Sensory, Attentional And Perceptual Processes — Psychology STD 11 Humanities — Question

The structure of an ear is divided into 3 segments, called the external ear, the midDifferntial thresholde ear and the inner ear.

1. External Ear: It contains 2 main structures namely Pinna and auditory meatus. Pinna is a cartilaginous funnel-soaped structure that collects sound waves from the surroundings. Auditory meatus is a canal protected by hair and wax that carries sound waves from pinna to the tympanum or ear drum.
2. Middle Ear: The middle ear starts with tympanum, a thin membrane highly sensitive to sound vibration. This is followed by the tympanic cavity. It is connected to the pharynx with the help of Eustachian tube which maintains the air pressure in tympanic cavity. From the cavity the vibrations pass to three ossicles known as malleus (hammer), incus (anvil) and stapes (stirrup). They increase the intensity of sound vibrations about 10 times, and send them to each inner ear.
3. Inner Ear: The inner ear has a complicated structure known as membranous labyrinth, which is encapsulated in a bony shell called bony labyrinth. A lymphlike fluid is found in the space between bony labyrinth and membranous labyrinth. This is called perilymph.

The bony labyrinth has 3 semicircular canals at right angle to each other, a cavity called vestibule and a coiled structure called cochlea the semi circular canals have fines hair cells, which are highly sensitive to postural changes as well as changes in the body orientation. Inside the body cochlea there is a membranous cochlea, which is also known as scalae media. It is filled with endolymph called basilar membrane has got fine hair cells arranged in a series to form the organ of corti. This is the main organ for hearing.