Subject: Concept about analyzers, their departments. Functional features of analyzers. LECTURE PLAN: 1. The doctrine of Nominative of Pavlov about analyzers. Analyzer departments. 2. Classification of receptors. 3. Morfo-funktsionalnye features of analyzers. 4. The mechanism of exaltation of receptors at stimulus action.
The analyzer (sensory system) is the difficult morfofunktsionaly system which is carrying out perception of information, coding, carrying out and the analysis, synthesis in a cerebral cortex and formation of feelings (Pavlov I. P. ).
Departments of the analyzer and their function: Peripheric (receptor) department - perception of separate types of a boring, transformation of all types of external energy in nervous impulse and information coding. Conduction department (afferent fibers, neurones and the subcortical centers) - information transfer from receptors in a CNS and information preprocessing. The central department (sites of a cortex of larger hemispheres of a brain) - perception of afferent signals, processing the analysis and synthesis of received information and formation of feelings.
Classification of receptors. On nature of the feelings arising at a boring of receptors: - visual, - acoustical, - olfactory, - gustatory, - tactile, - painful, - thermoreceptors, - proprioretseptor - vestibuloretseptor.
Classification of receptors. Depending on a locating of receptors: External (eksteroretseptor) – acoustical, visual, olfactory, gustatory, tactile. Internal (interoretseptor): a) vestibulo-and proprioretseptor (locomotorium receptors) b) vistseroretseptor
III. Depending on the stimulus nature: Photoceptors – visual. Mechanioreceptors – acoustical, tangoreceptors, vestibulo-and proprioretseptor, baroreceptors of cardiovascular system. Chemoceptors – taste and olfaction receptors, vascular and fabric receptors. Thermoreceptors – receptors of a skin and an internal. Painful (notsitseptivny) receptors are allocated especially.
IV. On nature of contact to medium: Distantnye – visual, acoustical and olfactory. The contact – gustatory, tactile. V. Depending on structural features: Primary feeling (PD generation in the 1 st neurone) – olfaction receptors, tactile and proprioretseptor. Secondary feeling (through a receptor cell PD generation in the 1 st neurone) – receptors of vision, hearing, taste, a vestibular mechanism.
MECHANISM OF EXALTATION OF RECEPTORS. I. Primary the feeling. Stimulus action - interaction with an albuminous molecule of a membrane of a receptor (І a neurone) - change of permeability of a membrane for ions - depolarization - PD. II. Secondary the feeling. Stimulus action - interaction with membrane receptors receptor potential - mediator allocation generating potential - PD.
The characteristic primary and again feeling receptors ► ► ► Initially feeling receptors there is no special receptor cell perceives incentive the sensitive termination of an afferent neurone there is no mediator allocation receptor and generating potentials coincide PD arises at the axon basis (an aksonny hill) or in Ranvye's first interception of an axon ► ► ► Again feeling receptors there is a special receptor cell perceives incentive a special receptor cell which is bound to the termination of an afferent neurone by a synapse the mediator is allocated generating potential is formed on a postsynaptic membrane PD emergence close to a postsynaptic membrane
MORFO-FUNKTSIONALY OF FEATURE OF ANALYZERS. Morphological features: 1. Multiple layers - existence of several layers of the nervous cells, the first layer the last layer – with neurones of a cortex of larger hemispheres is bound to receptor department.
2. Mnogokanalnost – existence in each of layers of the nervous elements bound to a set of elements of the following layer, and they send impulses to elements of higher layer.
3. Existence of "sensory funnels". Physiological sense of "a meeting funnel" – in decrease of redundancy of information, and "an extending funnel" – in providing the complex and fractional analysis of different signs of a signal.
4. Differentiation across and verticals. Differentiation down – departments consist of several neuronic layers. Differentiation across - various properties of receptors, neurones and communications between them within each of layers.
Physiological features of analyzers: 1. High sensitivity of receptors to an adequate stimulus. (the visual analyzer can perceive some quanta of light, the olfactory analyzer – 0, 00004 ml/g of substance) 2. Low sensitivity of receptors to an inadequate stimulus (for example at strong blow in an eye - sparks)
3. Adaptation – the adaptation to is long to an operating stimulus (i. e. dropping of sensitivity of receptors to stimulus action) 4. Weber-Fekhnera law (relation to a stimulus gain). The gain of a boring is noticeable we (will feel) if it makes 1/30 in relation to the previous influence.
5. Distinction, transformation and information coding. Information on a boring is transferred in a type of groups, or "packs of impulses" standard parameter (amplitude, duration, a form), and number of impulses in a pack, their frequency, duration are various depending on nature of incentive.
