Contents
What does movement of the endolymph do?
The acceleration of endolymph within regions of the vestibular apparatus allows for our perception of balance and equilibrium. This occurs through head movement that causes endolymph to move specialized cells known as hair cells.
How does the endolymph affect the cupula during movement?
When the head rotates, the endolymph filling the semicircular ducts initially lags behind due to inertia. As a result, the cupula is deflected opposite the direction of head movement. As the endolymph pushes the cupula, the stereocilia is bent as well, stimulating the hair cells within the crista ampullaris.
What are the 3 ways the head can move?
These consist of three tubes, positioned approximately at right angles to one another, that are each situated in a plane in which the head can rotate. This design allows each of the canals to detect one of the following head movements: nodding up and down, shaking side to side, or tilting left and right.
When the head moves the stereocilia move in this way?
The hair cells have long threadlike extensions, called stereocilia, that extend into the gel. When the head moves, fluid inside the semicircular canal moves. This motion causes the cupula to bend and the stereocilia within it to tilt to one side.
Does the endolymph move?
The organ of hearing and balance The endolymph in the semicircular ducts is the only body fluid that does not follow the fluid movements of the body, but is set in motion by the external world. Through the organ of balance, therefore, body position in space is experienced in both dynamic and static terms.
Where does endolymph drain to?
From the posterior wall of the saccule a canal, the endolymphatic duct, is given off; this duct is joined by the ductus utriculosaccularis, and then passes along the aquaeductus vestibuli and ends in a blind pouch (endolymphatic sac) on the posterior surface of the petrous portion of the temporal bone, where it is in …
How does endolymph drain?
The endolymphatic duct and sac drain endolymph from the auditory and vestibular apparatus. Endolymph is produced continuously. It is drained and its fluid secretion is regulated via the endolymphatic sac. The sac has fenestrated blood vessels that are leaky and can allow fluid to pass between their membranes.
What is the difference between perilymph and endolymph?
The main difference between endolymph and perilymph is that the endolymph is the fluid found in the membranous labyrinth whereas the perilymph is the fluid that surrounds the endolymph, located inside the bony labyrinth.
What is equilibrium movement?
When all the forces that act upon an object are balanced, then the object is said to be in a state of equilibrium. Thus, the net force is zero and the acceleration is 0 m/s/s. Objects at equilibrium must have an acceleration of 0 m/s/s. This extends from Newton’s first law of motion.
Which part of ear has Endolymph?
inner ear
(Endolymph is located in the cochlear duct – the light green region at the middle of the diagram.) Endolymph is the fluid contained in the membranous labyrinth of the inner ear.
What happens when stereocilia band away from the tallest stereocilia?
Vestibular pathway Bending the stereocilia toward the kinocilium depolarizes the cell and results in increased afferent activity. Bending the stereocilia away from the kinocilium hyperpolarizes the cell and results in a decrease in afferent activity.
What causes bending of stereocilia?
OHC stereocilia are bent by a shearing force that occurs when up-and-down movements of the basilar membrane cause it to slide relative to the tectorial membrane, a jelly-like sheet that covers the organ of Corti and in which many OHC stereocilia are embedded.
How does the endolymph lag behind the canal?
The hair bundles of the hair cells are inserted into a gelatinous mass (the cupula), which spans the diameter of the ampulla. During an angular acceleration, the endolymph within the canal, by virtue of its inertia, lags behind the canal itself, just as water within a rotated glass lags behind the wall of the glass.
What happens to the endolymph during motion sickness?
Disruption of the endolymph due to jerky movements (like spinning around or driving over bumps while riding in a car) can cause motion sickness. A condition where the volume of the endolymph is greatly enlarged is called endolymphatic hydrops and has been linked to Ménière’s disease.
Why does the endolymph have a high positive potential?
This is known as the mechano-electric transduction (MET) current. Endolymph has a high positive potential (80–120 mV in the cochlea), relative to other nearby fluids such as perilymph, due to its high concentration of positively charged ions.
How is cupula excited by the flow of endolymph?
Cupula is a hydro gelatinous mechanical sensor situated in semicircular canal. It is excited by the flow of endolymph. Mechanical deformation of cupula is converted into electrical signals by hair cells which is sent to brain for further reflexes.