effective with sudden loud noises This response takes time. Sudden noise causes huge damage to inner ear, specifically the hairs in the Organ of Corti

What structures are for hearing?