BB EOYS6 Flashcards

Question

This photo shows the strucutres inside of a semi-circular canal. Label A-C

Answer 1

A: **ampulla** B: **cupulla** C: **crista**

Answer 2

A: ampulla B: endolymph C: membranous labyrinth D: perilymph E: bony labyrinth

Answer 3

Ampulla Hair cells Endolymph Crista **Cupulla**

Answer 4

Ampulla Hair cells Endolymph **Crista** Cupulla

Answer 5

Carotid artery

Answer 6

The vestibular system is connected with the **spinal cord** via which **medial and lateral vestibulospinal** tracts The vestibular system is connected with the **cerebellum** via the **floccculonodular lobe and fastigial nucleus** The vestibular system is connected to **CN III, IV & VI**

Answer 7

A: (Macula of) **utricle** B: (Macula of) **saccule** C: **cochlea** D: **posterior semilunar canal** E: **Stapes** F: **Malleus and incus**

Answer 8

**Endolymph** * inside the **semicircular canals** and moves, and provides most of the **signalling** for the **vestibular hair cells** **Perilymph** * fills the **scalae tympani and vestibuli.**

Answer 9

**Perilymph**: has similar concentrations of ions to plasma; **high sodium and low potassium** **Endolymph**: extremely **low sodium and high potassium**

Answer 10

There are three semicircular canals: **anterior, posterior, and lateral**. located in a different plane and each connect to an **ampulla** (widening of the canal) which conncects to the **utricle** Within each ampulla there are **hair cells** and **cristae** with a **gelatinous cupula** above the hair cells * crista Each canal is a **continuous endolymph filled loop**, when the head rotates endolymph displaces the gelitinous cupula and **excites the hair cells** causing **depolarisation or hyperpolarisation** Movement **towards** the kinocilium causes the opening of channels and a subsequent **depolarization** of the cell. Movement **away** from the kinocilium causes the closure of channels leading to **hyperpolarization** of nerve fibers.

Answer 11

Saccule and utricle is to **keep the head vertically oriented with respect to gravity** **Macula of utricle / saccle**: cilia of hair cells embedded in a gelatinous mass. Contains calcium carbonate crystals call **otoliths**

Answer 12

Utricle: **longitudinal acceleration**, Saccule: **acceleration** along the **vertical** axis Mechanism: * **otoliths** provide the **inertia**, so that when movement to one side occurs, the otolith-gel mass causes the hair cells to deviate * The hair cells are **excited, or inhibited**, by bending of the **stereocilia towards or away** from the kinocilium, just as the hair cells in the semi-circular canals * Linear acceleration of the head causes a shear force **between the otolithic membrane and macula**, causing **displacement of the hair bundles.**

Answer 13

Automatically sensing **head rotations** and elicits a **compensatory adjustment in the opposite direction of the eyes** Causes innervation on the **medial-lateral** **rectus** **muscles** (adduction / abduction), the **inferior rectus-superior oblique pair** (depression and extorsion, elevation and intorsion) and the **superior rectus-inferior oblique pair** (elevation and intorsion, depression and extorsion via the **ascending medial longitudinal fasciulus**

Answer 14

The axonal connections between the vestibular and oculomotor nuclei that mediate the VOR travel in a tract called the **medial longitudinal fasciculus (MLF)**

Answer 15

superior and medial: **semi-circular canals** lateral, inferior and medial: **saccule and utricle** (together aka maculae)

Answer 16

Semi-circular goes to **ocular nuclei** and **reticular formation**, **gaze centres** and **tectal nuclei** (double check which pathways these are sent via) Saccule and utricle goes to **spinal motor nuclei** via the **lateral and medial VSTs**, which are involved in **postural balance**

Answer 17

The superior and lateral vestibular nuclei also interact with the **flocculo-nodular lobe of the cerebellum**

Answer 18

Second order **vestibular neurones** project to the **contralateral ventral posterior nucleus** of the **thalamus**, and from there the **somatosensory cortex and posterior parietal cortex**.

Answer 19

**Parietal insular vestibular cortex** Remember that this is responsible for the **contralateral side of the body/limb**.

Answer 20

A brief, 60 second, intense sensation of vertigo that occurs because of a specific positional change of the head Dislodged otolith from the utricle, which then gets stuck in the ampulla, making it sensitive to gravity. In certain positions, the otolith can stimulate the cupula, causing abnormal sensations. These persist until the crystals relocate elsewhere or disperse

Answer 21

Inner ear fluid balance disorder that causes episodes of **vertigo, fluctuating hearing loss, tinnitus** and the **sensation of fullness in the ear** Caused by an **imbalance** between the **production and reabsorption of endolymph**, which eventually **ruptures the membranes**, causing **changes in ion concentration of the solute**, leading to **depolarisation** of the **endolymph fluid**, ultimately **killing** the **hair cells.**

Answer 22

* Labyrinthitis is an infection or inflammation of the **semi-circular canals** causing **dizziness and loss of balance**

Answer 23

* Vestibular neuritis is a **viral infection of the vestibular nerve** * Perilymph fistula is a **leakage of inner ear fluid into the middle ear**. It can occur after head injury or physical exertion, or is idiopathic

