1. The ears are the sensory organs for hearing and are sensitive to sound.
2. The human ear is divided into three parts:
(a) Outer ear - filled with air
(b) Middle ear - filled with air
(c) Inner ear - filled with fluid
3. Each part of the ear has its own function
4. The hearing mechanism:
(a) The earlobe collects and directs sound waves into the eardrum through the ear canal.
(b) The eardrum vibrates and the sound vibration in tranferred to the ear bones (ossicle).
(c) The ossicles strenghen these vibrations snd convey them to the oval window.
(d) The vibrations of the oval window cause the fluid in the cochlea to produce nerve impulses.
(e) The nerve impulses are sent to the brain by the auditory nerve to be interpreted.
5. The ear as a balancing organ:
(a) Apart from functioning as a hearing organ, the ear also controls the balance of the body.
(b) Any bodily movements will stimulate the receptors in the semicircular canals to produce impulses.
(c) The brain will interpret these impulses and direct the muscles to respond and to balance up the body.
The pinna collects sound waves which passes through the auditory canal and then hits the eardrum causing it to vibrate. This vibration is then picked up by the 3 small bones called the ossicles which makes the vibration much stronger. The ossicles consists of the hammer, anvil and stirrup When the ossicles vibrate, this passes to the oval window and then to the cochela of the inner ear. The cochela contains fluid and tiny hairs which are stimulated from the vibration , which then produces impulses in the auditory nerve. The auditory nerve sends a signal to the brain and it recognizes the sounds.
Semicircular Canals – Helps us to keep our balance. Fluid in the canal moves when we spin which sometimes make us dizzy.
Eustachian Tube – Connects the middle ear to the throat. It’s usually closed, but opens when we swallow and helps us to balance the pressure in our eardrum.