The structure of the organ of hearing 1. Auditory receptors convert sound signals into nerve impulses that are transmitted to the auditory zone of the cerebral cortex. 2. Perceives the position of the body in space and transmits impulses to the medulla oblongata, then to the vestibular zone of the cerebral cortex. 1 organ of hearing: cochlea with a cavity filled with liquid 2 organ of balance consists of three semicircular canals Inner ear Conduct and amplify sound vibrations. Connected to the nasopharynx and equalizes pressure on the eardrum. 1 auditory ossicles: - hammer, - anvil, - stirrup; 2 Eustachian tube Middle ear Picks up sound and sends it to the ear canal. Conducts sound, contains glands that secrete sulfur. Converts air sound waves into mechanical ones, vibrates the auditory ossicles. 1 auricle 2 external auditory canal 3 tympanic membrane Outer ear Functions Structure Departments of the organ of hearing
Sound wave The tympanic membrane The auditory ossicles The membrane of the oval window (inner ear) Fluid in the cochlea The basilar membrane Receptor cells with hairs The integumentary membrane Nerve impulse The brain
Inner ear (cochlea) The inner ear is a bony labyrinth (cochlea and semicircular canals), inside which lies, repeating its shape, a membranous labyrinth. The membranous labyrinth is filled with endolymph, the space between the membranous and bony labyrinth is filled with perilymph (perilymphatic space). Normally, a constant volume and electrolyte composition (potassium, sodium, chlorine, etc.) of each of the fluids is maintained
The organ of Corti The organ of Corti is the receptor part of the auditory analyzer, which converts the energy of sound vibrations into nervous excitation. The organ of Corti is located on the main membrane in the cochlear canal of the inner ear, filled with endolymph. The organ of Corti consists of a number of inner and three rows of outer sound-perceiving hair cells, from which fibers of the auditory nerve depart.
Vestibular apparatus The vestibular apparatus is an organ that perceives changes in the position of the head and body in space and the direction of body movement in vertebrates and humans; part of the inner ear. The vestibular apparatus is a complex receptor of the vestibular analyzer. The structural basis of the vestibular apparatus is a complex of clusters of ciliated cells of the inner ear, endolymph, calcareous formations included in it - otoliths and jelly-like cupules in the ampullae of the semicircular canals.
Hearing impairments Hearing impairment is a complete (deafness) or partial (hard of hearing) reduction in the ability to detect and understand sounds. Any organism capable of perceiving sound can suffer from hearing loss. Sound waves vary in frequency and amplitude. The loss of the ability to detect some (or all) frequencies, or the inability to distinguish low amplitude sounds, is called hearing loss.
Defects: loudness, frequency detection, sound recognition The minimum loudness that an individual can perceive is called the hearing threshold. In the case of humans and some animals, this value can be measured using behavioral audiograms. Sounds are recorded from the quietest to the loudest of various frequencies, which should cause a certain reaction of the person being tested. There are also electrophysiological tests that can be performed without studying behavioral responses.
An individual is said to be hearing impaired if his perception of sounds that are normally perceived by a healthy person is impaired. In humans, the term "hearing impairment" is usually applied to those who have partially or completely lost the ability to distinguish sounds at frequencies of human speech. The degree of disturbance is determined by how much louder the sound must become compared to the normal level in order for the listener to begin to distinguish it. In cases of profound deafness, the listener cannot distinguish even the loudest sounds emitted by the audiometer.
Classification of hearing impairments Conductive hearing loss is a hearing impairment in which sound waves are difficult to conduct along the path: the outer ear, the eardrum, the auditory ossicles of the middle ear, the inner ear. "The sound-conducting apparatus includes the outer and middle ear, as well as the peri- and endolymphatic spaces of the inner ear, the basilar plate and the vestibular membrane of the cochlea."
With conductive hearing loss, the conduction of a sound wave is blocked even before it reaches the sensory epithelial (hair) cells of the organ of Corti, associated with the endings of the auditory nerve. The same patient may have a combination of conductive (bass) and sensorineural hearing loss (mixed hearing loss). [ Purely conductive hearing loss also occurs [
Sensorineural hearing loss (synonymous with sensorineural hearing loss) is a hearing loss caused by damage to the structures of the inner ear, the vestibulocochlear nerve (VIII), or the central parts of the auditory analyzer (in the brain stem and auditory cortex).
