Case 6

Question 1

What are the features of the biggest commissure in the brain?

Answer 1

• Rostrum
• Genu
• Body
• Splenium

Question 2

Where is the location and what is the function of the insula?

Answer 2

• found deep in lateral sulcus/fissure

- it puts into effect autonomic effects on emotion changes

Question 3

Blood supply to the brain (Circle of Willis):

Outline briefly the circle of Willis, where do the 3 cerebral arteries branch from?

Answer 3

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• posterior cerebral - vertebrobasilar - basilar artery branches
• middle cerebral - internal carotid branch
• anterior cerebral - internal carotid branch

Question 4

What parts of the brain does the anterior cerebral artery supple?
More specifically what cortices?

Answer 4

Medial surface - most of medial and and lateral surface
Lateral surface - superior surface

• PRIMARY MOTOR CORTEX
• PRIMARY SOMATOSENSORY CORTEX

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Question 5

What parts of the brain does the middle cerebral artery supply? Cortical areas?

Answer 5

Medial surface;
- tip of temporal lobe

Lateral surface;
- most of inner medial surface

• PRIMARY MOTOR CORTEX
• SOMATOSENSORY CORTEX
• PRIMARY AUDITORY CORTEX
• BROCA’S AREA

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Question 6

What parts of the brain does the posterior cerebral artery supply?

Answer 6

Medial surface;
- posterior surface

Lateral surface;
- posterior surface

• PRIMARY VISUAL CORTEX

Question 7

What does ‘Weigert’s stain’ stain in the CNS tissue?

Answer 7

• stains lipids in myelin sheath
• WHITE MATTER (myelinated axons) - therefore dark
• GREY MATTER (cell bodies) - unstained

Question 8

How many are the lobes of the cerebral hemisphere separated?

Answer 8

Frontal and Parietal - by CENTRAL SULCUS
Temporal and (Frontal and Parietal) - by LATERAL SULCUS
Parietal and Occipital - PARIETAOCCIPITAL SULCUS
** No sulcus between temporal and occipital **

Question 9

What is the normal human hearing range?

Answer 9

20 - 20,000 Hz

Question 10

What is serous otitis media and how is it treated?

Answer 10

Problem with drainage of the eustachian tube often linked to respiratory infection. It is treated by puncturing the tympanic membrane and inserting a grommet after draining.

Question 11

What is otosclerosis?

Answer 11

Calcification of the joints of the (usually) stapes bone. The bone growth of the bone leads to;

• limited free movement of the stapes
• affects hearing

Question 12

What is the treatment of otosclerosis?

Answer 12

1) Prostatic replacement of the stapes

Question 13

When a prostatic replacement of stapes is being carried out, why is it important to know the anatomy of the ear?

Answer 13

As the procedure is done by cutting the tympanic membrane, the CHRODA TYMPANI NERVE runs BEHIND the tympanic membrane.. If damaged would cause ***loss of taste at anterior 2/3 of tongue ** and **less salivary gland secretion **

Question 14

What are the function of the inner hair cells?

Answer 14

1) PITCH DETERMINATION - send auditory signals tithe brainvia the auditory nerve

ONE ROW

Question 15

What is the function of the outer hair cells?

Answer 15

1) COCHLEAR AMPLIFIER

Amplify vibrations even more, the outer hair cells shorten on depolarisation and lengthen on hyperpolarisation

Question 16

A rise in 3 decibels will mean what in terms of safe exposure time? Why is this?

Answer 16

A rise in 3 decibels means the sound energy is doubled… Therefore, safe exposure time HALVES with an increase of 3 decibels.

Question 17

What are the causes of tinnitus?

Answer 17

1) conditions that reduce perception of external sounds e.g. Ear wax, otosclerosis, ear infection
2) Hair cell damage due to 1) high intensity exposure or 2) drug side effects (aspirin, antibiotics)
3) Lesions of auditory nerve e.g. Acoustic neuroma

Question 18

Why does noise induced frequency first appear as a reduction in sensitivity at about 4 kHz?

Answer 18

This is the resonance frequency of the external auditory canal so that it is transmitted most efficiently to the eardrum

Question 19

How do you perform Weber’s test?

Answer 19

1) Striking tuning fork against the bench and place against vertex of skull
2) Sound softer in one ear indicates sensorineural or conductive hearing loss

Question 20

How do you perform Rinne’s test?

Answer 20

1) Strike tuning fork and place on stem of mastoid bone
2) bring close to ear canal
3) airborne sound louder than bone conducted sound - patient is either normal or has sensorineural deafness
4) airborne sound is quieter than bone conducted sound - patient has conductive hearing loss

Question 21

What is the or name of age related deafness?

Answer 21

Presbycusis