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; c) 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
SUBJECT: “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 is the same
- 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 part of the 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 of the cerebral cortex
eyebrow
upper eyelid
eyelashes
lower eyelid
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
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.
Preview:
Municipal educational institution Koshelikhinskaya secondary school
Biology lesson
Subject: Visual analyzer
Grade: 8
The purpose of the lesson: introduce students to general plan structure and function of the organ of vision.
Tasks: educational:1) introduce students to the structure of the organ of vision;
2) familiarization with the functions of the visual analyzer;
educational: 1) continue to develop students’ scientific worldview and understanding of the world;
developing: 1) development and deepening of students’ knowledge about the structure of the senses and the human body as a whole.
Methods: verbal (conversation, story), visual (demonstration of tables and pictures in the textbook).
Equipment: table “Visual analyzer”, model of the eye, textbook illustrations (pp. 78,79,80,81).
During the classes:
1. Organizing time. (2 minutes.)
2. Testing students' knowledge and skills. (8 min.)
3. Studying new material. (28 min.)
The person is surrounded amazing world, rich in colors, sounds, smells. We perceive it either with admiration or with fear. All information about what is happening in environment We receive through the senses - sight, hearing, touch, smell, taste. The first to take on environmental influences receptors – these are the endings of nerve cell processes or specialized cells that respond to certain stimuli. They are located in the sensory organs, in the skin, mucous membranes. There are many receptors in the body: per 1 cm² of skin there are up to 400 sensitive nerve endings, which are receptors.
The analysis of irritations begins already in receptors and receptor cells. Thus, the receptors of the organ of vision are stimulated only by light, and the receptors of hearing - only by sounds. Supreme center analysis of information about the world around us is the cerebral cortex. The system responsible for analyzing any type of information is called an analyzer.
Analyzer is a system that provides perception, delivery to the brain and analysis of any type of information (visual, auditory, olfactory, etc.). Each analyzer consists of a peripheral section (receptors), a conductive section (nerve pathways) and a central section (centres that analyze this type information).
Visual analyzer
The organ of vision consists ofeyeball And auxiliary apparatus. The accessory apparatus includes the eyebrows, eyelids and eyelashes, the lacrimal gland, lacrimal canaliculi, extraocular muscles, nerves and blood vessels (p. 78).
Eyebrows and eyelashes protect eyes from dust. In addition, eyebrows drain sweat from the forehead. Everyone knows that a person blinks constantly (2-5 eyelid movements per minute). Do they know why? It turns out that at the moment of blinking, the surface of the eye is moistened with tear fluid, which protects it from drying out, while at the same time being cleansed of dust. Tear fluid is produced by the lacrimal gland. It contains 99% water and 1% salt. Up to 1 g of tear fluid is secreted per day, it collects in the inner corner of the eye, and then enters the lacrimal canaliculi, which discharge it into the nasal cavity. If a person cries, the tear fluid does not have time to escape through the canaliculi into the nasal cavity. Then tears flow through the lower eyelid and run down the face in drops.
The eyeball is located in the recess of the skull - eye socket (demonstration of table and eye model). It has a spherical shape and consists of an inner core covered with three shells: the outer - fibrous, the middle - vascular and the inner - reticular (p. 79, table).Fibrous membranedivided into the rear opaque part -tunica albuginea, or sclera , and the front transparent - cornea. Cornea It is a convex-concave lens through which light penetrates into the eye.Choroidlocated under the sclera. Its front part is called iris , it contains pigment that determines eye color. There is a small hole in the center of the iris - pupil , which reflexively, with the help of smooth muscles, can expand or contract, allowing the required amount of light into the eye.
The choroid itself is penetrated by a dense network of blood vessels that supply the eyeball. From inside to choroid There is a layer of pigment cells adjacent that absorb light, so light is not scattered or reflected inside the eyeball.
Directly behind the pupil is a biconvex lens . It can reflexively change its curvature, providing a clear image on retina - the inner lining of the eye. Receptors are located in the retina (Fig. 3): sticks (twilight light receptors that distinguish light from dark) and cones (they have less light sensitivity, but distinguish colors). Most cones are located on the retina opposite the pupil, in macula . Next to this spot is the exit pointoptic nerve, there are no receptors here, that's why it's called blind spot . The inside of the eye is filled with transparent and colorlessvitreous.
Perception of visual stimuli
Light enters the eyeball through the pupil. The lens and vitreous body serve to conduct and focus light rays onto the retina (p. 80). Six oculomotor muscles ensure that the eyeball is positioned so that the image of an object falls exactly on the retina, on its macula. Receptors in the retina convert light into nerve impulses, which optic nerve transmitted to the brain through the nuclei of the midbrain and diencephalon - to the visual zone of the cerebral cortex, located in the occipital region. The perception of color, shape, illumination of an object, and its details, which begins in the retina, ends with analysis in the visual cortex. Here all the information is collected, deciphered and summarized. As a result, an idea of the subject is formed.