Sensorineural (sensorineural) hearing loss occurs when the inner ear stops processing sound normally. This is caused by various reasons, the most common is damage to the hair cells of the cochlea due to loud sound and (or) age-related processes. When the hair cells are insensitive, sounds are not transmitted normally to the auditory nerve in the brain. Sensorineural hearing loss accounts for 90% of all cases of hearing loss. Although sensorineural hearing loss is irreversible, more damage can be avoided by using ear plugs when listening to loud sounds or by listening to music at a lower volume.
Hearing aid Treatment of hearing loss caused by changes in the sound-conducting apparatus is carried out quite successfully. In case of damage to the sound-perceiving apparatus, a complex of medical, physiotherapeutic agents is used. With insufficient effectiveness of these measures, hearing aids are used - the selection of hearing aids that amplify sound. The suitability of the hearing aid is assessed after an adaptation period during which the patient gets used to the unusual volume of perceived speech and various extraneous noises.
The technical perfection of the equipment and the correctness of individual selection determine the effectiveness of hearing aids. Patients with sensorineural hearing loss are subject to dispensary observation, maximum rehabilitation and, if possible, employment. Deaf society plays an important role in solving these issues. After an examination of the ability to work, such patients are assigned to special enterprises or receive a recommendation to limit certain types of labor activity.
Rehabilitation of children with hearing impairment Individual and group lessons, choral recitation with musical accompaniment are used in the process of rehabilitation. In the future, speech classes are conducted with the help of amplifiers and hearing aids. Such work is carried out in special kindergartens for hearing-impaired children, starting from 2-3 years of age. In the future, it continues in specialized schools.
In many cases, rehabilitation work is carried out by parents in the conditions of natural verbal communication. This requires invariably more labor and time, but often gives good results. But this work should be joint with deaf teachers and take place under their supervision, thus, the components of successful rehabilitation of the hearing impaired are as follows: Early detection of hearing impairment and early start of rehabilitation measures. Ensuring sufficient volume of speech signals. The intensity and systematic nature of auditory training, which is the basis of the rehabilitation process.
The most valuable period for rehabilitation is the first three years of a child's life. With hearing loss that has arisen in a person who can speak, speech disorders develop in the form of monotony, irregularity. In addition, the resulting hearing loss makes it difficult to communicate with others. To diagnose hearing loss in adults, there are a large number of methods and tests. An important goal of this study is to elucidate the cause of the developed hearing loss, the defeat of the sound-conducting or sound-receiving system.
slide 2
- The human ear perceives sounds from 16 to 20000 Hz.
- maximum sensitivity from 1000 to 4000 Hz
slide 3
main speech field
- is in the range of 200 - 3200 Hz.
- Old people often do not hear high frequencies.
slide 4
- Tones - contain sounds of the same frequency.
- Noises are sounds made up of unrelated frequencies.
- Timbre is a characteristic of sound determined by the shape of the sound wave.
Slide 7
Psychological correlates of loudness of sound.
- whispered speech - 30 dB
- colloquial speech - 40 - 60 dB
- street noise - 70 dB
- scream at the ear - 110 dB
- loud speech - 80 dB
- jet engine - 120 dB
- pain threshold - 130 - 140 dB
Slide 8
ear structure
Slide 9
outer ear
Slide 10
- The auricle is a sound catcher, a resonator.
- The eardrum receives sound pressure and transmits it to the ossicles of the middle ear.
slide 11
- It does not have its own oscillation period, because its fibers have a different direction.
- Doesn't distort sound. The vibrations of the membrane at very strong sounds are limited by the musculus tensor timpani.
slide 12
Middle ear
slide 13
The handle of the malleus is woven into the eardrum.
Information transfer sequence:
- Hammer→
- Anvil→
- Stremechko →
- oval window →
- perilymph → scala vestibularis
slide 15
- musclestapedius. limits the movement of the stirrup.
- The reflex occurs 10ms after the action of strong sounds on the ear.
slide 16
The transmission of a sound wave in the outer and middle ear occurs in the air.
Slide 19
- The bony canal is separated by two membranes: a thin vestibular membrane (Reissner)
- and a dense, resilient base membrane.
- At the top of the cochlea, both of these membranes are connected, they have a hole in the helicotrema.
- 2 membranes divide the bony canal of the cochlea into 3 passages.
