The two sets of rods are capped by a membrane called tecforial membrane'I The hairs arising om the hair

On the other hand, in an aeroplane journey, where there is no provision for iressunzed chamber', the air of The middle ear can expand because of fall of atmospheric pressure in the altitude and ause discomfort. Cotton plugs may be used or frequent acts of swallowings (by sucking lozenges) helps to reduce such iscomfurts. (Students accustomed to travel by air may recall. Indian Airlines supply lozenges on board. ) The internal ear ig 10B2.4. 3) The cochlea (so named because of its appear ence; cochlea = a snail) consists of 23/4 turns. By two hembranes, viz. the Reissner's membrane and the basilar membrane, the canal of cochlea is subdivided into three avities, (i) scafa vestibuli, (ii) scab media, and the (iii) scalatympani (fig 10B2. 4.4). On the top of Reissner's membrane es the scala vestibuli (fig.10B2.4.3 and fig.10B2.4.4) containing a fluid called 'penlymph" Between the Reissner's hembrane and the basilar membrane, lies the scala media, containing 'endolymph 'whereas below Ihe basiJar membrane, i the penlymph filled cavity called scala tympani. On the basilar membrane, rests the organ of Corti fig.10B2.4.4). Near ie apex of the cochlea, the scala vestibulr communicates with the scala tympani via helicolrema (fig. 102.4.) ig.10B2.4.3. Schematic view of middle and internal ear. Organ of Corti (fig 10B2. 4.4. & 10B2 4.5) There is one organ of orti in each ear. This structure (fig 10B2.4.4 & 10B2.4. 5) resis on the basilar membrane and consists of two sets of rods, he (i) inner and (ii) The outer rods. Inner to The inner rod, There is one row of 'hair cells' and outer to The external rod he our rows of hair cells. The two sets of rods are capped by a membrane called tecforial membrane'I The hairs arising om the hair cells are embedded in the teclonal membrane. (In between the two sets rods, lies a tunnel, called the tunnel