COM 1 Histology week 7

Question 1

What does the internal ear consist of

Answer 1

bony labyrinth and membranous labyrinth

Question 2

What is bony labyrinth

Answer 2

A set of interconnected spaces

Question 3

What is the membranous labyrinth

Answer 3

• interconnected spaces that is lined with epithelum and smaller

Question 4

What does the membranous labyrinth originate from+ week

Answer 4

• Otic vesicle
• 4 th week of embryonic development

Question 5

What does the membranous labyrinth includes :

Answer 5

• Utricle and saccule
• Semiciruclar dicts
  -Cochlear duct

Question 6

What does the membranous labyritnh contain

Answer 6

mechanorecptors called, hair cells

Question 7

Name the specialised sensory regions that the mechanorecptors, hair cells from the membranous labyrinth is

Answer 7

• maculae
  -Cristae ampullares
  -Organ of corti

Question 8

Name the 3 regions of the bony labyrinth+ 2function+ contents

Answer 8

• The vestibule, houses the utricle and saccule
  -Semicircular canals , encloses the smicircular ducts
  -The cochlea, contains the cochlear duct

Question 9

What does the cochlea make turns around

Answer 9

• modiolus

Question 10

What does the modiolus contsin

Answer 10

• blood vessels and the cell bodies and processes of the acoustic branch of the 8 cranial nerve

Question 11

Name the 2 fluids in the inner ear

Answer 11

• Perilymph
  -Endolymph

Question 12

What does perilymph fill

Answer 12

Bony labyrinth

Question 13

Where is perilymph fluid produced in + where does it drain into

Answer 13

Microvasculature of the periosteum , drains into the subarachnoid space

Question 14

What does the perilymph support

Answer 14

Supports the membranous labyrinth

Question 15

What does the endolymph fill

Answer 15

They fil the membranous labyrinth

Question 16

Explain the ion content in the endolymph

Answer 16

• has High k+ and lwo Na

Question 17

What is the utricle and saccule

Answer 17

Membranous sacs in the bestibule

Question 18

What is maculae +what does it contain

Answer 18

Specialised sensory areas
- Contains hair cells and supoorting cells

Question 19

Explain the plane of the maculae in the utricle

Answer 19

Horizontal plane

Question 20

Explain the plane of the maculae in the saccule

Answer 20

Vertical plane

Question 21

What does each hair cell contain

Answer 21

Kinocilium

Question 22

What does the upper part of hair cells contain

Answer 22

otoliths

Question 23

Name the types of hair cells

Answer 23

• Type 1 hair cell
  -Type 2 hair cell

Question 24

Explain the structure of type 1 hair cell

Answer 24

• Rounded base,

Question 25

Explain the structure of type 2 hair cell

Answer 25

More numerous -cylindrical with bouton synapses

Question 26

Explain the process in deflection towarda the kinocilium in mechanotransduction: -Starting from tip links

Answer 26

Tip links pull open cation channels. K⁺ influx (from endolymph) → depolarization. Ca²⁺ channels open → neurotransmitter release → afferent nerve impulse.

Question 27

Explain the process in deflection away from kinocilium in mechanotransduction

Answer 27

-Tip links slack → cation channels close. Hair cell hyperpolarizes → Ca²⁺ channels close → less neurotransmitter release.

Question 28

In resting state, when the head stops movving what happens to stereocilia

Answer 28

It straighens

Question 29

What is uricle and saccule lined with

Answer 29

stratied squamos epithelium

Question 30

Name all the semicircular ducts

Answer 30

Anterior posterior lateral

Question 31

What does each semicircular duct connect to

Answer 31

utricle

Question 32

Where is the cristae amullaris located + what does it contain

Answer 32

- In ampulla - Hair cells and supporting cells

Question 33

What is the function of the cristae ampullaris

Answer 33

- Detects the rotational movements of the ehad

Question 33

What is vertigo

Answer 33

False sensations of spinnign

Question 34

In the vestivular inputs whereis the sensory input from

Answer 34

- Semicircular ducts -Utricle and saccule -Proprioceptors

Question 35

What is vertigo caused by

Answer 35

Inflammatio overstimulation of criste ampullares and maculae

Question 36

What are symotoms of meniere disease

Answer 36

- Vertigo hearing loss tinnitus

Question 37

What does the meniere disease cause

Answer 37

Increased endolymph pressure

Question 38

What is BPPV(benign Paroxysmal postitional vertigo) TRIGGERED by

Answer 38

- Sudden head movemnts

Question 39

What is BPPV caused by

Answer 39

- Otoliths detaching from the utricle

Question 40

How is BPPV treated

Answer 40

Epley maneuver

Question 41

Where does the organ of corti sit

Answer 41

On the basilar membrane

Question 42

Name the supporting cells the organ of corti contains

Answer 42

- Phalangeal cells -Pillar cells

Question 43

What is the tectorial membrane + what is it made out of

Answer 43

- Gel like membrane made out of collagne and proteoglycan

Question 44

Explain the process in hair cell activation starting from a vibration

Answer 44

Hair Cell Activation: Vibration deflects stereocilia → depolarization → neurotransmitter release. Outer hair cells use prestin to change length → pull on tectorial membrane → enhance inner hair cell stimulation.

Question 45

What is the funcion of outer hair cells

Answer 45

- Fine tune and ampify vibrations for precise hearign

Question 46

What are cochlear implants used for

Answer 46

- USED For sensorineural deafness ( nerve deafness)

Question 47

How does cochlear impkants help with sensorineural deafness

Answer 47

Helps with speach perception

Question 48

Name the 2 types of hearing loss

Answer 48

- Conductive hearing loss -Sensorineural hearing loss

Question 49

What are the causes of conductive hearing loss

Answer 49

otosclerosis -Otitis media