1. Human Anatomy & Physiology Connective Tissues

2.  All connective tissues consist of living cells surrounded by a matrix.  The difference in the type of matrix is reflected in each of the types of connective tissues.  From most rigid to softest, the major classes are: bone, cartilage, dense connective tissue, loose connective tissue, and blood.

3. Matrix (AKA extra-cellular) Two main elements 1. Ground substance – mostly water along with some proteins and polysaccharide (sugar) molecules 2. Fibers  Three types  Collagen fibers (flexible)  Elastic fibers(stretchy)  Reticular fibers (thin elastic)

4. Bone (Osseous) Tissue Composed of:  Bone cells (osteocytes) in lacunae  Hard matrix of calcium salts with a large numbers of collagen fibers Used to protect and support the body

5. Composed of:  chondrocytes (cartilage cells) in lacunae Less hard and more flexible than bone 1. Elastic Cartilage 2. Hyaline Cartilage 3. Fibrocartilage most dense least dense

6. Elastic Cartilage  Matrix is primarily elastic fibers with a few collagen fibers  Maintains shape while allowing flexibility  Example: supports the external ear, the epiglottis, and the larynx

7. Hyaline Cartilage  Matrix is rubbery but firm with collagen fibers.  Most common cartilage.  Found at the end of long bones, trachea, bronchi and in the ribcage.  Entire fetal skeleton is hyaline cartilage

8. Fibrocartilage  Matrix is rigid and packed with collagen fibers  Highly compressible  Forms the: intervertebral discs, pubis symphysis, and meniscus of the knee

9. Dense Connective Tissue AKA: Dense Fibrous Conn. Tissue  Matrix consists of densely packed collagen fibers  Examples 1. Tendon – attach muscle to bone 2. Ligaments – attach bone to bone * Ligaments also have elastic fibers

10. Softer tissues consisting of large number of cells and fewer fibers: 1.Adipose 2.Areolar 3.Reticular most amount of matrix least amount of matrix

11. Adipose Tissue  Matrix of collagen and elastic fibers in limited spaces around adipocytes (fat cells)  Functions  Insulates the body  Protects some organs  Serves as a site of fuel storage

12. Areolar Tissue Most common CT  Matrix is soft gel with collagen and elastic fibers  Cushions organs and holds them in place.  Stretchy and permits some movement.  Can soak up excess fluid

13. Reticular Tissue  Function: Filters injurious substances from the blood  Forms the:  Lymph nodes  Spleen  Bone marrow Matrix is a network of thin elastic fibers, proteins and sugars around reticular cells and blood cells

14. Blood  Blood cells are surrounded by fluid matrix (plasma)  Protein fibers are present during clotting  Transports respiratory gases, nutrients, and wastes