Auditory Pathway Flashcards
What are the auditory ossicles of the middle ear?
- Malleus.
- Incus.
- Stapes.
The cochlear nerve runs through what to reach the cochlea of the inner ear?
Internal acoustic meatus.
How many turns are in the spiral of the cochlea?
2.5
The organ of Corti contains what?
Inner and outer hair cells.
What is the Spiral Ganglion of the Cochlea?
A group of bipolar neurons stimulated by hair cells. They carry APs from the Organ of Corti to the cochlear nuclei in the pons.
Superior to the cochlear nuclei, input is essentially what?
Bilateral.
Structures important in sound localisation and as relays for stapedial and tensor tympani reflexes.
- Superior olivary nucleus.
- Nucleus of lateral lemniscus.
Tonotopic organisation is present where?
The Auditory Cortex.
Fibres carrying information regarding low frequency sound end in which part of the auditory cortex?
The anterolateral part.
Fibres carrying information regarding high frequency sound end in which part of the auditory cortex?
The posteromedial part.
What may arise as a result of trauma to Broca’s area?
- Difficulty in producing language (using few words, only saying the most important words in a sentence).
- However, there is usually no difficulty comprehending language.
What is the name of the condition arising from damage to Broca’s area?
Broca’s/ motor/ expressive aphasia.
What may arise as a result of trauma to Wernicke’s area?
- Difficulty comprehending language.
- Using words out of order.
- Meaningless words.
What is the name of the condition arising from damage to Wernicke’s area?
Wernicke’s/ sensory/ receptive aphasia.
Maintaining equilibrium requires information from what?
- Vision.
- Proprioception.
- Vestibular apparatus (labyrinth).
How many semi-circular canals in the inner ear?
3 in each ear.
What nerve is most associated with hearing?
Cochlear nerve.
What nerve is most associated with balance?
Vestibular nerve.
Name 3 areas upon which vestibular information has been found to converge?
- Area of parietal cortex just posterior to the area of the postcentral gyrus that represents the hand and mouth.
- Area just rostral to the primary auditory cortex.
- Posterior insular cortex.
Due to the lens, objects are projected onto the retina how?
Reversed and upside down.
Each optic tract, lateral geniculate nucleus, optic radiation and visual cortex deals with visual information from which visual field?
The contralateral visual field.
Output of the superior colliculi is to?
- Nuclei of CN III, IV and VI.
- Motor nucleus of VII.
- Spinal cord.
The lower visual field is projected to where?
The gyrus superior to the calcarine sulcus.
The upper visual field is projected to where?
The gyrus inferior to the calcarine sulcus.
The macula projects to which pole of the visual cortex?
The posterior pole.
What is significant about the macula and its relationship with the visual cortex?
The macula occupies a much greater proportion of the cortex relative to the size of the visual field it covers.
Fibres of the geniculocalcarine tract initially form what?
Part of the internal capsule.
Fibres of the geniculocalcine tract carrying visual information from the upper half of the visual field loop around what?
Anteriorly around the temporal part of the lateral ventricle in MEYER’S LOOP.
Where do fibres of the geniculocalcine tract carrying visual information from the upper half of the visual field end after Meyer’s loop?
Below the calcarine sulcus.
The visual cortex generally provides for eye movements in response to what?
Visual stimuli e.g. tracking moving objects.
The frontal eye fields control what?
“Movements of command” i.e. movements independent of moving visual stimuli.
How do tracking movements differ from movements of command?
- Tracking movements tend to be smooth.
- Movements of command tend to be jumpy (Saccadic).
What term is given to the jumpy movements generally seen in movements of command of the eye?
Saccadic.
If a light is shone into the right eye, what is the resultant direct light reflex?
- The right pupil constricts.
If a light is shone into the right eye, what is the resultant consensual light reflex?
The left pupil constricts.
The pretectal fibres of the consensual light reflex project where?
Bilaterally to the Edinger-Westphal nucleus.
In contrast to the pupillary light reflex, the accommodation reflex requires what?
Input to the oculomotor and Edinger-Westphal nucleus from the visual cortex.
What is hemianopia?
Blindness for half the field of vision in one or both eyes.
A term for the same visual field loss in both eyes.
Homonymous.
A term for opposite visual field loss in both eyes.
Heteronymous.
The name given to the cerebral hemisphere which “takes the lead” in certain higher functions.
Dominant hemisphere.
For most truly right-handed people, which hemisphere is usually dominant for language?
The left cerebral hemisphere.
Association fibres connect to cortical sites located where?
In the same cerebral hemisphere.
Commissural fibres connect what?
One cerebral hemisphere to the other, usually connecting areas with similar function.
Projection fibres connect what?
Hemispheres to deeper structures e.g. thalamus, corpus striatum, brain stem and spinal cord.
