Ear Flashcards

Question

How does vestibular system help?

Answer 1

- sensing **accleration of head** movement -sensing **direction of gravitational** pull - controls **eye movement**

Answer 2

not able to balance, dizzy, unsafe vision

Answer 3

It detects acceleration in linear axis and vertical access (gravity) 1. The (static organ) is connect via a passage from middle ear 2. The organ has 2 chambers- Utricle and Saccule filled with liquid (cupula) 3. There are hairs with crystals called Otolith inside the utricle and saccule **Gravity:** If you tilt your head and there is a 1g gravitational pull, the top heavy hairs will bend in the direction of the gravity, and sends signals to the brain via vestibular nerves. The brain understand the direction of the tilt with respect to gravity **In linear accelaration: ** The cupula in the static organ also detects linear accelerations. During a linear acceleration, the body accelerates away from it and the cupula is temporarily ‘left behind’, causing the hairs to bend and send a new signal to the brain. They will return to their normal position once the body is no longer accelerating and is moving at a steady speed (which may be zero). if your head is tilted back but you are accellerated forward, your braind thinks you are tumbling backwards

Answer 4

It detects angular acceleration (rotation of the head) in 3 planes 1. There are 3 semi-circular canals integral to the skull positioned at right angles, with fluid inside them (pitch, role, yaw) 2. The semi circular canals end in little bulbs called ampula which have hairs in them When you rotate your head, the canals move with it. But since the canals have their own fluid, they have their own inertia - the fluid moves later after the head as moved and in the opposite direction, pushing the hairs into the direction of the head movement **(ie head/hair moves opposite of the fluid, during accerlation)** The movement of the fluid in canals cause the hairs in the ampula to bend in the same direction Each signal from a canal is sensed by the brain as a rotation in each plane when the angular accelleration is ceased: the fluid moves with the canal in the same direction. Hairs will no longer bend. Brain will no longer sense any angular accelleration, even if steady angular turn is happening.

Answer 5

Mismatch between the signals recieved by the brain from vestibular system and the visuals seen by your eyes Such as motion sickness **most reliable sense here is vision to help with this** **rely on your instruments**

Answer 6

dizzy, nausea, vomit hot flushes, clammy hands headache fatigue and yawning salivation **Hyperventilation (fear and anxiety induced)**

Answer 7

**vibration of eyeballs **(rapid intake of visual field vs intake from the eye) **simulator sickness:** due to the different between simular display and its motion, or its motion vs motion perceived by the pilot **mismatch accelration: **when you change acceleration suddenly after being on a constant speed. If you bank after cruising, the change of g force can create a mismatch

Answer 8

Address the mismatch ideally by 1) fillin in the visual fields with cueues such as focusing on the horizon 2)removing inputs by standing up to gain balance, distracting yourself 3)hydration 4) control breathing and breath more/deeply 5) lay flat/horizontally

Answer 9

1. system assumes your body's linear acceleration is 1 g from head to toe due to gravity. 2. system only detects initial rotational movement 3.system has a threshold under which external stimuli doesn't trigger any action

Answer 10

Somatogravic illusion

Answer 11

- Illusion related to linear acceleration - Usually happens when visual cues are absent - Example - If the head is upright and then tilted back, the hairs are deflected back to sense the tilt. - But if the head then moves forward but the hairs are still deflected back, the brand doesn’t sense the change - Happens with the hair crystals in the Utricle and saccule are deflected and the brain serene the deflection as title even though that head isn’t tilted anymore **Scenario: take off** A large forward acceleration feels like you are pitching up and you end up pushing forward with the controls away **Scenario: landing** A slow forward acceleration feels like you are pitching down

Answer 12

**Somotagyral illusion - false perception of rotation ** Visual queues are not present (ie orbiting at night or in cloud) The semicircular canals detect an initial angular accerlation. The natural inertia of the fluid inside the canal causes a pronounced relative movement between the fluid and canal The hairs of the ampulla are bent But in a prolonged acceleration, the fluid accelerates at the same speed as the rotation, and hairs stand straight so the body doesn’t sense the angular rotation anymore. If you stop suddenly, the inertia of the fluid causes the fluid to continue rotation even if the canals stoped. The hair is bent the opposite direction so senses opposite rotation

Answer 13

**it's a type of somotogyral illusion** when you feel that the **aircraft is pitching or rolling **despite the instuments proving otherwise or despite you are at win level - due to the **detection below threshold of the canals (ie movement not detected) ** **Scenario 1 **1)if you make tip to one side quickly that you feel the tilt, and you make and adjustment to wing level slowly/below the detection threshold of the semi circular canals. Your body feels like it's still tilted to that side and you will lean away from the perceived tilting **Scenario 2** You come to know of a long turn that went un noticed and you make a sudden adjustment to wing level. Your body feels like it's banking in the opposite direction. **Scenario 3** if let's say you roll left, you sense this angular accelration But if you stay in the left turn for 15 sec, the motion is no longer sense and you think you are wing levelled. you then might roll to the right to try to 'level' the wing the vesitublar system registers you are rolling right from the 'wing level',so you are sensing rolling to the right unwantendly 'graveyeard spiral' | Look at your insturments

