Review: Epithelial Tissue 1 “There are 2 basic kinds of epithelial tissues.” What could that mean? You are looking at epithelial cells from the intestine. What do you expect to see? You are looking at epithelial cells from the trachea. What do you expect to see?

4-1 Four Types of Tissue Tissue TypeRole(s) - Covers surfaces/passages - Forms glands - Structural support - Fills internal spaces - Transports materials - Contraction! - Transmits information (electrically) 2

Classification of connective tissue 1.Connective tissue proper 1a. Loose: areolar, adipose, reticular 1b. Dense: dense regular, dense irregular, elastic 2.Fluid connective tissue 2a. Blood: red blood cells, white blood cells, platelets 2b. Lymph 3.Supporting connective tissue 3a. Cartilage: hyaline, elastic, fibrocartilage 3b. Bone 3

Defining connective tissue by the process of elimination 4

LAB MANUAL Figure 6.4 Areolar connective tissue: A prototype (model) connective tissue. Macrophage Fibroblast Lymphocyte Adipocyte Mast cell Capillary Reticular fiber Elastic fiber Collagen fiber Cell types Extracellular matrix Fibers Ground substance 5

The Cells of Connective Tissue Proper Melanocytes and macrophages, mesenchymal, mast; Adipo- / lympho- / fibrocytes and also fibroblasts. These are the cells of connective tissue proper; Sing this song the whole day long until you know them all! Melody playback: 6

4-4 Connective Tissue: importance of extracellular matrix! Tissue TypeExtracellular stuff? 7

Extracellular matrix = ground substance + extracellular protein fibers © 2015 Pearson Education, Inc. 8

Proteins’ structures suggest their functional properties 9 Which is elastin, and which is collagen?

Tie-in with Chapter 3: Where are extracellular proteins made? How do they reach their final destination? © 2015 Pearson Education, Inc. 10

LAB MANUAL Figure 6.5a Connective tissues. Embryonic connective tissue: Mesenchyme Fibers Ground substance Mesenchymal cell Description: * gel-like ground substance * sparse, fine fibers * star-shaped mesenchymal cells Function: Location: Primarily in embryo 11

LAB MANUAL Figure 6.5b Connective tissues. Connective tissue proper: loose connective tissue, areolar Collagen fibers Fibroblast nuclei Elastic fibers Lamina propria Epithelium Description: * gel-like matrix with all 3 fiber types * cells: many types! Function: Location: Widely distributed under epithelia 12

LAB MANUAL Figure 6.5c Connective tissues. Connective tissue proper: loose connective tissue, adipose Vacuole containing fat droplet Nuclei of fat cells Description: * sparse matrix * closely packed adipocytes * nucleus pushed to the side Function: Location: * under skin * around kidneys & eyes * abdomen * breasts 13

LAB MANUAL Figure 6.5d Connective tissues. Connective tissue proper: loose connective tissue, reticular White blood cell (lymphocyte) Reticular fibers Description: * network of reticular fibers * loose ground substance * reticular cells Function: Location: Lymphoid organs (lymph nodes, bone marrow, spleen) Spleen 14

LAB MANUAL Figure 6.5e Connective tissues. Connective tissue proper: dense connective tissue, dense regular Collagen fibers Nuclei of fibroblasts Shoulder joint Ligament Tendon Description: * primarily parallel collagen fibers * major cell type: fibroblast Function: Location: * Tendons * Ligaments 15

Figure 6.5f Connective tissues. Photomicrograph: Elastic connective tissue in the wall of the aorta (250  ). Connective tissue proper: dense connective tissue, elastic Elastic fibers Heart Aorta Description: * Mostly elastic fibers Function: Location: * Walls of large arteries * Between vertebrae 16

LAB MANUAL Figure 6.5g Connective tissues. Connective tissue proper: dense connective tissue, dense irregular Nuclei of fibroblasts Collagen fibers Fibrous joint capsule Description: * primarily irregularly arranged collagen fibers * major cell type: fibroblast Function: Location: * capsules of organs & joints * dermis of skin 17

LAB MANUAL Figure 6.5h Connective tissues. Cartilage: hyaline Chondrocyte in lacuna Matrix Costal cartilages Description: * amorphous but firm matrix * collagen fibers form an imperceptible network Function: Location: * ends of long bones * ribs * nose, trachea, larynx 18

LAB MANUAL Figure 6.5i Connective tissues. Cartilage: elastic Chondrocyte in lacuna Matrix Description: * Similar to hyaline cartilage, but more elastic fibers Function: Location: * external ear (auricle) * epiglottis 19

LAB MANUAL Figure 6.5j Connective tissues. Photomicrograph: Fibrocartilage of an intervertebral disc (160  ). Special staining produced the blue color seen. Cartilage : fibrocartilage Chondrocytes in lacunae Collagen fiber Intervertebral discs Description: * Matrix similar to but less firm than hyaline cartilage’s * Mostly thick collagen fibers Function: Location: * intervertebral discs * pubic bones * knee joint 20

LAB MANUAL Figure 6.5k Connective tissues. Bones (osseous tissue) Central canal Lacunae Lamella Description: * hard, calcified matrix with many collagen fibers * osteocytes in lacunae * abundant blood supply Function: Location: 21

LAB MANUAL Figure 6.5l Connective tissues. Photomicrograph: Smear of human blood (1000  ); two white blood cells (neutrophil and lymphocyte) are seen surrounded by red blood cells. Blood Plasma Neutrophil Red blood cells Lymphocyte Description: * fluid matrix (plasma) Function: Location: 22

4-4 Connective Tissue Functions of Connective Tissues? (summary of previous slides…) 1. Connective tissue proper 2.Fluid connective tissues 3. Supporting connective tissues 23

Review: Connective Tissue Which is stiffer? 24

Review: Connective Tissue Which is stiffest, based on location in body? Hyaline cartilage Elastic cartilage Fibrocartilage 25