In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear. Its function is to transmit sound from the air to the ossicles inside the middle ear, and then to the oval window in the fluid-filled cochlea.
What is the structure of the middle ear?
The middle ear is the structure that begins at the end of the tympanic membrane. There are three tiny bones known as the ossicles that make up the middle ear. These bones connect the eardrum to the inner ear. Sound waves funneled in through the pinna, hit the eardrum.
What are the two structures that vibrate inside the ear?
The tympanic membrane (eardrum) and auditory ossicles vibrating inside a human ear. Encyclopædia Britannica, Inc. See all videos for this article The thin semitransparent tympanic membrane, or eardrum, which forms the boundary between the outer ear and the middle ear, is stretched obliquely across the end of the external canal.
What are the mechanical properties of the ear-drum?
The mechanical properties of the ear-drum and attached structures are very poorly known, particularly with respect to isotropy, uniformity and damping. A historical review of observations of ear-drum vibration patterns shows general agreement that at low frequencies the displacements of the manubrium are smaller than those of the surrounding drum.
What is the shape of the human eardrum?
Conical shape. The mammalian eardrum is approximately conical, with the apex pointing medially. {Fumagalli (1949)} found that the eardrum shapes of all of the nine species he observed could be represented approximately by a cone with an apex angle of 120 o, cut at various angles by the plane of the tympanic ring.
What structure is also known as the ear drum?
The tympanic membrane is also called the eardrum. It separates the outer ear from the middle ear. When sound waves reach the tympanic membrane they cause it to vibrate. The vibrations are then transferred to the tiny bones in the middle ear.
What is the structure and function of the eardrum?
The eardrum is a thin flap of skin that is stretched tight like a drum and vibrates when sound hits it. These vibrations move the tiny bones of the middle ear, which send vibrations to the inner ear. From the inner ear, the message is sent to the brain, which says, “Hey!
What is the functional unit of the ear?
The inner ear consists of two functional units: the vestibular apparatus, consisting of the vestibule and semicircular canals, which contains the sensory organs of postural equilibrium; and the snail-shell-like cochlea, which contains the sensory organ of hearing.
What is ear drum made of?
The tympanic membrane, or eardrum, is a three-layer tissue composed of epidermal (to the outer ear) and mucosal (to the middle ear) epithelia covering a connective tissue proper with different collagen fiber arrangements (mainly collagen type II), outer radial, and inner circular with a parabolic beam having fulcrum in …
How is the structure of the ear similar to the eye?
Just as the curved cornea of the eye angles light onto the pupil, so too the ear cartilage and ear canal concentrate sound onto the eardrum. In the eye, further focus is achieved by the lens, which concentrates light-rays onto the photosensitive retina lining the back of the eye.
Where is the eardrum located quizlet?
commonly called the eardrum. it is the paper thin connective tissue membrane that’s tightly stretched across the opening between the external auditory canal and the middle ear canal.
Where is the ear drum?
At the end of the ear canal is the ear drum. The ear drum is a thin membrane which separates the ear canal from the middle ear. The ear drum is fixed to part of the first hearing bone which is called the malleus. The ear canal and the ear drum are covered with skin just like the skin on the outside of the body.
What are the structures of the ear?
The parts of the ear include:External or outer ear, consisting of: Pinna or auricle. This is the outside part of the ear. … Tympanic membrane (eardrum). The tympanic membrane divides the external ear from the middle ear.Middle ear (tympanic cavity), consisting of: Ossicles. … Inner ear, consisting of: Cochlea.
Where is the eardrum located?
The eardrum divides the outer ear from the middle ear. The eardrum sits between the end of the external ear canal and the auditory ossicles, which are three tiny bones in the middle ear, called the malleus, incus, and stapes.
Can you hear without a eardrum?
Can you hear without an intact eardrum? A. “When the eardrum is not intact, there is usually some degree of hearing loss until it heals,” said Dr.
Is the eardrum a muscle?
The tensor tympani is a muscle within the middle ear, located in the bony canal above the bony part of the auditory tube, and connects to the malleus bone….Tensor tympani muscleArterySuperior tympanic arteryNerveMedial pterygoid nerve from the mandibular nerve (V3)ActionsTensing the tympanic membraneIdentifiers10 more rows
Is the eardrum a bone?
