Physiology of Balance, Taste and Smell Flashcards
What are the 2 functions of the vestibular system?
- balance
- spatial awareness
What does otolith mean?
1 - greek for ear
2 - greek for ear stone
3 - greek for hearing loss
4 - greek for heavy
2 - greek for ear stone
Otolith is greek for ear stone. What are the otoliths in the ears?
1 - Ca2+ carbonate sits on top of a gelatinous matrix in the macula of utricle and saccula
2 - Ca2+ carbonate that sits between the utricle and saccula
3 - Ca2+ carbonate acts as a gateway between vestibule and cochlea systems
4 - Ca2+ carbonate sits in the ampulla of the semi-circular canals
1 - Ca2+ carbonate sits on top of a gelatinous matrix in the macula of utricle
- horizontal movements = macula of utricle
- vertical movements = macula of saccule
What 2 parts of the vestibular system that contain otoliths?
1 - utricle and ampulla
2 - utricle and scale vestibule
3 - saccule and utricle
4 - ampulla and scale vestibule
3 - saccule and utricle
Why are the semi-circular canals arranged at 90 degrees to one another?
- to allow 3 dimensional awareness
Which cranial nerve supplies the vestibular system?
- cranial nerve VIII (8) vestibulocochlear nerve
- vestibular branch
What is endolymph?
1 - fluid in bony labyrinth high in K+
2 - fluid in bony labyrinth high in Na+
3 - fluid in membranous labyrinth high in K+
4 - fluid in membranous labyrinth high in Na+
3 - fluid in membranous labyrinth high in K+
- clear fluid located in the membranous labyrinth of the inner ear
- contains high K+ (140 mEq/L) and low Na+ concentration (15 mEq/L)
What is static equilibrium in relation to body movement?
- when the body is not moving
The saccule and utricle contain a macula, which is filled with sensory mechanoreceptors that are supported by epithelial cells. What are these mechanoreceptors located in the macula called?
1 - oliths
2 - ampulla
3 - hair cells
4 - follicular cells
3 - hair cells
- type I and type II
The saccule and utricle are at aprox 90 degrees to one another. Why is this important?
- hair cells are orientated in multiple directions
- allows detection of head tilt in any direction
- utricle macula = horizontal plane pointing up remember the boys name HUgh
- saccule macula = vertical plane pointing out remember Very Small
The hair cells contain cilia that are able to detect horizontal (utricle) and vertical (saccule) acceleration. There are 2 types of cilia, one of which is much larger than the others, what are they both called?
1- stereocilia and epicillia
2 - stereocilia and macucillia
3 - kiniocillia and stereocilia
4 - kiniocillia and large kiniocillia
3 - kiniocillia and stereocilia
- kiniocillia = 1 large in each hair cell
- stereocilia = mulitple of these in each hair cell
The otolith organs contained within the utricle and saccule contain type I and II hair cells that are able to detect movement in the macula. What are the hair cells embedded in?
1 - mucus
2 - gelatinous matrix
3 - columnar epithelial cells
4 - ear wax
2 - gelatinous matrix
The utricle macula contains hair cells in the horizontal plane pointing up. What type of motion are the hair cells of the utricle able to detect?
- linear acceleration in a horizontal plane
- head tilt (left, right, forward)
- like driving a car, sudden break and the head moves forward
The saccule macula contains hair cells in the vertical plane pointing up. What type of motion are the hair cells of the utricle able to detect?
- vertical linear acceleration/deceleration
- moving up and down
Label the image of the macula below using the names below:
- cilia
- supporting cells
- vestibular nerve axons
- gelatinous matrix
- hair cell
- otoliths
1 = otoliths
2 = gelatinous matrix
3 = cilia
4 = hair cell
5 = supporting cells
6 = vestibular nerve axons
The gelatinous matrix of the otolith cells contains otoliths on its surface. What are otoliths?
- calcium carbonate stones
- when movement happens these cause gel matrix to move in a specific direction
The gelatinous matrix of the otolith cells contains otoliths on its surface which are heavy calcium carbonate stones. Why are these important in being able to detect movement in the macule?
- as we accelerate/decelerate the stones are heavy and pull the gelatinous matrix in a specific direction
- pulling of the gelatinous matrix is detected by hair cells
Each hair cell in the vestibular system have cilia like projections and one large projection at the end, what are these called?
1- stereocilia and epicillia
2 - stereocilia and macucillia
3 - kiniocillia and stereocilia
4 - kiniocillia and large kiniocillia
3 - kiniocillia and stereocilia
- small = sterocilia
- large = kinocilium
In addition to the multiple sterocilia (small) and the singular kinocilium (large) on hair cells in the vestibular system there is something in between each sterocilia (small) and the singular kinocilium (large). What is this call and what is its purpose?
