Epithelial tissue
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Transcript of Epithelial tissue
Epithelial Tissue (pg 2)
Tissue = collection of cells that have similar structure and function together as a unit
Tissue = collection of cells that have similar structure and function together as a unit
Histology = Study of tissues
Epithelial Tissues
• Form the covering of all body surfaces, line body cavities and organs, and form glands
Epithelial Tissues
• Form the covering of all body surfaces, line body cavities and organs, and form glands
• Cells are tightly packed
Epithelial Tissues
• Form the covering of all body surfaces, line body cavities and organs, and form glands
• Cells are tightly packed
• One free surface
Epithelial Tissues
• Form the covering of all body surfaces, line body cavities and organs, and form glands
• Tightly packed
• One free surface
• Avascular (no blood vessels)
Epithelial Tissues
• Form the covering of all body surfaces, line body cavities and organs, and form glands
• Tightly packed
• One free surface
• Avascular (no blood vessels)
• Regenerate quickly
Shapes1. Squamous = flat cells, thin nuclei
Shapes1. Squamous = flat cells, thin nuclei
2. Cuboidal = cubelike cells, spherical central nuclei
Shapes1. Squamous = flat cells, thin nuclei
2. Cuboidal = cubelike cells, spherical central nuclei
3. Columnar = Tall narrow
cells, nuclei near bottom
Number of Layers
1. Simple = 1 layer
Number of Layers
1. Simple = 1 layer
2. Stratified = Multiple layers of cells. Named according to the type of cells at the free surface of the tissue
Number of Layers
1. Simple = 1 layer
2. Stratified = Multiple layers of cells. Named according to the type of cells at the free surface of the tissue
3. Pseudostratified = appears to be multiple layers, but is really only 1 layer
Glandular Epithelium
• Exocrine glands = secrete products onto a surface via a duct
Glandular Epithelium
• Exocrine glands = secrete products onto a surface via a duct
• Can be unicellular (goblet cells) or multicellular
Exocrine Glands
Classified according to STRUCTURE1. Simple: duct has no branches
2. Compound: duct has branches
Exocrine Glands
Classified according to STRUCTURE1. Simple: duct has no branches
2. Compound: duct has branches
3. Tubular: gland has the same diameter as the duct
4. Acinar (Alveolar): gland is saclike
Exocrine GlandsClassified according to SECRETIONS
1. Merocrine: fluid released by exocytosis
Example: salivary and pancreatic glands
Exocrine Glands• Classified according to SECRETIONS
1. Merocrine: fluid released by exocytosis
Example: salivary and pancreatic glands
2. Apocrine: small portion of cell is pinched off
Example: Mammary glands
Exocrine Glands• Classified according to SECRETIONS
1. Merocrine: fluid released by exocytosis
Example: salivary and pancreatic glands
2. Apocrine: small portion of cell is pinched off
Example: Mammary glands
3. Holocrine: Cells fill with product and rupture
Example: Sebaceous (oil) glands