Ear Wikipedia. The ear is the organ of hearing and, in mammals, balance. In mammals, the ear is usually described as having three partsthe outer ear, middle ear and the inner ear. The outer ear consists of the pinna and the ear canal. Since the outer ear is the only visible portion of the ear in most animals, the word ear often refers to the external part alone. The middle ear includes the tympanic cavity and the three ossicles. The inner ear sits in the bony labyrinth, and contains structures which are key to several senses the semicircular canals, which enable balance and eye tracking when moving the utricle and saccule, which enable balance when stationary and the cochlea, which enables hearing. The ears of vertebrates are placed somewhat symmetrically on either side of the head, an arrangement that aids sound localisation. The ear develops from the first pharyngeal pouch and six small swellings that develop in the early embryo called otic placodes, which are derived from ectoderm. The ear may be affected by disease, including infection and traumatic damage. Diseases of the ear may lead to hearing loss, tinnitus and balance disorders such as vertigo, although many of these conditions may also be affected by damage to the brain or neural pathways leading from the ear. The ear has been adorned by earrings and other jewellery in numerous cultures for thousands of years, and has been subjected to surgical and cosmetic alterations. Download Keygen For Mac. Structure. The eardrum as viewed from the outside using an otoscope. The outer ear ends at the eardrum, and the middle ear can be seen in the tympanic cavity behind. Moore Clinically Oriented Anatomy 7Th Pdf Reader' title='Moore Clinically Oriented Anatomy 7Th Pdf Reader' />Express Helpline Get answer of your question fast from real experts. Kilauea Mount Etna Mount Yasur Mount Nyiragongo and Nyamuragira Piton de la Fournaise Erta Ale. QR56cPl_k/hqdefault.jpg' alt='Moore Clinically Oriented Anatomy 7Th Pdf Reader' title='Moore Clinically Oriented Anatomy 7Th Pdf Reader' />The human ear consists of three partsthe 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. The middle ear contains the three small bonesthe ossiclesinvolved in the transmission of sound, and is connected to the throat at the nasopharynx, via the pharyngeal opening of the Eustachian tube. The inner ear contains the otolith organsthe utricle and sacculeand the semicircular canals belonging to the vestibular system, as well as the cochlea of the auditory system. Outer ear. The outer ear is the external portion of the ear and includes the fleshy visible pinna also called the auricle, the ear canal, and the outer layer of the eardrum also called the tympanic membrane. The pinna consists of the curving outer rim called the helix, the inner curved rim called the antihelix, and opens into the ear canal. The tragus protrudes and partially obscures the ear canal, as does the facing antitragus. The hollow region in front of the ear canal is called the concha. The ear canal stretches for about 1 inch 2. The first part of the canal is surrounded by cartilage, while the second part near the eardrum is surrounded by bone. This bony part is known as the auditory bulla and is formed by the tympanic part of the temporal bone. The skin surrounding the ear canal contains ceruminous and sebaceous glands that produce protective ear wax. The ear canal ends at the external surface of the eardrum. Two sets of muscles are associated with the outer ear the intrinsic and extrinsic muscles. In some mammals, these muscles can adjust the direction of the pinna. In humans, these muscles have little or no effect. The ear muscles are supplied by the facial nerve, which also supplies sensation to the skin of the ear itself, as well as to the external ear cavity. Issuu is a digital publishing platform that makes it simple to publish magazines, catalogs, newspapers, books, and more online. Easily share your publications and get. Clinical Guidelines, Diagnosis and Treatment Manuals, Handbooks, Clinical Textbooks, Treatment Protocols, etc. The heart is a muscular organ in humans and other animals, which pumps blood through the blood vessels of the circulatory system. Blood provides the body with oxygen. The great auricular nerve, auricular nerve, auriculotemporal nerve, and lesser and greater occipital nerves of the cervical plexus all supply sensation to parts of the outer ear and the surrounding skin. The pinna consists of a single piece of elastic cartilage with a complicated relief on its inner surface and a fairly smooth configuration on its posterior surface. A tubercle, known as Darwins tubercle, is sometimes present, lying in the descending part of the helix and corresponding to the ear tip of mammals. The earlobe consists of areola and adipose tissue. The symmetrical arrangement of the two ears allows for the localisation of sound. The brain accomplishes this by comparing arrival times and intensities from each ear, in circuits located in the superior olivary complex and the trapezoid bodies which are connected via pathways to both ears. Middle ear. The middle ear lies between the outer ear and the inner ear. It consists of an air filled cavity called the tympanic cavity and includes the three ossicles and their attaching ligaments the auditory tube and the round and oval windows. The ossicles are three small bones that function together to receive, amplify, and transmit the sound from the eardrum to the inner ear. The ossicles are the malleus hammer, incus anvil, and the stapes stirrup. The stapes is the smallest named bone in the body. The middle ear also connects to the upper throat at the nasopharynx via the pharyngeal opening of the Eustachian tube. The three ossicles transmit sound from the outer ear to the inner ear. The malleus receives vibrations from sound pressure on the eardrum, where it is connected at its longest part the manubrium or handle by a ligament. It transmits vibrations to the incus, which in turn transmits the vibrations to the small stapes bone. The wide base of the stapes rests on the oval window. As the stapes vibrates, vibrations are transmitted through the oval window, causing movement of fluid within the cochlea. The round window allows for the fluid within the inner ear to move. As the stapes pushes the secondary tympanic membrane, fluid in the inner ear moves and pushes the membrane of the round window out by a corresponding amount into the middle ear. The ossicles help amplify sound waves by nearly 1. Inner ear. The inner ear sits within the temporal bone in a complex cavity called the bony labyrinth. A central area known as the vestibule contains two small fluid filled recesses, the utricle and saccule. These connect to the semicircular canals and the cochlea. There are three semicircular canals angled at right angles to each other which are responsible for dynamic balance. The cochlea is a spiral shell shaped organ responsible for the sense of hearing. These structures together create the membranous labyrinth. The bony labyrinth refers to the bony compartment which contains the membranous labyrinth, contained within the temporal bone. The inner ear structurally begins at the oval window, which receives vibrations from the incus of the middle ear. Vibrations are transmitted into the inner ear into a fluid called endolymph, which fills the membranous labyrinth. The endolymph is situated in two vestibules, the utricle and saccule, and eventually transmits to the cochlea, a spiral shaped structure. The cochlea consists of three fluid filled spaces the vestibular duct, the cochlear duct, and the tympanic duct. Hair cells responsible for transductionchanging mechanical changes into electrical stimuli are present in the organ of Corti in the cochlea. Blood supply. The blood supply of the ear differs according to each part of the ear. The outer ear is supplied by a number of arteries. The posterior auricular artery provides the majority of the blood supply. The anterior auricular arteries provide some supply to the outer rim of the ear and scalp behind it. The posterior auricular artery is a direct branch of the external carotid artery, and the anterior auricular arteries are branches from the superficial temporal artery. The occipital artery also plays a role. The middle ear is supplied by the mastoid branch of either the occipital or posterior auricular arteries and the deep auricular artery, a branch of the maxillary artery.