HEARING -

1. Sound waves struck ear drum, it starts vibrations, these vibrations are carried to MIS → f. ovalis → S. vestibule →  Hellicotrema → S. Tympani → f. rotundus → middle ear.
2. In this way organ of corti are affected indirectly & sense of hearing is carried to brain by auditory nerve.
3. Man can hear frequencies as low as 20 cycles per second & as high as 20,000 cps.
4. The audible range of dog ranges 40,000 cps, and that of bat 1,00,000 cps.

Note : Common house cricket is having auditory receptors on legs, cockroach on anal cerci and antennae.