The Human Ear
Science: KS3, topic 3.3.15
The Human Ear
We can hear sounds through our ears. The ears contain some of the smallest bones in the human body.
Ears
- We can detect sound waves with our ears.
- Ears are made up of three main parts.
- The outer ear.
- The middle ear.
- The inner ear.
The outer ear
- The outer ear is made up of:
- The pinna - the part of the ear that is visible on the side of the head. It funnels sound into the ear.
- Ear canal - a 2cm passage way that leads from the pinna to the ear drum.
- Ear drum - a thin flap of skin that vibrates with sound.
The middle ear
- The middle ear is made up of the ossicles, which are three very small bones. In fact, they are the smallest in the human body.
- The ossicles, which are the same size from birth, amplify any sounds and are made up of:
- The hammer - in contact with the ear drum.
- The anvil - in contact with the hammer.
- The stirrup - transmits sounds to the cochlea.
Otosclerosis
- Otosclerosis is a condition which causes hearing loss.
- This is caused when the stirrup fuses with the surrounding ones so it is unable to vibrate.
The inner ear
- The inner ear is made up of:
- The cochlea - a spiral-shaped structure with hairs around it, which is filled with fluid. As the fluid moves, it vibrates the hairs. This turns sound waves into electrical signals. The cochlea is also responsible for your balance.
- Auditory nerve - sends electrical impulses to the brain.
- Brain - turns this impulses into what we hear as sound.
Test yourself on The Human Ear
Which of these is NOT a part of the outer ear?
Which of these are true of the middle ear?
Which of these best describes the cochlea?
A person's auditory nerve is damaged, but their cochlea still turns sound into electrical signals normally. What would most likely happen?