Medical Science: Inner Ear Anatomy and Physiology Research (Research Paper Sample)

* Inner ear anatomy and physiology
It is the mammals’ the inner most part of the ear also referred to as Auris interna, it represents the inner section of the vertebrate ear, and it is connected to the middle ear to the oval window. The inner ear is responsible for the detection of sound and balance among the vertebrates (Wada 12). The structure is the final part of the ear, where the vestibular nerve and the cochlea nerve are located, both nerves ar vital for balancing and hearing respectively.
The inner ear is made up of the following arts:
* Oval window
* Semicircular ducts
* Cochlea
* Auditory tube
Internal ear is comprised of the bony labyrinth, which is the hollow space in the temporal bone with a structural passage that consists of the following functional parts.
Semicircular ducts- section packed with fluid, it is attached to the nerves and the cochlea. Its function is to transmit information on the balance and also the head position of the brain.
Auditory tube: - it channels fluid from the middle ear up to the throat, at the section behind the nose.
Cochlea: - This is the structured spiral section of the hearing. This part is made up of the cochlear duct of the membranous labyrinth. The hearing is offered by the receptors that are in the cochlear duct. A set of perilymph-filled chambers are located on the sides of the duct. All the apparatus makes their turns around the central bony hub, just like a snail.
The function of the cochlea involves the changing of the sound waves to electrical impulses and then tramsmitting them to the brain’s auditory nerve. When received by the brain, the impulse is then converted into sounds that one can comprehend.
Though, for the free fluid movement within the cochlea from side to side, its wall membrane has a small hole in it known as the helicotrema. The wall is significant for safeguarding the vibration that comes from an oval window and is conveyed to the entire fluid that is inside the cochlea. Once the fluid gets in the cochlea, many of the microscopic hair fibers that are inside the divided wall, move in motion. There are nearly 24,000 of such hair fibers existing in sets of four long rows (Wada 15).
The vestibular System– the balance mechanism
The organ is structured for balance mechanism. Its role is to identify the movement of the body, therefore ensuring that the body balance is being maintained. Vestibular system is made up of three major ring-shaped passages, leaning in three diverse planes. The three passages contain fluid that moves respectively to the movements of the body. Apart from the fluid, the passages are composed of numerous hair fibers that respond to the fluid movement relying upon slight impulses to the brain. Once the impulses are received in the brain, they are decoded and thus enhances body balance (Pujol and Hilding 343).
The auditory nerve
This is the series of nerve fibers which are responsible for conveying information from the cochlea (inner ear) up to the brain. The auditory nerve has the function of carrying sound signals from the part of the inner ear, through the nerves,up to the brain. The hair fibers move in motion when they transmit electrical signals towards the brain through the auditory nerve that is linked to the auditory center. In the brain, the electric pulse is decoded into a sound. As a result, hair fibers are vital to human hearing ability. When these hair fibres are damaged, the hearing capacity of an individual is weakened (Cathers 230).
The bony labyrinth, also known as the osseous labyrinth, is the passage network that has bony walls with periosteum lined to it. The membranous labyrinth is found in the bony labyrinth, between them, it contains layers of perilymph. The three major sections of the bony labyrinth are the cochlea, the semicircular canals, and the vestibule of the ear (Willott 40).
In the inner ear, the round window is made up of a thin partition which separates the air-filled middle ear from the perilymph of the cochlea. The perilymph, a fluid located in the cochlea, has its properties similar to that of the cerebrospinal fluid. The perilymph flows between membranous and bony labyrinths. The endolymph is another fluid that is found within the membranous labyrinth; however, endolymph is concentrated with the electrolytes that vary from the body fluids. Furthermore, the bony labyrinth may be divided up into, the cochlea, the three semicircular canals, and the vestibule. In the vestibule, there are two sets of membranous sacs, namely, the utricle (utriculus) and the saccule (sacculus). Receptors found inside the vestibule offer sensations of linear acceleration and gravity.
