1. Tissue: The Living Fabric
Part II – Connective Tissue

2. Connective Tissue Specialized
Most abundant and widely distributed tissue
Main classes:
Connective tissue proper (loose & dense)
Cartilage
Bone
Blood
Functions:
Binding and support
Protection
Insulation
Transport of substances
Specialized

3. Characteristics of Connective Tissue
Do not appear on surface
Completely different from epithelial!
Beneath the surface, providing support and stability
Extracellular matrix
Composed of ground substance and various fibers
Ground substance: fills spaces, surrounds fibers, clear, colorless, and has the consistency of syrup
Made from: water + adhesion proteins + polysaccharides
3 main types of cells found in connective tissue
Fibroblasts produce the fibers of the matrix and ground substance
Macrophages scavenge the tissue as an immune cell
Mast cells release chemicals in response to stress

4. Characteristics of Connective Tissue
Fibers
Provide support
Collagen - no branching; provide strength; flexible
Most abundant fiber present in connective tissues
Elastic – branched; stretch and recoil (elasticity)
Reticular – fine branched network, “skeleton” of organs
Variation in Blood supply
Vascular – connective tissue proper, blood, bone
Tendons & ligaments are poorly vascular
Cartilage is avascular

5. Connective Tissue Proper

6. Loose Connective Tissue
Known as the universal packing material
Subclasses: areolar, adipose, reticular
Structure: softer, fewer fibers, gel-like matrix
Functions:
Cushion & protect organs (areolar, fat)
Store nutrients (fat)
Internal framework of support (reticular)
Fight infection (areolar)
Cellular makeup: fibroblasts, adipocytes (fat cells)
Locations: under skin, lymph nodes, hips, behind eyeballs

7. Areolar tissue
Functions: Cushioning surrounding organs, connecting different tissues, and supporting blood vessels 
Found: between muscle/skin; around nerves and blood vessels
Made up of: collagenous, elastic and reticular fibers and ground substance

8. Adipose Tissue
Functions: store energy in the form of fat, cushions and insulates the body to help prevent heat loss
Found: located beneath the skin, but is also found around internal organs such as the heart and kidneys

9. *Fascia Connective tissue made primarily of collagen fibers
3-D spider web of fibrous, gluey, and wet proteins that binds all organs and tissues together in their proper placement
Proprioception: ability to sense stimuli arising within the body regarding position, motion, and equilibrium

10. Reticular Tissue
Named for the reticular fibers which are the main structural part of the tissue.
Cells that make the reticular fibers are fibroblasts called reticular cells. 
Function: fibers form a soft internal skeleton that supports other tissues
Found: lymph organs, spleen, and bone marrow

11. Cellulite?
Poor circulation, build up of toxins, pressure on connective tissue
Hormones to blame?
90% of women have it
Why not seen in men as much?
Women have less supportive connective tissue to keep fat cells in place.

12. Dense Connective Tissue
Subclasses: dense regular, dense irregular, elastic
Structure: mainly collagen fibers
Functions:
Elastic
Resist tension
Cells: fibroblast
Locations: tendons (muscle-bone), ligaments (bone-bone), lower layers of skin.

13. Dense Regular vs. Dense irregular
Parallel fibers
Tears when stressed in the incorrect direction
Found: tendons, ligaments
Woven network of fibers
Can be stressed in many directions
Found: lower levels of skin
4/5 of all skin tissues are dense irregular
Regular
Irregular

14. Elastic Connective Tissue
Lots of elastic fibers give “squiggly” appearance
Function: Allows stretching of organs 
Found: lungs, various blood vessels, and vocal cords

15. Specialized Connective Tissue

16. Cartilage Subclasses: hyaline, elastic, fibrocartilage
Structure: flexible, no nerves or blood
Functions:
Support
Compression
Cells: chondrocytes
Create and maintain the cartilaginous matrix
Locations: larynx, joints, tip of nose, ear, intervertebral discs, rib-breastbone, knee joint

17. Hyaline cartilage Elastic cartilage
Helps with joint movement, bone growth, strengthens respiratory tract
Most abundant cartilage type!
Found in bronchi, joint surface, larynx (milky white appearance)
Elastic cartilage
Resembles hyaline cartilage but contains elastic fibers
Provides flexibility and support
Found in the outer ear, epiglottis, larynx
Forms much of the fetal skeleton

18. Fibrocartilage Densley packed collagen fibers
Fibers that are in wavy lines/patterns
Function: Support and protection
Found: menisci, invertebral discs, sites of healing fractures

19. Bone Osseous tissue Subclasses: compact, spongy
Structure: hard, calcified matrix; blood vessels
Functions:
Support & protection
Store calcium
Blood cell formation (marrow)
Cells: Osteocytes (+2)
Synthesize bone
Locations: bones

20. BloOd Vascular tissue Breakdown: cellular 45%, plasma 55%
Structure: fluid within blood vessels, no fibers
Functions:
Transport vehicle (nutrients, wastes, gases, hormones)
Cells: white blood cells (leukocytes), red blood cells (erythrocytes), platelets
Locations: blood vessels