Stapes. As you read this article discussing what bones are in the ear, you may be thinking that the outer ear “bone” was overlooked. However, this part of your ear is actually made up of flexible cartilage, not bone tissue. Your ears also contain soft tissues and sensitive membranes like the tympanic membrane (eardrum) …
What is the structure of the eardrum Brainly?
The tympanic membrane, also called the eardrum (or just the drum), is a stiff (but flexible), translucent, diaphragmlike structure. The eardrum moves synchronously in response to variations in air pressures, which constitute sound waves. The drum’s vibrations are transmitted through the ossicular chain to the cochlea.
What is the purpose of the eardrum quizlet?
Function of the eardrum is to carry sound waves to bones that are located in the middle ear. These bones are called ossicles.
What is the structure of human ear?
Structure. The human ear consists of three parts—the outer ear, middle ear and inner ear. The ear canal of the outer ear is separated from the air-filled tympanic cavity of the middle ear by the eardrum.
What is the structure of the outer ear?
The medical term for the outer ear is the auricle or pinna. The outer ear is made up of cartilage and skin. There are three different parts to the outer ear; the tragus, helix and the lobule. The ear canal starts at the outer ear and ends at the ear drum.
What is the shape of the eardrum?
Conical shape. The mammalian eardrum is approximately conical, with the apex pointing medially. {Fumagalli (1949)} found that the eardrum shapes of all of the nine species he observed could be represented approximately by a cone with an apex angle of 120o, cut at various angles by the plane of the tympanic ring.
What is the eardrum made of?
The typical mammalian eardrum consists basically of a very thin sheet of connective tissue (pars tensa). The annular ligament firmly anchors it to bone around most of its circumference, and the manubrium of the malleus is tightly coupled to it. The outline of the pars tensa varies in different species from more or less circular to a somewhat elongated ellipse. The manubrium may be placed symmetrically, or it may be somewhat closer to the anterosuperior edge of the pars tensa. The significance of these variations is unclear.
What are the factors that affect the operation of the middle ear?
The operation of the middle ear is affected by a number of factors (such as external ear-canal shape, eardrum curvature, the mode of vibration of the eardrum, the nature of the ossicular suspension and muscles, and the ossicular load) about which little or nothing is known in most species.
Why did Békésy and Kirikae’s experiments not detect eardrum tension?
The fact that Békésy’s and Kirikae’s experiments were done on cadaver ears obviously means that they could not detect any component of eardrum tension due to tonus in the tensor tympani. Also, any tension maintained passively by the ossicular ligaments might be sensitive to post-mortem tissue changes.
How does the size of the eardrum vary?
The size of the eardrum tends to vary less from species to species than does overall body size . {Khanna & Tonndorf (1969)} demonstrated that a linear dimension of the eardrum (square root of the area) is approximately proportional to the square root of a linear dimension of the whole body (i.e., of the cube root of weight) among seven diverse mammalian species. Hunt & Korth (1980)} calculated a regression line with a slope of 0.26 relating the logarithm of eardrum area to the logarithm of body weight among 40 mammalian species; this corresponds to an exponent of about 0.4 when comparing linear dimensions, close to the value of 0.5 of Khanna & Tonndorf. The size of the rest of the middle ear is generally comparable to that of the eardrum. {Webster & Webster (1975)}, for example, have shown that among one group of rodents a linear dimension of the eardrum is approximately proportional to a linear dimension (cube root of the volume) of the middle-ear cavity. In fact, the values for the cat and guinea pig fall quite close to the same straight line.
Where are the eardrums not directly inserted?
As noted above, the fibres of the eardrum are not directly inserted into the middle third of the manubrium, at least in the human. {Tonndorf & Khanna (1972)} noted that the drum and manubrium did not seem to be so tightly coupled in this region, although the effect was quite small.
How thick is the eardrum?
{Kojo (1954)} measured the thickness at seven locations on each of seven human eardrums: the total range was from 30 to 120 um, with the average values for the seven locations ranging from 55 to 90 um, the smallest values being in between the periphery and the manubrium. By comparison, {Lim (1970)} reported that the human eardrum varies in thickness from 30 to 90 um. The cat drum is 30 to 50 um thick, and the guinea-pig drum is about 10 um thick ({Lim, 1968a)}. More detailed measurements are required on variations of over-all thickness across the surface of the drum, and also on the thicknesses of the constituent layers discussed below.
