1. Connective Tissue Found everywhere in the body Includes the most abundant and widely distributed tissues Functions –Binds body tissues together –Supports the body –Provides protection

2. Connective Tissue Characteristics Variations in blood supply –Some tissue types are well vascularized –Some have poor blood supply or are avascular Extracellular matrix –Non-living material that surrounds living cells

3. Extracellular Matrix Two main elements 1. Ground substance – mostly water along with adhesion proteins and polysaccharide molecules 2. Fibers Produced by the cells called fibroblasts Three types –Collagen fibers –Elastic fibers –Reticular fibers

4. Connective Tissue Types 1. Areolar Tissue –Most widely distributed connective tissue –Soft, pliable. A type of “Loose Connective Tissue” –Contains all fiber types –Binds skin to underlying organs –Fills spaces between muscles –Common connective tissue beneath epithelium Figure 3.19e

7. Connective Tissue Types 2. Adipose tissue (fat) –Matrix is an areolar tissue in which fat globules predominate –Many cells contain large lipid deposits (Adipocytes) –Functions Insulates the body Protects some organs (kidneys) Serves as a site of energy storage

10. Connective Tissue Types 3. Dense connective tissue –Main matrix elements are closely packed collagen fibers –Cells are fibroblasts –Very strong tissue. –Poor blood supply. Long repair time –Examples Tendon – attach muscle to bone Ligaments – attach bone to bone

12. Connective Tissue Types 4.Cartilage. A rigid connective tissue composed of cells called Chondrocytes surrounded by a rubbery matrix. 3 types, each with a different matrix Figure 3.19b

13. Hyaline Cartilage Most common cartilage Composed of: Abundant collagen fibers in a rubbery matrix Locations: Entire fetal skeleton is hyaline cartilage Ends of bones Soft part of nose Elastic cartilage –Provides elasticity. More Elastin fibers –Example: supports the external ear

14. Fibrocartilage –Highly compressible, composed of tightly packed collagen fibers –Example: forms cushion-like discs between adjacent vertebrae Figure 3.19c

17. Connective Tissue Types 5. Bone (osseous tissue) –Composed of: Bone cells called Osteocytes, in lacunae (cavities) Hard matrix of calcium phosphate cementing large numbers of collagen fibers together –Used to protect and support the body –Site of blood cell formation –Store Calcium –Highly organized, excellent blood supply, very active tissue, heals rapidly.

19. Connective Tissue Types 6. Blood –Blood cells surrounded by fluid matrix –Fibers are visible during clotting –Functions as the transport vehicle for materials

22. Muscle Tissue Composed of elongated cells Have the ability to contract or shorten and produce movement Three types –Skeletal muscle –Cardiac muscle –Smooth muscle

23. Muscle Tissue Types 1. Skeletal muscle –Can be controlled voluntarily –Attached to bones –Cells are long and threadlike (called fibers) –Cells are striated –Cells have more than one nucleus (multinucleated) Figure 3.20a

25. Muscle Tissue Types 2. Smooth muscle –Involuntary muscle (cannot be consciously controlled) –Surrounds hollow organs (stomach, intestines, blood vessels) –Attached to other smooth muscle cells –No visible striations –One nucleus per cell

27. Muscle Tissue Types 3. Cardiac muscle –Found only in the heart –Function is to pump blood (involuntary) –Cells attached to other cardiac muscle cells at intercalated disks –Cells are striated –One nucleus per cell –Does not need nervous stimulation to contract.

29. Nervous Tissue Neurons and nerve support cells (neuroglia) Function is to send impulses to other areas of the body –Irritability –Conductivity Figure 3.21