Full Anatomy of Human Ear | 3D Physiology Illustration Model Animation

[00:00] The human ear is a complex organ responsible for hearing and balance. It is divided into three main sections, the outer ear, the middle ear, and the inner ear. Each part plays a crucial role in the process of hearing and maintaining equilibrium. Outer ear. Pina or oracle, the visible part of the ear that is on the

[00:20] the outside of the head. It's made of cartilage and skin and is shaped to capture sound waves and funnel them into the ear canal. Ear canal or external auditory meat is a tube-like structure that leads from the pina to the eardrum. It helps to further direct sound waves towards the eardrum. Middle ear tympanic

[00:40] membrane or eardrum, a thin, cone-shaped membrane that separates the outer ear from the middle ear. It vibrates when sound waves hit it, converting these waves into mechanical vibrations. Ossicles, three tiny bones in the middle ear called the malleus, incus, and stapes. These bones are the smallest in the human body.

[01:00] body and they amplify and transmit the vibrations from the eardrum to the inner ear. Inner Ear Cochlea, a spiral-shaped, fluid-filled tube that is responsible for converting mechanical vibrations into electrical signals that the brain interprets as sound. It contains tiny hair cells that move in response to fluid vibrations.

[01:20] creating nerve impulses. Vestibular system, this includes the semicircular canals and the otolithic organs, utricle and sacule, which are crucial for balance. These structures detect changes in head position and movement, helping to maintain equilibrium. Let's start with the outer ear.

[01:40] components which are pina and ear canal. Pina. The pina, also known as the oracle, is the visible part of the ear that is located on the outside of the head. It's a key component of the outer ear and plays an important role in the hearing process. Here are some details about the pina. Structure and composition.

[02:00] The pina is primarily made up of cartilage covered by skin. The cartilage gives it a firm yet flexible structure. It has a unique, complex shape with ridges and folds, such as the helix, the lobule, and the tragus. Function in hearing. The primary function of the pina is to capture sound waves

[02:20] from the environment and funnel them into the ear canal towards the eardrum. Its shape is designed to efficiently collect and direct sound. Different parts of the pina help in gathering sounds coming from various directions, which is important for locating the source of a sound in the environment. Role in sound localization. The pina plays a

[02:40] significant role in vertical sound localization, determining whether a sound is coming from above, below, or at the same level as the listener. The folds and contours of the pina effect sound waves differently depending on their origin, creating subtle changes in the sound that help the brain determine the sound's location. Individual variation.

[03:00] The shape and size of the pina vary greatly among individuals, and these variations can affect the way sound is perceived. Despite these differences, the basic function of sound collection and direction remains consistent. Non-hearing functions. The pina also contributes to the aesthetic and facial identity of an individual.

[03:20] It can be a site for adornment, such as earrings, which is a common cultural practice across many societies. Limitations While the pinna is important for sound collection and localization, it does not play a role in the actual processing of sound, this is done by the inner parts of the ear and the brain.

[03:40] canal or external auditory meatus. The ear canal, also known as the external auditory meatus, is a key component of the outer ear and plays a crucial role in the hearing process. Here's a detailed explanation of its structure and function. Structure. The ear canal is a tube-like passage approximately

[04:00] 2.5 centimeters, 1 inch, in length in adults, leading from the outer ear to the eardrum. It is slightly curved in shape, which helps protect the eardrum by preventing direct entry of foreign objects. The outer third of the canal is made of cartilage, similar to the pina, while the inner two-thirds consist of bone.

[04:20] The bony part is surrounded by a thin layer of skin. Lining The skin lining the ear canal contains hair follicles and glands that produce earwax, serumine. This wax plays several important roles in ear health. Function and hearing The primary function of the ear canal is to conduct sound waves from

[04:40] outer ear to the eardrum. Its shape and length are designed to amplify these sound waves and optimize their transmission. Protection Earwax produced in the ear canal has protective properties. It traps dust, dirt, and other particles, preventing them from reaching and potentially damaging the eardrum. The wax

[05:00] also has antibacterial and antifungal properties helping to keep the ear canal healthy. The slight curve of the canal, along with the presence of hair, also helps in protecting the deeper structures of the ear from foreign objects and insects. Maintenance of ear health. Normally, the ear canal is self-cleaning.

[05:20] Stax and debris gradually move out of the canal due to the movement of the jaw, like when chewing, eventually drying up and falling out of the ear. Over-cleaning or using inappropriate objects to clean the ear can disrupt this natural process and lead to problems like impaction, irritation, or infection. Sensitivity. The skin in the ear canal

[05:40] is thin and sensitive, making it susceptible to irritation and infection. Conditions like otitis externa, swimmers' ear, can occur due to inflammation or infection of the ear canal. Resonance The ear canal also contributes to the resonance of sound frequencies, particularly those important for understanding speak.

[06:00] This resonance enhances certain frequencies, making it easier to hear and interpret spoken words. Lobule, earlobe Structure Composition, unlike the rest of the pina, the earlobe contains no cartilage. It is composed of connective and adipose tissue, making it soft and pliable.

