SENSE ORGANS THE AUDIOVESTIBULAR ORGAN 1 2 3
SENSE ORGANS THE AUDIOVESTIBULAR ORGAN 1. 2. 3. 4. 5. 6. Taste buds Audiovestibular analizator Audiovestibular organ External ear Middle ear Internal ear: a) bony labyrinth; b) membranous labyrinth 7. Hair cells 8. Audiovestibular organ histophysiology
ANALIZATOR sense organ + nerve + cortex (field) Sense organs Primary sensory Secondary sensory Sensory endings 1. Eye 2. Smell organ Ear Taste buds 1. Receptor of pain 2. Paccinian body 3. Bulb of Krause… (receptors)
Organ of taste (taste buds) (50%) in foliate papillae (50%) in circumvallate papillae (few in lips, epiglottis, vocal folds)
Taste buds (2000, calliculi gustatoriae) Fundamental taste sensations sweet bitter acid salty glutamate Structure of taste bud Taste pit Taste pore Bud like aggregation of 40 -60 cells 1. Sensoepithelial cells 2. Supporting cells 3. Basal cells
AUDIOVESTIBULAR ORGAN (EAR) Functions –hearing and balance External ear Middle ear Internal
External ear (pinna, external auditory tube, tympanic membrane) Receives sound waves Middle ear (tympanic cavity, auditory ossicles, auditory tube) Transforms sound waves into mechanical oscillation of ossicles Internal ear (vestibule, 3 semicircular canals, cochlea) Converts mechanical oscillations in nerve impulses
External ear Pinna (auricle) funnel like plate of elastic cartilage + skin External auditory tube – 2, 5 -3 cm Cartilage and bony portion Lined with skin Has sebaceous and ceruminous glands (apocrine sweat glands producing ear wax- cerumen-for protection) Tympanic membrane
Tympanic membrane Functions 1. Separates tympanic cavity of middle ear and external auditory tube; 2. Transmits sound waves to ossicles (malleus) Structure 1. Skin 2. Fibrous connective tissue 3. Simple squamous epithelium of mucosa
Middle ear Tympanic cavity – irregular airfilled space in temporal bone, lined with mucosa Auditory ossicles – malleus, incus and stapes – transmit mechanical oscillations to oval window of inner ear Auditory tube – Eustachian tube, 4 cm, extends from tympanic cavity to nasopharinx, lined with mucosa
INTERNAL EAR vestibule+3 semicircular canals +cochlea Bony labyrinth Membranous labyrinth Otolith membrane Hair cells Maculae Organ of Corti Tectorial membrane Cristae ampullaris Cupula Hair cells Organ of Corti Crista ampullaris
Perilymph (bony labyrinth) 1. Like extracellular fluid 2. Low protein content 3. Is connected with subdural space by perilymphatic duct Endolymph (membranous labyrinth) 1. Low protein content 2. Low Na content 3. High K content 4. Is connected with endolymphatic sac by endolymphatic duct
Membranous labyrinth (cochlear duct) Maculae of utricle Maculae of saccule Cochlear duct Ampullary crests
Maculae
Cells of maculae Sensory cells: cylindrical and piriform Have 60 -80 stereocilia (40 mkm) and 1 kinocilium Supporting cells
Crista ampullaris
Cells of ampullary crest
Cochlea axial section Helicotrema Modiolus Scala vestibuli Spiral ganglion Cochlear duct Scala tympani Cohlear nerve
MEMBRANOUS LABYRINTH • Cochlear duct - triangular
Membranous labyrinth (scheme) Vestibular membrane Basilar membrane Stria vascularis Scala vestibuli Cochlear duct Spiral ligament Stria vascularis Basilar membrane Vestibular membrane Tectorial membrane Spiral limbus Spiral tunnel Spiral bony lamella Cochlear nerve Scala tympani
Membranous labyrinth or cochlear duct Vestibular membrane – Reissner’s membrane – epithelium, BM, epithelium Basilar membrane – consists of fibers (collagen) and epithelia Stria vascularis – lies over spiral ligament, epithelium contains capillaries
Corti’s organ Stria vascularis Hair cells Hensen cells Outer Basilar phalangeal cells membrane Pillar cells
Corti’s organ Outer hair cells Tectorial membrane Outer border cells Spiral tunnel Outer Supporting cells Nerve fibers Inner hair cells Inner border cells Inner tunnel Cochlear nerve Betshar’s cells Outer phalangeal cells Inner and outer Basilar membrane pillar cells
Corti’s organ Tunnel (pillar cells) Outer cells: A. Supporting 1. Phalangeal (Deyters) 2. Border (Hensen) 3. Outer supporting (Claudius) 4. Betshar’s cells B. Hair cells (3 -5) Inner cells A. Supporting 1. Phalangeal 2. Inner supporting B. Hair cells (1 -2)
Apical portion of outer phalangeal and hair cells 1 2 3 4 1. Stereocilia 2. Cuticula 3. Phalangeal processes 4. Hair cells bodies
Phalangeal and hair cells (scheme) Stereocilia Cuticular lamella Phalangeal process Marginal network Outer hair cell Outer phalangeal cell Basilar membrane Afferent and efferent nerve fibers
Hair cells stereocilia Excitation Apical junctions Stereocilia Basal body Cuticular lamella Microtubuli
Audiovestibular organ histophysiology Subarachnoidal space Semicircular canals Ampulae Endolymphatic sac Endolymphatic duct Perilymphatic duct Scala vestibuli Processsus mastoideus Cochlear duct Oval window External auditory tube Scala tympani Stapes Uncus Maleus Cochlea Eustachian tube Tympanic membrane
Hearing histophysiology Scala vestibuli Oval window Vestibular membrane Cochlear duct Tectorial membrane Organ of Corti Round window Basilar membrane Cochlear nerve Spiral ganglion Scala tympani
Functions of audiovestibular organ 1. Organ of Corti – hearing 2. Maculae of saccule – gravity and vibration 3. Maculae of utricle - gravity and linear acceleration 4. Ampullary crests – circular accelaration and equilibrium
Deafness 1. Conductive loss – problem is connected with disorders of sound waves passage from external environment to inner ear 2. Sensory-neural – problem of nerves 3. Pressbyacussis - aging
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