Applied Anatomy and Physiology: The Ear

Protects middle and inner ear & serves as channel for sound transmission

Aditus ad antrum

Tympanum, Eustachian tube, and mastoid air cell system

<p>Deficient aeration of mastoid cell system</p> Signup and view all the answers

<p>Outer cartilaginous portion</p> Signup and view all the answers

<p>The three main functions of the Eustachian tube are: 1) Ventilation and pressure regulation of the middle ear, 2) Protection of the middle ear from ascending nasopharyngeal secretions and pathogens, and 3) Clearance of middle ear secretions towards the nasopharynx.</p> Signup and view all the answers

<p>The Eustachian tube is more horizontal and shorter in children compared to adults, which is the reason why infections are more common in infants and small children.</p> Signup and view all the answers

<p>The major cation in perilymph is sodium, as in extracellular fluid, but the major cation in endolymph is potassium, which is vital for the functioning of the inner ear.</p> Signup and view all the answers

<p>The oval window (fenestra vestibuli/ovalis) is the opening leading from the tympanic cavity into the vestibule of the internal ear. The round window (fenestra cochleae/rotunda) is situated inferior and a little posterior to the oval window, from which it is separated by the rounded elevation called the promontory.</p> Signup and view all the answers

<p>The bony labyrinth is the system of cavities within the petrous portion of the temporal bone that protects the delicate structures of the membranous labyrinth and is filled with perilymph fluid. The membranous labyrinth is the system of ducts and sacs within the bony labyrinth, filled with endolymph fluid.</p> Signup and view all the answers