Slide 20
- Stapes
- round window
- oval window
- basement membrane
- Three channel cochlea
- Reisner's membrane
slide 21
cochlear channels
slide 22
1) The superior canal is the scala vestibularis (from the oval window to the top of the cochlea).
2) The lower channel is a tympanic staircase (from the round window). The canals communicate, are filled with perilymph and form a single canal.
3) The middle or membranous canal is filled with ENDOLYMPH.
slide 23
Endolymph is formed by a vascular strip on the outer wall of the middle scala.
slide 26
Internal
- arranged in one row
- there are about 3500 of them.
- They have 30 - 40 thick and very short hairs (4 - 5 MK).
Slide 27
outdoor
- arranged in 3 - 4 rows,
- there are 12,000 - 20,000 cells.
- They have 65 - 120 thin and long hairs.
Slide 28
The hairs of the receptor cells are washed by the endolymph and come into contact with the tectorial membrane.
Slide 29
The structure of the organ of Corti
slide 30
- Internal phonoreceptors
- tectorial membrane
- External phonoreceptors
- Nerve fibers
- basement membrane
- supporting cells
Slide 31
Excitation of phonoreceptors
slide 32
- Under the action of sounds, the main membrane begins to oscillate.
- The hairs of the receptor cells touch the tectorial membrane
- and deform.
Slide 33
- In phonoreceptors, a receptor potential arises and the auditory nerve is excited according to the scheme of secondary sensory receptors.
- The auditory nerve is formed by processes of neurons of the spiral ganglion.
slide 34
Electric potentials of the cochlea
Slide 35
5 electrical phenomena:
1.membrane potential of the phonoreceptor. 2. endolymph potential (both are not related to the action of sound);
3.microphone,
4.summing
5.potential of the auditory nerve (arise under the influence of sound stimuli).
slide 36
Characterization of cochlea potentials
Slide 37
1) The membrane potential of the receptor cell is the potential difference between the inner and outer sides of the membrane. MP = -70 - 80 MV.
2) Endolymph potential or endocochlear potential.
Endolymph has a positive potential in relation to perilymph. This difference is equal to 80mV.
Slide 38
3) Microphone potential (MP).
- It is registered when the electrodes are located on a round window or near receptors in the scala tympani.
- The MP frequency corresponds to the frequency of sound vibrations entering the oval window.
- The amplitude of these potentials is proportional to the sound intensity.
Slide 40
5) Action potential of auditory nerve fibers
It is a consequence of the appearance of microphone and summation potentials in hair cells. The amount depends on the frequency of the acting sound.
Slide 41
- If there are sounds up to 1000 Hz,
- then PD of the corresponding frequency occurs in the auditory nerve.
- At higher frequencies, the frequency of AP in the auditory nerve decreases.
Slide 42
At low frequencies, APs are observed in a large number, and at high frequencies, in a small number of nerve fibers.
slide 43
Block diagram of the auditory system
Slide 44
Sensory cells of the cochlea
- Spiral ganglion neurons
- Cochlear nuclei of the medulla oblongata
- Inferior tubercles of the quadrigemina (midbrain)
- Medial geniculate body of thalamus diencephalon)
- Temporal cortex (fields 41, 42 according to Brodmann)
Slide 45
The role of various departments of the central nervous system
Slide 46
- Cochlear nuclei - primary recognition of the characteristics of sounds.
- The inferior colliculi of the quadrigemina provide primary orienting reflexes to sound.
The auditory cortex provides:
1) reaction to a moving sound;
2) selection of biologically important sounds;
3) reaction to a complex sound, speech.
Slide 47
Theories of perception of sounds of different heights (frequency)
1. Resonance theory of Helmholtz.
2. Rutherford's telephone theory.
3.Theory of spatial coding.
Slide 48
Helmholtz resonance theory
Each fiber of the main cochlear membrane is tuned to its own sound frequency:
At low frequencies - long fibers at the top;
At high frequencies - short fibers at the base.
Slide 49
The theory has not been confirmed because:
The membrane fibers are not stretched and do not have "resonant" vibration frequencies.
Slide 50
Rutherford's telephone theory (1880)
Slide 51
Sound vibrations → foramen ovale → oscillation of the scala vestibular perilymph → through helicotrema oscillation of the scala tympani perilymph → oscillation of the main membrane
→ excitation of phonoreceptors
Slide 52
- The AP frequencies in the auditory nerve correspond to the frequencies of the sound acting on the ear.
- However, this is only true up to 1000 Hz.
