1. Connective Tissue

2. General Information Types and functions:
Loose connective tissue: fat, areolar – insulation, protection
Dense Connective: Ligaments and tendons – binding and support
Cartilage – protection, support
Bone - support
Blood- transportation

3. Common Characteristics
All Connective tissue share the following characteristics, despite the variety.
Develop from the same embryonic tissue
Composed of many different types of cells within the tissue.
Contains extracellular matrix
Great variation in the amount of blood supply (vascularization)

4. Cells in Matrix
Cells in connective tissue make and maintain the ground substance and fibers.
Each type of conn. Tissue have immature and mature forms of these cells.
Immature cells have suffix “-blast” – actively produce matrix.
Mature cells have suffix “-cyte” – maintain health of matrix, reverting to blasts to regenerate matrix after injury.
Fibroblasts – make conn. Tissue/fibers
Chondroblasts – make cartilage,
Osteoblasts – make bone
Hematopoeitic stem cells – make blood

5. Cells in Matrix Other cells present:
White blood cells (macrophages, plasma cells)– responsible for immune response
Mast cells – responsible for inflammation following injury or infection.

6. Extracellular Matrix
Extracellular matrix is the substance that connective cells are embedded within.
Made of nonliving material called ground substance.
Can be liquid, gel-like, semi-solid or hard.
Texture depends on amount of cell adhesion proteins: proteoglycans which trap water forming a gel. More proteins, more solid ground substance.
Contains fibers that provide great strength, or flexibility, or both.
Extracellular matrix allows Conn. Tissue to bear weight, mechanical abuse – protects!!

7. Dense connective tissue, lots of fibers, little open space.

8. Lots of ground substance – fewer fibers

9. Fibers
Fibers are embedded in ground substance to add strength/flexibility.
Dense fibous (Collagen): stronger than steel of the same size. STRENGTH!
Two types:
Regularly arranged in tendons,ligament
Irregularly arranged: in dermis give elasticity to the skin

10. Dense continued Dense Irregular Fibers run in different directions.
Tissue is found where tension is applied in different directions
Example: Dermis of skin

11. Dense Regular

12. Collagen

13. Ereolar: btw organs,submucosa
Fun : connection
Reticular: delicate, forms nets that support free cells.

14. Loose Continued Reticular Only contains reticular fibers.
VERY DELICATE – a fine net of fibers.
Supports free blood cells.
Found in lymph nodes, bone marrow,spleen,liver.

15. Reticular

16. Elastic

17. Loose Connective Tissue
Areolar – most widely distributed type.
Serves as “packing material” cushioning organs, subcutaneous, attaches skin to muscle.
Contains all three fibers
Gelatinous
Very loosely packed, lots of liquid
Swells during inflammation (edema)

20. Loose Continued Adipose = Fat! Loosely packed with little matrix
Highly cellular : 90% of tissue is adipocytes
Nutrient storage, cushioning.
Richly vascularized
Develops within areolar tissue/subcutaneous
18% of an average person’s weight
50% of chubby person

21. Adipose
Adipose

24. Dense Regular
Dense Irregular

25. Cartilage Characteristics Resists tension and pressure
Tough and flexible
No nerves or blood vessels
Lots of collagen and elastic fibers.
80% water
Chondroblasts make matrix until end of human adolescence.
Mature Chondrocytes found in cavities called lacunae (pit)
Condrotin sulfate give matrix semisolid property

26. Hyaline Cartilage Looks glassy (hyalin = glass)
Few chondrocytes, all located in lacunae
Mostly matrix – lots of collagen
Reduces friction, absorbs pressure
Covers ends of bones, connects ribs to sternum, forms rings in trachea and bronchi

28. Elastic Cartilage Looks almost identical to hyaline
Matrix appears more fibrous (chondriocytes)
Many more elastic fibers – makes it very flexible.
Found in nose, ear and epiglottis
Fun: maintain shape, support.

30. Fibrocartilage Very tough, almost like bone
Consists of rows of chondrocytes and collagen fibers
Withstands great pressure
Found in intervertebral discs.

31. Fibrous Cartilage

32. Bone Most supportive tissue in body.
Matrix is composed of collagen fibers surrounded by calcium salts.
Osteoblasts make collagen fibers and calcium salts deposited between fibers.
Well vascularized
Osteocytes stored in lacunae
Bone marrow stores fat and makes blood cells.

34. Osteocytes

35. Blood Atypical connective tissue
Only classified as such because it arises from same embryonic tissue
Blood cells are within a matrix of blood plasma.
Fibers apparent only when blood clots.