Presentation is loading. Please wait.

Presentation is loading. Please wait.

The Ear: Physiology Balance and Hearing. Mechanoreceptors Can respond to deformation (bending), resulting in a change in ion flow Get a hyper/depolarization.

Similar presentations


Presentation on theme: "The Ear: Physiology Balance and Hearing. Mechanoreceptors Can respond to deformation (bending), resulting in a change in ion flow Get a hyper/depolarization."— Presentation transcript:

1 The Ear: Physiology Balance and Hearing

2 Mechanoreceptors Can respond to deformation (bending), resulting in a change in ion flow Get a hyper/depolarization depending on the direction ◦ Can differentiate between direction of bending Often grouped Often attached to a gelatinous mass, which is influenced by the environment’s movement

3 Inner Ear Anatomy

4 Semicircular canals Surrounded by both a membranous labyrinth and a bony labyrinth ◦ Can’t expand/change shape ◦ Held still even when body is in motion ◦ Movement of fluid causes a traveling disturbance whose force isn’t lost against an expanding wall Tubular structure that contains both perilymph and endolymph Each canal ends with an ampulla

5 Cristae ampullaris Contain “tufts” of hair cells, called cristae Affected by movement Are in planes perpendicular to one another (able to interpret any possible movement) cupola

6 Vestibular Apparatus Enlargements extend from the vestibular apparatus ◦ Utriculus and sacculus Gelatinous mass with CaCO 3 “ear stones” = cupola This extra mass helps increase density ◦ A more efficient position receptor ◦ Allows proprioceptors a reference point to which it can compare the rest of the body

7 Endolymph is continuous throughout the vestibular apparatus and semicircular canals During rotation of canals ◦ Inertia moves the walls relative to the fluid ◦ Fluid gains inertia of its own ◦ When the wall stops, fluid moves relative to the wall Endoloymph is also continuous throughout the cochlea

8 The Cochlea

9 Cochlea – A Hearing Structure 1 central canal, filled with endolymph 2 adjacent canals, filled with perilymph  This fluid allows vibration of the walls of the central canal

10 Vibration Transmission Tympanic membrane vibrates along with sound waves  Translated into the motion of the bones of the inner ear  Stapes attached to the oval window  The oval window vibrates at the same frequency

11

12 Vibration of oval window causes disturbance in the fluid behind it ◦ High surface area leads to an amplification of the sound ◦ The pressure on the perilymph in the vestibular canal is great, causing pressure waves Round window acts as a pressure release

13

14

15 Sound detection Vibrations produced in the perilymph are translated into traveling waves along the basilar membrane ◦ Frequency of the vibration determines how far it goes ◦ High = proximal membrane ◦ Low = distal end A maximal response happens along the portion of the membrane that vibrates the most

16

17 Hearing in detail… 2 groups of hair cells along basilar membrane ◦ Single, inner row (closest to bony ridge) ◦ Vibrate with basilar membrane ◦ Communicate with auditory cortex of brain via a single nerve fiber in auditory nerve

18 Why does this matter? Your brain can “tell” what type of sound was perceived ◦ A fairly strong stimulation needed to stimulate the hair cells so close to the bony ridge ◦ If this nerve fiber is stimulated, the sound must be loud

19 Outer, Triple Row Sensitive to the same frequency as the inner, single row Easier to stimulate, though Brain can’t distinguish the specific frequency that stimulates these cells, though  Harder to identify quieter sounds Turning up volume helps!


Download ppt "The Ear: Physiology Balance and Hearing. Mechanoreceptors Can respond to deformation (bending), resulting in a change in ion flow Get a hyper/depolarization."

Similar presentations


Ads by Google