The slender semicircular ducts are surrounded by the semicircular canals. The receptors that are found in this section are accelerated by the head rotation. Alongside with the vestibule, this is referred to as the vestibular complex. The chambers that are filled with fluid in the vestibule are usually constant with that of the semicircular canals (Willott 44).
* Semicircular Canals 
The semicircular canal also referred to as semicircular duct is made up of the three semicircular, tubes that are interconnected found inside every ear. The three canals are as follows:
1 The superior semicircular canal/ anterior semicircular canal
2 The posterior semicircular canal/ inferior semicircular canal
3 The horizontal semicircular canal/ lateral semicircular canal
Both the posterior and aterior canals can be referred to as the vertical semicircular canals. The function of the semicircular canal system is the detection of the rotational movements. In order to attain its detection property, the semicircular canals are effectively used as the tools for that purpose.
1 Horizontal semicircular canal
This is the shortest of the three canals. The fluid movements that occur in the canal are in respect of the head rotation around the vertical axis, this means the neck, in other terms transverse plane rotation. This occurs when one turns his head towards the right and left side before crossing the road. The lateral canal in one ear is very close to the equal angle as the other, whereas the superior canal of one of the ears is almost parallel to that of the posterior canal of the another ear.
2 Superior semicircular canal
This is a section of the vestibular system which the head rotation around the horizontal axis, or in other terms rotation within the sagittal plane. This is an event when nodding the head.
3 Posterior semicircular canal
Its function is to detect the head rotation around the anterior-posterior or rostral-caudal axis; also, referred to as the rotation within the coronal plane. For instance, when one moves his head to reach his shoulder, or while doing the cartwheel.
* Otolith Organs
The otolith organs sense gravity and linear acceleration, as due to initiation of movement in a straight line. Persons or animals without otolith organs or with defective otoliths have poorer abilities to sense motion as well as orientation to gravity.
The otolith is a structure of the utricle or saccule found in the inner ear, and more specific in the vestibular labyrinth. Both the utricle and the saccule in line, make up the otolith organs. The structures are sensitive to the linear acceleration and gravity. Due to their location of the utricle, in the head, they respond to the to the variation in the horizontal movement, and then the saccule provides the information concerning the vertical acceleration (Cathers, Ian, Brian, and Richard, 230).
Both the utricle and the saccule has the sensory epithelium, which is the macula that is made up of the hair cells and the related supporting cells. Beyond the hair bundles and the hair cells is the gelatinous layer, together with the fibrous structure, which is referred to as otolithic membrane; they are rooted with crystals of calcium carbonate referred to as otoconia. The otolithic membrane is made considerably heavier by the otoconia, as compared to the structure together with the surrounding fluid; therefore, when the head is tilted, the gravity trigger off the membrane to move comparatively to the sensory epithelium. The subsequent shearing motion that is there between the macula and the otolithic membrane moves the hair bundles; they are embedded within the lower, sticky side of the membrane.  Receptor potential is produced within the hair cells as the result of the movement of the hair bundles (Cathers, Ian, Brian, and Richard, 234).
The shearing movement between the otolithic membrane and macula likewise happens when the head experienced linear accelerations. The extreme comparative weight of the otolithic membrane, leads to its temporarily lagging behind the macula, causing the hair bundle to displace briefly. The same effect applies to the otolithic hair cells, when the particular tilting of the head and the linear accelerations clarifies the perceptual equivalence of these diverse stimuli in the absence of the visual feedback, as it happens in the dark or when then closing the eyes. The hair cell bundles orientatuin is relatively organized to the striola, therefore demarcating the covering layer of otoconia. Therefore, a tilt by the striola axis, while one side stimulates the hair cells, leads to restraining the hair cells that are on the other edge (Fernandez, Cesar, and Jay 225).
The utricular macula is positioned horizontally, and the saccular macula vertically, with the constant disparity in the morphological polarization within the hair cells found in each macula. Scrutiny of the excitatory orientations within the maculae shows that the utricle reacts to the head's fast in the horizontal angle, like sideward head tilts as well as the lateral displacements. Whereas the sacculus reacts to ...