Visual analyzer. Presentation on the topic "visual analyzer" Organ of vision presentation 8 grades
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The visual analyzer, its structure and functions, the organ of vision. Author of the presentation: Pechenkina V.A. Teacher, Municipal Educational Institution “Gymnasium No. 10”, Pushkino
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Analyzers These are sensitive systems nerve formations, perceiving and analyzing various external and internal stimuli.
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Visual analyzer The visual analyzer consists of eyeball, auxiliary apparatus, pathways and visual cortex brain.
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1.Where is the eye located, what auxiliary organs protect our eyes? 2. How many muscles can the eyeball move? Organ vision - eye
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The eyeball and the auxiliary apparatus of the eye. The eyeball is located in the orbit of the skull. The auxiliary apparatus of the eye includes the eyelids, lacrimal apparatus, muscles of the eyeball, and eyebrows. Motility of the eye is provided by six extrinsic muscles...
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Diagram of the structure of the eye Fig. 1. Scheme of the structure of the eye 1 - sclera, 2 - choroid, 3 - retina, 4 - cornea, 5 - iris, 6 - ciliary muscle, 7 - lens, 8 - vitreous, 9 - optic disc, 10 - optic nerve, 11 - macula.
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Sclera The sclera is the protein shell - the outer dense connective tissue membrane of the eye, which performs a protective and supporting function.
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The main substance of the cornea consists of a transparent connective tissue stroma and corneal bodies. In front, the cornea is covered with multilayered epithelium. Cornea ( cornea) - the anterior most convex transparent part of the eyeball, one of the light-refracting media of the eye.
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The choroid of the eye is the middle layer of the eyeball. Playing important role V metabolic processes, providing nutrition to the eye and removal of metabolic products. She's rich blood vessels and pigment of the eyeball (in Fig. 2)
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The iris (iris) is the thin, movable diaphragm of the eye with a hole (pupil) in the center; located behind the cornea, in front of the lens. The iris contains varying amounts of pigment, which determines its color - “eye color”. Pupil - round a hole through which light rays penetrate inside and reach the retina (the size of the pupil changes [depending on the intensity of the light flux: in bright light it is narrower, in weak light and in the dark it is wider].
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Detect constriction and dilation of the pupil. - Look into the eyes of your desk neighbor and note the size of the pupil. -Close your eyes and shade them with your palm. -Count to 60 and open your eyes. -Observe changes in pupil size. How can we explain this phenomenon?
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The face of the eye is a transparent body located inside the eyeball opposite the pupil; being a biological lens, the lens makes up important part light refractive apparatus of the eye. The lens is a transparent biconvex round elastic formation,
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The lens is strengthened inside the eye by special very thin ligaments. Replacing the lens of the eye.
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Retina of the eye Retina (lat. retina) - inner shell eyes, which is the peripheral part of the visual analyzer.
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Structure of the retina: Anatomically, the retina is a thin membrane adjacent along its entire length to inside to the vitreous body, and from the outside - to choroid eyeball. There are two parts in it: the visual part (receptive field - the area with photoreceptor cells (rods or cones) and the blind part (an area on the retina that is not sensitive to light). Light falls from the left and passes through all layers, reaching the photoreceptors (cones and sticks) which transmit the signal optic nerve into the brain.
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How does the eye see? The path of rays from an object and the construction of an image on the retina (a). Scheme of refraction in a normal (b), myopic (c) and farsighted (d) eye. The eye, like any converging lens, produces an inverted image on the retina, real and reduced.
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Ecology and visual hygiene it is better to use fluorescent lamps, it does not strain the eyesight so much
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Myopia Myopia (myopia) is a vision defect (refractive error) in which the image falls not on the retina, but in front of it. The most common cause is an enlarged (relative to normal) eyeball in length. A rarer option is when the refractive system of the eye focuses the rays more strongly than necessary (and, as a result, they again converge not on the retina, but in front of it). In any of the options, when viewing distant objects, a fuzzy, blurry image appears on the retina. Myopia most often develops in school years, as well as while studying in secondary and higher educational institutions and is associated with prolonged visual work at close range (reading, writing, drawing), especially in poor lighting and poor hygienic conditions. With the introduction of computer science in schools and the spread of personal computers, the situation became even more serious.
