Tag: biology

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Multiple choice biology sensory organs of humans - sense organs ear : the organ of hearing and equilibrium ear and its function ear

Which one is used in balancing?

  1. Organ of Corti

  2. Vestibular region

  3. Middle ear

  4. Cochlea
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Vestibular region or vestibular apparatus is a complex system present in the inner ear. It consists of three semi-circular canals and a otolith organ that contains saccule and utricle having a projecting ridge called macula. The bony canals contain perilymph and surrounds membranous canals. The base of canals is swollen and known as ampulla that contains a projecting ridge called crista ampullaris possessing hair cells. Crista and macula are the receptors of vestibular apparatus which are responsible to maintaining balance and posture of body.
So, the correct answer is 'Vestibular region'.
Multiple choice biology sensory organs of humans - sense organs ear : the organ of hearing and equilibrium ear and its function ear

Identify the wrong statement regarding the mechanism of hearing.

  1. External ear receives and directs the sound waves to ear drum

  2. Vibrations produced in ear drum are transmitted through ear ossicles and oval window to fluid-filled inner ear

  3. Movement of basilar membrane bends the hair cells

  4. Nerve impulses are generated and transmitted by efferent fibres to the auditory cortex of brain

  5. Cerebellum integrates information from semicircular canals of ear and auditory system.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Mechanism of hearing is as follows:
  • When sound waves from the environment enter the external ear, they are directed to ear drum (tympanic membrane). 
  • The ear drum vibrates on receiving sound waves and the vibrations are sent to oval window through ear ossicles which are malleus, incus and stapes. 
  • From the oval window, these vibrations are passed onto fluid of cochlea where waves are generated into lymph due to these vibrations. 
  • These waves generate vibrations in the basilar membrane which bend the hair cells and press them against the tectorial membrane.
  • This results in the generation of nerve impulses in afferent neurons which are transmitted by afferent fibres to auditory cortex of brain. 
  • The impulses are analysed and recognised in brain.
Cerebellum integrates information about static equilibrium and motion or movement from semi-circular canals of ear and auditory system.
Hence, statement D is incorrect.
So, the correct answer is 'Nerve impulses are generated and transmitted by efferent fibres to the auditory cortex of brain'.
Multiple choice biology sensory organs of humans - sense organs ear : the organ of hearing and equilibrium ear and its function ear

The correct path followed by sound waves from external ear to inner ear is

  1. Ear drum - basilar membrane - auditory ossicles - fluid of cochlea - hair cells

  2. Ear drum - auditory ossicles - fluid of cochlea - basilar membrane - hair cells

  3. Ear drum - hair cells - auditory ossicles - basilar membrane - fluid of cochlea

  4. Ear drum - fluid of cochlea - auditory ossicles - hair cells - basilar membrane
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

  • Sound waves from the environment enter the external ear and are directed to ear drum (tympanic membrane). 
  • The ear drum vibrates on receiving sound waves and the vibrations are sent to oval window through ear ossicles which are malleus, incus and stapes. 
  • From the oval window, these vibrations are passed onto fluid of cochlea where waves are generated into lymph due to these vibrations. 
  • These waves generate vibrations in the basilar membrane which bend the hair cells and press them against the tectorial membrane.
So, the correct answer is 'Ear drum - auditory ossicles - fluid of cochlea - basilar membrane - hair cells'.

Multiple choice biology sensory organs of humans - sense organs ear : the organ of hearing and equilibrium ear and its function ear

Maculae maintains

  1. Static equilibrium

  2. Dynamic equilibrium

  3. Both A and B

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Maculae are the specialized mechanoreceptors within the utricle and saccule for the detection of static equilibrium, they make use of the hair cells to detect the movements of the otolithic membrane, the nerve impulses thus generated and transmitted along the vestibular branch of the cranial nerve to the central nervous system.

So, the correct option is c 'Both a and b'.

Multiple choice biology sensory organs of humans - sense organs ear : the organ of hearing and equilibrium ear and its function ear

The balancing organ of ear is

  1. Lagena and Sacculus

  2. Semicircular canal and Utriculus

  3. Semicircular canal and Ossicles

  4. Otolith and Lagena
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The vestibular system, which is responsible for balance, consists of the semicircular canals and the otolith organs, which include the utriculus and sacculus.

Multiple choice biology sensory organs of humans - sense organs ear : the organ of hearing and equilibrium ear and its function ear

The sensory receptors that respond to sound, develop receptor potentials when their

  1. Hairs are absent

  2. Pigments absorb pressure

  3. Surface proteins are altered by a change in pH

  4. Sodium-potassium pumps become deactivated.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The organ of Corti is a structure located on the basilar membrane which contains hair cells that act as auditory receptors. Movements of the basilar membrane bend the hair cells, pressing them against the technical membrane. As a result, nerve impulses are generated in the association afferent neurons. These impulses are transmitted by the afferent fibers via auditory nerves to the auditory cortex of the brain, where the impulses are analyses and the sound is recognized.
So the correct answer is 'Hairs are absent'.
Multiple choice biology sensory organs of humans - sense organs ear : the organ of hearing and equilibrium ear and its function ear

Membranous labyrinth is concerned with

  1. Sensing

  2. Hearing with balancing

  3. vagus nerve

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The functional components of the membranous labyrinth involved in the sensations of static and dynamic equilibrium are a system of thin walled, intercommunicating tubes and ducts situated within the petrous part of the temporal bone at the base of the skull. There are five vestibular structures, each containing a specialized mechanoreceptor, (maculae), within the utricle and saccule, and cristae within the ampulla of the superior, horizontal, and posterior semicircular canals.

Multiple choice biology sensory organs of humans - sense organs ear : the organ of hearing and equilibrium ear and its function ear

Sensation of hearing is produced as a result of the

  1. Presence of the helicotrema

  2. Vibrations set in the external auditory meatus

  3. Vibrations of the ear ossicles

  4. Nerve impulses generated by the hair cells of the organ of Corti
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Within the bony labyrinth, is the membranous labyrinth; filled with the fluid called as endolymph. The membranous labyrinth within the cochlea contains the organ of Corti containing the inner and outer hair cells, that generate the nerve impulses required for hearing. Nerve impulses generated in the inner ear travel along the vestibulocochlear nerve (cranial nerve VIII) to the brain.