The document discusses the physiology of hearing and theories of sound transduction. It describes three functional units within the cochlea: the organ of Corti which senses sound, the stria vascularis which generates the endocochlear potential, and the spiral ganglion which relays signals to the brain. Sound causes vibrations of the basilar membrane that are transduced by hair cells into nerve impulses. Theories discussed include place coding of frequency along the cochlea and traveling wave propagation of vibrations from basal to apical regions.
BRAINSTEM EVOKED RESPONSE AUDIOMETRY (BERA), AUDIOTORY BRAINSTEM RESPONSE (ABR)Girish S
Neurologic objective, noninvasive test of auditory brainstem function in response to auditory (click) stimuli. It’s a set of seven positive waves recorded during the first 10 milli seconds after a click stimuli. They are labeled as I - VII. Also called Jewet bumps.
BRAINSTEM EVOKED RESPONSE AUDIOMETRY (BERA), AUDIOTORY BRAINSTEM RESPONSE (ABR)Girish S
Neurologic objective, noninvasive test of auditory brainstem function in response to auditory (click) stimuli. It’s a set of seven positive waves recorded during the first 10 milli seconds after a click stimuli. They are labeled as I - VII. Also called Jewet bumps.
Cochlear Fluid is the one of the most important fluid not only for hearing sensation but also for the balance of human body. It is very important to know the embryology, anatomy, and physiology of cochlear fluid mechanism to know the various pathological conditions of inner ear.
human's inner ear ,which is third part of ear, Having cochlea and vestibular system.in this slide we will discuss about the anatomy and physiology of inner ear.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
How to Split Bills in the Odoo 17 POS ModuleCeline George
Bills have a main role in point of sale procedure. It will help to track sales, handling payments and giving receipts to customers. Bill splitting also has an important role in POS. For example, If some friends come together for dinner and if they want to divide the bill then it is possible by POS bill splitting. This slide will show how to split bills in odoo 17 POS.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
2. THREE FUNCTIONAL UNITS
WITHIN COCHLEA
• ORGAN OF CORTI- the sensor
• STRIA VASCULARIS- the battery
generating endocochlear potential
• SPIRAL GANGLION- electrical wires
connecting cochlea to CNS
3.
4. – Movement of basilar membrane
– Shear force between tectorial membrane &
hair cells
– Cochlear microphonics
– Nerve impulses
Transduction of mechanical
energy to electrical impulses
10. • The tops of the hair cells in
the organ of Corti are held
rigid by the reticular lamina,
and the hairs of the outer
hair cells are embedded in
the tectorial membrane
• The hairs of the inner hair
cells are not attached to the
tectorial membrane, but they
are apparently bent by fluid
moving between the tectorial
membrane and the
underlying hair cells.
11. • Upward movement of the basilar
fiber rocks the reticular lamina
upward and inward toward the
modiolus.Then, when the basilar
membrane moves downward,the
reticular lamina rocks downward
and outward.
•
• The inward and outward motion
causes the hairs on the hair cells
to shear back and forth against
the tectorial membrane.Thus, the
hair cells are excited whenever
the basilar membrane vibrates
12.
13. Tip links
• the tops of the
shorter stereocilia
are attached by
thin filaments to
the back sides of
their adjacent
longer stereocilia
• .
15. Mutation in human genes encoding
CADHERIN 23 or PROTOCADHERIN 15
causes USHER SYNDROME
-congenital hearing loss
-progressive loss of vision due to retinitis
pigmentosa
16. Depolarization/activation
• when the cilia are bent in
the direction of the longer
ones, the tips of the
smaller stereocilia are
tugged outward.This
causes a mechanical
transduction that opens
200 to 300 cation-
conducting channels,
allowing rapid movement
of potassium ions from the
surrounding scala media
fluid into the stereocilia,
which causes
depolarization of the hair
cell membrane
17. • The influx of potassium
inside the cell causes
activation of calcium
channels
• This calcium drags the
neurotransmitter filled
vesicle to fuse with cell
membrane at base of
cell.
• Neurotransmitter
(glutamate)releases and
excites the dendrites of
afferent nerve fibres.
22. Endocochlear potential
• An electrical potential of
about +80 millivolts
exists all the time
between endolymph and
perilymph, with positivity
inside the scala media
and negativity outside.
• This is called the
endocochlear potential,
and it is generated by
continual secretion of
positive potassium ions
into the scala media by
the stria vascularis
23.
24. OUTER HAIR CELLS &
AMPLIFICATION
• Outer hair cells play a key role in amplification
of basilar membrane motion.
• One mechanism is somatic electromotility
• Upward stimulation of basilar membrane moves
stereocilia in excitatory direction and
depolarizes outer hair cells,which in turn
shorten,further pulling basilar membrane
upward and amplifies its motion.
• This provides an extra gain of 40-50dB to the
system
25. STRIA VASCULARIS
• Generates endocochlear potential and
maintains unique ion composition of
endolymph
• Comprised of 3 cell types
-marginal
-intermediate
-basal cells
27. • Mutation of human genes KCNE1 &
KCNQ1 cause JERWELL and LANGE-
NIELSEN syndrome(hearing loss and
cardiac arrhythmia)
• Mutation of BARTIN gene or mutation of
ClC-Ka and ClC-Kb subunits of basolateral
chloride channel leads to BARTER
SYNDROME type 4(deafness and renal
salt wasting)
28. SPIRAL GANGLION
• Located in Rosenthal canal within
modiolus of cochlea.
• 95% of afferent fibres are thick and
myelinated and exclusively innervate inner
hair cells.
• Remaining fibres are thin and
unmyelinated,contact outer hair cells.
• Efferent fibres originate in brain stem from
superior olivary complex,allows CNS to
modulate operations of cochlea
32. Theories of hearing
Place / Resonance Theory (Helmholtz, 1857)
Perception of pitch depends on selective
vibration of specific place on basilar membrane.
Telephone Theory (Rutherford, 1886)
Entire basilar membrane vibrates. Pitch related
to rate of firing of individual auditory nerve
fibers.
33. Theories of hearing
Volley Theory (Wever, 1949)
> 5 KHz: Place theory; <400 Hz: Telephone theory
400 – 5000 Hz: Volley theory
Groups of fibres fire asynchronously (volley
mechanism). Required frequency signal is
presented to C.N.S. by sequential firing in groups
of 2 - 5 fibers as each fiber has limitation of 1 Khz.
34.
35. Sound stimulus produces a wave-like vibration of
basilar membrane starting from basal turn towards
apex of cochlea . It increases in amplitude as it moves
until it reaches a maximum & dies off. Sound
frequency is determined by point of maximum
amplitude. High frequency sounds cause wave with
maximum amplitude near to basal turn of cochlea.
Low frequency sound waves have their maximum
amplitude near cochlear apex.
Bekesy’s travelling wave theory