Visual analyzer The visual system gives 90% of all sensory information going to a brain. Eye as the organ, consists of 2 parts: Svetoprelomlyayushchey 2. Svetovosprinimayushchey (retina). 1.
REFRACTING MEDIUMS OF THE EYE - Cornea - Forward measure - Lens - Vitreous The refracting force of a lens with focal length 1 m is a 1 diopriya. The refracting force of an eye makes when examining: far subjects - 59 D, close subjects - 70, 5 D.
ACCOMMODATION is an adaptation of an eye to clear vision of the objects removed on different distance. Accommodation begins at subject vision at distance of 65 m, is distinct – from 50 m to 10 cm. Subjects closer than 10 cm can't be clear are visible the person. Point of clear vision – the smallest distance between a subject and an eye at which this subject is clearly visible.
Accommodation mechanisms: Change of a form (curvature) of a lens at reduction of tsiliarny ciliary muscles and price ligaments. 1. Change of diameter of a pupil at the expense of reduction of muscles of an iris of the eye (at approach of subjects - the pupil is narrowed) 2. Convergence - a convergence of visual axes of both eyes on a surveyed subject.
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Eye refraction – a diffraction of beams without akkomodatsionny changes ►Spherical aberration – the rays of light which are passing through the periphery of a lens refract more strongly, than beams, passing through its center
Anomalies of a refraction and their correction: ► Myopia or myopia (biconcave lenses). ► Hyperopia or hypermetropia (biconcave lenses) ► Astigmatism ► Presbyopy (cylinder lenses). – a senile hyperopia. Presbyopy (senile hyperopia) – senile weakening of accommodation in connection with loss by an elastance lens.
Anomalies of a refraction and their correction. N an eye axis – 22, 5 -23 MM Eye axis <22, 5 -23 MM Biconcave lenses Eye axis> 22, 5 -23 MM Biconcave lenses
CHARACTERISTIC OF DEPARTMENTS OF THE VISUAL ANALYZER. 1. Peripheric department: receptors. retina I. photoceptors – rods (110 -125 million) and flasks (6 -7 million) II. layer of bipolar cells III. ganglionic nervous cells.
Distribution of photoceptors in a retina irregularly: rods – on peripheries, flasks – in the center. The central fossa (fovea centralis) contains only flasks (140 thousand on 1 mm 2), a place of the best vision of an eye. On a place of an exit of an optic nerve photoceptors are absent - blind maculae.
2. Conduction department: fibers of an optic nerve of at the brain basis decussation (хиазма) mesencephalon (top hillocks chetverokholmiya) intermediate brain (lateral geniculate bodies). 3. The central department – an occipital share of a cortex of larger hemispheres, area of a shporny sulcus (fissura calcarina).
RHODOPSINS In rods: – rhodopsin (visual purple). In flasks: – йодопсин: absorption maximum in zhelny part of a range, - хлоролаб - an absorption maximum in green part of a range, - эритролаб - an absorption maximum in red part of a range.
PHOTOCHEMICAL REACTIONS IN RETINA RECEPTORS. Rhodopsin – a complex ретиналя (vitamin A aldehyde) and an opsin (protein). Absorption of quantum of light of rhodopsin disintegration on ретиналь and an opsin, an isomerization tsisretinalya trance-retinal activation of ions of Sa 2 +, permeability change for Na ions + emergence of receptor potential of allocation of a mediator of PD.
VISUAL ADAPTATION The eye adaptation to vision at different degree of the illuminating intensity, bound to change of sensitivity of photoceptors, is called as eye adaptation. Light adaptation – dropping of sensitivity of an eye to light, being the adaptation to conditions of bright illuminating intensity. Dark adaptation - rising of sensitivity of an eye to light (in connection with restoration of rhodopsins), being the eye adaptation to conditions of small illuminating intensity.
COLOR VISION Three-component theory of a color perception (M. V. Lomonosov, T. Yung, G. Helmholtz). In an eye retina - 3 types of flasks: 1. sensitive to red color, 2. sensitive to green color, 3. sensitive to blue color. Any color has effect on all three types of flasks, but in different degree. Exaltations are summarized by visual neurones and, having reached a cerebral cortex give feeling of this or that color.
Disturbances of color vision (color blindness): ► Anomaly of color perception – a daltonism (lack of certain genes in the H-chromosome of men). ► Total color blindness – an achromasia (a lesion of the coneal device). ► Versions of a partial color blindness: - protanopia (absence of perception of red color) - deuteranopia (absence of perception of eeleny color) - tritanopia (absence of perception of blue and violet flowers)
For determination of anomalies of perception of color Rabkin's tables are used.
