Equilibrium Flashcards
(22 cards)
Describe the role of the vestibular apparatus in equilibrium.
The vestibular apparatus contains equilibrium receptors located in the semicircular canals and vestibule, which help maintain balance by responding to head movements.
Explain the difference between static and dynamic equilibrium.
Static equilibrium is monitored by maculae, which respond to the position of the head and linear acceleration, while dynamic equilibrium is monitored by semicircular canal receptors, which respond to rotational movements.
Define maculae and their function in the vestibular system.
Maculae are sensory receptor organs located in the saccule and utricle that monitor static equilibrium and the position of the head in space.
How do the utricle and saccule maculae differ in their orientation and response to movement?
Utricle maculae are horizontal with vertical hairs and respond to horizontal plane changes, while saccule maculae are vertical with horizontal hairs and respond to vertical plane changes.
Describe the structure of a macula.
A macula consists of a flat epithelial patch containing hair cells and supporting cells, with hair cells having stereocilia and a kinocilium embedded in an otolith membrane.
Explain the role of otoliths in the maculae.
Otoliths are calcium carbonate stones that increase the weight and inertia of the otolith membrane, enhancing its response to head movements.
How do hair cells in the maculae communicate with the brain?
Hair cells release neurotransmitters continuously, and changes in head movement alter the amount released, affecting the action potential frequency sent to the brain via the vestibular nerve.
What happens to hair cells during head movement?
During head movement, the otolith membrane lags behind, causing the tips of stereocilia to bend, which leads to depolarization and increased neurotransmitter release.
Describe the process of depolarization in hair cells of the macula.
Bending of hairs towards the kinocilia depolarizes hair cells, increasing neurotransmitter release and resulting in more impulses traveling to the brain.
Explain the significance of the vestibulocochlear cranial nerve in equilibrium.
The vestibulocochlear cranial nerve, which includes fibers from the vestibular nerve, is crucial for transmitting sensory information from the maculae to the brain for balance and spatial orientation.
Describe the effect of bending hairs away from kinocilia in hair cells.
Bending hairs away from kinocilia hyperpolarizes receptors, leading to less neurotransmitter release and a reduced rate of impulse generation, informing the brain of changes in head position.
Explain the role of the crista ampullaris in the semicircular canals.
The crista ampullaris is the receptor for rotational acceleration located in the ampulla of each semicircular canal, excited by head acceleration and deceleration.
How do cristae respond to rotational movements of the head?
Cristae respond to changes in velocity of rotational movements by detecting the bending of hair cells due to the movement of endolymph in the semicircular ducts.
Define the function of the ampullary cupula in the vestibular system.
The ampullary cupula is a gel-like mass that hair cells extend into, and it plays a crucial role in detecting head movements by bending hair cells in response to endolymph movement.
What happens to hair cells when the head rotates in one direction?
When the head rotates in one direction, hair cells in the cristae bend, causing depolarization and rapid impulses to reach the brain, indicating the direction of rotation.
Describe the relationship between hair cell orientation in complementary semicircular ducts.
The axes of hair cells in complementary semicircular ducts are opposite, resulting in depolarization in one ear while hyperpolarization occurs in the other ear during head rotation.
Explain the significance of inertia in the ampullary cupula during head movement.
Inertia in the ampullary cupula causes the endolymph in semicircular ducts to move in the opposite direction of the body’s rotation, leading to the bending of hair cells and signaling changes in movement.
How does the brain process equilibrium information from the vestibular system?
Equilibrium information from the vestibular receptors travels to reflex centers in the brain stem, allowing for fast, reflexive responses to maintain balance.
What are the three modes of input for balance and orientation?
The three modes of input for balance and orientation are vestibular receptors, visual receptors, and somatic receptors.
Describe the neural pathways involved in the balance and orientation system.
Impulses from activated vestibular receptors travel to either the vestibular nuclei in the brain stem or to the cerebellum, contributing to balance and orientation.
Define sensorineural deafness and its treatment options.
Sensorineural deafness is a type of hearing loss due to damage in the cochlea or auditory nerve, and cochlear implants can effectively convert sound energy into electrical signals for those with congenital or age/noise-related cochlear damage.
Explain how cochlear implants function for individuals with hearing loss.
Cochlear implants convert sound energy into electrical signals and are surgically inserted into the temporal bone, allowing deaf children to learn to speak.
