1. CONNECTIVE TISSUES Most abundant type of tissue
Fills internal spaces, provides structural support for other tissues, and stores energy reserves
Includes tissues such as fat, bone, and blood
Most types are well vascularized
All types have a common origin (mesenchyme)
Includes 3 components:
specialized cells
extracellular protein fibers
ground substance
fluid or semi-solid which surrounds cells
MMM

2. 3 Major Cell Types Fibroblast Most common fixed cell
Large, star shaped
Produces fibers by secreting protein into matrix

3. Macrophages Wandering Cells that originate as WBC’s
Function as scavengers that clear foreign particles  Phagocytosis
Also, play a role in immunity by allerting other WBC’s of foreign particles

4. Mast Cells
Large, widely distributed cells
Associated with inflammation
Releases heparin and histamine

5. CLASSIFICATION 3 CATEGORIES: Connective tissue proper
tissue with many types of cells and extracellular fibers in a syrupy ground substance ex. Adipose tissue
Fluid connective tissue
cells suspended in a watery matrix that contains dissolved proteins ex. Blood
Supporting connective tissue
low diverse cell population and a matrix of closely packed fibers ex. Bone and cartilage

6. CONNECTIVE TISSUE PROPER
Composed of many kinds of cells
Fibroblasts, Macrophages, Adipocytes
3 types of fibers
Collagen - long, straight unbranched; flexible but strong ex: tendons, ligaments
Reticular – cells suspended in a watery matrix that contains dissolved proteins Bone & Cartilage: stabilizes cells & vessels
Elastic - contains the protein “elastin”. Branched, wavy, will contract after stretching ex: elastic ligaments
Ground Tissue -
high viscosity; slows the spread of pathogens to make them easier for phagocytes to catch

7. Real life apps

8. Connective Tissue Proper
Loose connective tissue (areolar)
characterized by white and yellow fibers between fibroblasts
packing material of the body, cushions, attaches skin to the body, supports blood vessels

9. Adipose tissue dominated by adipocytes
energy storage, brown fat in infants (highly vascularized)
each cell consists of large vacuole filled with triglycerides

10. Reticular Connective Tissue
complex open framework of reticular fibers
supports walls of organs such as liver and spleen

11. Dense Connective Tissue
consists of many closely packed collagen fibers, elastin fibers, and few fibroblasts
regular - collagen fibers are parallel to each other
tendons, ligaments
irregular - collagen fibers are randomly arranged and interwoven : provides strength to resist forces applied from many directions; interwoven meshwork
dermis

12. Elastic Connective Tissue
- consists of mainly yellow elastic fibers
parallel or branching
walls of hollow organs, large arteries, heart etc.

13. FLUID CONNECTIVE TISSUES
Ground substance – plasma
Blood contains formed elements: Erythrocytes, leukocytes, Platelets
Arteries carry blood from heart to capillaries, water and solutes move into interstitial fluid, Veins return blood to heart

14. Erythrocytes: carry oxygen (confined to vessels)
Leukocytes: fight infection (wander)
Platelets: blood clotting

15. Supportive Connective Tissue Bone & Cartilage
I. Cartilage
Cells: Chondrocytes
Matrix: Firm gel of proteoglycans
Avascular: heals slowly
Covering: Perichondrium: Composed of 2 layers
Outer layer: dense irregular tissue
Inner layer: cells
Growth: Interstitial & Appositional
Appositional: undergoes extensive remodeling on a regular basis
Interstitial:
3 main types

16. Hyaline - Tightly packed collagen fibers
Most Common Type
Looks like white glass
Functions: Reduces friction, important in growth and repair of bones
Locations: Between bone surfaces, nose, trachea, intercostal cartilage

17. Elastic - Numerous elastic fibers
flexible
Functions: Provides support but distorts without damage
Locations: Ears, nose, epiglottis
Fibrocartilage - matrix dominated by collagen fibers
Extremely durable
Functions: Resists compression, limits movement
Locations: Between vertebrae, pads within knee joints

18. II. Bone - Most rigid connective tissue
Cells - Osteocytes
Matrix - 1/3 collagen fibers & mixture of calcium salts
Vascularized - caniculi - extensive blood vessels in matrix for exchange of materials
Covering - Periosteum (2 layers)
fibrous outer layer
cellular inner layer
Growth - Appositional
undergoes extensive remodeling on a regular basis
responds to stresses: grow thicker & stronger = exercise