Copy of Histology Virtual Lab - Epithelial Tissues PDF

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Histology Virtual Lab - Epithelial Tissues Introduction Epithelia are tissues consisting of closely opposed cells without intervening intercellular substances. Epithelia are avascular, but all epithelia "grow" on an underlying layer of vascular connective tissue. The connective tissue and the epithelium are separated by a basement membrane. Epithelium covers all free surfaces of the body. Epithelium also lines the large internal body cavities, where it is termed mesothelium. Furthermore, the internal surfaces of blood and lymph vessels are lined by epithelium, here called endothelium.

Epithelia are classified on the basis of the number of cell layers and the shape of the cells in the surface layer. ★ If there is only one layer of cells in the epithelium, it is designated as simple ★ If there are two or more layers of cells, it is termed stratified.

★ Cells in the surface layer are, as a rule, described according to their height as squamous (scale- or plate-like), cuboidal, or columnar.

Histology Virtual Lab - Epithelial Tissues

Examine each of the basic types of cells so that you get an understanding for how the layers are organized and how they are named.

Pseudostratified epithelium appears to be layered (stratified) because the cell nuclei occur in two or more levels in a row of aligned cells

Histology Virtual Lab - Epithelial Tissues

Click and view each of the following slides - Don't forget to sketch and label each. 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

Questions: 1. Epithelia are classified by the number of cell layers and the ______shape______________ of the cells.

Histology Virtual Lab - Epithelial Tissues 2. Distinguish between simple and stratified. Simple is when there is only one layer of a cell and stratified is when there are multiple layers stacked on top of each other 3. Describe the 3 main shapes of epithelial cells Squamous is a flat cell in the shape of a scale. Cuboidal is a cell the shape of a cube and columnar is a cell that is stretched upwards so it looks like a column. 4. Scientific Drawings: ● ● ●

Use a sheet of paper or the back of this page to make a sketch of each of the different tissues, these are to be hand drawn not copied and pasted. Label each drawing with the type of tissue, its location found, and function Identify any important structures (nuclei, cell membrane, cytoplasm, cilia, basement layer..etc) on your drawings. The drawings can be used when you take the quiz later in the unit....