Exam 3: Cm 14 Membranous Vestibule & Semicircular Canals

Front 1

Describe the travels of endolymph

Back 1

goes through the endolymphatic duct rises through the endolymphatic sac which sits in the duralining of the brain.

Front 2

Describe the travels of perilymph

Back 2

goes through the cochlear aqueduct moves to cerebral spinal fluid in CNS

Front 3

Describe the connective tissue of the inner ear

Back 3

Membranous duct is inside the osseous duct and is supported by connective tissue. SSC have the most connective tissue, vestibule has less and cochlea has NONE.

Front 4

Name the 2 bulbous shapes of the inner ear

Back 4

Utricle and Saccule

Front 5

What is the Canal Reunions?

Back 5

Little tube that runs down and plugs into the cochlea; it is how endolymph gets from the saccule to the cochlea

Front 6

What combines to create the 8th nerve/accoustic nerve

Back 6

Large nerve trunk off the back of cochlea is the COCHLEAR nerve, (FACIAL nerve?), and VESTIBULAR nerve off the semicircular canals

Front 7

What kind of system is the membranous vestibule? What plane does it give us information on.

Back 7

STATIC system. Sense organs in vestibule give us a sense of our position when we are NOT MOVING. It gives perception of position in space on VERTICAL plane

Front 8

What word is latin for bag? What word is latin for sac?

Back 8

Utricle/Saccule

Front 9

Describe the Utricle

Back 9

Larger; occupies upper posterior vestibule; fits into the elliptical recess of the osseous vestibule; more oval

Front 10

Describe the Saccule

Back 10

Smaller; occupies the spherical recess; more round; near opening of scala vestubli of cochlea

Front 11

Describe the duct work in the utricle and saccule

Back 11

Utricle and Saccule duct combine to form the endolymphatic duct and feed into the endolymphatic sac

Front 12

What does the Endolymphatic duct travel through?

Back 12

Vestibular Aqueduct

Front 13

How does endolymph go from the vestibular area to the cochlea?

Back 13

Canal Reunions

Front 14

What nerve are the nerve tufts from the utricle and saccule part of? What do they send information about?

Back 14

Vestibular nerve and sends neural info to brain about balance

Front 15

What is the macula?

Back 15

Sense organ in the vestibular area, small area with in wall of utrical and another in the saccule (2 total), bed of epithelial cells that constitute sensory patches and is embedded into epithelial hair cells

Front 16

Describe the macula.

Back 16

The macula consists of three layers.

The bottom layer is made of sensory hair cells which are embedded in bottom of a gelatinous layer.

On top of this layer lie calcium carbonate crystals called statoconia or otoliths.

The gelatinous layer and the statoconia together are referred to as the otolithic membrane. When the head is tilted such that gravity pulls on the statoconia the gelatinous layer is pulled in the same direction also causing the sensory hairs to bend.

Front 17

Describe epithelial hair cells of macula.

Back 17

Individual cells that when stimulated that is where neural activity is initiated and sent off to the brain. Tip of each sensory cell has a row of sterocilia and a rather large coarse hair-kenocillium. These touch the bottom of the gelatinous mass. Each hair cell has a nerve fiber coming of the bottom that combines into cable/branch of vestibular nerve.

Front 18

What is positioned on top of the hair cells of the macula?

Back 18

A gelatinous mass of which the density is slightly greater than the endolymph it is floating in. This gelatinous covering stimulates the hair cells.

Front 19

What are otoliths?

Back 19

Calcium carbonate crystals located in the gelatinous mass that assist in stimulating hair cells. Also known as "ear rocks"

Front 20

What is the Crista Ampularis?

Back 20

sense organ in the ampulla

Front 21

What kind of system is the Crista Ampularis?

Back 21

Dynamic system that operates under conditions of acceleration and deceleration to help with balance

Front 22

Compare the crista ampularis to the macula

Back 22

Somewhat similar to membrane vestibule macula. Has hair cells, nerve fibers and gelatinous mass. However, nerve fibers exit through little perforations in the bone and the gelatinous cupula functions through inertia; making endolymph go in opposite direction of the crista ampularis thus stimulating hair cells.

Front 23

What is on the tip of each hair cell touching the bottom of the gelatinous mass

Back 23

row of sterocilla and a large course kenocilium

Front 24

Describe the activation of the different scc and their planes

Back 24

Lateral semicircular canal; detects rotation of the head around a vertical axis (i.e. the neck), as when doing a pirouette or shaking head "no." (horizontal plane)

Superior semicircular canal (aka Anterior semicircular canal); detects rotations of the head in the sagittal plane, move head from ear to ear or side to side

Posterior semicircular canal; detects rotation of the head around an anterior-posterior axis, as when cartwheeling. Move your nose up and down vertically from ceiling to floor.

Each canal is filled with a fluid called endolymph and contains a motion sensor with little hairs (cilia) whose ends are embedded in a gelatinous structure called the cupula. As the skull twists in any direction, the endolymph is thrown into different sections of the canals. The cilia detect when the endolymph rushes past, and a signal is then sent to the brain.

Front 25

Describe the endolymphatic perilymph relationship

Back 25

Perilymph and endolymph are of very different chemical composition. Under normal conditions they occupy separate compartments and, hence, do not mix. Endolymph higher in potassium (K).
Perilymph is higher in sodium (NA) and resembles in its chemical composition other extracellular fluids that are characterized by high Na+ concentration

Front 26

What is the membranous labyrinth filled with?

Back 26

endolymph

Front 27

What are the three divisions of the membranous labyrinth?

Back 27

semicircular canals, utricle & saccule, and the cochlear duct (scala media)

Front 28

Name the membranous parts that comprise the systems of hearing and balance

Back 28

cochlear duct=hearing;
utricle, saccule and semicircular canals=equilibrium

Front 29

What can the system for equilibrium be further divided into?

Back 29

STATIC system which functions in the perception of position in space in the vertical plan and a KINETIC system which functions in the perception of rotation and accelration of the head.

Front 30

Describe the openings of the membranous scc

Back 30

5 openings all entering utricle of vestibule, membranous ampullae correspond to their location to the osseous ampullae

Front 31

What do the membranous ampullae contain?

Back 31

small aggregations of connective tissue upon which are situated the crista ampularis, cupola and hair cells

Front 32

What sensory organ is found in the utricle and saccule?

Back 32

Macculae; responds to linnear forward and sideways movements of the head.

Front 33

What is the role of the membraneous labyrinth?

Back 33

Fundamentally an organ of reflex action for the maintenance of equilibrium and is important in the preservation of a constant field of vision.

Front 34

How do the utricle and saccule communicate?

Back 34

They communicate indirectly by way of the utricular and saccular ducts which join to form a common endolymphatic duct

Front 35

How do the saccule and cochlear duct communicate?

Back 35

Canal reuniens; some believe it is destroyed in adult human. Prevents high frequency disturbances of endolymph transmission from cochlea to vestibule