Which structure runs from the skull and bends around to terminate at the ear lobe?
Notable among these is the outer rim or helix, which runs from the skull and bends around to terminate at the ear lobe. Parallel to this is another curved structure called the antihelix, which has a triangular upper fossa (or space) bound by the borders of the helix and antihelix.
What are the three parts of the ear?
In the broadest terms, the ear is divided into three portions: the outer ear (which includes the visible outer portion, as well as the ear canal), the middle ear, and the inner ear, representing the portion deepest in the skull. Each of these sections has a number of components. The outer ear contains the ear canal, …
Why does my ear ring?
Tinnitus: This persistent ringing in the ear can be subjective—likely occurring due to abnormal activity in the auditory nerve of the brain—or objective, in which a muscle spasm or other process in the middle ear is the cause . Tinnitus may be the result of age-related hearing loss, overexposure to loud noises, physical injury, Meniere’s disease (see below), or neurological disorders. Treatment may include correcting the hearing loss with hearing aids, modifying lifestyle, or cognitive behavioral therapy (CBT).
Why does my ear look buried?
Cryptotia: Due to malformation of ear cartilage, this variant gives off the appearance that the upper portion of the ear is buried inside the head.
What is the outer ear?
The outer ear contains the ear canal, as well as several other major parts: 2 . Auricle: The outwardly visible part of the ear, this blend of skin and cartilage attaches to the skull. It has an outer (lateral) aspect as well as an inner (medial) one.
Which bone connects with the incus?
Stapes (stirrup): The last of these bones connects with the incus on the side via the incudostapedial joint, while, in its middle, it accesses the oval window as part of the mechanism that carries sound to the inner ear. This bone also has a head, which connects with the lenticular process, as well as two limbs that attach to the oval base, which connect with the oval window.
How is hearing loss tested?
Speech testing: Hearing loss can also be tested by having patients repeat certain words or phrases played at specific volumes.
What are the parts of the middle ear?
Middle ear. Parts: tympanic cavity, auditory ossicles, muscles of the ossicles. Function: transforming a high-amplitude low-force sound wave into a low-amplitude high-force vibration and transmitting it to the internal ear. Internal ear.
What is the external ear?
External ear. The external ear, like the middle ear, serves only to conduct sound to the inner ear. It consists of the auricle and external acoustic meatus (or ear canal). Key facts about the external ear. Parts. Auricle, external acoustic meatus. Blood supply.
Why do you pull the helix of the auricle posterosuperiorly?
This procedure provides an examination of the external ear and the tympanic membrane. Because of the natural curvature of the external acoustic meatus, the physician needs to pull the helix of the auricle posterosuperiorly, in order to align the meatus in a straight direction.
What nerve is at the bottom of the ear canal?
Function. Conducts sound to the inner ear. At the bottom of the ear canal is the tympanic membrane which establishes the border between the external and middle ear.
Where is the tympanic membrane located?
The tympanic membrane, or simply the eardrum, is found at the bottom of the bony external acoustic meatus and it is the border between the external and middle ear. It is attached with a fibrocartilaginous ring to the tympanic part of the temporal bone.
What is the function of the smallest bones?
Their main function is to transmit sounds to the internal ear, precisely to the labyrinth within the internal ear. They articulate with each other with synovial joints, and transmit vibrations by being moved by the muscles of the middle ear. In order from the tympanic membrane to the internal ear (lateral to medial), these bones are:
What is the auricle?
Auricle. The auricle, also known as pinna, is a wrinkly musculocutaneous tissue that is attached to the skull and it functions to capture sound. The auricle is mostly made up of cartilage that is covered with skin. There are two aspects of the auricle: and medial (inner) and lateral (outer).
What are the structures of the middle ear?
structures of the middle ear. The auditory ossicles of the middle ear and the structures surrounding them. Encyclopædia Britannica, Inc. The malleus consists of a handle and a head. The handle is firmly attached to the tympanic membrane from the centre (umbo) to the upper margin.
What is the tympanic membrane?
The tympanic membrane (eardrum) and auditory ossicles vibrating inside a human ear. Encyclopædia Britannica, Inc. See all videos for this article. The thin semitransparent tympanic membrane, or eardrum, which forms the boundary between the outer ear and the middle ear, is stretched obliquely across the end of the external canal.