Answer 14

shifting of the semicircular canals out of their plan of rotaion Cross coupled stimulation from 2 or more canals caused by head movement while aircraft is turning - without visual queue Scenario: if you look down at your chart while aircraft is turning..and you look up again, Feeling of pitching, rolling or tumbling at the same time can cause motion sickness and losing control of aircraft solution: keep head straight relative to the body and avoid extreme head movements while making turns

Answer 15

feeling of spinning while stationary / or feeling stationary while you are spinning brought on by moving the head, heavy accleration usually a defect in the vestibular system infection or alchol sudden pressure change (ie. blowing nose strongly) flicker vertigo (brought on by flashing light or sunlight reflecting on rotating propellors) pressure vertigo: flying with block eustachian tube losing visual reference / horizon reference going into spins , spiral dives avoid alchol 3 days prior to flight

Answer 16

Inner ear balance mechanism is over stimulated high g, turbulence fear and anxity misbalance from the ear and eye signals (like doing a bank in a simulator visually gives the illusion of a turn, but vestibular signals show straight and not moving) when your body can't detect small accelerations making it difficult to sense movement. Example: train accelerates slowly and vestibular system doesn’t detect this. Without looking out to a fixed reference like the platform, you can’t tell if your train is moving or the other train next to you. to avoid: fly aircraft sensibly with control avoid manoevres that involve unusual gforce avoid turbelence ventilate cabin look out at a distance recline seat vertically land if required

Answer 17

When you have prolonged exposure to stimuli resulting in decreased responses from sensory neurons Example: If you drive at high speed for a prolonged time and come to exit at low speed, this low speed feels ‘very slow’ because the motion detection apparatus of our visual system has ‘habituated’ to a higher speed

Answer 18

when you can hear a message important to you despite various noises and stimuli

Answer 19

can induce long/short term hearing. also drugs/meds

Answer 20

wear hearing protection like noise canceling headsets, ear plugs and ear muffs when using radio - lower the volume, and use squelch to control the hash/static

Answer 21

no it cannot sense stead speed in a straight line, it can only sense acceleration ( change of speed)

Answer 22

signals connecting brain to ear balancing (vestibular) + vision + muscle/tendon and organ propioceptors to sense these help body react to acceleration, change of speed and direction

Answer 23

Linear: you go up the elevator and you experience a change in 'g' compared to normal angular: when you spin

Answer 24

**Up is always the direction of the g force on your body according to the static organ** if you roll at 60 degrees, you will experience a 2g force on yoru body. you will feel the anuglar accellartion at tehe beginning when you are in/out of hte turn. However, when the motion stops or stays constant, the fluid goes back to being steady and stops sensing the turn if your eyes are shut, it will still feel like you are sitting upright but you need your eyes or instruments to confirm that you are not.

Answer 25

ability to determine your position achieved by: Vision (strongest sense) balance (gravity, linear and angular) seat of the pants( proprioceptive)

Answer 26

pilot might look down at the charts an make a very slow bank and not realize it its' because that small rolle was insignificant and the fuid didn't move in the canals to sense the accleration

Answer 27

In a turn, the body experiences a force on the seat-of-the-pants greater than 1g normally exerted on it by the seat in straight-andlevel flight, the same feeling as if the aeroplane was being pulled up from straight-and-level into a climb. pilot tends to push the control column forward thinking he'll climb but in fact he'll descend

Answer 28

After being in a steady turn for some time, the body gradually gets used to the increased g-forces. Immediately after rolling back to wings-level, and reducing the g-forces to just 1g, the body feels this reduced g-force as less than 1g, the same effect as pushing the nose over into a descent. Use your eyes to check the horizon or the flight instruments to avoid making incorrect inputs on the controls.

Answer 29

In a state of rest or steady velocity (i.e. no acceleration), the body experiences an upward force from the seat. If you now accelerate strongly, there is a further force from the back of the seat accelerating you forwards, and your vestibular apparatus, as well as the seat-of-your-pants, interprets this as a g-force angled forwards. Since you are used to g-forces always being ‘up’, you interpret the tilted direction of the new g-force as being ‘up’; in other words, you must have tumbled backwards. This is known as the oculogravic illusion or the somatogravic illusion. a result of this illusion of tumbling backwards during strong accelerations, to want to push the nose of the aeroplane down – a tendency which you can avoid if you use your eyes.

Answer 30

The converse happens when you are travelling fast, and then decelerate rapidly. The seat-belt now exerts a force on you, and the resultant g-force from this and the force of gravity is now angled backwards. You sense this direction as ‘up’, so you imagine that you must have pitched forward. The tendency is to pull the control column back, which you can resist if you use your eyes.

Answer 31

the vibrating chain of ossicles induces pressure waves in the endolymph

Answer 32

angular acceleration linear acceleration noise

Answer 33

measuring linear and radial acceleration within the inner ear

Ear Flashcards

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