Source: Video and Images Created by Amanda Soderlind
Welcome to this lesson today on ear anatomy. Today we will be discussing the structure and function of the ear.
So, the function of the ear is to be able to detect sound. And sound travels as a wave. So your ear has several structures within it that are able to detect sound waves and then interpret them. And sound is measured in a unit called decibels.
So, we're going to take a look at the three main areas of the ear and then take a look at the structures located within those three main areas.
So, the first main area of your ear is called the outer ear. And the outer ear is composed of the part of your ear that you can see from the outside as well as the auditory canal. And the auditory canal, it's purpose is to direct sound waves inward. So, a sound wave will enter your ear and then be directed through the auditory canal towards the inner part of your ear.
The next part of the ear we're going to take a look at is the part here in purple and this is your middle ear. So there are several components that compose your middle ear. The middle ear is made up of the tympanic membrane, which is also commonly known as the eardrum. So, we have our tympanic membrane right here.
So basically, a sound wave will enter the ear, be focused through the auditory canal, and then cause this tympanic membrane to vibrate, which then vibrates your three ear bones, which are located in the middle ear.
So, you have a total of three ear bones, and they're called the hammer, the anvil, and the stirrup. So, this is the-- oops, I'm sorry --this is the hammer, the anvil, and the stirrup. So, these are the three bones of the inner ear.
The next part of the ear we're going to take a look at is the inner ear. So, we have our outer ear, our middle ear, and our inner ear in green. So, everything labeled in green here is a part of our inner ear. Hope you can see that OK.
So, our inner ear is, again, composed of several different structures. One here that we're talking about first is the cochlea. So, the cochlea here is a coiled structure. So this here is the cochlea. And the cochlea contains several different structures, including the organ of Corti and the tectorial membrane. So, the organ of Corti has little hair cells, which are mechanoreceptors, and they interact with the tectorial membrane, which helps to detect the intensity of a sound.
So, the cochlea itself is composed of a few different structures as well. We have the round window, which is this little, if you can see the darker green little circle right here, is our round window. And the round window basically acts as a pressure release valve if too much pressure builds up in the ear. And we also have another structure in our ear that allows for pressure release as well.
And then, if we take a look here, this in the darker green is our auditory nerve. And our auditory nerve will basically send signals to the brain. So, as sound waves travel through our ear they travel through all these different signals, signals are interpreted, and then auditory nerve will send those signals up to the brain to process that information.
And above our auditory nerve we have our semicircular canals. So, we actually have three of them. There's one here, one here, and one here. So, semicircular canals.
So, the semicircular canals and vestibular apparatus play roles in balance and equilibrium. The vestibular apparatus is composed of the semicircular canals and two fluid filled sacs, which will help maintain equilibrium. Otolith organs are bits of calcium carbonate within the fluid filled sacs of the vestibular apparatus that move as the head's position in space changes. So, for example, if you were to turn your head to the side, the otolith organs shift to the side as well, allowing the head's movement and position in space to be detected.
So, this lesson has been an overview on anatomy of the ear.
Otherwise known as the ear canal and a part of the outer ear; the auditory canal guides sound waves toward the tympanic membrane.
The nerve that projects auditory information detected by the hair cells in the cochlea to the primary auditory cortex of the temporal lobe.
The organ of hearing found within the inner ear; contains the sensory receptors for hearing (hair cells/stereocilia), organ of Corti, tectoral membrane, round window and the auditory nerve.
A unit of measurement which indicates the loudness of a sound.
The actual receptors for hearing within the cochlea; the hair cells bend due to mechanical fluid vibrations within the cochlea. The bending of the hair cells causes them to depolarize and generate action potentials. The hair cells are also called stereocilia.
The inner portion of the ear deeply embedded within the temporal bone; contains the organs of hearing and balance/equilibrium. Organs within the inner ear are the cochlea, the vestibular system, organ of Corti, tectorial membrane, hair cells (stereocilia), round window, otolith organs, auditory nerve, and the semicircular canals.
The middle portion of the ear that is primarily designed to mechanically amplify the sound waves that enter the ear. Anatomic structures included are the tympanic membrane (ear drum), auditory ossicles (malleus, incus, stapes), and the eustachian tube.
A highly specialized organ found within the cochlea that contains the hair cells/stereocilia and their supporting structures (tectoral membrane, basilar membrane).
The saccule and utricle, each with an otolith (hard bits of calcium carbonate).
Anatomically the outer part of the ear that traps and funnels compressed air inward toward the middle ear. Anatomic structures included are the auricle/pinna, auditory canal.
A structure in the cochlea that acts to dampen the mechanical fluid vibrations within the cochlea to prevent damage to the hair cells.
A system of canals in the vestibular system of the inner ear that provide feeback about body position.
One of two gel membranes located within the cochlea of the ear and is part of the organ of Corti. The two gel membranes contribute to the mechanical process of hearing.
A thin, highly innervated tissue at the end of the auditory canal that is attached to the auditory ossicles. When sound waves strike the tympanic membrane it vibrates, which causes the auditory ossicles to shift and press against the cochlea. Commonly referred to as the "ear drum."
A system within the inner ear that provides us with feedback about our body position and balance; consists of the semicircular canals and the otolith organs.