1. Chapter 14
Section
Equilibrium

2. Balance- how good are you?
Follow mrs. Aitken to see how good you are

3. Static and Dynamic Equilibrium
Balance consists of 2 components:
STATIC EQUILIBRIUM– monitoring head position.
DYNAMIC EQUILIBRIUM – monitoring movement of limbs.

4. Static Equilibrium
At the entrance to the inner ear is the VESTIBULE which contains two sacs of fluid called the UTRICLE and the SACCULE.
They are sensory organs responsible for detecting and transmitting information regarding balance, position in space, acceleration, and deceleration.
Floating in the fluid are calcium carbonate stones called OTOLITHS.

6. Static Equilibrium Cont’d
As the head moves from one position to the other, these ear stones will move too.
The otoliths brush against sensory nerve hairs that line the utricle and saccule.
Brushing against the nerve hairs causes depolarization and sends a nerve impulse to the brain about the head position.

7. Dynamic Equilibrium
The SEMICIRCULAR CANALS also contain fluid and are responsible for detecting changes in motion.
There are three semicircular canals (all at different angles).
Within each canal is a pocket called an AMPULLA which holds a CUPULA.
Inside the cupula are CILIA (hair cells).

9. Dynamic Equilibrium Cont’d
When movement occurs the cilia bend.
Once the hair cells bend, they initiate depolarization and a nerve impulse is sent to the brain.
The nerve impulses are carried to the cerebellum where they are interpreted.

10. Hearing Loss One type of hearing loss is known as CONDUCTIVE.
In conductive hearing loss, sound waves have trouble entering the inner ear.
This can be caused by a buildup of wax in outer ear, middle ear infections, or a punctured ear drum.
It is corrected by medical or surgical procedures.

11. Hearing Loss Cont’d
Another type of hearing loss is known as SENSORINEURAL.
In this type the auditory nerve is severed or the hair cells of the cochlea are damaged or dead.
It can be caused by aging, exposure to loud noises, head trauma, or genetic conditions.
Often, hearing loss is a mixture of both types.

12. Treatment for Hearing Loss
Hearing Aids
- use microphones to pick up sound then amplify it
- increases the loudness of the sound
- used for conductive hearing loss
Cochlear Implants
- allows the damaged parts of the ear to be bypassed so impulse is sent to the brain
- used for sensorineural hearing loss

13. Deafness Deafness is simply the complete blockage of sound.
Can be either by conductive or sensorineural.

14. Video https://www.youtube.com/watch?v=ahCbGjasm_E