Histology and Embryology of Eye and Ear for Foreign Students - P.J. Šafárik University, Study notes of Histology

Download Histology and Embryology of Eye and Ear for Foreign Students - P.J. Šafárik University and more Study notes Histology in PDF only on Docsity! Department of Histology and Embryology, P. J. Šafárik University, Medical Faculty, Košice Sense organs : Sylabus for foreign students Authors: Prof. MUDr. Eva Mechírová, CSc., MVDr. Štefan Tóth, PhD. Development of the eye Layers of the eye – three concentric layers a. Tunica fibrosa bulbi → connective tissue – Tennon´ s capsule ○ sclera ○ cornea b. Tunica vasculosa bulbi → vascular layer ○ choroid ○ ciliary body ○ iris c. Tunica nervosa bulbi –retina optical part blind part ○ macula lutea with fovea centralis → maximal visual acuity ○ papilla nervi optici or optic disc →blind part Refractive structures: cornea, humor aquaeus, lens, corpus vitreum Accesory structures of the eye: a. musculi bulbi b. eyelids - palpebrae oculi c. conjunctiva d. lacrimal apparatus 3.Tunica nervosa bulbi - retina most inner layer © composed of 2 parts— optical and blind part © pars optica retinae — pigment epithelium + nervous layer of retina - 10 layers — inner plexiform layer inner nuclear layer outer plexiform layer outer nuclear layer membrana limitans externa ‘— rods and cones pigment epithelium choroid (1) - Membrana limitans interna- end parts of Muller call procesess, limited by lamina basalls (2) - Layer ofnerve fibers-s layer of parallal axons of ganglionic calls (3) - Layer of ganglionic cells (4) - Inner plexiform layer = synapaiss between axons of bipolar cells and dendrites of multipolar ganglionic calls (5) - Inner nuclear layer © coll bodies and nuciel of bipolar, amacring and Miller celle (6) - Outer plexiform layer = synapelae between cons and rodes anddandrites of bipolar calls (7) - Outer nuclear layer- call bodies with nuciel of cones and rode (8) - Membrana limitans externa-procassas of supporting MUller calla (3) - Cones and rods- penpneral segments of photosenattive cole (10) — Pigment epithelium- yer of cupoial calle, cytopiaemkc processes contain pigment — metanin Cones and rods [Mic | Mc. > o, A -Cone cells + fotopigment -iodopsin 3 types of cones sensitive for red, green, and blue color B- Rod cells » fotopigment- rhodopsin = sharp black and white vision a — axon, Mc— Miller cell, is— inner segment, 05 — outer segment The ear — vestibulo—cochlear apparatus Development of the ear 4week « The ear gives rise from: 4. otic (ear) ectodermal placode on lateral part of developing rhombencephalonand neuroectoderm of neural crest together form internal ear - labyrinthus membranaceus from otic placode — otic pit — otic vesicle 2. bony labyrint — mesenchyme of temporal bone 3. tympanic cavity — endodermal origin of 1. pharyngeal pouch 4. auditory ossicles — mesenchymal origin — cartilages of 1.and 2. branchial arches: 5. meatus acusticus externus — ectoderm of 1. branchial groove 6. auricle gives rise from 6 swellings of mesenchyme around the 1. branchial groove. and is covered by ectoderm Development of otic vesicle 4. Dorsal part-3 semicircular ducts 2. Central part- utricle, saccule 3. Ventral part- cochlear duct Internal ear-cochlea 2% turns of the bony cochlea Organ of Corti .labium vestibulare limbi spiralis 2.epith.of limbus 2.epith.of sulous spiralis int. 4. sulous spiralis int.. ‘S.tectorial membrane €. outer hair cells 7.Hensen cells 8.Claudius cells §.basilar membrane 10. tunel of Corti 11. nerv fibers Vestibular apparatus - equilibrium ● proprioreceptors are concentrated in : a) macula sacculi et utriculi – identical histologic structure ○ ovoid plates of sensory epithelium inervated by branches of vestibular nerve, situated in the wall of saccule and utricle ○ contain proprioreceptors (hair cells) and supporting cells ○ there is a gelatinous glycoprotein layer on the surface + otolites = crystals of CaCO3 b) in semicircular ducts are cristae amplullares ○ receptors form ridge-like structures – cristae ○ histologic structure is similar to maculae ○ glycoprotein layer is thicker and is not covered by otoliths, is conical in shape - cupula Function in head movement → change in movement of endolymph → otolites movement → movement of glycoprotein layer with the processes of hair cells → stimulation of nerve endings around hair cells Hair cells of macula sacculi et utriculi » apical part of cells contains: 40-80 stereocilia + 1 kinocilium Cristae ampullares