March 25th, 2010

• Objective: Review the workings of the nose, tongue, and ear. – Coloring– Notes

• Do Now – get markers and start coloring!

Things to color• Auricle / pinna• External auditory meatus (canal)• Tympanic membrane• Malleus/incus/stapes (aka hammer/anvil/stirrup)• (labeled on pic ) semicircular canal, vestibular nerve• Cochlea (& round window)• Auditory tubes• Vestibule• Oval window• Basilar membrane• Organ of corti• Inner hair cells• Outer hair cells• Cochlear nerve fibers

The Ear

Slide 8.20Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Houses two senses· Hearing

· Equilibrium (balance)

Anatomy of the Ear

Slide 8.21Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· The ear is divided into three areas· Outer

(external) ear

· Middle ear

· Inner ear

Figure 8.12

The External Ear

Slide 8.22Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Involved in hearing only

· Structures of the external ear· Pinna

(auricle)· External

auditory canalFigure 8.12

The External Auditory Canal

Slide 8.23Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Narrow chamber in the temporal bone

· Lined with skin

· Ceruminous (wax) glands are present

· Ends at the tympanic membrane (eardrum)

The Middle Ear or Tympanic Cavity

Slide 8.24a

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Air-filled cavity within the temporal bone

· Only involved in the sense of hearing

The Middle Ear or Tympanic Cavity

Slide 8.24b

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Two tubes are associated with the inner ear· The opening from the auditory canal is

covered by the tympanic membrane

· The auditory tube connecting the middle ear with the throat· Allows for equalizing pressure during yawning

or swallowing

· This tube is otherwise collapsed

Bones of the Tympanic Cavity

Slide 8.25a

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Three bones span the cavity· Malleus

(hammer)

· Incus (anvil)

· Stapes (stirrip)

Figure 8.12

Bones of the Tympanic Cavity

Slide 8.25b

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Vibrations from eardrum move the malleus

· These bones transfer sound to the inner ear

Figure 8.12

Inner Ear or Bony Labyrinth

Slide 8.26a

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Includes sense organs for hearing and balance

· Filled with perilymph

Figure 8.12

Inner Ear or Bony Labrynth

Slide 8.26b

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· A maze of bony chambers within the temporal bone· Cochlea

· Vestibule

· Semicircular canals

Figure 8.12

Organs of Hearing

Slide 8.27a

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Organ of Corti· Located within the cochlea

· Receptors = hair cells on the basilar membrane

· Gel-like tectorial membrane is capable of bending hair cells

· Cochlear nerve attached to hair cells transmits nerve impulses to auditory cortex on temporal lobe

Organs of Hearing

Slide 8.27b

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 8.13

Mechanisms of Hearing

Slide 8.28Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Vibrations from sound waves move tectorial membrane

· Hair cells are bent by the membrane

· An action potential starts in the cochlear nerve

· Continued stimulation can lead to adaptation

Mechanisms of Hearing

Slide 8.29Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 8.14

Organs of Equilibrium

Slide 8.30a

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Receptor cells are in two structures· Vestibule

· Semicircular canals

Figure 8.16a, b

Organs of Equilibrium

Slide 8.30b

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Equilibrium has two functional parts· Static equilibrium – sense of gravity at rest

· Dynamic equilibrium – angular and rotary head movements

Figure 8.16a, b

Function of Maculae

Slide 8.32Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 8.15

The End

• Of the ear

• Now to some games!