192 



THE HUMAN BODY 



round foramen, which, as has already been pointed out, is closed by 

 a membrane. The membranous cochlea contains certain solid 



FIG. 73. Section of one coil of the cochlea, magnified. SV, scala vestibuli; 

 R, membrane of Reissner; CC, membranous cochlea (scala media); Us, limbus 

 laminae spiralis; t, tectorial membrane; ST, scala tympani; Iso, spiral lamina; 

 Co, rods of Corti; b, basilar membrane. 



structures seated on the basilar membrane and forming the organ 

 of Corti; the rest of its cavity is filled with endolymph, which has 

 free passage to that in the sacculus. 



The Organ of Corti. This contains the end organs of the cochlear 

 nerves. Lining the sulcus spiralis are cuboidal cells; on the inner 

 margin of the basilar membrane the cells become columnar, and 

 then are succeeded by a row which bear on their upper ends a set of 



A B 



4' ** 



Fio. 74. The rods of Corti. A, a pair of rods separated from the rest; B, a bit 

 of the basilar membrane with several rods on it, snowing how they cover in the 

 tunnel of Corti; i, inner, and e, outer rods ; b, basilar membrane : r, recticular mem- 

 brane. 



short stiff hairs, and constitute the inner hair-cells, which are fixed 

 below by a narrow apex to the basilar membrane; nerve-fibers 

 enter them. To the inner hair-cells succeed the rods of Corti (Co, 

 Fig. 73), which are represented much magnified in Fig. 74. These 



