Middle Ear: How Does it Look?
The human ear can be divided into three important parts; the external ear, middle ear, and inner ear. In this article, students will get to learn about the middle ear. The middle ear lies close to the temporal bone. The extension of the middle ear occurs from the ear’s tympanic membrane and it moves to the lateral wall that is present in the inner ear.
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One of the primary functions that the middle ear has is the transmission of vibrations that are sent from the tympanic membrane to the inner ear. Students can learn what is middle ear is from this article.
What is Middle Ear?
The middle ear cavity or more commonly known as just the middle term is also called the tympanum or the tympanic cavity. It is a chamber in the ear that is filled with air. The location of the middle ear is on the petrous section that the temporal bone has. The tympanic membrane separates the inner ear from the external section of the ear.
Also, the medial wall situated in the tympanic cavity is responsible for the separation of the inner ear and the middle ear. There are three auditory ossicles are one of the primary middle ear structures that are present in the inner ear. These ossicles help in the amplification and transmission of sound.
Middle Ear Anatomy
The anatomy of the middle ear in human beings consists of different parts such as the tympanic membrane, the ossicles, the tympanic cavity, etc. This diagram of the middle ear will help the students understand the anatomy of the middle ear better.
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Tympanic Membrane- A very important part of the middle ear structure is the tympanic membrane. It is commonly known as the eardrum. The external ear and the middle ear are completely separated by the presence of this structure. It is semi-transparent in its appearance and has air surrounding it on both sides when the circumstances are normal. The tympanic membrane is about one mm thick and has a diameter of approximately 10 mm. The shape of the tympanic membrane happens to be slightly concave. There is a tense portion situated in the tympanic membrane and it is known as pars tensa. The membrane also has a flaccid and loose portion that is known as the pars flaccida. Mostly collagen fibers and epithelial cells are used in the creation of the tympanic membrane.
The Tympanic Cavity- Another one of the middle ear parts is the tympanic cavity which is situated medially to the entire tympanic membrane. This is the main constituent of the middle ear. The shape of the cavity is rectangular and there are four walls, a floor, and a ceiling. There is the lateral wall that is created with the tympanic membrane. The roof of the cavity separates the middle cranial fossa and the middle ear. The cavity’s floor separates the jugular vein and the middle ear. The tympanic cavity anatomy suggests that there is a particularly distinct budge present in the medial wall and it is created using the facial nerve.
The Ossicles- The 3 middle ear bones are known as ossicles. These structures mainly focus on the conduction of sound in the middle ear. The main bones are named malleus or the hammer, stapes or the stirrup, and incus or the anvil. Several ligaments as well as the synovial joints tend to connect the ossicles together. The three bones are combined in order to create the ossicular chain. The oval window receives certain vibrations through the tympanic membrane with the help of this chain. A very important thing to note about the bones in the middle ear is that the bone ‘stapes’ is considered to be the smallest bone to exist in the human bone.
The Eustachian or Auditory Tube- This tube runs from the middle ear’s anterior wall to the back of the throat where the nasopharynx is located. The tube’s inside is consistent with cilia or the small hairs that sweep the mucus particles out. The length of the auditory tube goes up to about 31-38 mm.
What is Middle Ear Function?
The sound that enters the human ear through the outer ear section is transported to the section of the inner ear through the middle ear. It is a primary middle ear function. It is in the inner ear’s cochlea where the sound inputs are further provided to the brain. The sound waves that are funneled into the section of the outer ear tend to hit the tympanic membrane which results in the vibration of sound which is then carried through the ossicles.
The middle ear is an essential component of the human ear as it helps us listen to the sounds that are produced. The human ear helps in providing sound inputs to the brain and the middle ear acts as the transportation channel between the outer section and the inner section of the ear.
FAQs on Middle Ear
1. What is the main function of the middle ear?
The main function of the middle ear is to take sound waves collected by the outer ear and turn them into vibrations for the inner ear. It acts as a mechanical amplifier, making sounds louder so they can be processed effectively. It also contains the Eustachian tube, which helps equalise air pressure on both sides of the eardrum.
2. What are the three small bones in the middle ear and what do they do?
The three small bones in the middle ear are called the ear ossicles. Their job is to transmit and amplify sound vibrations from the eardrum to the inner ear. The three bones are:
- Malleus (Hammer): Attached to the eardrum, it vibrates when sound waves hit.
- Incus (Anvil): The middle bone that passes vibrations from the malleus to the stapes.
- Stapes (Stirrup): The smallest bone, it pushes against the oval window of the inner ear, sending the vibrations into the fluid-filled cochlea.
3. What is another name for the middle ear?
Another name for the middle ear is the tympanic cavity. This name refers to the air-filled space located behind the eardrum (tympanic membrane).
4. What is the role of the muscles inside the middle ear?
The middle ear has two tiny muscles, the tensor tympani and the stapedius. Their main role is protective. When you hear a very loud noise, these muscles contract automatically. This action, called the acoustic reflex, stiffens the ear ossicles and reduces the intensity of the vibrations passed to the inner ear, helping to prevent damage.
5. How does the middle ear actually make sounds louder?
The middle ear amplifies sound in two main ways. First, the surface area of the eardrum is much larger than the area of the stapes footplate pressing on the inner ear. Concentrating the force from a large area to a small area increases the pressure. Second, the ear ossicles act as a lever system, which further increases the force of the vibrations as they pass from the malleus to the stapes.
6. Why is the Eustachian tube so important for our hearing?
The Eustachian tube is a small passageway that connects the middle ear to the back of the nose and throat. It is crucial because it balances the air pressure inside your middle ear with the pressure outside your body. For the eardrum to vibrate properly, the pressure on both sides must be equal. Without the Eustachian tube, pressure differences could build up, causing discomfort, muffled hearing, and even pain.
7. Why do my ears 'pop' when I'm on an airplane or going up a hill?
That 'popping' sound is your Eustachian tube at work. As you go up in altitude (like in an airplane or up a mountain), the air pressure outside your body decreases. The Eustachian tube opens to release the higher-pressure air from your middle ear, creating the 'pop' as the pressure equalises. The same thing happens in reverse when you descend.
8. What happens to your hearing if the eardrum gets a hole in it?
A hole or tear in the eardrum is called a ruptured or perforated eardrum. This condition can cause several problems, including sharp ear pain, fluid leakage, a ringing sound (tinnitus), and some degree of hearing loss. Because the eardrum can't vibrate properly, its ability to transmit sound to the middle ear bones is reduced. Small holes often heal on their own, but larger ones may require medical treatment.
9. How is the middle ear different from the inner ear?
The main difference lies in their structure and function. The middle ear is an air-filled cavity that uses bones (ossicles) to mechanically amplify sound vibrations. Its job is transmission and amplification. In contrast, the inner ear is a fluid-filled cavity containing the cochlea. Its job is transduction—it converts the mechanical vibrations received from the middle ear into electrical nerve signals that the brain can interpret as sound.
