1. The Ear

2. Functions of the Ear 1. 1. 2. 2. There are three parts to the Ear: 1. 2. 3.

3. Anatomy of Ear Label the diagram (on the next slide) of the ear using the terms : 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

6. Ear Anatomy…

7. Anatomy of the Ear Outer Ear Function: Function: Made of skin and cartilage. Made of skin and cartilage. The ear flap is called the _________________ The ear flap is called the _________________

8. Outer Ear Pinna Auditory Canal Tympanic Membrane (aka. Ear Drum)

12. Middle Ear The Eardrum is connected to the three smallest bones in the body: --- Together these are known as the _________.

14. Middle Ear The bones are attached to each other by ligaments that allow them to move back and forth & _____________ the sound! The last ossicle, the stirrup, is attached to the ___________________.

15. Sound Intensity and Pitch Sound intensity – Pitch (hi or low note) –

16. The _____________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

17. Size of tube compared to coin

19. Inner Ear Function#1: Hearing. Converts sound vibrations from the ossicles into ___________________!!! Function #2: Balance. The Cochlea is the organ that is responsible for hearing (this is the place where neurons attach). 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. The Cochlea is coiled, like a snail shell. It is divided into scala vestibule and scala tympani by the cochlear duct. It is divided into scala vestibule and scala tympani by the cochlear duct.

21. Cochlea – Cross Section

22. Inner Ear

23. The cochlear duct contains the ___________ where sound receptors (four rows of hair cells) are found. The cochlear duct contains the ___________ where sound receptors (four rows of hair cells) are found. A fluid (called __________) surrounds the Organ of Corti. A fluid (called __________) surrounds the Organ of Corti. The utricle, saccule, and semicircular canals are responsible for ____________ and body position The utricle, saccule, and semicircular canals are responsible for ____________ and body position

25. The Mechanics of Hearing Longitudinal sound waves travel down the _______ _____________ Longitudinal sound waves travel down the _______ _____________ __________________________vibrates. __________________________vibrates. ____________ (malleus, incus, & stapes) move. ____________ (malleus, incus, & stapes) move. Stapes is connected to the ___________. When the stapes moves, it causes this window to bulge. Stapes is connected to the ___________. 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. The oval window bulging causes the fluid in the outer two parts of the cochlea to move. This puts pressure on the ____________ duct. This puts pressure on the ____________ duct.

26. The Mechanics of Hearing The pressure waves cause the ________membrane to move which causes the hairs in the organ of Corti to bend against the tectorial membrane. The pressure waves cause the ________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. 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. 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 temporal lobe of the cerebral cortex interprets the impulses as sound.

31. The Mechanics of Balance The ______, ________, and _________________are important structures for balance & are filled with fluid and contain sensory hairs. The ______, ________, and _________________are important structures for balance & are filled with fluid and contain sensory hairs. The utricle & saccule contain small calcium carbonate particles called __________ (ear stones). The utricle & saccule contain small calcium carbonate particles called __________ (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. 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 saccule contains sensory hairs as well

32. 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 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. The brain then signals the appropriate muscles to maintain balance.

33. Semicircular Canals

34. Ear Safety Small muscles in your ears help protect your hearing When loud noises are around, 1. 1. 2. 2. Not effective with sudden loud noises This response takes time. This response takes time. Sudden noise causes huge damage to inner ear, specifically the hairs in the Organ of Corti Sudden noise causes huge damage to inner ear, specifically the hairs in the Organ of Corti

35. What structures are for hearing?