- The nerve cannot reproduce a higher frequency of AP
Slide 53
Bekesy's spatial coding theory. (Traveling wave theory, place theory)
Explains the perception of sound with frequencies above 1000 Hz
Slide 54
- Under the action of sound, the stirrup continuously transmits vibrations to the perilymph.
- Through a thin vestibular membrane, they are transmitted to the endolymph.
Slide 55
- A "traveling wave" propagates along the endolymphatic canal to the helicotrema.
- The rate of its spread gradually decreases,
Slide 56
- The amplitude of the wave first increases,
- then decreases and weakens
- without reaching the helicotrema.
- Between the place of origin of the wave and the point of its attenuation lies the amplitude maximum.
biology presentation - auditory analyzer
auditory analyzer- a set of structures that provide the perception of sound information, convert it into nerve impulses, its subsequent transmission and processing in the central nervous system.
The structure of the hearing aid
The organ of hearing and balance in mammals and humans consists of:
Outer and middle ear(sound conductive)
Inner ear (perceiving sound)
inner ear (snail)
The inner ear is a bony labyrinth (cochlea and semicircular canals), inside which lies,
repeating its shape, a membranous labyrinth. The membranous labyrinth is filled with endolymph, the space between the membranous and bony labyrinth is filled with perilymph (perilymphatic space). Normally, a constant volume and electrolyte composition (potassium, sodium, chlorine, etc.) of each of the fluids is maintained
Organ of Corti
The organ of Corti is the receptor part of the auditory analyzer, which converts the energy of sound vibrations into nervous excitation. The organ of Corti is located on the main membrane in the cochlear canal of the inner ear, filled with endolymph. The organ of Corti consists of a number of inner and three rows of outer sound-perceiving hair cells, from which fibers of the auditory nerve depart.
vestibular apparatus
The vestibular apparatus is an organ that perceives changes in the position of the head and body in space and the direction of body movement in vertebrates and humans; part of the inner ear. The vestibular apparatus is a complex receptor of the vestibular analyzer. The structural basis of the vestibular apparatus is a complex of accumulations of ciliated cells
inner ear, endolymph, calcareous formations included in it - otoliths and jelly-like cupules in the ampullae of the semicircular canals.
Ear diseases
Cold wind or frost, trauma, boils, inflammation, sulfur accumulation and much more can cause pulling or cutting pain in the ear, leading to the formation of an abscess. The most common cause of deafness is a buildup of earwax. Chronic disease of the ear canal, infections can cause swelling and hearing loss. The cause of hearing loss is also a mechanical injury to the eardrum, scars on it. In older people, the tiny bones behind the eardrum often fuse together and they become deaf. Obesity, kidney disease, nicotine abuse, allergies, large doses of aspirin, antibiotics, diuretics, heart drugs, tonic worsens hearing. Severe runny nose worsens hearing for several days
Ear hygiene
Nature surprisingly provided for periodic cleaning of the ear by moving sulfur. The condition of the ear, surprisingly, is reflected in overall health. For example, due to the increase in sulfur pressure on the eardrum, dizziness is possible. It is best to crush the outer ear (auricle) with your hand, rotating it in all directions, pulling it down, forward, forcing the earwax and its remnants to move and come out. The auditory canal needs no less attention and care. In a healthy ear, sulfur does not accumulate. Local ear pain, itching, irritation or inflammation of the canal can not only be easily prevented, but even cured with a little daily care of this organ. Ear drops soften wax, can increase its mass and increase pressure, without bringing any benefit. Daily cleaning of the auricle consists in irrigating the holes and washing the outer parts with ordinary water. The index finger should be inserted into the ear and with a slow movement from side to side with a slight pressure on the wall, remove sulfur, dry dead cells and dust accumulated during the day.
Download Biology Presentation - Auditory analyzer
Publication date: 09.11.2010 05:12 UTC
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The purpose of the lesson: to form students' knowledge about the importance of hearing in human life on the basis of interdisciplinary integration.
Lesson objectives:
Educational:
to continue the formation of knowledge about the structure of analyzers on the example of the auditory analyzer;
consider the structure and functions of the ear;
to study how sound energy is converted into mechanical energy;
develop rules for hearing hygiene.
Educational:
develop the ability to compare, analyze, formulate conclusions, work independently with information sources, apply the acquired knowledge to solve practical problems;
to promote the development of the ability to integrate the material of different sciences (biology, physics, history, music, literature).
