L25 The Vestibular System X Flashcards
(23 cards)
What role does the vestibular system have in our body?
- They keep our eyes still when we move.
- They maintain our upright posture
- Our ability to percieve our own movement within space.
What is the vestibular system?
The vestibular system is a complex sensory system located in the inner ear that plays a crucial role in balance, spatial orientation, and the coordination of movement.
What sections are within the vestibular system?
- Otolith organs
- Semicircular canals
- Ampulla
- Vestibular nerves.
What does the Otolith organs do? And what are the two types?
They detect linear motions (acceleration) and head tilt
Utricle - horizontal
Saccule - vertical
What does the semicircular canals?
They detect rotations
What does the hair cells in the vestibular system sit?
In the ampulla
What are the 2 types of liquids within the vestibular labyrinth?
Endolymph
Perilymph
What do vestibular hair cells have?
They have:
1. A hair bundle with stereocilia and tip links
2. A kinocilium throughout life.
What is the difference in terms of structure between Vestibular and Cochlear inner hair cells?
The vestibular inner hair cells have a kinocilium whereas the cochlear do not have kinocilium.
Why does the Vestibular hair cell detect lower mechanical movement with lower frequencies (0-20H)?
How does the vestibular hair cells react the same way as nerve impulses ?
As hair cells move towards the (name of peak of hair cells - top bundle) which depolarises the
(Look at recording) also talk about the mechanism.
MET channels closes,
Do vestibular hair cells produce action potentials at rest? And why?
The vestibular hair cells themselves produce a tonic receptor potential and a continuos release of neurotransmiter because it is needed for encoding bidirectional movement abs static head position with high sensitivity.
How is Type I different to Type II vestibular hair cell?
Type I has a calyx ( a massive dendritic terminal which envelops around the whole of the hair cell - reliable transmission)
Type II has a normal afferent dendrite
What is the macula?
The macula is a sensory epithelium located within the two otolith organs of the vestibular system: the utricle and the saccule. These otolith organs are found in the vestibule of the inner ear and are crucial for detecting linear acceleration and static head tilt.
What is the striola?
Direction of the hair bundles are opposite on either side of the line
Why is the Gelatinous otolithic membrane important?
The gelatinous otolithic membrane acts as a mechanical link that translates the physical forces acting on the otoconia into a stimulus that the hair cells can detect and convert into neural signals for the brain to interpret as linear motion and head orientation
What is the cupula?
The cupula is a gelatinous structure penetrated by hair bundles
Where is the cupula located?
In the semicircular canals.
Does the semicircular canals on either side work in pair?
Yes in proportion to the direction of rotation of head.
How does the semicircular canals detect angular acceleration (rotation)?
The inertia of endolymph during rotation displaces the cupula which is detected by the hair bundles and is sent to the brain
Which system is quicker in signalling - vestibular sytem or visual sytem?
Vestibular system is faster than the visual system
