1. Connective Tissue

2. Connective Tissue
Binds together, supports and strengthens other body tissues
Protects and insulates internal organs
Compartmentalizes structures such as skeletal muscle
The major transport system within the body
Site of stored energy reserves
Main site of immune responses
Fills spaces
Produces blood cells
Stores fat

3. General Features of Connective Tissue
2 basic parts:
Cells and Matrix
Matrix – material between widely spaced cells
Consists of protein fibers and ground substance

4. Connective Tissue Cells
Fibroblasts – large flat cells with branching processes. Migrate throughout connective tissue secreting the fibers and ground substance
Macrophages – develop from white blood cells. Surround and engulf material by phagocytosis
Mast Cells – alongside blood vessels that supply connective tissue. Produce histamine – a chemical that dilates blood vessels.
Adipocytes – “fat cells” store triglycerides.

5. Connective Tissue Matrix – Ground Substance
Ground Substance – component of a connective tissue between the cells and fibers, supports cells, binds them together, and provides a medium through which substances are exchanged.
Ex. Hyaluronic Acid

6. Fibers of the Matrix
White fibers – contain collagen which gives the fibers flexibility and strength
Yellow fibers – contain elastin more elastic than collagen but not as strong
Reticular fibers – thin, highly branched collagenous fibers that provide support

7. Connective Tissue Matrix – Fibers
Strengthens and supports connective tissue
Collagen Fibers
Strong, resist pulling forces, flexible
Made of the protein collagen which is the most abundant protein in your body
Elastic Fibers
smaller in diameter than collagen fibers, branch to form network
Made of the protein elastin
Reticular Fibers
Provide support for the walls of blood vessels
Made of collagen with a glycoprotein covering

9. Types of the Connective Tissue
1. Fibrous Connective Tissue
2. Cartilage
3. Bone
4. Blood
A. Loose CT
B. Dense CT
C. Reticular CT
Hyaline
Compact
Elastic
Spongy
Regular
Adipose
Fibrocartilage
Irregular
Areolar
Elastic

10. 1. Fibrous Connective Tissue
Loose (areolar) connective tissue
adipose
Dense connective tissue
Regular
irregular
Reticular connective tissue

11. A. Loose (areolar) Connective Tissue
Lies between other tissues or between organs binding them
Cells made of fibroblasts – large, star-shaped cells
Contains many white fibers (strong and flexible) and yellow fibers (very elastic)

13. Loose Connective Tissue
Fibers are loosely intertwined among many cells.
Types of loose connective tissue
Areolar Connective Tissue – one of the most widely distributed connective tissues in the body.
Contains fibroblasts, macrophages, plasma cells, mast cells, adipocytes and a few white blood cells as well as all 3 types of fibers
Helps to form the subcutaneous layer

14. Loose Connective Tissue
Adipose Tissue – The cells, called adipocytes, are specialized for storage of triglycerides. Adipocytes fill up with a large fat droplet so the nucleus gets pushed to one side of the cell.
Used for insulation, protection and as an energy reserve

17. Adipose tissue is a type of loose connective tissue
- stores fats, provides insulation
- found beneath skin, around kidney & heart, breast

18. B. Dense Connective Tissue
Regular
Consists of parallel bundles of collagenous fibers
Found in tendons & ligaments
Binds organs together
Irregular
Bundles run in different direction
Found in inner portion of skin

19. Dense Irregular
Dense Regular

20. B. Dense Connective Tissue
Contains more numerous, thicker and denser fibers but fewer cells than loose connective tissue.
3 types:
Dense regular connective tissue
Dense Irregular connective tissue
Elastic Connective Tissue

21. B1. Dense Regular Connective Tissue
Bundles of collagen fibers are arranged regularly in parallel patterns that give it strength.
Withstands pulling from the ends, but unravels when pulled from the side
Silvery white in appearance. Tough and pliable
Found in tendons and ligaments

23. B2. Dense Irregular Connective Tissue
Collagen fibers are packed closely together in an irregular, random pattern
Found in parts of the body where pulling forces are exerted in various directions
Usually found in sheets
Examples: Dermis of the skin, heart valves, perichondrium and periosteum

25. B3. Elastic Connective Tissue
Contains branching elastic fibers and fibroblasts
Yellowish in color
Strong, can regain shape after stretching
Found in lungs and arteries

27. C. Reticular Connective Tissue
Has reticular cells and reticular fibers
Also called lymphatic tissue
Found in lymph nodes, spleen, thymus, and red bone marrow
Store and produce white blood cells
Part of immune system

28. C. Reticular Connective Tissue
Reticular Connective Tissue – made of interlacing reticular fibers and reticular cells that connect to each other to form a network.
Used to bind together smooth muscle cells and to filter out worn out blood cells and bacteria

30. 2. Cartilage
The cell (chondrocytes) lies in small chambers called lacunae
Matrix is solid yet flexible
Lacks direct blood supply, as a result, it heals slowly

31. 3 types
A. Hyaline cartilage
B. Elastic cartilage
C. Fibrocartilage

32. A. Hyaline Cartilage Most common
Matrix contains fine collagenous fibers
Glassy, white, opaque
Found in the nose, ends of the long bones and ribs, rings in the trachea

33. A. Hyaline Cartilage
Gel like ground substance, collagen fibers (not visible with normal stains) and prominent chondrocytes
Most abundant cartilage in the body
Found at the end of long bones to cushion joints and at epiphyseal plates (growth plates in bones)
Weakest of the 3 types of cartilage

35. B. Elastic Cartilage Contains elastic and collagenous fibers
Found in the outer ear

37. B. Elastic Cartilage
Chondrocytes located in a threadlike network of elastic fibers
Provides strength, elasticity and maintains the shape of certain structures (like the external ear)

39. C. Fibrocartilage Matrix contains strong collagenous fibers
Function: absorbs shocks and reduces friction between joints
Found in the pads between the vertebrae and knee joints

41. C. Fibrocartilage
Chondrocytes scattered among visible bundles of collagen fibers
No perichondrium
Strongest of the 3 types of cartilage
Found in the intervertebral discs

43. 3. Bones Most rigid of the connective tissues
Minerals and protein fibers gives bone rigidity, elasticity and strength
Two types:
Compact bone
Spongy bone

44. Bone Tissue (osseous tissue)
2 types – compact and spongy
Compact
Osteon – basic unit of compact bone
Lamellae – concentric circles of matrix
Lacunae – spaces in the matrix that house cells
Osteocytes – mature bone cells
Spongy
Trabeculae – columns of bone with spaces filled with red bone marrow

45. A. Compact Bone Found in the outer portion of long bones
Consists of many cylindrical-shaped units called osteon

48. B. Spongy Bone Found on ends of long bone
Contains bony bars and plates called trabeculae separated by irregular spaces
Blood cells are made within the red marrow found in the spongy bone

50. Micrograph of Spongy Bone
An electron micrograph scan of spongy bone in an osteoporosis patient. Osteoporosis occurs when a body's blood calcium level is low and calcium from bones is dissolved into the blood to maintain a proper balance.

51. 4. Blood
Connective tissue composed of cells suspended in liquid matrix called plasma
Red blood cells (erythrocytes) – carries oxygen
White blood cells (leukocytes) – fights infection
Platelets – fragment of giant cells found in bone marrow

52. Blood Tissue Connective Tissue with a liquid matrix
Red Blood Cells (erythrocytes) – transport oxygen
White Blood Cells – function in immunity
Neutrophils, Eosinophils, Basophils, T and B leukocytes, natural killer cells and Monocytes
Platelets – participate in blood clotting