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farsightedness Farsightedness (hyperopia) is a feature of the refraction of the eye, consisting in the fact that images of distant objects at rest of accommodation are focused behind the retina. IN at a young age if farsightedness is not too high, using the accommodation voltage, you can focus the image on the retina. One of the reasons for farsightedness may be a reduced size of the eyeball by anterior-posterior axis. Almost all babies are farsighted. But with age, in most people this defect disappears due to the growth of the eyeball. The cause of age-related (senile) farsightedness (presbyopia) is a decrease in the ability of the lens to change curvature. This process begins at the age of about 25 years, but only by the age of 40-50 years it leads to a decrease in visual acuity when reading at the usual distance from the eyes (25-30 cm).
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What is the structure of the eye? Place signs. sclera Vitreous body retina lens pupil Choroid Oculomotor muscles iris cornea
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Screening test on the topic “Visual Analyzer” Select the correct answer 1. Transparent part outer shell eyes are: a) retina b) Cornea c) Iris 2. The cornea of the eye performs the function of: a) nutrition b) transmission sun rays c) protection 3. The pupil is located: a) in the lens b) in the vitreous c) in the iris 4. The membrane of the eye containing rods and cones is: a) tunica albuginea b) retina c) choroid 5. Rods are: a) twilight light receptors b) parts of the vitreous c) color vision receptors 6. Cones are: a) twilight light receptors b) parts of the cornea c) receptors that perceive color 7. K night blindness leads to dysfunction of: a) rods b) cones c) lens 8. In weak light, the pupil: a) reflexively narrows b) reflexively expands c) does not change 9. The retina of the eye: a) protects from mechanical damage b) supplies the eye with blood c) converts light rays into nerve impulses 10. If light rays are focused behind the retina, it causes: a) myopia b) farsightedness c) blindness
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Test yourself! 1. The transparent part of the outer shell of the eye is: a) retina b) Cornea c) Iris 2. The cornea of the eye performs the function of: a) nutrition b) transmission of sunlight c) protection 3. The pupil is located: a) in the lens b) in the vitreous body c) in the iris 4. The membrane of the eye containing rods and cones is: a) tunica albuginea b) retina c) choroid 5. Rods are: a) twilight light receptors b) parts of the vitreous c) color vision receptors 6 Cones are: a) receptors for twilight light b) parts of the cornea c) receptors that perceive color 7. Night blindness is caused by dysfunction of: a) rods b) cones c) lens 8. In low light the pupil: a) reflexively narrows b. ) reflexively expands c) does not change 9. The retina of the eye: a) protects from mechanical damage b) supplies the eye with blood c) converts light rays into nerve impulses 10. If light rays are focused behind the retina, this causes: a) myopia b) farsightedness c ) blindness
hearing, vision, touch, smell.
- 1.2. Place the parts of the analyzer in order.
a) association zone of the cerebral cortex,
b) receptors, c) pathways
- 1.3. Match the analyzers with their representations in the brain:
1) occipital zone; a) Hearing analyzer:
2) temporal zone; b) Visual analyzer;
3) parietal zone; V) Taste analyzer
F.S. Rokotov Portrait of A. Struyskaya
Love painting, poets Only she, the only one, was given. Souls of changeable signs. Transfer to canvas.
Her eyes are like two fogs, Half smile, half cry, Her eyes are like two deceptions, Failures covered in darkness. ...Do you remember how “out of the darkness of the past, Barely wrapped in satin, From Rokotov's portrait again. Was Struyskaya looking at us?
