1 Bio211 Laboratory 2 Epithelial and Connective Tissues

2 Tissues Tissues to be examined under the microscope –Epithelial Tissue (p. 79 Lab Manual) [TODAY] –Connective Tissue (p. 93 Lab Manual) [TODAY] –Muscle/Nervous Tissues (p. 109/117 Lab Manual) [NEXT LAB] –Integument (p. 123 Lab Manual) [NEXT LAB] Refer to your –Wood’s Lab Manual for pictures of tissues/guidance –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

3 Tissues - Overview Recall that tissues are layers or masses of cells that have common functions The study of tissues is called…? Usually the cells within tissues are separated by nonliving, intercellular materials that the cells produce. Histology

4 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.

5 Hematoxylin and Eosin (H&E) Stain Hematoxylin – deep purple or blue Eosin – red (pink) color

6 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

7 Epithelial Tissue - Epithelial tissues are classified by a combination of two characteristics: –Layering (or stratification) Simple (single layer) Stratified (two or more layers) Pseudostratified (‘false’ stratification – really one layer) Transitional (can change shape when stretched) –Cell shape Squamous (flat) Cuboidal (cube-shaped) Columnar (elongated; rectangles)

8 Simple Squamous Epithelial Tissue Free surface

9 Stratified Squamous Epithelium

10 Simple Cuboidal Epithelium

11 Simple Columnar Epithelium Note ‘brush border’ on the free surface of simple columnar cells and scattered goblet (mucus- producing) cells

12 Pseudostratified Ciliated Epithelium 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

13 Connective Tissue Most abundant type of tissue by weight Bind, support, protect, fill in spaces, and aid in repair Cells are farther apart than epithelium Have abundant intercellular matrix, consisting of fibers and ‘ground substance’ Can usually divide Usually has a good blood supply

14 Connective Tissue Two major types of connective tissue –Connective Tissue Proper Loose and dense connective tissue Adipose (fat) tissue Elastic (and reticular) connective tissue –Specialized Connective Tissue Cartilage Bone Blood

15 Loose (areolar) Connective Tissue Collagen fibers are thick bundles Elastic fibers are thinner, more ‘wavy’

16 Dense (Regular) Connective Tissue Note the dense packing of collagen fibers and the fact that all the fibers run in the same direction (regular) Note that collagen fibers are OUTSIDE of the fibroblasts

17 Adipose (fat) Tissue Note the nuclei are pushed to one side of the cell by the fat droplets in the cell cytoplasm

18 Cartilage Overview

19 Hyaline Cartilage ‘Chondro’ = cartilage Cartilage cell = chondrocyte

20 Fibrocartilage Note the collagen bundles present in fibrocartilage that are NOT present in hyaline cartilage Note also fibers are large relative to chondrocytes

21 Elastic Cartilage Note that the elastic fibers are small and ‘wavy’ as compared to the thick collagen fibers of fibrocartilage Note that fibers are small relative to chondrocytes

22 Bone ‘Osteo’ = bone; Bone cell = osteocyte

23 Structure of Osteons Know the structures that make up osteons (Note: Central canal = Haversian canal = Osteonic canal

24 Blood Be able to distinguish among erythrocytes (RBCs), leukocytes (WBCs), and platelets (Erythrocytes) (Leukocytes)

25 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

26 Review Connective Tissue Proper –Loose (areolar) –Dense connective tissue –Adipose tissue Specialized connective tissue –Cartilage Hyaline (prominent lacunae) Fibrocartilage (thick collagen fibers) Elastic cartilage (thinner, wavy elastic fibers) –Bone (have circular osteons) –Blood

27 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 Connective tissue 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 Come up and get tested on slides for today (identification only – not location in body)

28 For next lab… For Muscle and Nervous Tissue –Read Exercise 9 & 10 in Wood’s Lab Manual –Look at the histological photos in your Lab Manual and in your textbook For Integument –Read Exercise 11 in Wood’s Lab Manual –Look at histological photos in your Lab Manual and in your textbook