Answer 24

* **Hallpike’s Manoeuvre**: With the patient lying in supine position, the head is lowered quickly below the horizontal plane of the table and turned to one side. The patient then sits up and the test is repeated, turning the head to the other side. If there is vestibular dysfunction, the patient will develop nystagmus and complain of vertigo within 10 seconds of head movement * **Audiometry** * **The caloric test**: weak nystagmus or the absence of nystagmus may indicate an inner ear disorder. The way to remember the correct response is COWS: cold water in the ear should cause the nystagmus to be away from this ear, whereas warm water causes the nystagmus to be flickering towards this ear * **Imaging of the head and brain** * **Posturography**: this requires the individual to stand on a tilt table, capable of movement within a controlled visual environment. Body sway is recorded in response to movement of the platform and/or visual environment * **Videonystagmography** * **Electronystagmography**

Answer 25

Which of the following is caused by 'imbalance of production and absorbtion of endolymph, which ulitmately can result in tympanic membrane bursting' benign paroxysmal positional vertigo (BPPV) labyrinthitis **ménière's disease** vestibular neuritis perilymph fistula

Answer 26

What does this image depict? benign paroxysmal positional vertigo (BPPV) labyrinthitis **ménière's disease** vestibular neuritis perilymph fistula

Answer 27

What does this image depict? **benign paroxysmal positional vertigo (BPPV)** labyrinthitis ménière's disease vestibular neuritis perilymph fistula

Answer 28

Hallpike’s Manoeuvre:

Answer 29

With the patient lying in supine position, the head is lowered quickly below the horizontal plane of the table and **turned to one side.** The patient then sits up and the test is repeated, turning the **head to the other side**. If there is vestibular dysfunction, the patient will **develop nystagmus** and complain of vertigo within 10 seconds of head movement

Answer 30

Vestibular-ocular reflex

Answer 31

A 17-year-old female presents with worsening hearing on her right side. The clinician identifies a significant amount of cerumen impaction in the right external auditory canal. The patient is positioned supine, and her head is elevated 30 degrees. The right auditory meatus is irrigated with warm water. After a large piece of cerumen dislodges, the clinician continues to irrigate; however, the patient states she "feels funny." What will most likely be seen on an ocular exam? **A. Fast beating nystagmus towards the right** B. Fast beating nystagmus towards the left C. Conjugate eye deviation towards the right D. Conjugate eye deviation towards the left

Answer 32

**B. Stimulation of the left ear with cold water causes right nystagmus** This patient has suffered a traumatic brain injury (TBI). With an intact gag reflex, CN IX and X are intact, as is the vestibulo-ocular reflex (CV VIII and III/IV). Therefore, one would expect a positive response to caloric testing, which can be remembered by recalling the pneumonic "COWS," cold opposite, warm same.

Answer 33

A: ampullae B: utricle C: saccle

Answer 34

A: Ampulla B: Cupulla C: Crista D: Vestibulocochlea nerve

Answer 35

**Acid-sensing ion channel (ASIC)** channel: * cation channel activated by **pH changes** and other stimuli - important in **inflammatory** response **(TRPM8)channel (cold and menthol receptor 1):** * ion channel activated by cold temperature and cooling agents (**menthol**). **Transient receptor potential cation channel subfamily V member 1 (TRPV1) channel (capsaicin receptor/vanilloid receptors 1):** * Non-selective cation channel that is activated by **temperature, acid, capsaicin, and mustard/wasabi**.

Answer 36

Loss of **NaV1.7** (sodium channel subunit). **SCN9A** gene (encode sodium channel NaV1.7).

Answer 37

**Congenital insensitivity to pain (CIP)**: Rare condition in which individual cannot feel pain so often have wounds, broken bones, health issues not detected.

Answer 38

**Inherited erythromelalgia (IE):** A painful neuropathy involving severe chronic burning pain sensations in hands and feet.

Answer 39

**Congenital insensitivity to pain with anhidrosis (CIPA)** * **TRKA gene** codes for **TrKA receptor** to create **nerve growth factor (NGF)** * NGF is crucial for development of **Adelta and C-fibres**

Answer 40

Lamina found within dorsal horn: Lamina I to V * **Aβ**: project deepest - **lamina IV & V** * **Aδ** project middle: **lamina I** * **C fibres** project into **lamina I & II**

Answer 41

Aδ nociceptor axon projects on to **Lamina I** via **excitatory glutamate synapse** on to either **NMDA or AMPA receptors**

Answer 42

C fibres activate lamina I cells via **gluatmata onto excitatory interneurons in lamina II**, which then excites **lamina I dendrite with glutamate**

Answer 43

**herniations** (if bleed big enough) * subfalcine hernia; * transtentorial hernia (ascending or descending) * tonsillar hernia **Raise ICP** - reduces brain perfusion **Hydrocephalus**: blood into ventricles can clog up CSF drainage pathways / cerebral aquaduct is block

Answer 44

Confirm if on aspirin and warfarin & stop. Warfarin worsens the severity of hemorrhage and dramatically increases the risk of mortality from ICH.

Answer 45

Cellular ischaemia: - Na / K+ pump failure - Causes depolarisation - Causes Ca2+ food in - Cascade of enzymes that respond to ischaemia (like caspases) - Causes cell death

Answer 46

Carotid dissections

Answer 47

**Hypertension** **Hypercholesteroamia** **Diabetes** Cardiac - **AF**