- mechanotransducotors
- connected to spring-gated ion channels
In addition to the multiple sterocilia (small) and the singular kinocilium (large) on hair cells in the vestibular system there is something in-between each sterocilia (small) and the singular kinocilium (large) called tip links. When there is movement the otoliths that are on top of the gelatinous membrane drag the gelatinous membrane. As they drag the gelatinous membrane the hair cells inside also move. When the hair cells detect movement the tip links come into closer contact with the adjacent sterocilia and kinocilium. When this occurs what happens?
1 - tip links open mechanically gated Na+ channels
2 - tip links open mechanically gated Ca2+ channels
3 - tip links open mechanically gated Mg+ channels
4 - tip links open mechanically gated K+ channels
4 - tip links open mechanically gated K+ channels
- increased K+ causes depolarisation
In addition to the multiple sterocilia (small) and the singular kinocilium (large) on hair cells in the vestibular system there is something in-between each sterocilia (small) and the singular kinocilium (large) called tip links. When the hair cells detect movement the tip links come into closer contact with the adjacent sterocilia and kinocilium. When this occurs tip links open mechanically gated K+ channels and increased K+ causes depolarisation. What then happens at the base of the hair cell?
- depolarisation of the hair cell causes Ca2+ release at the bottom of the hair cells
- Ca2+ causes vesicles containing glutamate to fuse with membrane, releasing glutamate
- glutamate (stored in vesicles) is released into synaptic space
- glutamate binds to glutamate receptors and depolarises the axon, sending a signal to the brain
When our heads are in a stationary position we are constantly generating action potentials to tell the brain about our head position. However, if we change position and move towards or away from the kinocilium, do the action potentials increase or decrease?
- towards = increased action potentials
- away = decreased action potentials
There are 3 semi-circular canals which are continuations of the utricle. What are the 3 positions (names) of the canals?
1 - superior, posterior and inferior
2 - superior, inferior and lateral
3 - anterior, posterior and lateral
4 - lateral, medial and inferior
3 - anterior, posterior and lateral
- anterior (like handle on a handbag)
- posterior (like handle on a mug)
- lateral (like a shelf draw pulling out)
Together they provide 3 dimensional information
The semicircular canals are continuations of the utricle, and therefore contain the same fluid, which is called what, endolymph or perilymph?
- endolymph
- high in K+ and low in Na+
The semicircular canals are continuations of the utricle, and therefore contain the same fluid, called endolymph. There is also an enlarged portion at the end of each of the semi-circular canals (so 3 in total), called what?
1 - macula
2 - canaliculi
3 - fossa
4 - ampulla
4 - ampulla
In the ampulla is the crista ampullaris, which is the sensory organ that is able to detect rotation and angular acceleration and deceleration. What is contained within the crista ampullaris?
1 - cisterna
2 - hair cells type I and II
3 - Ca2+ channels
4 - otoliths
2 - hair cells type I and II
- a gelatinous mass called the capula that covers hair cells
In the ampulla is the crista ampullaris, which is the sensory organ that is able to detect rotation and angular acceleration and deceleration. Within the crista ampullaris are hair cells type I and II covered in a gelatinous mass called the cupula. Each hair cell is the same as those contained within the saccula and utricle, meaning they have lots of sterovilli, one kinocilium and tip links that connect sterovilli and the kinocilium. What happens if the hair cells are stimulated and the sterovilli and the kinocilium move towards a stimulus?
- tip links open mechanically gated K+ channels
- K+ causes depolarisation
- depolarisation causes Ca2+ channels to open
- Ca2+ causes the release of glutamate into synaptic space
- glutamate binds to receptors causing action potential to be sent to the brain via cranial nerve VIII (8) the vestibulocochlear
Once the semi-circular afferent nerves have been stimulated they will travel along cranial nerve VIII (8) vestibulocochlear nerve. Where is the first place they will synapse?
- superior and medial vestibular nuclei
- group of cell bodies from vestibule branch of CN VIII (8) the vestibulocochlear nerve
- located in the lower pons and upper medulla
How many parts of the vestibular nuclei (VN) are there?
- 4 parts located in lower pons and upper medulla
1 - superior VN
2 - lateral VN
3 - medial VN
4 - inferior VN
Once the utricle macula stimulate the afferent nerves they will travel along cranial nerve VIII (8) vestibulocochlear nerve to where?
- lateral vestibular nuclei
- lateral because they detect horizontal/lateral motion
- located in the lower pons and upper medulla
Once the saccule macula stimulate the afferent nerves they will travel along cranial nerve VIII (8) vestibulocochlear nerve to where?
- lateral and inferior vestibular nuclei
- inferior as they detect vertical movements
- located in the lower pons and upper medulla