UNIT 2 The Tissue Level. Epithelial Tissue PDF

TYPES of TISSUES in the HUMAN BODY: Gland, Muscular, connective and nervous ©Copyright Universidad Europea. Todos los derechos reservados TYPES of TISSUES: -Embryological origin : Endoderm:epithelial. Mesoderm: epithelial, connective a n d muscular. Ectoderm: epithelial a n d nervous. ©Copyrigh...

TYPES of TISSUES in the HUMAN BODY: Gland, Muscular, connective and nervous ©Copyright Universidad Europea. Todos los derechos reservados TYPES of TISSUES: -Embryological origin : Endoderm:epithelial. Mesoderm: epithelial, connective a n d muscular. Ectoderm: epithelial a n d nervous. ©Copyright Universidad Europea. Todos los derechos reservados TYPES of TISSUES Epithelial cells: To cover something inside or outside / Epithelial tissu= one or + layer of cells Epithelial tissue: covers body surfaces, lines hollow organs, body cavities, a nd ducts, an d forms glands. It allows interaction with external and internal environments. Connective tissue: protects a nd supports the body a nd its organs, binds organs together, stores energy reserves as fat, and provides immunity. Muscle tissue: responsible for movement a nd generation of force a nd heat. Nervous tissue: initiates a nd transmits action potentials (nerve impulses) that help coordinate body activities. ©Copyright Universidad Europea. Todos los derechos reservados GENERAL CHARACTERISTICS: epithelial tissue Letters ✔ Syllabes Words Sentences Apical cell Many cells with tight cellular cohesion (small intercellular spaces) arranged in either single or multiple layers. ✔ Avascular: DIFFUSION. ✔ Innervation: neuroepithelium. ✔ Polarization. ✔ Cell division, ability to constantly renew itself. ✔ Moist surfaces due to the presence of mucus and other secretions; except the epidermis. Simple epithelium = WITH ONE LAYER Stratified epithelium SKIN WHITH PLUSIEUR LAYER ©Copyright Universidad Europea. Todos los derechos reservados ECTODERM CONTACT AVC ENVIRONMENT ✔ The sensory epithelia of the eye, ear, and nose. E C TODERM ECTODER M ✔ Lining of anterior tongue, hard palate and sides of the mouth. ✔ The epidermis and its appendages (the nails and hair). ©C opyrigh t Universidad Europea. Todos los derechos reservados MESODERM ABLE TO PRODUICE MAJORITY TISSUE Tubular renal epithelium MESODER M Endocardiu m Ureter ©Copyright Universidad Europea. Todos los derechos reservados ENDODERM ✔ Epithelial lining of the respiratory and gastrointestinal tracts. ENDODER M ✔ Lining of posterior tongue, soft palate and floor of the mouth. ✔ Biliary tree, liver. ©Copyright Universidad Europea. Todos los derechos reservados ✔ Female and male urethra. CHARACTERISTICS epithelial tissue POLARITY An epithelium has a free surface, the apical surface, exposed to the outside, an d a n attached surface, the basal surface, resting on the underlying connective tissue. - Apical surface (free): specialized structures. Texte - Basal surface (resting on basal lamina)-he midesmoso mes. - Lateral surface: tight junctions, adherens junctions, ©Copyright Universidad Europea. Todos los derechos reservados desmosomes, g a p APICAL SURFACE SPECIALICED STRUCTURES Intestinal brush border Ciliated columnar epithelium of the respiratory tract. Microvilli BASEMENT MEMBRANE Epithelium Connective tissue ©Copyright Universidad Europea. Todos los derechos reservados Basal lamina Closer to and secreted from epithelial cells. C ontains laminin, inte grins, c ollage n, glycoproteins... Reticular lamina C loser to and sec re te d by connective tissue cells. Re ticular fibers, c ontains c ollage n too. Functions: ✔ Guidance for cell migration during development and wound healing. ✔ Atta c hme nt and support for epithelium. ✔ Restriction of passage of large molec ules b e tw e e n e pithe lium and connective tissue. FUNCTIONS OF EPITHELIUM GENERAL covering an d (epidermis, gastric epithelium). □ Protection: lining epithelium □Absorption: simple epithelium (small intestine…). □Diffusion: endothelium, lung alveoli epithelium. □Secretion: glandular e pithe lium (muc us, e nzyme s, sweat…). ©Copyright Universidad Europea. Todos los derechos reservados FUNCTIONS OF EPITHELIUM SPECIFIC □Sensory reception: olfactory neuroepithelium, taste bud epithelium. Transport carefully the embryon □Transport: respiratory epithelium, fallopian tubes epithelium. □Contractile: sweat glands, mammar y glands, salivary glands. □Excretion: renal epithelium, sweat gland. □Lubrication of surfaces (secretion): serous and mucous glands. □Reduction of visceral friction (protection): serous membranes or mesothelium (pleura, pericardium, peritoneum). ©Copyright Universidad Europea. Todos los derechos reservados