UNIT 2 THE TISSUE LEVEL. EPITHELIAL TISSUE copie.pdf

TYPES of TISSUES in the HUMAN BODY GLAND CONNECTIVE © Copyright Universidad Europea. Todos los derechos reservados MUSCULAR NERVOUS TYPES of TISSUES Embryological origin Endoderm: epithelial. Mesoderm: epithelial, connective and muscular. Ectoderm: epithelial and nervous. © Copyright Universi...

TYPES of TISSUES in the HUMAN BODY GLAND CONNECTIVE © Copyright Universidad Europea. Todos los derechos reservados MUSCULAR NERVOUS TYPES of TISSUES Embryological origin Endoderm: epithelial. Mesoderm: epithelial, connective and muscular. Ectoderm: epithelial and nervous. © Copyright Universidad Europea. Todos los derechos reservados ECTO= EXTERNAL : OUTSIDE ENDO = INSIDE 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, and ducts, and forms glands. It allows interaction with external and internal environments. Connective tissue: protects and supports the body and its organs, binds organs together, stores energy reserves as fat, and provides immunity. Muscle tissue: responsible for movement and generation of force and heat. Nervous tissue: initiates and 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. Simple epithelium = WITH ONE LAYER ✔ Innervation: neuroepithelium. ✔ Polarization. ✔ Cell division, ability to constantly renew itself. ✔ Moist surfaces due to the presence of mucus and other secretions; except the epidermis. © Copyright Universidad Europea. Todos los derechos reservados Stratified epithelium SKIN WHITH PLUSIEUR LAYER EMBRYOLOGICAL ORIGIN ECTODERM ✔ The sensory epithelia of the eye, ear, and nose. ECTODERM ECTODER M CONTACT AVC ENVIRONEMENT ✔ Lining of anterior tongue, hard palate and sides of the mouth. ✔ The epidermis and its appendages (the nails and hair). © Copyright Universidad Europea. Todos los derechos reservados EMBRYOLOGICAL ORIGIN MESODERM ABLE TO PRODUICE MAJORITY TISSUE Tubular renal epithelium MESODER M Endocardiu m Ureter © Copyright Universidad Europea. Todos los derechos reservados EMBRYOLOGICAL ORIGIN 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, and an attached surface, the basal surface, resting on the underlying connective tissue. - Apical surface (free): specialized structures. Texte - Basal surface (resting on basal lamina)-hemidesmoso mes. © Copyright Universidad Europea. Todos los derechos reservados - Lateral surface: tight junctions, adherens junctions, desmosomes, gap 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. Contains laminin, integrins, collagen, glycoproteins... Reticular lamina Closer to and secreted by connective tissue cells. Reticular fibers, contains collagen too. Functions: ✔ Guidance for cell migration during development and wound healing. ✔ Attachment and support for epithelium. ✔ Restriction of passage of large molecules between epithelium and connective tissue. BASEMENT MEMBRANE © Copyright Universidad Europea. Todos los derechos reservados FUNCTIONS OF EPITHELIUM GENERAL Protection: covering and (epidermis, gastric epithelium). lining epithelium Absorption: simple epithelium (small intestine…). Diffusion: endothelium, lung alveoli epithelium. Secretion: glandular epithelium (mucus, enzymes, 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, mammary 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