F.S. Rokotov (1735-1808)
- Catherine II
TOPIC: “Organ of vision. Visual analyzer"
- 8th grade
- 201 3 /201 4 academic year
- Teacher: Grechukhina Svetlana Anatolyevna
"It's better to see once,
than to hear a hundred times"
Meaning
Structure
Visual analyzer
Diseases
First aid
if damaged
COLOR VISION IN ANIMALS
This is how a person sees a flower
And this is how an insect sees the same flower
- 1. Eyebrows and eyelashes perform a protective function
- 2. Doctor treating eye disease - ophthalmologist
- 3. The visual analyzer consists of three parts
- 4. Eye and visual analyzer- it's the same thing
- 5. An inverted image of an object is formed on the retina
- 6. Tears serve a protective function.
- 7. Pupil diameter is always constant
- 8. The pupil is a hole in the iris of the eye
The meaning of vision
- Thanks to our eyes, you and I get 8 5 % of information about the world around them, they are, according to calculations by I.M. Sechenov, give a person up to 1000 sensations per minute.
- The eye allows you to see objects, their shape, size, color, movements.
- The eye is able to distinguish a well-lit object with a diameter of one tenth of a millimeter at a distance of 25 centimeters. But if the object itself glows, it can be much smaller.
- Theoretically, a person could see a candle light at a distance of 200 km.
- The eye is capable of distinguishing 130-250 pure color tones and 5-10 million mixed shades.
- Complete adaptation of the eye to darkness takes 60-80 minutes.
What is an analyzer?
This is a system that provides perception, delivery to
brain and analysis of any information.
What parts does the analyzer consist of?
3. Central department brain
1. receptors
2. nerve pathways
Take on environmental influences
(these are the ends of the processes nerve cells or specialized cells)
Optic nerve
Occipital lobe cortex cerebral hemispheres
eyebrow
upper eyelid
eyelashes
lower eyelid
lacrimal gland
ducts of the lacrimal gland
opening of the lacrimal canaliculus
lacrimal canaliculus
Structure of the eye
1 – cornea
2 – iris
3 – tunica albuginea (sclera)
4 – choroid
5 – optic nerve
6 – retina
7 - pupil
8– lens ligaments
9 – lens
10 – vitreous body
Now let's have a little rest! Physical exercise. Watch the balls!!!
Retina
- Inner membrane containing photoreceptors:
sticks
cones
cones
1. Where are the light-sensitive receptors in the eyes located?
a) in the retina; b) in the lens;
c) in the iris; d) in the tunica albuginea
2. The pigmentation of which part of the eye determines its color:
a) retina; b) lens; c) iris; d) tunica albuginea
3. Conductive part of the visual analyzer:
a) retina; b) pupil; c) optic nerve; d) visual cortex
4. What is the retina of the eye made of?
a) from the iris; b) from blood vessels;
c) from photosensitive receptors; d) from the tunica albuginea?
5. What are the nutritional membranes of the eyes called:
a) iris; b) vitreous body;
c) choroid; d) tunica albuginea?
6. Structure related to the auxiliary system of the eye:
a) Cornea b) Eyelid c) Lens d) Iris
7. Biconvex elastic transparent lens surrounded by ciliary muscle:
- a) Lens b) Pupil c) Iris d) Vitreous body
8. Place of exit of the optic nerve:
A) White spot b) yellow spot c) Dark area d) Blind spot
The lesson was interesting. He was useful to me.
I'm satisfied with the lesson
but I didn't show enough activity in it.
The importance of vision Thanks to the eyes, you and I receive 85% of the information about the world around us; they are the same, according to calculations by I.M. Sechenov, give a person up to 1000 sensations per minute. The eye allows you to see objects, their shape, size, color, movements. The eye is able to distinguish a well-lit object with a diameter of one tenth of a millimeter at a distance of 25 centimeters. But if the object itself glows, it can be much smaller. Theoretically, a person could see a candle light at a distance of 200 km. The eye is capable of distinguishing between pure color tones and 5-10 million mixed shades. Complete adaptation of the eye to the dark takes minutes.
Diagram of the structure of the eye Fig. 1. Scheme of the structure of the eye 1 - sclera, 2 - choroid, 3 - retina, 4 - cornea, 5 - iris, 6 - ciliary muscle, 7 - lens, 8 - vitreous body, 9 - optic disc, 10 - optic nerve, 11 - yellow spot.