[06:20] Variability, earlobes vary greatly among individuals in size, shape, and whether they are free or attached. Function. Cultural and cosmetic, the earlobe doesn't have a direct role in hearing. Its significance is more cultural and cosmetic, often being a site for jewelry, earrings, and

[06:40] body modification. Genetic marker, the characteristic of having attached or detached earlobes is a commonly cited example of a simple genetic trait. Middle ear. Middle ear have two major components, tympanic membrane and oscicles. tympanic membrane or eardrum. The tympanic membrane

[07:00] membrane, commonly known as the eardrum, is a critical component of the human ear, playing an essential role in the process of hearing. Here's a detailed explanation of its structure, function and importance. Structure The eardrum is a thin, semitransparent membrane that separates the outer ear from the middle ear. It's rough

[07:20] They're roughly oval in shape and measures about 8 to 10 millimeters in diameter in adults. The membrane is composed of three layers. The outer layer is continuous with the skin lining the ear canal. The middle layer is fibrous and gives the eardrum its strength and ability to vibrate. The inner layer is mucus membrane,

[07:40] similar to the lining of the middle ear. Function and hearing. The primary function of the eardrum is to convert sound waves that travel through the air into mechanical vibrations. When sound waves enter the ear canal, they strike the eardrum and cause it to vibrate. The frequency and intensity of these vibrations correspond to the

[08:00] frequency and loudness of the sound waves. These vibrations are then transmitted to the three small bones, ossicles, in the middle ear, the malleus, incus, and stapes. Role in middle ear protection. The eardrum acts as a barrier, protecting the delicate structures of the middle ear from foreign objects, back to the middle ear.

[08:20] anterior, and water that could enter through the ear canal. It also helps to maintain the proper pressure balance between the external environment and the middle ear, which is crucial for the proper functioning of the middle ear bones. Sensitivity and Damage The eardrum is sensitive and can be damaged by various factors, such as loud noises, and pain.

[08:40] sudden pressure changes, infections, or physical trauma, like poking it with a cotton swab or other object. A perforated eardrum, a tear or hole in the eardrum, can lead to hearing loss, pain, and increased susceptibility to ear infections. Healing. In many cases, a damaged eardrum can

[09:00] heel on its own, but severe tears may require medical intervention, such as surgery. Diagnostic relevance. Examination of the eardrum can provide valuable information about the health of the ear. Changes in its appearance can indicate various conditions, such as infections, fluid in the middle ear, or eardrum perforation.

[09:20] Effect on hearing. The efficiency of sound transmission through the eardrum is crucial for normal hearing. Any alteration in its structure or function can lead to conductive hearing loss. Ossicles. The ossicles are a group of three tiny bones in the middle ear known as the malleus, incus, and stapes.

[09:40] They are the smallest bones in the human body and play a crucial role in the process of hearing by transmitting sound vibrations from the eardrum to the inner ear. Here's a detailed explanation of each ossicle and their collective function. Malleus or hammer. The malleus is the first of the three ossicles and is attached to the inner surface of the

[10:00] of the tympanic membrane, eardrum. It resembles a hammer in shape, with a long handle attached to the eardrum and a head that connects to the next bone, the incus. When sound waves cause the eardrum to vibrate, these vibrations are transferred to the malleus. Incus or anvil. The incus is the middle bone,

[10:20] situated between the malleus and stapes. It has an anvil-like shape and serves as a bridge for transmitting vibrations from the malleus to the stapes. The joint between the malleus and incus allows efficient transmission and amplification of these vibrations. Stapes or stirrup. The stapes is the smallest and last of the

[10:40] name for its sterophilic shape. It has a footplate that fits into the oval window, a membrane-covered opening to the inner ear. Vibrations transmitted to the stapes cause the footplate to move in and out of the oval window, creating waves in the fluid of the inner ear or cochlea.

[11:00] Transmission and amplification. The primary function of the ossicles is to transmit sound vibrations from the eardrum to the inner ear. As the vibrations move from the larger surface area of the eardrum to the smaller area of the stapes footplate, they are amplified. This amplification is crucial for efficient hearing as the sound

[11:20] waves need to be strong enough to create waves in the fluid of the cochlea. Impedance matching. The ossicles also play a role in impedance matching between the air in the external auditory canal and the fluid of the cochlea. Impedance matching ensures that most of the sound energy is transferred into the inner ear rather than being reflected and lost.

[11:40] which is important for the sensitive process of converting sound waves into neural signals.

[12:00] loud sounds, reducing the transmission of sound energy to the inner ear and helping to protect it from damage. Inner ear Inner ear consists of cochlea and vestibular system. Cochlea The cochlea is an intricate and essential component of the inner ear, playing a critical role in the auditory system.