Visual impairment
People's vision changes with age, as the lens loses elasticity and the ability to change its curvature. In this case, the arrangement of closely located objects becomes blurred - it develops farsightedness. Other vision defect myopia (p. 81), when people, on the contrary, have difficulty seeing distant objects; it develops after long-term stress, improper lighting. Myopia often occurs in children school age because of wrong mode labor, poor lighting of the workplace. With myopia, the image is focused in front of the retina, and with farsightedness, the image is focused behind the retina and is therefore perceived as blurry. These visual defects can also be caused by congenital changes in the eyeball. Myopia and farsightedness are corrected with specially selected glasses or lenses.
4. Consolidation of the studied material. (5 minutes.)
Test tasks:
Choose the correct answer:
- The visual area of the cerebral hemispheres is located in:
A) parietal lobe;
B) temporal lobe;
B) occipital lobe.
2. Gives color to the eye:
A) sclera;
B) lens;
B) iris.
3. What do we consider the auxiliary organs of the eye:
A) lens;
B) oculomotor muscles;
B) lacrimal glands;
D) vitreous body.
4. How many membranes does the eyeball have:
A) one;
B) two;
At three o'clok.
5. Which part of the eyeball is a convex-concave lens:
A) lens;
B) cornea.
5. Homework. (2 minutes.)
Page 76 – page 84 of the textbook.
1 slide
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
2 slide
Analyzers These are systems of sensitive nervous formations that perceive and analyze various external and internal stimuli.
3 slide
Visual analyzer The visual analyzer consists of the eyeball, auxiliary apparatus, pathways and visual cortex of the brain.
4 slide
1.Where is the eye located, what auxiliary organs protect our eyes? 2. How many muscles can the eyeball move? Organ vision - eye
5 slide
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...
6 slide
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.
7 slide
Sclera The sclera is the protein shell - the outer dense connective tissue membrane of the eye, which performs a protective and supporting function.
8 slide
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.
Slide 9
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)
10 slide
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].
11 slide
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?
12 slide
The face of the eye 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,
Slide 13
The lens is strengthened inside the eye by special very thin ligaments. Replacing the lens of the eye.
Slide 14
Retina of the eye Retina (lat. retina) is the inner membrane of the eye, which is peripheral department visual analyzer.
15 slide
16 slide
Structure of the retina: Anatomically, the retina is thin shell, adjacent along its entire length to inside to the vitreous body, and from the outside - to the choroid of the 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 rods), which transmit the signal along the optic nerve to the brain.
Slide 17
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.
18 slide
Ecology and visual hygiene it is better to use fluorescent lamps, it does not strain the eyesight so much
Slide 19
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. More rare option- 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.
20 slide
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 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 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).
Slide 23
What is the structure of the eye? Place signs. sclera Vitreous body retina lens pupil Choroid Oculomotor muscles iris cornea
24 slide
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 body c) color vision receptors 6. Cones are: a) twilight light receptors 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 weak light, the pupil: a) reflexively narrows b) reflexively dilates 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
25 slide
Check 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
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
pathways with switching at different levels of the central nervous system
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 the cells of the 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 cortical section carried out by the highest
analysis and synthesis of afferent excitations, providing
formation of a complete understanding of 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 front and rear camera eyes.
Slide 3
Why do they say that the eye looks, but the brain sees?
Slide 4
Structure of the organ of vision
The organ of vision is the most important of the senses, providing a person with up to 95% of information.
Slide 5
Slide 6
Functions of parts of the eye
Slide 7
The principle of the eye is similar to that of a camera.
Slide 8
Optical system and light-receiving part of the eye
Slide 9
Retina
The light-receiving part is the retina. It contains light-sensitive cells - visual receptors, about 130 million rods, providing black and white vision, and about 7 million cones, providing information about color.
Slide 10
Structure of the retina
Slide 11
The retina consists of several layers of cells:
- The outer layer adjacent to the choroid is a layer of black pigment cells. This layer absorbs light, preventing its scattering and reflection;
- three layers of cells: bipolar, ganglion, then their axons, uniting into the optic nerve;
Next comes the layer containing rods and cones.
Slide 12
- The maximum number of cones is located in the retina on the optical axis of the eye, opposite the pupil, this area is called the macula.
- In the place where the optic nerve leaves the eyeball, there are no receptors in the retina - a blind spot.
- The maximum number of rods is located on the periphery of the eye.
- Sticks contain visual pigment rhodopsin, a small amount of light is enough for its decomposition.
- In cones, under the influence of light, iodopsin decomposes, but more light is needed to excite the cones.
Slide 13
What happens on the retina
The light flux passes through:
- Cornea
- Iris
- Pupil
- Lens
- Vitreous body
- Retina
Retinal image is reduced and inverted
Slide 14
Slide 15
- Light hits photosensitive cells;
- A photochemical reaction occurs (rhodopsin breakdown);
- The potential of photoreceptors changes;
- Excitement occurs;
- Along the optic nerve, excitation goes to the visual center of the cerebral cortex;
- The final analysis of excitation, image discrimination and sensation formation take place in the cortex.
Slide 16
As a result
- The brain sees, not the eye.
- Vision is a cortical process and depends on the quality of information received from the eye.
- That is why the eye looks and the brain sees.
