During rotational acceleration, the cupula moves in the opposite direction of head rotation due to inertia, causing the hair cells to bend and trigger a signal to the brain indicating movement. During deceleration, the cupula moves in the direction of head rotation, also activating the hair cells to signal changes in movement.
which receptor is involved in the sense of rotational equilibrium
At the base of each semicircular canal is a structure called the ampulla, which contains a cluster of hair cells embedded in a gelatinous substance known as the cupula. These hair cells detect rotational motion of the head, as the movement causes the endolymph fluid within the canals to flow, bending the cupula and stimulating the hair cells. This sensory input is then transmitted to the brain, helping to maintain balance and spatial orientation.
Scarpa's fluid.
The three semicircular canals (SSCs) within the vestibular organ of each ear contain fluid and hair receptor cells encased inside a fragile membrane called the cupula. The cupula is located in a widened area of each canal called the ampulla. When you move your head, the fluid in the ampulla lags behind, pushing the cupula a very tiny bit which causes the hairs to also bend a very tiny bit. The bending hairs stimulate the hair cells, which in turn trigger sensory impulses in the vestibular nerve going to the brain to "report" the movement. Hair cells are amazingly sensitive. For example, a cupula movement of even a thousandth of an inch is detected by the brain as a big stimulus. The three canals are positioned roughly at right angles to one another in the three planes of space. Thus, the canals react separately and in combination to detect different types of swiveling head movement. They detect when we nod in an up and down motion (pitch), when we tilt our head to the side towards our shoulder (roll), and when we shake our head "no" in a side to side motion (yaw). The semicircular canals are responsible for detecting any kind of rotational motion in the head.
The cristae ampullaris are found in the semicircular canals of the inner ear. They are specialized sensory structures that are involved in detecting rotational movements of the head and helping with balance and equilibrium.
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.
Tectorial membrane does not belong in the group because it is a structure of the cochlea in the inner ear, while the rest - Crista ampullaris, Semicircular canals, and Cupula - are structures of the vestibular system in the inner ear involved in balance and spatial orientation.
The hair cells have a special type of ion channel that is gated by mechanical deformation. Depending on which way the hair cell bends, the neuron will either become hyperpolarised or depolarised. Deformation of the hair cells is caused by two separate mechanisms depending on which part of the vestibular system is in question. For the semicircular canals (SCCs) - these are filled with a fluid, such that when the head moves, the fluid momentarily lags behind exerting pressure on a membrane called a cupula. At its base are hair cells that project up into the cupula. When the cupula is deflected, so are the hair cells. The second component is the otolithic organs. These consist of a flat, top heavy bed of tissue with hair cells at their base. When the head moves up/down or side-to-side, the tissue (otolithic membrane) momentarily lags behind and the hair cells are deformed. In both cases the transduction is mechanical -> electrical; but whereas the SCCs rely on fluid movement for the mechanical force, the otoliths don't.
The inner ear includes the three semicircular canals. They (plus the base of each called the ampullaris) are involved in: 1. Static Equilibrium is in the ampulla which contains the sense for position of head when body is not moving. Static balance is associated with the vestibule and is involved in evaluating the position of the head relative to gravity. Tiny stones called otholiths on a membrane filled with hairs cause this sensation. The system also responds to linear acceleration or deceleration, such as when a person is in a car that is increasing or decreasing speed. 2. Dynamic Equilibrium is in the semicircular canals which senses rotation and movement of head and body. Dynamic balance is associated with the semicircular canals and is involved in evaluating changes in the direction and rate of head movements and doesn't use gravity. The semicircular canals detect changes in the rate of movement rather than movement alone because displacement of the cupula is most intense when the rate of head movement changes rapidly. As with the static balance, the information the brain obtains regarding dynamic balance is largely subconscious.
Saccule and utricle"Static" means stationary or at rest. the 4 functions are vestibular nerve, ampulla, cupula, and otoliths
The gel-like membrane overlying the hair cells of the organ of Corti is called the tectorial membrane. It plays a crucial role in the transmission of sound waves and vibration to the hair cells, which are the sensory receptors responsible for detecting sound. The movement of the hair cells against the tectorial membrane initiates the generation of electrical signals that eventually get sent to the brain for sound processing.
A function in dynamic equilibrium means that there is a balance between opposing processes, where the overall function is stable over time. This balance allows the system to adjust and respond to changes to maintain stability. Examples include chemical reactions, physiological processes in the body, and ecosystem dynamics.