The main substance of the cornea consists of a transparent connective tissue stroma and corneal bodies. In front, the cornea is covered with multilayered epithelium. The cornea (cornea) is the anterior most convex transparent part of the eyeball, one of the light-refracting media of the eye.
The iris (iris) is the thin, movable diaphragm of the eye with a hole (pupil) in the center; located behind the cornea, in front of the lens. The iris contains varying amounts of pigment, which determines its color “eye color”. The pupil is a round hole through which light rays penetrate inside and reach the retina (the size of the pupil changes [depending on the intensity of the light flux: in bright light it is narrower, in weak light and in the dark it is wider].
The lens is a transparent body located inside the eyeball opposite the pupil; Being a biological lens, the lens is an important part of the light-refracting apparatus of the eye. The lens is a transparent biconvex round elastic formation,
Photoreceptors signs rods cones Length 0.06 mm 0.035 mm Diameter 0.002 mm 0.006 mm Number 125 – 130 million 6 – 7 million Image Black and white Colored Substance Rhodopsin (visual purple) iodopsin location Predominant in the periphery Predominant in the central part of the retina Macula – a collection of cones, the blind spot – the exit point of the optic nerve (no receptors)
Structure of the retina: Anatomically, the retina is a thin membrane, adjacent along its entire length from the inside to the vitreous body, and from the outside to the choroid of the eyeball. There are two parts in it: the visual part (the receptive field - the area with photoreceptor cells (rods or cones) and the blind part (the area on the retina that is not sensitive to light). Light falls from the left and passes through all the layers, reaching the photoreceptors (cones and rods) ), which transmit the signal along the optic nerve to the brain.
Myopia Myopia (myopia) is a vision defect (refractive error) in which the image falls not on the retina, but in front of it. The most common cause is an enlarged (relative to normal) eyeball in length. A rarer option is when the refractive system of the eye focuses the rays more strongly than necessary (and, as a result, they again converge not on the retina, but in front of it). In any of the options, when viewing distant objects, a fuzzy, blurry image appears on the retina. Myopia most often develops during school years, as well as during studies in secondary and higher educational institutions, and is associated with prolonged visual work at close range (reading, writing, drawing), especially in poor lighting and poor hygienic conditions. With the introduction of computer science in schools and the spread of personal computers, the situation has become even more serious.
Farsightedness (hyperopia) is a feature of the refraction of the eye, consisting in the fact that images of distant objects at rest of accommodation are focused behind the retina. At a young age, if farsightedness is not too high, using accommodation voltage, you can focus the image on the retina. One of the causes of farsightedness may be a reduced size of the eyeball on the anterior-posterior axis. Almost all babies are farsighted. But with age, in most people this defect disappears due to the growth of the eyeball. The cause of age-related (senile) farsightedness (presbyopia) is a decrease in the ability of the lens to change curvature. This process begins at about 25 years of age, but only by 4050 years of age leads to a decrease in visual acuity when reading at the usual distance from the eyes (2530 cm). Colorblindness Up to 14 months in newborn girls and up to 16 months in boys, there is a period of complete inability to perceive colors. The formation of color perception ends by the age of 7.5 in girls and by the age of 8 in boys. About 10% of men and less than 1% of women have the defect color vision(inability to distinguish between red and green or, less commonly, blue; there may be complete indistinction between colors)
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Lesson topic: “The organ of vision and the visual analyzer”
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Organ of vision
The organ of vision (eye) is the perceptive section of the visual analyzer, which serves to perceive light stimuli.
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External structure of the eye
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Internal structure of the eye
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Accommodation of the lens
Accommodation is the ability of the eye to clearly see objects located at different distances from us. If we look into the distance, the lens becomes flatter; if we look at objects close up, it becomes more convex. Thanks to this, the lens directs rays strictly to the retina. He focuses the image on her.
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The structure of the retina
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Retinal image and visual image
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Structure of the visual analyzer
Peripheral section 1 - retina Conductor section 2 - optic nerves Central section 3 - visual zone of the cerebral cortex
The visual analyzer provides the perception of the size, shape, color of objects, their relative position and the distance between them.
