Connective tissue is found throughout the body and binds tissues together. It has various types including connective tissue proper, fluid connective tissue, and supportive connective tissue. Connective tissue proper contains fibroblasts, macrophages, mast cells, and an extracellular matrix with ground substance and fibers like collagen, elastic, and reticular fibers. It includes areolar, adipose, dense, and reticular connective tissues. Fluid connective tissue includes blood with its fluid plasma and blood cells. Supportive connective tissues are bone, hyaline cartilage, elastic cartilage, and fibrocartilage which provide structure and support.

1. Tissues Chapter 3.3 Connective Tissue

2. Connective Tissue Variations in blood supply Some tissue types are well vascularized Some have poor blood supply or are avascular Have receptors for Pain, pressure, temperature Extracellular matrix Non-living material that surrounds living cells Found everywhere in the body Never exposed to the outside environment Includes the most abundant and widely distributed tissues Functions Binds body tissues together Supports the body Provides protection Transports materials

3. Extracellular Matrix Two main elements Ground substance – mostly water along with adhesion proteins and polysaccharide molecules Fibers Produced by the cells Three types Collagen fibers Elastic fibers Reticular fibers The combination of and the type of the two elements determines the connective tissue type Connective tissue proper Fluid connective tissue Supporting connective tissue

4. Connective Tissue Proper Many types of cells, fibers and syrupy ground substance Fibroblasts Large, star-shaped cell that produces fibers by secreting proteins into the matrix Macrophages Function as defensive cells, clearing foreign particles Mast cells Begin body’s defense actions after injury or infection Matrix Ground substance Syrupy, clear, colorless Fibers Collagen fibers - strong and flexible Elastic fibers - stretches, but returns to original length Reticular fibers - interwoven network Examples Skin Fatty tissue Tendons and ligaments

5. Types Connective Tissue Proper Areolar connective tissue Most widely distributed connective tissue Soft, pliable tissue (Cobweb-like)

6. Types Connective Tissue Proper Areolar connective tissue Most widely distributed connective tissue Soft, pliable tissue (Cobweb-like) Contains all fiber types Can soak up excess fluid Cusions and protects body organs Separates from and attaches skin to muscles

7. Types Connective Tissue Proper Adipose tissue Matrix is an areolar tissue fat globules stored in cytoplasm Many cells contain large lipid deposits

8. Types Connective Tissue Proper Adipose tissue Matrix is an areolar tissue fat globules stored in cytoplasm Many cells contain large lipid deposits Functions Insulates the body Protects some organs Serves as a site of fuel storage

9. Types Connective Tissue Proper Dense connective tissue Main matrix element is collagen fibers closely packed Cells are fibroblasts

10. Types Connective Tissue Proper Dense connective tissue Main matrix element is collagen fibers closely packed Cells are fibroblasts Examples Tendon – attach muscle to bone Ligaments – attach bone to bone

11. Types Connective Tissue Proper Reticular connective tissue Delicate network of interwoven fibers

12. Types Connective Tissue Proper Reticular connective tissue Delicate network of interwoven fibers Forms stroma (internal supporting network) of lymphoid organs Lymph nodes Spleen and liver Bone marrow

13. Fluid Connective Tissue Blood Blood cells (red, white, platelets) surrounded by fluid matrix (blood plasma) Fibers are visible during clotting Figure 3.19h

14. Fluid Connective Tissue Blood Blood cells (red, white, platelets) surrounded by fluid matrix (blood plasma) Fibers are visible during clotting Functions as the transport vehicle for materials Figure 3.19h

15. Type Supportive Connective Tissue Bone (osseous tissue) Hardest of connective tissues Functions Used to protect and support the body Forms “levers” for movement Forms red blood cells Stores calcium and phosphorus

16. Type Supportive Connective Tissue Bone (osseous tissue) Hardest of connective tissues Functions Used to protect and support the body Forms “levers” for movement Forms red blood cells Stores calcium and phosphorus Composed of: Bone cells (osteocytes) in lacunae (cavities) Hard matrix of calcium phosphate salts Large numbers of collagen fibers

17. Type Supportive Connective Tissue Hyaline cartilage Most common cartilage Found on ends of bones in joints Soft part of nose Supporting rings in respiratory passages Entire fetal skeleton

18. Type Supportive Connective Tissue Hyaline cartilage Most common cartilage Found on ends of bones in joints Soft part of nose Supporting rings in respiratory passages Entire fetal skeleton Composed of: Abundant, very fine collagen fibers Rubbery matrix

19. Type Supportive Connective Tissue Elastic cartilage Dense network of elastic fibers More flexible than hyaline cartilage

20. Type Supportive Connective Tissue Elastic cartilage Dense network of elastic fibers More flexible than hyaline cartilage Provides elasticity and support Found External ear Epiglottis Parts of larynx

21. Type Supportive Connective Tissue Fibrocartilage Highly compressible and very tough Examples Cushion-like discs between vertebrae Cushions bones in knees and pelvic girdle