Ear, inner
Ear, inner: A highly complex structure whose essential component for hearing is the membranous labyrinth, where the fibers of the auditory nerve connect the ear to the brain. The membranous labyrinth is a system of communicating sacs and ducts (tubes) filled with fluid (endolymph), and it is lodged within a cavity called the bony labyrinth. At some points the membranous labyrinth is attached to the bony labyrinth, and at other points the membranous labyrinth is suspended within the bony labyrinth in a fluid called perilymph. The bony labyrinth has three parts: a central cavity called the vestibule; semicircular canals, which open into the vestibule; and a spiraling tube called the cochlea. The membranous labyrinth also has a vestibule, which consists of two sacs (the utriculus and sacculus) that are connected by a narrow tube. The larger of the two sacs, the utriculus, is the principal organ of the vestibular system, which is the system of balance. This system informs a person about the position and movement of the head. The smaller of the two sacs, the sacculus, is also connected by a membranous tube to the cochlea that contains the organ of Corti. The hair cells, which are the special sensory receptors for hearing, are in the organ of Corti.
Read Also:
- Ear, internal
Ear, internal: There are three sections of the ear. They are the external ear, the middle ear, and the internal ear. The internal ear is far and away the most highly complex. The essential component of the internal ear for hearing is the membranous labyrinth, located inside the bony cochlea, where the fibers of the […]
- Ear, low-set
Ear, low-set: A minor anomaly involving an ear situated down below its normal location. The ear is low-set when the helix (of the ear) meets the cranium at a level below that of a horizontal plane through both inner canthi (the inside corners of the eyes). .
- Ear, middle
Ear, middle: A part of the ear that consists of the eardrum (tympanic membrane) and, beyond it, a cavity (tympanum). This cavity is connected to the pharynx (nasopharynx) via a canal known as the Eustachian tube. The middle ear cavity also contains a chain of three little bones, the ossicles (the malleus, incus, and stapes), […]
- Ear, outer
Ear, outer: The part of the ear that is visible along the side of the head. The outer ear consists of the pinna, or auricle (the visible projecting portion of the ear), the external acoustic meatus (the outside opening to the ear canal), and the external ear canal, which leads to the eardrum. The outer […]
- Ear, slanted
Ear, slanted: An ear that is slanted more than usual, with the angle of the slope of the auricle more than 15 degrees from the perpendicular. Also called a malrotated ear.