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1.Epithelial Tissue.ppt

  1. Tissue Types
  2. Key Terms • Differentiation = produces specialized cells during embryonic development • Tissues = groups of cells which are similar in structure and which perform common or related functions • Histology = the study of tissues
  3. Four Basic Kinds of Tissues • Epithelial Tissue • Connective Tissue • Muscle Tissue • Nervous Tissue
  4. Epithelial Tissue • Locations: – Covers the body – Lines organs, body cavities, and ducts – Forms glands • Functions: – Protection from injury and microbial invasion – Regulates permeability – Secretes fluids to lubricate structures
  5. Characteristics: • Avascular (no blood vessels) • Cells may show polarity (apical & basal surface, they are chemically and structurally different from one another) • A basement membrane attaches epithelia to underlying connective tissues • High rate of cell division (allows repair by sloughing off dead or injured cells, important because epithelium is exposed to physical stress) Epithelial Tissue
  6. The Polarity of Epithelial Cells
  7. • Number of cell layers pg 113 – Simple (single layer) – Stratified (several layers) – Pseudostratified (nuclei are at different levels & not all cells reach the apical surface) • Shape of cells (draw, location, function) – Squamous (thin, flat, irregular cells) pg 115 – Cuboidal (cube shaped cells) pg 116 – Columnar, ciliated and nonciliated (tall & slender cells) pg 116, 117 – Transitional (change shape from flat to cuboidal and back) pg 119 Classification of Epithelia
  8. Squamous Epithelia
  9. Cuboidal Epithelia
  10. Cuboidal Epithelia Cont.
  11. Special Cuboidal Epithelia: Transitional Epithelia cells can stretch
  12. Columnar Epithelia
  13. Columnar Epithelia
  14. Columnar Epithelia
  15. Many epithelia contain gland cells that produce secretions Exocrine glands: – Produce secretions such as mucus and/or watery solution through ducts onto the epithelial surface Endocrine glands: – Ductless, release secretions directly into bloodstream Glandular epithelia
  16. Exocrine vs. Endocrine Glands
  17. Examples of Exocrine Glands
  18. Time to Review Simple squamous epithelium (lining of body cavities) Simple cuboidal epithelium (lining of glands and ducts)
  19. Simple columnar epithelium (lining of stomach, intestines)
  20. Stratified squamous epithelium (skin)
  21. Simple columnar epithelium (lining of digestive tract)
  22. Simple cuboidal epithelium (lining of ducts in kidneys)
  23. Simple squamous epithelium (lining of the heart)
  24. Pseudostratified columnar epithelium (lining of nasal cavity)
  25. Transitional epithelium (urinary bladder)
  26. Stratified squamous epithelium (lining of mouth)
  27. Type of Tissue Function Location Pseudostratified columnar removing dust and particles from airways, has cilia lines the respiratory passageways Simple Columnar Absorption lines the uterus and most organs of the digestive tract Simple Cuboidal Secretion and Absorption glands, kidney tubules, ovaries Simple Squamous Diffusion and Filtration lungs, walls of capillaries and vessels Stratified Squamous Protects underlying cells skin(keratinized) and the throat, vagina, mouth (soft) Stratified Cuboidal Protection lines ducts of the mammary glands, sweat glands, pancreas Stratified Columnar Protection, secretion male urethra and vas deferens, parts of the pharynx Transitional (unstretched) Specialized to become distended urinary tract

Notas do Editor

  1. High rate of cell division allows them to repair themselves by sloughing off dead and injured cells – it is important because epithelium is exposed to physical stress