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Tissues Histology: the study of tissues Slide 2 Tissues A group of interrelated cells that function together and perform specialized activities 4 Types of Tissues in the body Epithelial Epithelial Connective Connective Muscle Muscle Nervous Nervous Slide 3 Epithelial Tissue AKA: Epithelium (epi- upon or above) Functions: Functions: (P) Protection (S) Secretions (A) Absorption (F) Filtration Slide 4 Epithelial Tissue Characteristics Closely packed flat cells Closely packed flat cells Avascular (a- without vasc- blood supply), needs are met through diffusion from neighboring cells Avascular (a- without vasc- blood supply), needs are met through diffusion from neighboring cells Slide 5 Epithelial Tissue Location Coverings or linings of organs Coverings or linings of organs Always has a surface exposed to open space or the outside of the body (apical surface)Always has a surface exposed to open space or the outside of the body (apical surface) Underside always attached to connective tissue by a basement membraneUnderside always attached to connective tissue by a basement membrane Mitosis is frequent to replace damaged cells since they are exposed Mitosis is frequent to replace damaged cells since they are exposed Slide 6 Types Glandular Epithelium- Exocrine- secretes products into ducts Exocrine- secretes products into ducts This allows for the substance to be concentrated to one specific areaThis allows for the substance to be concentrated to one specific area Endocrine- secretes directly into blood Endocrine- secretes directly into blood nonspecificnonspecific endocrine exocrine Slide 7 Types Epithelial tissue is classified two ways By the cell shape By the cell shape By the number of cell layers By the number of cell layers Some may contain goblet cells.these cells are filled with and release mucus. (This type lines the digestive tract and are sometimes referred to as mucosae) Slide 8 Epithelial Cell Shapes Squamous- (squashed) flat, nucleus near surface Cuboidal- (cube) thicker, square shaped with central nucleus Slide 9 Epithelial Cell Shapes Columnar- (column) elongated cells, some have microvilli (fingerlike projections that increase surface area), some have cilia (tiny hair-like structures that help move materials along) Slide 10 Epithelial Cell Shapes Transitional- appearance ranges from flat to columnar, cells can stretch and compress (different shapes in the same layer) Slide 11 Arrangement of Layers Simple- single layer, thinness allows substances to permeate easily Stratified- (strat-layers) multiple layers, protection for areas that endure large amounts of stress, cells grow from the bottom layer up Pseudostratified- (psuedo-false) one layer, but appears to be multilayered. All cells are attached to the basement membrane, but not all the cells reach the surface Slide 12 Practice Looks Epithelia Page Epithelia Page Epithelia Page 1. Simple Squamous 2. Simple Squamous 3. Simple Cuboidal 4. Simple Cuboidal 5. Simple Columnar 6. Simple Columnar 7. Pseudostratified Columnnar 8. Pseudostratified Columnnar (Ciliated) 9. Transitional 10. Transitional 11. Stratified Squamous 12. Stratified Squamous 13. Stratified Squamous 14. Stratified Squamous (Keratinized) 15. Stratified Squamous (Keratinized 16. Stratified (High) Cuboidal 17. Stratified Cuboidal 1. Simple Squamous 2. Simple Squamous 3. Simple Cuboidal 4. Simple Cuboidal 5. Simple Columnar 6. Simple Columnar 7. Pseudostratified Columnnar 8. Pseudostratified Columnnar (Ciliated) 9. Transitional 10. Transitional 11. Stratified Squamous 12. Stratified Squamous 13. Stratified Squamous 14. Stratified Squamous (Keratinized) 15. Stratified Squamous (Keratinized 16. Stratified (High) Cuboidal 17. Stratified Cuboidal 1. Simple Squamous 2. Simple Squamous 3. Simple Cuboidal 4. Simple Cuboidal 5. Simple Columnar 6. Simple Columnar 7. Pseudostratified Columnnar 8. Pseudostratified Columnnar (Ciliated) 9. Transitional 10. Transitional 11. Stratified Squamous 12. Stratified Squamous 13. Stratified Squamous 14. Stratified Squamous (Keratinized) 15. Stratified Squamous (Keratinized 16. Stratified (High) Cuboidal 17. Stratified Cuboidal Slide 13 Epithelial Tissue Extra Slides for at Home Review Slide 14 Types of Epithelium Simple Squamous- single, flat cell layer, nucleus in middle of the cell Slide 15 Types of Epithelium Simple Cuboidal- Single layer of cubed shaped cells, nucleus in the middle Slide 16 Types continued Simple Columnar- single layer of rectangular cells, nucleus at base, Non-ciliated- contains goblet cells (mucous) and microvilli (increase surface area) in some areas Non-ciliated- contains goblet cells (mucous) and microvilli (increase surface area) in some areas Slide 17 Simple Columnar- Ciliated- single layer of rectangular cells, nucleus at the base Ciliated- single layer of rectangular cells, nucleus at the base Slide 18 Types- continued Stratified Squamous- Several layers, larger at the bottom and flattened out at the top, bottom replaces top as the superficial layers shed, can produce keratin Slide 19 Types- Continued Stratified Cuboidal- two or more layers, cubed shaped cell Slide 20 Types- Continued Stratified Columnar- several layers on columnar in superficial layers Slide 21 Types Pseudostratified Columnar- single layer, nucleus at different levels, all cells attached to basement membrane Slide 22 Types Transitional- range from squamous to cuboidal appearance