Question

‘Tensor tympani’ and ‘stapedius’ muscles are found in
A. External ear
B. Middle ear
C. Internal ear
D. External auditory meatus

Answer 1

Hint: The ear is a sense organ in vertebrates. It is also an organ of balance in mammals. The ear has three parts – the outer ear, middle ear and inner ear. Each of these parts are involved in the process of hearing. Apart from cavities and bony structures, the parts of the ear have muscles associated with them that help in protection of the ear from loud noises.

Complete answer:
Option (a) is incorrect. External ear is the visible part of the ear. It is also known as the pinna. The external ear opens into the ear canal. It is associated with two sets of muscles – the intrinsic and extrinsic muscles. These muscles have little function in human beings. However, in certain mammals, these muscles help to move the pinna.
Option (b) is correct. Middle ear is present in between the outer and inner era. It is responsible for transmitting sound waves from the outer ear to inner ear. It is composed of three tiny bones named malleus, incus and stapes. The muscles associated with the middle ear are called tensor tympani and stapedius. The tensor tympani are attached to the malleus. It functions to reduce the sounds made by chewing. The stapedius is the smallest known muscle in the body. It functions to stabilize the stapes and reduce excess movement of the bone.
Option (c) is incorrect. The internal ear is the innermost part of the ear. Apart from detection of sound, the inner ear is also involved in maintaining the balance of the body. It remains associated with the eighth cranial nerve of the nervous system.
Option (d) is incorrect. External auditory meatus extends from the outer ear and ends before the eardrum. The canal has a cartilaginous part and bony part. There are specialized apocrine glands in the auditory canal that secrete ear wax or cerumen. It helps to clean the ear and protect it against bacteria and fungi.

Hence, the correct answer is option (B).

Note: The human ear is an organ of hearing. It comprises bones, canals and its associated muscles. The ‘Tensor tympani’ and the ‘Stapedius’ are muscles present in the middle ear. They help to protect the ear against loud noises and help to control the movement of the bones present in the middle ear.