NERVOUS SYSTEM Session 7

Question 1

What are three division of the ear?

Answer 1

• Outer , Middle and Inner

Question 2

What does the Outer ear consist of ?

Answer 2

• Consists of the pinna and the auditory canal

Question 3

Where is the Middle of the ear classified as ?

Answer 3

• begins at the tympanic membrane ( eardrum ) and ends at a bony wall containing two small openings covered by membranes

Question 4

What are the two small openings in the middle ear known as ?

Answer 4

• Oval window and round window

Question 5

What three small bones found here ( ossicles )

Answer 5

• Malleus ( hammer , touches the tympanic membrane )
• Incus ( anvil )
• Stapes ( stirrup , which touches the oval window )

Question 6

What connects the middle ear to the nasopharynx ?

Answer 6

• the auditory tube

Question 7

What are the three areas of the inner ear and what do each of them do ?

Answer 7

• The semicircular canals and vestibule both handle equilibrium and the cochlea handles hearing

Question 8

How does the auditory pathway work to the brain ?

Answer 8

• sound waves strike the tympanic membrane , which causes vibrations of the malleus , incus and then the stapes
• the ossicles actually amplify the vibrations and then the stapes strikes the oval window causing it to vibrate which then passes the pressure to the fluid within the cochlea
• Which then causes the basilar membrane to move up and down , bending the sterocillia of the hair cells embedded in the tectorial membrane .
• Lastly Nerve signals now begin in the cochlear nerve and travel to the auditory cortex in the temporal lobe , where they are interpreted as sound .

Question 9

What are the three different canals of the cochlea ?

Answer 9

• Vestibular , Cochlear , Tympanic

Question 10

What is the Spiral organ (Organ of Corti) ?

Answer 10

• The sense organ of hearing

Question 11

How are low and high pitches interpreted in the spiral organ ?

Answer 11

• The tip of the spiral organ respond to low pitches and the base respond to higher pitches

Question 12

How is the volumed effect the activity in the cochlea ?

Answer 12

• If it is louder , it causes the fluid in the vestibular canal to exert more pressure and the basilar membrane to vibrate to a greater extent

Question 13

What is the sense of equilibrium ?

Answer 13

• It is the position in space which is transmitted by vestibular nerve taking information from the semicircular canals , saccule and utricle , which then takes signals to the Brian stem and cerebellum

Question 14

How is rotational equilibrium handled?

Answer 14

• By the mechanoreceptors in the semicircular canals.

Question 15

What is the ampulla and what does it contain ?

Answer 15

• it is the base and it contains hair cells , whose steroecillia is embedded within the cupula

Question 16

How does the rotational equilibrium pathway work ?

Answer 16

• As fluid ( endolymph ) within a semicircular canal flows over and displaces a cupola , the stereocilia of the hair cells bend , then the vestibular nerve carries signals generated here to the brain.
• Then appropriate motor output to various skeletal muscles corrects the body position in space as needed

Question 17

What does the gravitational equilibrium include ?

Answer 17

• movement of head relative to gravity

Question 18

what are the two membrane races located near the semicircular canals called and what do each of the deal with ?

Answer 18

• Utricle : deals with the vertical changes
• Saccule : deals with the horizontal changes

Question 19

Where are the stereocilia embedded of Utricle and Saccule ?

Answer 19

• In the otolithic membrane

Question 20

What is a Otoliths ?

Answer 20

• they are calcium carbonate granules that rest on the otolithic membrane

Question 21

How does the resting position of the Otoliths vary in relation to movement ?

Answer 21

• When the body is still , the otoliths rest on the otolithic membrane above the hair cells
• When the body moves in the horizontal and vertical planes the otoliths are displaced

Question 22

What is the increase and decrease in the vestibular nerve caused by ?

Answer 22

• When the stereocilia bend toward the largest steroecilium ( kinocilium ) nerve impulses increases in the vestibular nerve
• When the sterocilia move away from the kinocilium , nerve impulse decreases