NB23 Ear

Question 1

How is sounds detected through the ear?

Answer 1

	Pressure waves conducted through middle and inner ear
	Frequency - Hz
	Generates waves in fluid in cochlear
	Hair cells move
	Triggers hair cell receptor activation

Question 2

What does saccule detect?

Answer 2

forwards and backwards movemetn

Question 3

What is contained in the urticle?

Answer 3

hair cells that monitro movement

Question 4

1) What vibrates against the tectorial membrane?

2) What does the tecotorial membrane cause to vibrate?

Answer 4

organ of corti

2) ?????spiral ganglion

Question 5

As you age what happens to your cochlea?

2)

Answer 5

1) it unravels

so you can’t detect as high a frequency

Question 6

Wherein the cochlea is

1) high frequencies heard?
2) low frequecncies?

Answer 6

1) base
2) apex
of cochlea

Question 7

Which hair cells recieve efferent from superior olive?

Answer 7

outer hair cells

Question 8

Describe the mechanism fro sound being transduced in a inner hair cell?

Answer 8

1) stereocilia move (joined together to aid movement)
2) K+ channels open
3) K+ moves in= hyperopolarisiaiton
4) Ca++ channels open= vescicles exocyutosied
5) neurotransmittor, glutamate released

Question 9

Why is the auditory pathway bilateral?

Answer 9

so we can work out where the sound is coming from,

Question 10

Describe the auditory pathway:

Answer 10

1) from dorsal and ventral cochlear nuclei to superior olivary nucleus
2) to inferior colliculus
3) to medial geniculate nucleus

Question 11

What is skipped in the auditory reflex pathway?

Answer 11

the superior olivary nucleus

Question 12

From the primmary auditory cortex descibe how speech is initiated:

Answer 12

1. primmary auditory cortex
2. association auditory cortex
3. wernicke’s area
4. arcuate fasciculus
5. Broca’s area
6. Motor cortices

Question 13

How is orientation detected in the ear?

Answer 13

in the vestibular apparatus

Question 14

What does the vestibular apparatus consist of?

Answer 14

3 semi-circular canals

which ends widen into 2 sac the utricle and saccule

Question 15

What is contained within the utricle and saccule of the ear?

Answer 15

otolith organs

Question 16

Describe the vestibular nerve pathway for info from

1) semi-circular canals:

Answer 16

1) input into vestibular nucleus
2) This info is sent to the cerebellum, spinal cord, nucleus 6 or via the medial longitudinal fasciculus (MLF) to nuclei CN 3 &4
3) Nucleus CN3 then sends axons to extraocular muscles

Question 17

What detects position in the semi-circular canals?

How do they work?

Answer 17

ampullae which are hair cells. Whose cilia is encapsulated in a cupula in endolymph.
2) When the endolymph flows it pushes on the cupula and thus the cilia, so movement is detected in hair cells.

Question 18

What inputs into the vestibular nucleus?

B) Where is the vestibular nucleus?

Answer 18

1.ampulae of semicircular canals
2. maculae of utricle
3. maculae of saccule
B) in the brainstem

Question 19

What are the otolith organs?

2) What do the 2 otolith organs detect?

Answer 19

saccule and utricle

2) Saccule- vertical acceleration (such as when in an elevator).
2) Utricle- horizontal movement,

Question 20

What is contained in the sacculae and utricle?

Answer 20

hair cells known as maculae. Within each maculae, the stereocilia are embedded in a gelatinous mass known as the otolithic membrane, which contains small stonelike calcium carbonate particles called otoconia

Question 21

What is within each maculae

Answer 21

It is a cell whoses stereocilia are embedded in a gelatinous mass known as the otolithic membrane, which contains small stonelike calcium carbonate particles called otoconia. They move with gravity

Question 22

Describe the vestibular nerve pathway for info from

2) macula

Answer 22

1) input into vestibular nucleus

2) This info is sent to the cerebellum and spinal cord,

Question 23

Why is info sent from vestibular nucleus to cerebellum and spinal cord?

Answer 23

for balance