Ear We Go Outer Ear Pinna Ear Canal

Ear We Go

Outer Ear (Pinna, Ear Canal, Surface of Ear Drum) • Pinna – not vital for hearing although does help capture sound • Ear Canal is the most functional part of the outer ear • Ear wax (cerumen) produced by glands in the skin of the outer portion of the ear canal • Outer ear canal skin is cartilage based while deeper ear canal skin is laid upon bone of the skull

Middle Ear (Cavity behind ear drum, Ear Bones) • Cavity behind ear drum is filled with air • This tympanic cavity is a hollow mucosa lined cavity ventilated through nose • The Eustachian tube is usually closed but opens with swallowing and positive pressure • When taking off in an airplane, the surrounding air pressure goes from higher (on the ground) to lower (in the sky). The air in the middle ear expands as the plane gains altitude, and pushes its way into the back of the nose and mouth • Active opening of the Eustachian tube is required to equalize the pressure between the middle ear and the surrounding atmosphere

Middle Ear (Cavity behind ear drum, Ear Bones) • Ear Bones – malleus (hammer), incus (anvil) and stapes (stirrup) • Stapes is the smallest named bone in the body • Bones are arranged of these 3 bones is a sort of Rube Goldberg device • Movement of the surface of the ear drum causes the movement of the first bone, which causes movement of the second, which causes movement of the third which causes movement of the fluid in the cochlea • Using Q-tips may cause impacted ear wax – which will produce conductive hearing loss

Inner Ear (Cochlea, Vestibule, and Semi-Circular Canals) • Cochlea – organ of hearing – Three fluid filled spaces: the tympanic canal, the vestibular canal and the middle canal – When the movement from sound is transferred to the stapes it is then transferred to one of the canals in the cochlea – The fluid inside this canal moves, flowing against the receptor cells of the organ of Corti, which fire. These stimulate the Spiral Ganglion, which sends information through the auditory portion of the eighth cranial nerve to the brain stem • Vestibule – sense organ attuned to effects of both gravity and motion – Three semi-circular canals • Inner ear is encased in the hardest bone of the body

Ring tones that adults cannot hear Typical healthy young person can hear sounds from 2020, 000 Hz Dog is 40 -100, 000 Hz Let’s test your hearing range.

Vocal Cords Usually misspelled “vocal chords” because of the relationship to music

Anatomy

• • • The vocal folds, also known popularly as vocal cords, are composed of twin infoldings of mucous membrane stretched horizontally across the larynx They vibrate, changing the flow of air being expelled from the lungs during pronunciation Another name for the airway at the level of the vocal cords is the glottis, and the opening between the cords is called the glottic chink. The size of the glottic chink is important in respiration and phonation. Open during inhalation, closed when holding one's breath, and held apart just a tiny bit for speech or singing; the folds are controlled via the vagus nerve. They are white because of scant blood circulation. The folds vibrate when they are closed to obstruct the airflow through the glottis, the space between the folds: they are forced open by increased air pressure in the lungs, and closed again as the air rushes past the folds, lowering the pressure A person's voice pitch is determined by the resonant frequency of the vocal folds. In an adult male this frequency averages about 125 Hz, adult females around 210, in children the frequency is over 300 Hz.

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Adam’s Apple • The Adam's apple is typically more prominent in adult men than in women or prepubescent girls or boys. • The growth of the Adam's apple and the larynx during puberty is responsible for the voice cracking in teenage boys • The main reason for the Adam's apple usually being more prominent in males is that the two laminae of the thyroid cartilage that form the protrusion meet at an angle of 90° in males but that angle is usually 120° in females.