What is the inner layer of the mucous membrane?
The inner layer of mucous membrane is continuous with the lining of the tympanic cavity of the middle ear. Between these layers is a layer of fibrous tissue made up of circular and radial fibres that give the membrane its stiffness and tension. The membrane is well supplied with blood vessels and sensory nerve fibres that make it acutely sensitive …
Why is the eustachian tube closed?
The tube is closed at rest and opens during swallowing so that minor pressure differences are adjusted without conscious effort.
What is the back of the ear?
The back (posterior) wall partly separates the middle-ear cavity from another cavity, the mastoid antrum, but an opening in this wall leads to the antrum and to the small air cells of the mastoid process, which is the roughened, slightly bulging portion of the temporal bone just behind the external auditory canal and the auricle.
What is the middle ear space?
The middle-ear space roughly resembles a rectangular room with four walls, a floor, and a ceiling.
What is the outer wall of the middle ear?
The outer (lateral) wall of the middle-ear space is formed by the tympanic membrane. The ceiling (superior wall) is a thin plate of bone that separates the middle-ear cavity from the cranial cavity and brain above. The floor (inferior wall) is also a thin bony plate, in this case separating the middle-ear cavity from the jugular vein and …
What are the parts of the inner ear?
The inner ear includes: 1 oval window – connects the middle ear with the inner ear 2 semicircular ducts – filled with fluid; attached to cochlea and nerves; send information on balance and head position to the brain 3 cochlea – spiral-shaped organ of hearing; transforms sound into signals that get sent to the brain 4 auditory tube – drains fluid from the middle ear into the throat behind the nose
What is the outer ear?
The outer ear includes: auricle (cartilage covered by skin placed on opposite sides of the head) auditory canal (also called the ear canal) eardrum outer layer (also called the tympanic membrane) The outer part of the ear collects sound.
What is the middle ear?
The middle ear includes: eardrum. cavity (also called the tympanic cavity) ossicles (3 tiny bones that are attached) malleus (or hammer) – long handle attached to the eardrum. incus (or anvil) – the bridge bone between the malleus and the stapes. stapes (or stirrup) – the footplate; the smallest bone in the body.
Where does sound travel?
Sound travels through the auricle and the auditory canal, a short tube that ends at the eardrum. Sound entering the outer ear travels through the middle ear and causes the eardrum and ossicles in the middle ear to vibrate. As it travels, it amplifies (gets louder) and changes from air to liquid.
How do the brain and auditory system work together?
The brain and auditory system work together to control how we hear and how we balance ourselves. The human ear is a complex organ and many scientists consider hearing to be the most complex of the human senses.
What is the cancer of the outer ear?
Cancer of the Outer Ear. Symptoms: A scabbed area of skin that is jagged and irregular with crusting and oozing—usually on the upper edge of the outer part of the ear. This area may be present for many years and may or may not be associated with a swelling or lump in the neck. Cause: Long periods of time in the sun.
Where do the auditory pathways begin?
Auditory Pathways. The auditory pathways begin in the nerve fibers in the inner ear , where sound waves get converted into nerve impulses. These impulses then travel via the auditory nerve to the highest cerebral levels in the cortex of the brain. Hearing loss can happen for many reasons.
What are the parts of the ear called?
Outer Ear#N#The outer ear is made up of: 1 the part we see on the sides of our heads, known as pinna 2 the ear canal 3 the eardrum, sometimes called the tympanic membrane, which separates the outer and middle ear
What is the part of the ear that separates the outer and middle ear?
the part we see on the sides of our heads, known as pinna. the ear canal. the eardrum, sometimes called the tympanic membrane, which separates the outer and middle ear. Middle Ear. The middle ear is made up of: the eardrum. three small bones called ossicles that send the movement of the eardrum to the inner ear.
What are the different types of hearing loss?
There are four types of hearing loss: Hearing loss caused by something that stops sounds from getting through the outer or middle ear. This type of hearing loss can often be treated with medicine or surgery. Hearing loss that occurs when there is a problem in the way the inner ear or hearing nerve works.