[12:20] It is responsible for converting mechanical sound vibrations into electrical signals that the brain can interpret as sound. Here's a more detailed look at its structure and function. Structure of the cochlea. Spiral shape. The cochlea is a spiral-shaped, coiled tube resembling a snail shell. It makes about two

[12:40] 2.5 turns around a central bony pillar called the modiolus. Internal division. Inside, the cochlea is divided along its length by two membranes, the ricener's membrane and the basilar membrane. This division creates three parallel, fluid-filled chambers or canals, the scolavastibuli, scolametal.

[13:00] media, cochlear duct, and scolotimpony. Scolovestibuli and scolotimpony. These two chambers are filled with a fluid called perilymph, which is similar in composition to cerebrospinal fluid. The scolovestibuli begins near the oval window, where the stapes bone transmits sound vibrations into the cochlea.

[13:20] The scala timpani ends at the round window, another membrane-covered opening that allows for fluid displacement within the cochlea. Scala media or cochlear duct. The scala media contains a different fluid called endolymph, which is rich in potassium and crucial for the transduction process. It houses the organ of chordae.

[13:40] sensory organ of hearing. Organ of cordy. Located on the basilar membrane, it contains rows of sensory hair cells and supporting cells. Above the hair cells is the tectorial membrane, which plays a role in the stimulation of these cells. Hair Cells. There are two types of hair cells, inner hair cells.

[14:00] cells responsible for transmitting sound information to the brain and outer hair cells involved in amplifying and fine-tuning sound vibrations. The hair cells have tiny projections called stereocilia that protrude into the endolymph. Function of the cochlea. Sound wave transmission. Sound vibrations

[14:20] Enter the cochlea via the oval window, causing movement in the perilymph of the skull of a stibulae. Basilar membrane movement These movements create a traveling wave along the basilar membrane, causing it to move up and down. Stimulation of hair cells The movement of the basilar membrane causes the hair cells in the organ of cochlea.

[14:40] cordy to bend against the tectorial membrane. This bending opens eye on channels, leading to a change in the electrical potential of the hair cells, effectively converting mechanical energy into electrical signals. Auditory nerve stimulation. The electrical signals generated by the hair cells stimulate the auditory nerve fiber.

[15:00] fibers connected to them. These nerve fibers carry the auditory information to the brain, where it is interpreted as sound. Frequency mapping, tonotopy. Different frequencies of sound affect different parts of the cochlea. High-frequency sounds cause more movement at the base of the cochlea, while low-frequency sounds affect the apo-

[15:20] This tonicopic organization allows the brain to distinguish between different sound frequencies. Importance in hearing. The cochlea's ability to perform auditory transduction, converting sound waves into electrical signals, is fundamental to our sense of hearing. Damage or dysfunction in the cochlea can lead to hearing.

[15:40] loss, underscoring its critical role in the auditory system. Vestibular system. The vestibular system is a complex sensory system that is crucial for normal movement and balance. Located in the inner ear, it works closely with other sensory systems, such as vision and proprioception, the sense of body position to make

[16:00] maintain the body's position and equilibrium. Here's a detailed look at its structure and function. Structure of the vestibular system. Semicircular canals. There are three semicircular canals, anterior, posterior, and lateral, in each ear, oriented at roughly right angles to each other.

[16:20] These canals are filled with a fluid called endolymph and contain a sensory organ called the crista ampullaris. The crista ampullaris has hair cells similar to those in the cochlea, and their movement in response to fluid motion is crucial for detecting rotational movements of the head. Otolith organs. These consist of the utricle and sacule.

[16:40] which are responsible for detecting linear acceleration and gravity. Inside these organs are small crystals called otoliths, calcium carbonate crystals, that sit on top of a gelatinous layer covering the hair cells. Movement of the head causes the otoliths to shift, which bends the hair cells and sends signals to the brain about the head's position.

[17:00] relative to gravity and linear motion. Function of the vestibular system. Balance and equilibrium. The vestibular system provides critical information about motion, head position and spatial orientation. It helps maintain balance and stabilize the eyes and body during movement.

[17:20] head movements. The semicircular canals detect rotational movements like turning the head side to side, nodding, or tilting. Each canal is sensitive to movements in a different plane, covering a full range of head rotations. Detection of linear movements and gravity. The otolith organs, utricle and sap,

[17:40] detect linear movements, such as forward-backward, up-down, and side-to-side motion, and the effects of gravity. They help in understanding the orientation of the head relative to the ground, aiding in balance and posture.

[18:00] movements in the opposite direction of head movement, allowing for clear vision while moving. Integration with other systems. The vestibular system works closely with the visual system and proprioceptive sensors in the body to maintain balance and spatial orientation. Information from the vestibular system is sent to the brainstem, cerebellum.

[18:20] and other areas of the brain to help coordinate movement and balance. Clinical importance Disorders of the vestibular system can lead to symptoms like dizziness, vertigo, balance disturbances, and visual disturbances during movement. Vestibular function is often assessed in patients with dizziness or balance problems to determine.

[18:40] determine the underlying cause.