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Binocular vision
Binocular or stereoscopic vision- this is vision with two eyes, which provides a clear three-dimensional perception of an object and its location in space.
Differences binocular vision from peripheral
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Consolidation
1
2
3
4
5
Identify the structures that make up the external structure of the eye
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Consolidation
1
2
3
4
5
6
7
8
9
10
11
12
Identify the structures that make up internal structure eyes
Slide 13
Consolidation
Solving biological problems
Task No. 1. At night, a man walked out of the illuminated room onto the street, into pitch darkness, where nothing was visible. However, after a while he began to distinguish the outlines of houses, trees and bushes, and then he saw a path. Give an explanation for this phenomenon.
Correct answer: In conditions of good lighting, a person perceives a light image with cones; in the dark, color perception fades, and rods act - cells of “night” vision, which are highly sensitive. Adaptation to darkness does not occur immediately, and it takes time to recover visual pigment(rhodopsin), since in daytime vision it is not present in the rods.
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Consolidation
Solving biological problems.
Problem No. 2. There are people who claim that they have seen “visions”, however modern science proves that no “visions” exist. Explain with scientific point view whether such phenomena are possible.
Correct answer: The appearance of visions is associated with a certain mental state a person, when under the influence of mental stress (in the evening in an abandoned park, a dark street), or suggestion (a story about a terrible thing), or the action of substances (poisons), in visual areas the cerebral cortex experiences strong arousal. This leads to the appearance of visual images (visions). The rods and cones of the retina are not excited, since in reality the object does not exist.
Slide 15
Homework
§ 46; answer questions. Creative task: compose 1 – 2 puzzles on the topic “The organ of vision and the visual analyzer.”
Visual analyzer Structural-functional
organization of the visual analyzer;
Light refractive apparatus of the eye;
Light-regulating apparatus of the eye;
Completed by: student of group 215, Osipova Anastasia
organ system that consists of receptors
apparatus represented by the organ of vision - the eye(1),
conducting paths (2) and the final section –
perceptive areas of the cerebral cortex (3).
3
2
1Structural and functional organization
visual analyzer
Visual analyzer
Receptor department
(peripheral)
Central
(cortical) department
Wiring department Receptor department
Purpose: perception and primary analysis of changes
external and internal environment body.
The perception of stimuli in receptors occurs due to
transformation of stimulus energy into a nerve impulse.
Rods
neurosensory cells
Perception of light rays
in conditions of weak
illumination (colorless
or achromatic vision).
Cone
neurosensory cells
Perception of light rays
in bright conditions
illumination (color or
chromatic vision). Wiring department
- includes afferent (peripheral) and intermediate
neurons of the stem and subcortical structures of the central nervous system. Carrying out
excitement by wiring department carried out by two
afferent pathways: thalamus
Specific projection path
- comes from the receptor along strictly designated specific
paths with switching to various levels CNS
Thalamus The visual pathway begins with the first receptors
neurons, represented by specific formations of rods and cones. Of these, irritation is transmitted
bipolar cells (second neuron), then - ganglion cells
(third neuron). Non-specific path
RF
At the level of the brain stem from specific path retreat
collaterals to cells reticular formation, to which
can converge afferent excitations, providing
interaction of information from various analyzers. Central department
Central part
Peripheral part
Specific neurons
processing
afferent impulses
from receptors
Neurons distributed throughout
cerebral cortex
At the level of the cortical department, the highest
analysis and synthesis of afferent excitations, providing
formation full presentation about the environment. Light refractive apparatus of the eye
The light refractive apparatus of the eye is
a complex system of lenses that forms on the retina
reduced and inverted image.
Includes:
cornea
(wired
function-corneal
reflex;
optical function - passage and refraction of rays),
lens
(accommodation-change
curvature
For
focusing the volume on the retina),
vitreous (conducts light rays to the retina,
thanks to the transparency of the environment),
fluid of the anterior and posterior chambers of the eye.