Educational:
to cultivate a sense of responsibility, mutual assistance, communication skills;
to continue the formation of skills and habits of respect for one's health.
Lesson type: combined.
Equipment: multimedia projector, computer, thought sheet, didactic material (biological loto - cards with a task for matching), cotton swabs.
During the classes
1. Organizational moment. Psychological attitude to the lesson.
Hello guys. Now I will ask everyone who came to school in a good mood to smile now. Now raise your hands those guys who were in a hurry to get to school. Those guys who will help me in the lesson today, clap your hands. I am also glad to meet you.
2. Actualization of knowledge and skills.
Today you will work not only with a textbook and presentation fragments, but also with thought sheets (application 2) that you see on your desk.
Tell me, what parts of the nervous system are we studying with you?
That's right, analyzers.
What are analyzers for?
Yes, to live in the world, to feel it, to know it. Any analyzer has its own components, name them.
(slide 2).Task number 1. Break into groups. On the slide you see the sections of the analyzer. On the thought sheet application 2 ) are departments of different analyzers. Break into groups.
Let's look at slide 3 and compare with the correct answer.
Task number 2. Remind me which analyzer we talked about in the last lesson.
That's right, about the visual.
Each of you has a biological loto on the tables, after working in pairs, connect the cards according to their meaning.
Let's check if we did it right ( slide 4).
Look at ( slide 5). What is he talking about?
That's right, about color blindness - a disease in which a person does not distinguish between certain colors.
(slide 6). The disease was named after the scientist Dalton, who suffered from this disease.
3. Learning new material.
Now look at the epigraph of our lesson, which is placed on the board. Let's read it aloud:
The world of sounds is so diverse
Rich, beautiful, diverse,
But we are all tormented by the question:
Where do sounds come from?
That our ears are delighted everywhere?
It's time to think seriously.
So what is the topic of our lesson?
auditory analyzer.
And what is sound, after reading Zabolotsky's poem on a mental sheet ( application 2 ), you will understand what it is.
Born of the desert, the sound fluctuates
A blue spider oscillates on a thread.
The air oscillates
Transparent and pure
In shining stars
The leaf is shaking.
(N. Zabolotsky)
Let's turn to physics. The fact is that sound is a mechanical vibration, occurring with a frequency of 20 to 20,000 Hz i.e. 20 to 20,000 times per second. Speaking about the structure of the human body, we should not forget that we study ourselves in order to maintain health.
4. Physical culture break.
Working in the classroom, we strain our eyes, so it is very important to do gymnastics for the eyes. We rotate our eyes, draw the sign of infinity with our eyes, look intently at the tip of the finger, bringing it closer and further away.
5. Continued study of new material.
Now we will talk about the structure of the auditory analyzer.
Receptors - the auditory nerve - the temporal zone of the cerebral cortex.
We study the structure of the ear. ( slide7): Organ of hearing - ear: outer, middle, inner.
Work with the textbook (pp. 85-87). Fill in the chart application 2 ):
Let's look at the board where the correctly completed diagram is placed, I suggest comparing and correcting the errors if you have any.
(slide 8.9) . Now let's talk about functions:
Auricle: picks up sounds
External auditory meatus: conducts sound vibrations
Eardrum: converts sound vibrations into mechanical vibrations, transmits them to the middle ear.
Auditory ossicles: the hammer and anvil are levers, the stirrup is a kind of piston. They amplify the weak vibrations of the eardrum and transmit them to the inner ear. The stirrup rests against the oval window.
auditory tube: connects the middle ear to the nasopharynx. Equalizes the pressure that occurs with increased noise. (Ear-nose-throat doctor).
Snail: sink in 2.5 turns. Inside the bony labyrinth of the cochlea is the membranous labyrinth. Both of them are filled with liquid, the vibrations of which are caused by the strikes of the stirrup against the oval window. Inside the membranous labyrinth, five rows of cells with the finest fibers (60-70 for each cell) stretch along the entire length of the coils of the cochlea. These are auditory hair cells (there are about 24 thousand of them) attached to the membrane, which consists of individual fibers. As soon as fluctuations arise in the fluid of the cochlea, the curtain begins to touch the hairs of the auditory cells, generating electrical impulses of various strengths. The auditory nerve collects these impulses and transmits them through the subcortical nodes to the cortex of the temporal lobes of the brain. They provide analysis and synthesis of sounds.
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