Ear and Balance

Otolith organs detects

Linear acceleration in different planes (utricle = horizontal and saccule = vertical)

The semicircular canals are arranged ____ and why is that significant

Perpendicular — to help us detect head rotation in any plane

Lateral axis

Pitch (up and down)

the ampulla is on the _____ side of the semicircular canals

Anterior

Romberg Balance Test

Ask the patient to close their eyes and stick their forearm out with their feet together and see if/how long they can remain balanced

When the sterocilia are moved and open the channel which NT are released

Aspartame/glutamate

Some nuclei go to the cerebellum and spinal cord which will help with what?

Balance

Both CN VII and VIII enter through the

Internal acoustic meatus

What are the 3 semicircular canal pairs?

1. L/F Horizontal 2. L anterior semicircular/R posterior semicircular 3. R. Anterior semicircular/L posterior semicircular

How many semicircular canals do we have?

3: anterior, lateral, and posterior (inferior)

Why do you use VOR Caloric Reflex?

A way to test VOR in someone who has potential brain stem damage and is in a coma (mostly use the cold/warm water in ear canal)

If you flood the ear with cold water on the left side, what will happen to the eyes? What happens with warm water? & why?

Cold: same side, Warm: on opposite side COWS - cold water, opposite directs, warm water same direction Nystagmus — fast phase (left ear, right nystagmus which is why it's technically opposite)

Otolith consists of (2) (hint: not utricle and saccule)

Consists of gelatinous matrix and statoconia

The striola and it's significance

Curved linear structure where all of the hairs are arranged towards the line — SIG: to activate one side and inhibit the other = would increase sensitivity and allows additional buffers increase if the other utricle is damaged

What is the purpose of the VOR (vestibulo-ocular reflex)

Detect head movement and generate an appropriate response — opposite eye movement to cancel the turbulance from the head movement

What type of lymph flows around the ampulla

Endolymph

T/F In the saccule the kinocilium are all pointing to the striola

F - they are pointing away

T/F the striola is located within the horizontal plane

F - vertical plane

T/F the R anterior semicircular canal works with the L anterior semicircular canal

F = it will work with the L posterior semicircular canal

T/F Romberg balance test will test cerebellum function

F — visual pathway, vestibular pathway, & DCML pathway functions — you don't need all three but you need at minimum of 2 of the 3 to maintain balance — with the patient's eyes closed, you're leaving them with only 2 pathways to test

T/F 2nd order neurons project to the cortex

False - 3rd order neurons

The utricle is within the _____ plane

Horizontal

When you look down 30 degrees our ______ is parallel to the ground & significance

Horizontal semicircular canal — because we walk with our head downward slightly

Where in the ampulla will you find the hair cells

In the cristae and cupula

Where are the hair cells within the utricle and saccule?

Maculae

They have _______ receptors

Mechanosensory

What is moving the cupula

Movement or rotation of the head pushes the endolymph

Hair cells are located in the

Otolith organs and ampulla of semicircular canal

Longitudinal axis

Roll (ear to shoulder)

Cell bodies are located in the

Scarpa's ganglion

We have 2 types of hair cells. What are they?

Sterocilia (shorter) and kinocilium (longer)

Vestibular nuclei is a complex made up of (4) nuclei which are

Superior, inferior, lateral, medial

T/F semicircular canals work in pairs

T — left and right horizontal canal form 1 pair. (Within horizontal plane or around vertical axis)

T/F as long as head is moving in space, the vestibulo-ocular reflex will be activated?

True

T/F first order neuron is the bipolar neurons within scarpa's ganglion

True

T/F when you rotate your head, you will see an increase in spikes/sec

True

T/F about 2/3 of kinocilium are located within the medial part of the striola of the utricle

True - 1/3 is lateral

T/F When you rotate your head, one side will be activated and the other side will be inhibited?

True - you know the level of the hair cell in one semicircular canal to increase sensitivity

otolith organs contains what (2)

Utricle and saccule

The saccule is within the ____ plane

Vertical

The first order neurons enter the brain stem where?

Vestibular nuclei

Some nuclei go to to III, IV, VI motor neurons that control eye movement. Why?

Vestibule-ocular reflex - to be able to maintain visual field on retina

Perpendicular axis

Yaw (vertical axis)

Ataxia

the loss of full control of bodily movements