PERCEPTION OF SPACE ► Visual acuity – the smallest distance between two points which the eye can distinguish. Is determined by the table. Visus = 1. ► Field of vision – the space seen by an eye at bracing of a view in one point. Borders of a field of vision for colourless subjects make: кнаружи – 90 о, inside – 60 о, up – 60 о, from top to bottom – 70 о. ► The solid vision is a vision both eyes when images of subjects get on a retina and in perception of the person these two images merge in one (the vision center).
SOMATOSENSORY ANALYZER. 1. Peripheric department: - skin receptors - proprioretseptor ►Types of proprioretseptor: - Primary terminations of muscular spindles. - Secondary terminations of muscular spindles. - Sukhozhilnye Goldzhi's receptors.
Types of dermal receptors: ►Touch receptors – Merkel's disks, Meysner's touch corpuscles. ►Pressure and vibration receptors – Fater-Pachini's little bodies ►The receptors sensitive to heat – Ruffini's little bodies ►The receptors sensitive to cold – flasks to Krauza ►Painful receptors (notsitseptor) – the free nervous terminations.
2. Conduction department. Signals from receptors of a skin, proprioretseptor are carried out on two main ways (tracts): to the lemniskovy to the spinotalamichesky.
► Lemniskovy way: signals from tactile and muscular receptors of a spinal ganglion (the 1 st neurones) back columns of an oblong brain - Gaulle and Burdakh's cores (the 2 nd neurones) decussation ventral cores of a thalamus (the 3 rd neurones).
► Spinotalamical way: signals of temperature and painful sensitivity of spinal ganglion (the 1 st neurones) gray substance of back horns of a spinal cord (the 2 nd neurones) spinotalamichesky tract of ventral cores of a thalamus (the 3 rd neurones).
3. Central department: The somatosensory cortex zone the larger hemispheres (postcentral gyrus).
ACOUSTIC ANALYZER, CHARACTERISTIC OF DEPARTMENTS. 1. Peripheric department – sensory voloskovy cells кортиева an organ located in an internal ear.
2. Conduction department. From a spiral ganglion of a cochlea of a cochlear nerve (as a part of VIII couples craniocerebral nerves) an oblong brain (neurones of cochlear kernels) an acoustical tract of neurones of the top oliva of the bottom hillocks a chetverokholmiya of a mesencephalon of internal (medial) geniculate bodies. 3. The central department – a temporal share of a cortex of larger hemispheres.
STRUCTURE AND FUNCTIONS OF THE EXTERNAL AND MIDDLE EAR. ► External ear (an auricle and external acoustical passage, a tympanic membrane) – catching and carrying out sound fluctuations to a tympanic membrane.
► Middle ear (a drum cavity with ossicles: hammer, anvil, стремечко and an Eustachian tube) – transfer of fluctuations from a tympanic membrane to an internal ear.
STRUCTURE AND FUNCTIONS OF THE INTERNAL EAR. Cochlea – the wide osteal spiral channel, 2, 5 rounds. The membranes parting the osteal channel of a cochlea: 1. Vestibular membrane (Reyssner's membrane) 2. Main membrane. Channels (courses) of a cochlea: 1. Top channel (vestibule ladder) 2. Average (webbed) channel 3. Bottom channel (drum ladder)
On the main membrane of the average channel - кортиев an organ. Over voloskovy cells кортиева an organ – tektorialny or Korti's cover membrane.
Transfer of sound fluctuations. Sound of наружный acoustical passage of tympanic membrane hammer an anvil of fluctuation of the oval window of fluctuation of a perilympha of the top and bottom channels of fluctuation of an endolymph of the average channel of fluctuation of voloskovy cells of the main membrane of deformation of voloskovy cells at contact to a cover membrane of emergence of receptor potential of PD nervous fibers.
THEORIES OF PERCEPTION OF THE SOUND: ►Helmholtz's ►Telephone resonant theory (1863) theory of the Rutherford (1880) ►Theory of "traveling wave" of Bekesha (1960 -1966).
Helmholtz's resonant theory (1863) M. basilaris reminds harp cords which have own frequency. At action of high-pitched sounds short fibers at the beginning of a cochlea resound. Low sounds cause fluctuation of long fibers at top of a cochlea.
Telephone theory of the Rutherford (1880) At perception of sounds frequency of fluctuations potentials in an acoustical nerve corresponds to the frequency of perception of sounds (as in phone). With a stimulus frequency More than 1000 Hz theory aren't confirmed.
Theory of "traveling wave" of Bekesha (1960 -1966). Sound fluctuations of high frequency involve in oscillatory process relymph on a limited site near an oval window also are transferred to endolymph on a short site. At lower sounds of max of fluctuations arises in average part of a cochlea.
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