sense organs 1.analizators 2.classification of sense organs 3.smell organ 4.visual organ eye general...
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Sense organs
1. Analizators2. Classification of sense
organs3. Smell organ4. Visual organ• Eye general structure• Sclera• Сornea• Choroid• Iris• Retina
ANALIZATOR
sense organ + nerve + cortex (field)
Sense organs
Primary sensory
1. Eye2. Smell organ
Secondary sensory
1. Ear2. Taste buds
Sensory endings (receptors)
1. Receptor of pain2. Paccinian body3. Bulb of Krause
Smell organOlfactory epithelium: olfactory cells, supporting
cells, basal cells
Smell analizator = olfactory mucosa+n.olfactorius+hippocamp
The olfactory epithelium
is tall, pseudostratified columnar epithelium about 60 mm in height
lacking goblet cells and with no distinct basal lamina
contains three types of cells: sustanticular or supporting, basal and olfactory.
EyeVisual analizator =
retina+n. opticus+occipital lobe cortex
Eye
Eye tunics
1. Fibrosa (sclera+cornea)
2. Vascular (uveal tract): choroid+ciliary body+iris
3. Retina: blind+visual
Eye systems
1. Dioptric (cornea, lens, vitreus body)
2. Visual (retina)
3. Accomodative (ciliary body)
TUNICA FIBROSA
The eye’s outermost tunic has two main components
The anterior surface forms the transparent cornea
The posterior – opaque (white) sclera.
The junction between the cornea and sclera is the limbus.
Cornea
Cornea
1.Anterior epithelium (str. sq. nonker.)
2.Ant. limiting membrane (Bowman’s)
3.Substantia propria
4.Post. limiting membrane (Descemet’s)
5.Endothelium
Sclera
is opaque white connective tissue (dense fibrous tissue, about 1mm thick)
is composed of flat bundles of collagen fibers, which lie mainly parallel to the surface
The sclera has three layers:
episclera
substantia propria
lamina fusca
TUNICA VASCULOSA (UVEAL TRACT)
components:
1) choroid (posterior part)
2) ciliary body (middle)
3) iris (anterior).
Choroid 1.Suprachoroid2.Vascular lamina (melanocytes)3.Choroidcapillaris4. Basal complex (membrane of Bruch)
Sclera and choroid
Ciliary body
Ciliary body
1. Suprachoroid
2. Vascular lamina
3. Basal complex (membrane of Bruch)
Has ciliary processes and the ciliary muscles
The ciliary processes are irregular epithelium covered connective tissue outgrowth of the ciliary body that extends toward the lens
Iris 1. Anterior epithelium2. Ant. limiting membrane3. Vascular layer4. Post. limiting membrane5. Posterior epithelium
Lens
capsuleepitheliumlens fibers
Lens
The lens capsule is an elastic and transparent basal lamina that covers the entire lens and prevents wandering cells from penetrating it.
Subcapsular epithelium. The height of this low cuboidal epithelium beneath the capsule on the anterior lens surface increases to columnar near the lens equator, where cell division occurs
Lens fibers are long, narrow, hexagonal, specialized epithelial cells that make up most of lens..
Retina blind and visual
Retina
Pigmental layer
Pigmented cells functions
1. Synthesis of melanin granules that absorb stray light in the eye chamber
2. Phagocytosis and digestion of apical parts of the photoreceptors
3. Active participation in ion transport, since they maintain an electrical potential between the two surfaces of the epithelium membrane
4. They participate in the processes of vitamin A esterification.
Scheme of retina
Nerve cells of retina
4
6
8
Nerve cells of retinaThere are three layers of retinal neurons
1st one (No4 - external nuclear layer) contains perikaryons of rode and cone cells - bipolar sensory cells
2nd - inner nuclear layer (No6) contains perikaryons of bipolar associative cells
3rd layer is ganglionic layer (No8) with large multipolar associative neurons.
Additional neurons horizontal and amacrine cells which lie in inner nuclear layer and have inhibiting function
• Horizontal and amacrine cells do not have axons or dendrites, only neuritic processes conducting in both directions.
Rod and cone cells
Retina’s layers
1. Pigment cell layer
2. Layer of rods and cones
3. External limiting membrane
4. External nuclear layer
5. External plexiform layer
6. Inner nuclear layer
7. Inner plexiform layer
8. Ganglionic layer
9. Layer of optic nerve fibers
10. Internal limiting membrane
Areas of retina with special functions
Blind macula - optic papillaYellow macula - fovea
Yellow macula - fovea
Blind macula - optic papilla
• The exit site from the retina of axons derived from ganglion cells is represented by the optic disc.
• The optic disc includes the optic papila, a protrusion formed by the axons entering the optic nerve, and the lamina cribrosa of the sclera, pierced by the axons of the optic nerve.
• Photoreceptors terminate at the edges of the optic disc, which represents the “blind spot” of the retina.
• The central artery and vein of the retina pass through the optic disc.