Tissues. Tissues - Overview. Bio 101 Laboratory 3. Epithelial Tissues and Integument

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1 Bio 101 Laboratory 3 Epithelial Tissues and Integument 1 Tissues Tissues to be examined under the microscope Epithelial Tissue Integument Connective Tissue **We will be doing muscle and nervous tissues later in the semester Lab Guide (handout) for a checklist of tissues/structures you are responsible for Objectives Learn to recognize each of the tissue types under the light microscope by structure, not color, and how they are constructed Provide at least one example of where each tissue is found in the body on lab exam 2 Tissues - Overview Recall that tissues are layers or masses of cells that have common functions The study of tissues is called? Histology Usually the cells within tissues are separated by nonliving, intercellular materials that the cells produce. 3 1

2 Sectioning and Staining of Tissues for Microscopy Four steps in tissue preparation - Fixation stabilizes and preserves the tissue - Embedding converts the tissue into a solid form which can be sliced ("sectioned") - Sectioning (slicing) provides the very thin specimens needed for microscopy (2-D) - Staining provides visual contrast and may help identify specific tissue components. 4 Hematoxylin and Eosin (H&E) Stain Hematoxylin deep purple or blue Eosin red (pink) color 5 Epithelial Tissue Widespread throughout body A covering and lining tissue Always has a free surface Underside of tissue is anchored to a basement membrane (nonliving layer) Lacks blood vessels Cells are tightly packed 6 2

3 Epithelial Tissue - Epithelial tissues are classified by a combination of two characteristics: - Cell shape Squamous (flat) Cuboidal (cube-shaped) Columnar (elongated; rectangles) Layering (or stratification) Simple (single layer) Stratified (two or more layers) Pseudostratified ( false stratification really one layer) Transitional (can change shape when stretched) 7 Free surface Simple Squamous Epithelial Tissue Found lining air sacs of lungs, blood vessels, ventral body cavities, kidney glomeruli, lymphatic vessels 8 Stratified Squamous Epithelium Found as 1) outer layer of skin (keratinized, non-mucous) 2) Mucous nonkeratinized linings in esophagus, mouth, vagina 9 3

4 Simple Cuboidal Epithelium Simple cuboidal: Found in kidney tubules, ducts of sweat glands and other glands, surface of ovary. (Stratified cubioidal) 10 Simple Columnar Epithelium Note brush border on the free surface of simple columnar cells and scattered goblet (mucusproducing) cells Found throughout digestive tract, uterine tubes, some regions of uterus 11 Pseudostratified Ciliated Epithelium Found in trachea and most of the upper respiratory tract. Appears stratified because nuclei are located at different levels However, ALL cells reach the basement membrane Note how different cilia look as compared to microvilli of brush border on simple columnar cells 12 4

5 Transitional Epithelium 13 Integumentary System The Integument is an Organ. Why? 14 Integumentary System From: ages/integumentary/integum.htm#sebaceous 16 5

6 Integumentary System From: /Integumentary/Integum.htm#sebaceous Sebaceous glands Hair follicles 17 Integumentary System From: ages/integumentary/integum.htm#sebaceous 18 Integumentary System From: ages/integumentary/integum.htm#sebaceous Sweat gland 19 6

7 Light Microscope View of Sweat Glands From: Martini, Anatomy & Physiology, Prentice Hall, What you should do in lab today Using the microscope and the slide boxes Look at the slides listed on your Laboratory Guide (handed out in first lab) for: Epithelial tissue Integumentary System BE SURE you can recognize each of the tissue types listed in your Laboratory Guide; check off ONLY after you can recognize a tissue KNOW at least one place in the body where each of the tissue types is found for lab exam Get tested on slides for today (identification only not location in body) 21 For Next Lab On Your Own: Do the Review Sheet Exercises for Exercise 6 and 7 Tissue Structure and Function - General review Epithelial Tissue Integument Read ahead: Connective Tissues in your Laboratory Manual 22 7

8 Review Epithelium Simple squamous single layer of flattened cells Simple cuboidal single layer of square cells Simple columnar single layer of rectangular cells; may have goblet (mucus) cells Stratified squamous stacked squamous cells Pseudostratified ciliated columnar Look like stratified by they are not Have cilia Have goblet cells 23 Review Integument Layers Epidermis, dermis = skin Subcutaneous (hypodermis, superficial fascia) Accessory structures Hair follicles in which hair grows Sebaceous glands Look fatty Look similar to adipose tissue except nucleus is in center of cell Usually found in a cluster of cells attached to a hair follicle Sweat glands Much more solid in appearance than sebaceous glands Ducts of sweat glands are lined with simple cuboidal epithelium Section through ducts gives varied appearance, i.e., some are circular, some longitudinal, some oblique 24 8