Unit 1 study cards (inner ear)

Question 1

Inner Ear

Answer 1

part of the ear where mechanical energy is TRANSDUCED into neural signals.

Structures of the inner ear are encased within the temporal bone

Two components of the Inner ear:
1. Cochlea - for hearing
—Three chambers/Scala (3 fluid filled spaces)
2. Vestibular system - (semi-circular canals, utricle and saccule in vestible) - balance
—Tube within a Tube (2 fluid filled spaces)

Question 2

Bony Labyrinth

Answer 2

The space within the temporal bone that encases the inner ear-cavities which contain fluids and and the membranous labyrinth.

Perilymph is between the Bony and Membranous Labyrinth but I am putting it on this flashcard for ease.

Question 3

Membranous Labyrinth

Answer 3

the inner core of the inner ear, encased in membranes.

contains Endolymph

Question 4

characteristics of the COCHLEA

Answer 4

Makes 2 3/4 turns

It is 35mm long from the base to the apex

about 6.8 mm high

Entirely enclosed in petrous temporal bone (otic capsule)

There are three chambers of the cochlea
1. Scala Vestibuli
2. Scala Media
3. Scala Tympani

Question 5

Chambers/Scala of the COCHLEA

Answer 5

1. Scala Vestibuli
2. Scala Media
3. Scala Tympani

Question 6

Endolymph Fluid

Answer 6

-High in potassium ions (K+)
-found ONLY in the Scala Media
-unique composition similar to saliva
-about 2.7 microliters in humans

Question 7

Perilymph Fluid

Answer 7

-High in sodium ions (Na+)
-found in Scala Tympani and Scala Vestibuli
-Similar to CSF
-about 16-23 microliters in humans

Question 8

Scala Vestibuli

Answer 8

-Perilymph filled (sodium fluid is between bony labyrinth and membranous labyrinth)
-superior to the Scala Media

Question 9

Scala Media

Answer 9

-Endolymph filled (potassium fluid is within the membranous labyrinth)

-action in terms of hearing sensation takes place here inside of the organ of corti.

-the BASILAR MEMBRANE makes up part of the floor of the scala media

Question 10

Scala Tympani

Answer 10

-Perilymph filled (sodium fluid is between bony labyrinth and membranous labyrinth)
- inferior to the scala media

Question 11

Osseous Spiral Lamina

Answer 11

It is a bony spiral plate and projection from the bony core at the center of the cochlea (Modiolus). It is shaped like a spiral ramp.

It makes up the floor of the SCALA MEDIA by connecting to the basilar membrane which makes up the rest of the floor.

Question 12

Modiolus

Answer 12

The core of temporal bone at the center of the cochlea. The 8th nerve fibers run though the hollow core and exit through openings in the Osseous Spiral Lamina to innervate the entire length of the Cochlea.

Question 13

Spiral Ganglion

Answer 13

Cell bodies of the fibers of the 8th nerve form a spiral ganglion because of the very special arrangement of the neurons of the 8th nerve (they run up through the modular core and fan out all the way along the spiral lamina).

Question 14

Helicotrema

Answer 14

The Helicotrema is the narrow passageway that connects the Scala Tympani and the Scala Vestibuli and allows the fluids to communicate.

Question 15

organ of corti

Answer 15

has the receptor cells and runs the entire length of the cochlea (36 mm long).

It is kind of like a long strip.

Question 16

Reisner’s membrane

Answer 16

Reisner’s membrane separates the SCALA MEDIA from the SCALA VESTIBULI

Question 17

Recticular Lamina

Answer 17

It is the covering of the organ of corti and it’s water tight. It prevents the perilymph fluid from mingling in a toxic way with the endolymph fluid in the Scala Media.

Question 18

Tunnel of Corti

Answer 18

What is in it? It is filled with Endolymph fluid

What supports it? It is supported by pillars of protein that separate the inner and outer hair cells.

Question 19

Stria Vascularis

Answer 19

It is on the lateral wall of the Scala Media.

It helps to provide the BATTERY that is necessary for ion flow to take place and neural firind to occur for transduction.

it provides electrical activity within the Cochlea