What are the bones that send sound to the brain?
three small bones called ossicles that send the movement of the eardrum to the inner ear. This nerve sends sound information from the ear to the brain. The auditory pathway processes sound information as it travels from the ear to the brain so that our brain pathways are part of our hearing.
Why is sound not organized in the brain?
Hearing loss that occurs when sound enters the ear normally, but because of damage to the inner ear or the hearing nerve, sound isn’t organized in a way that the brain can understand. For more information, visit the National Institute of Deafness and Other Communication Disorders. .
What does “stable” mean in hearing?
Fluctuating or Stable. Hearing loss gets either better or worse over time (fluctuating) or stays the same over time (stable). Congenital or Acquired/Delayed Onset. Hearing loss is present at birth (congenital) or appears sometime later in life (acquired or delayed onset).
Which nerve sends sound information from the ear to the brain?
Auditory (ear) Nerve. This nerve sends sound information from the ear to the brain. Auditory (Hearing) System. The auditory pathway processes sound information as it travels from the ear to the brain so that our brain pathways are part of our hearing.
Introduction
Structure of The Eardrum
- 2.1 Gross Anatomy
Tympanic ring and manubrium. The comparative gross anatomy of the middle ear has been described by a great many authors. {Fumagalli (1949)} and {Fleischer (1973)} have published particularly extensive accounts. The typical mammalian eardrum consists basically of a very thi… - 2.2 Microscopic Structure
Introduction. The pars tensa is composed of three layers: an outer epidermal layer; the lamina propria, consisting of two connective-tissue layers and a fibrous layer; and an inner mucosal layer. The pars flaccida is much the same as the pars tensa except that it lacks the highly organized la…
See more on audilab.bmed.mcgill.ca
Mechanical Properties of The Eardrum
- 3.1 Introduction
This section reviews the gross mechanical properties of the eardrum that determine its vibratory behaviour. The questions of whether these properties are isotropic (i.e., the same in all directions) and uniform (the same in all locations) have been treated by {Békésy (1941, 1949)} and {Kirikae … - 3.2 Stiffness
{Békésy (1949)} measured the bending stiffness of the human cadaver eardrum by cutting out a rectangular flap (2 mm x 0.5 mm) along three sides. He applied a pre-calibrated force to the free end and measured the displacement to be 50 um. Assuming the flap to be a uniform, isotropic c…
Properties of Structures Surrounding The Eardrum
- 4.1 Annular Ligament
The radial fibres of the eardrum, and some of the non-radial ones, extend into the annular ligament around the periphery of the pars tensa. This ligament is a fibrous thickening firmly attached to a sulcus in the bony tympanic ring, except superiorly where it separates the pars ten… - 4.2 Manubrium
The manubrium behaves as a rigid rod, at least by comparison with the eardrum ({Khanna, 1970}). It is much stiffer than the latter both because it is bone and because it is much thicker. As for the question of whether the eardrum is hinged or fully clamped at the manubrium, much the same c…
Experimental Observations of Eardrum Vibrations
- 5.1 Introduction
This section is a review of previously published observations of normal eardrum vibration patterns. Most of these observations have been at low frequencies, that is, zero to 1 or 2 kHz: the eardrum’s mode and amplitude of vibration are essentially constant over this frequency range. T… - 5.2 Low-Frequency Vibration Pattern
Visual observations I. {Kessel (1874)} reported direct visual observations of eardrum displacements due to static pressures in human cadaver ears, using a simple magnifying lens. With respect to the pars tensa, he found that under a positive pressure in the ear canal the eardr…
Discussion
- 6.1 Theories of Eardrum Function
The first attempt to synthesize a quantitative theory of eardrum function was that of {Helmholtz (1869)}. His ‘curved-membrane’ hypothesis was elaborated by {Esser (1947)}, and independently by {Guelke & Keen (1949)}, but seemed to be refuted by experimental work of {Békésy (1941)} an… - 6.2 Directions for Future Experimental Work
More information is required on the anatomyof the eardrum. Specifically, more quantitative data are needed to describe eardrum thickness and three-dimensional curvature, and the distribution and paths of the fibres. More work is also required to quantify the viscoelastic mechanical prope…
Acknowledgements
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This work has been supported by the Medical Research Council of Canada, le Ministère de l’Education du Québec, the McConnell Foundation, and the Macdonald-Stewart Foundation.