FirstRanker Logo

FirstRanker.com - FirstRanker's Choice is a hub of Question Papers & Study Materials for B-Tech, B.E, M-Tech, MCA, M.Sc, MBBS, BDS, MBA, B.Sc, Degree, B.Sc Nursing, B-Pharmacy, D-Pharmacy, MD, Medical, Dental, Engineering students. All services of FirstRanker.com are FREE

📱

Get the MBBS Question Bank Android App

Access previous years' papers, solved question papers, notes, and more on the go!

Install From Play Store

Download MBBS Anatomy PPT 43 Auditory Pathway Notes

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Human Anatomy ppt lectures Topic 43 Auditory Pathway Notes. - anatomy ppt free download human anatomy ppt lectures, medicine notes ppt, anatomy handwritten notes pdf, mbbs 1st year anatomy notes pdf download, best anatomy notes pdf, human anatomy notes pdf, anatomy easy notes pdf, anatomy notes online, anatomy short notes, Anatomy ppt, Powerpoint Presentations and lecture notes.

This post was last modified on 05 April 2022


Learning objectives

?Receptors

--- Content provided by FirstRanker.com ---

?Ascending pathway of hearing

?Involvement of nuclei at different level

?Applied anatomy

--- Content provided by FirstRanker.com ---


2

Auditory pathway

--- Content provided by FirstRanker.com ---

?Transmits auditory stimulus from hearing receptors

(organ of corti`s) to auditory area in cerebral cortex.

1. Organ of Corti (receptor)

--- Content provided by FirstRanker.com ---


2. Dorsal & ventral cochlear nuclei

3. Trapezoid body & Superior olivary nuclei

--- Content provided by FirstRanker.com ---

4. Lateral lamniscus

5. Inferior colliculus

6. Medial geniculate body

--- Content provided by FirstRanker.com ---


7. Auditory radiation

8. Auditory cortex

--- Content provided by FirstRanker.com ---

3

Auditory pathway

?Cochlear nu-receptors- hair cells in Organ of Corti

--- Content provided by FirstRanker.com ---

?1st order neuron- spiral ganglion- bipolar neurons ?

peripheral process- hair cells of spiral ganglion ? central
processes & axons - cochlear nerve- bifurcates & terminate
in Dorsal & Ventral Cochlear Nu ? 2nd order neurons -

--- Content provided by FirstRanker.com ---

dorsal & ventral ? axons CROSS & few uncrossed in dorsal
part of Lower part of pons - Superior Olivary nucleus-

?3rd Neuron ? Superior Olivary Nucleus - lateral lemniscus

--- Content provided by FirstRanker.com ---

Formation of Trapezoid body- In dorsal part of pons ?
intermediate /dorsal acoustic striae-nucleus of trapezoid
body.

?Lateral lemniscus ? terminate at ?Inferior Colliculus (MB)

--- Content provided by FirstRanker.com ---

?Inferior colliculus - 4th order of neuron- (Inf Brachiaum)


Auditory pathway

--- Content provided by FirstRanker.com ---

?Inferior colliculus - 4th Order Neuron - center for

auditory reflexes Medial Geniculate body
through inferior brachium.

--- Content provided by FirstRanker.com ---

?Medial Geniculate body - 5th order of neuron & is -

Final Relay Station - hearing pathway.

?5th order of neuron ? starts from MGB- forms

--- Content provided by FirstRanker.com ---


acoustic radiation -reaches- acoustic area of
cerebral hemisphere ?

?Acoustic area accepts bilateral impulses.

--- Content provided by FirstRanker.com ---


?Temporal lobe - Superior Temporal gyrus area

41,42.

--- Content provided by FirstRanker.com ---

8

9
Auditory area....

--- Content provided by FirstRanker.com ---

?Primary auditory area - floor of post ramus of lateral

sulcus.

?Superior surface of superior temporal gyrus has two

--- Content provided by FirstRanker.com ---


transverse temporal gyri (Heschl's gyrus)

? area-41 & 42 receives inputs from medial geniculate

--- Content provided by FirstRanker.com ---

body.

Auditory areas

?Primary auditory area ? area 41

--- Content provided by FirstRanker.com ---


?Superior temporal gyrus ? bilateral representation

?Detection of direction & frequency of sound.

--- Content provided by FirstRanker.com ---

?Lower frequencies are located in anterior/lateral

part & higher frequencies are located in
posterior/medial part

--- Content provided by FirstRanker.com ---

?Auditory association area - area 42 ? co-relates

and comprehension of present stimulus to past
ones

--- Content provided by FirstRanker.com ---

?Higher Auditory association area - area 22 ?

Wernicke's area- comprehension of spoken
language & interpretation of sound.

--- Content provided by FirstRanker.com ---

Auditory areas

?Lesion of primary auditory area 41 & 42 of one side

produces bilateral partial deafness, b/o bilateral

--- Content provided by FirstRanker.com ---

receiving of inputs via medial geniculate body.

?Auditory association cortex- area 22 , Wernicke's

speech area. Interpretation of sounds on past

--- Content provided by FirstRanker.com ---

experiences. Sensory aphasia.

?Olfactory area- 28 , lateral olfactory stria & gyrus

,anterior part of parahippocampal gyrus & uncinate

--- Content provided by FirstRanker.com ---

gyrus.

?Area 8 ? frontal eye field

?Area 44 & 45 ? Broca's speech area ? motor

--- Content provided by FirstRanker.com ---


speech area in dominant cerebral hemisphere.

?Prefrontal cortex- (area - 9-12)

--- Content provided by FirstRanker.com ---

?Depth of feeling

?Foresightedness

?Tactfulness

--- Content provided by FirstRanker.com ---


?Mature judgement

?Pleasure & displeasure
?Lesion of prefrontal cortex (9 -12) - Lack of self

--- Content provided by FirstRanker.com ---


responsibility ,Vulgarity of speech, euphoria ,
clownish behaviour

?Area-40- Astereognosis & tactile aphasia

--- Content provided by FirstRanker.com ---


?Area-39 ? word blindness ? unable to read

words even if were written by one self

--- Content provided by FirstRanker.com ---

?Area 22 - word deafness - sensory aphasia.

Decreased interpretation of sounds/words and

increased frequency of word produced....

--- Content provided by FirstRanker.com ---


?Area 44 & 45 ? motor aphasia

Speech area....

--- Content provided by FirstRanker.com ---

Wernicke's area- 22, dominant hemisphere ,

interpretation of spoken ,written ,symbols & signs.
Allows understanding of written & spoken language.
Angular gyrus - interconnects -visual area & auditory

--- Content provided by FirstRanker.com ---

areas.

Wernicke's is necessary for- language

comprehension while Broca's area, 44, language

--- Content provided by FirstRanker.com ---

production. Superior longitudinal fasciculus or
arcuate fasciculus interconnect these two areas.

Sensory aphasia- unable to understand written or

--- Content provided by FirstRanker.com ---

spoken words with normal vision/hearing.

Speech area's.....

?Apraxia- parietal lobe -impairment of performance

--- Content provided by FirstRanker.com ---


of learned movements.

?Wernicke's aphasia- inability to understand spoken or

--- Content provided by FirstRanker.com ---

written words ? Broca's ok- uses all meaningless and

incorrect words...no meaning. Called-fluent aphasia
or receptive aphasia ,

--- Content provided by FirstRanker.com ---

?Broca's aphasia- unable to articulate words-

nonfluent aphasia, hesitant aphasia /distorted-

?What they wish to say but can not speak.

--- Content provided by FirstRanker.com ---


?Global aphasia- extensive damage to cortex