Tag: ear

Receptors that sense the change in atmospheric pressure are classified under mechanoreceptors. Three pressure receptors are namely Pacinian corpuscles, Ruffini endings and Krause end bulbs which are located in skin. This makes option A incorrect. The three semicircular canals lie at right angle to each other in vestibular apparatus of inner ear and are filled with endolymph; this arrangement senses the change in movement (acceleration or deceleration) or position. The mechanism includes movement of cupula in response to movement of endolymph within the canal causing the bending of cilia to generate the nerve impulse. This makes option C correct and option D incorrect. Migratory birds and animals have receptors in their brain which are activated by direction of sunlight and orient their body at certain angle in relation to sun. This makes option B incorrect. Correct answer is C. 

Receptors that sense the change in atmospheric pressure are classified under mechanoreceptors. Three pressure receptors are namely Pacinian corpuscles, Ruffini endings and Krause end bulbs which are located in skin. This makes option A incorrect. The three semicircular canals lie at right angle to each other in vestibular apparatus of inner ear and are filled with endolymph; this arrangement senses the change in movement (acceleration or deceleration) or position. The mechanism includes movement of cupula in response to movement of endolymph within the canal causing the bending of cilia to generate the nerve impulse. Migratory birds and animals have receptors in their brain which are activated by direction of sunlight and orient their body at certain angle in relation to sun. Thus, the correct answer is option C.

The olfactory nerve is the second cranial nerve which transmits the nerve impulses from olfactory receptors, receptors of sense the smell that are located in nasal epithelium of roof of the nasal cavity, to the brain.

Statoreceptors are the receptors for sense of balance and equilibrium. They are present in vestibular apparatus of inner ear. 

The inner ear consists of two systems of canals which are namely cochlea and vestibular apparatus. The vestibular apparatus consists of three semicircular canals, cristae and two sacs called as saccule and utricle. The cochlea is the organ of hearing which contains mechanoreceptors for hearing. This makes option B incorrect. The three semicircular canals lie at the right angle to each other in vestibular apparatus of the inner ear and are filled with endolymph; this arrangement senses the change in movement (acceleration or deceleration) or position. The mechanism includes movement of cupula in response to movement of endolymph within the canal causing the bending of cilia to generate the nerve impulse. Hammer is one of the three ossicles of the middle ear which is concerned with amplification of air pressure while passing it from the inner surface of tympanic membrane via incus to stapes. The eustachian tube extends from each middle ear to nasopharynx and permits the equalization of air pressure. Thus, the correct answer is option A.

The human ear can generally hear sounds with frequencies between 20 Hz and 20 kHz. Although hearing requires an intact and functioning auditory portion of the central nervous system as well as a working ear, human deafness most commonly occurs because of abnormalities of the inner ear, rather than in the nerves or tracts of the central auditory system. Sound below 20 Hz is considered infrasonic, which the ear cannot process. Therefore, the correct answer is option A.

Ear of frog consists of only two parts - middle and internal ear but no external ear. In the rabbit, ear has three regions which are external, middle and internal. External ears consist of the pinna (auricle) and auditory canal (external auditory meatus). Pinna is provided with voluntary muscle and is supported by elastic fibrocartilage. Pinna helps in collecting the sound waves. So, hearing in the rabbit is better than the frog.

The semicircular canals are three canals used to provide information to the brain on directional balance and equilibrium. Each canal is lined with cilia and filled with a fluid called endolymph. As the head and body move, the fluid moves and pushes the cilia back and forth to create a motion sensor.