1. Connective Tissue Loose connective tissue Blood…why? Cartilage
Collagenous fiber
Plasma
White
blood cells
120 m
55 m
Elastic fiber
Cartilage
Red blood cells
Fibrous connective tissue
Chondrocytes
100 m
Figure 40.5 Exploring: Structure and Function in Animal Tissues
30 m
Chondroitin sulfate
Nuclei
Bone
Adipose tissue
Central
canal
Fat droplets
700 m
150 m
Osteon 1

2. Connective Tissue Most diverse tissue type
Binds together, supports and strengthens other tissues.
Protects and insulates internal organs
Compartmentalizes structures – e.g. skeletal muscles
Major transport system – ?
Store energy – ?
Immune response – ?
Two basic elements: cell and matrix – material between the cells.
Matrix contains: protein fibers and ground substance – the material between the cells and the fibers.
Nerve supply -- ?
Usually highly vascular: Exceptions are cartilage and tendons.

3. Types of Cells Widely spaced – Not tight packed like epithelial cells.
Fibroblasts that secrete the fibers and ground substance of the extracellular matrix
Macrophages that are involved in the immune system (fixed and wandering)
Mast cells produce histamine, a chemical that dilates small blood vessels as part of the inflammatory response – The body’s reaction to injury or infection.
Adipocytes are fat cells

4. Extracellular Matrix Two main elements
Ground substance – mostly water along with adhesion proteins and polysaccharide molecules
Supports cells
Binds cells together
Exchange of substances between blood and cells
Fibers
Produced by the cells
Three types
Collagen fibers
Elastic fibers
Reticular fibers
The matrix is firm in some parts of the body, but hard in others.
Examples: ?

5. Fibers (this they should know)

6. Fibers Collagen Fibers Made of protein called collagen
Strong yet flexible
Resist pulling forces
Found in:
Bone
Cartilage
Tendons
Ligaments

7. Fibers Elastic Fibers Thiner than collagen fibers
Made of the protein, elastin
Can be stretch without breaking
Found in:
Skin
Blood vessels
lungs

8. Fibers Reticular Fibers Much thinner than collagen fibers
Provide support for stroma (covering) of soft organs
Found in:
Basement membrane
Nerve fibers
Muscles
Spleen
Lymph nodes

9. Connective Tissue Fibers Summary
There are three types of connective tissue fiber, all made of protein:
Collagenous fibers provide strength and flexibility
Found in: tendon, ligament, skin, cornea, cartilage, bone, blood vessels, gut, and intervertebral disc.
Elastic fibers stretch and snap back to their original length
Found in: Skin, blood vessel walls, lung tissue
Reticular fibers join connective tissue to adjacent tissues
Found in: liver, bone marrow, lymphatic organs, basement membrane

10. Quiz Which type of protein are collagen fibers made of?
Which type of fiber provides support for soft organs?
Which type of protein are elastic fibers made of?
Which type of fibers can be found in blood vessels?
Which type of fiber provides the greatest strength?

11. Ground Substance
Forms the material between the cells and fibers of connective tissue.
Made of water, proteins, and polysaccharides
Instrumental in how tissues:
Develop
Migrate
Proliferate
Change shape
Metabolize

12. Connective Tissue Types
six major types of connective tissue:
Loose connective tissue
Dense connective tissue
Cartilage
Bone
Blood tissue
Lymph

13. Loose Connective Tissue
3 types of loose connective tissue
Areolar connective tissue
Adipose connective tissue
Reticular connective tissue

14. Areolar Connective Tissue
Forms the subcutaneous layer – Attaches skin to the underlying tissues and organs
Made of collagen, elastic and reticular fibers.
Made of fibroblast, macrophages, plasma, mast cells and adipocytes (fat cells)
Figure 3.19e

15. Adipose Tissue Cells store fat. Functions
Insulates the body
Protects some organs
Serves as a site of fuel storage
Does an obese person have more blood vessels?
Figure 3.19f

16. Reticular Connective Tissue
Delicate network of interwoven fibers
Forms stroma of lymphoid organs
Lymph nodes
Spleen
Bone marrow
Bind together smooth muscle cells
Filter worn out blood cells and bacteria.

17. Dense Connective Tissue
More and thicker fibers but fewer cells than loose connective tissue
Main matrix element is collagen fibers
Cells are fibroblasts
Examples
Tendon – attach muscle to bone
Ligaments – attach bone to bone
Figure 3.19d

18. Dense Connective Tissue
Dense Regular
Fibers arranged in parallel – Regular
Tendons and most ligaments
Dense Irregular
Fibers not parallel – Irregular
Heart valves
Elastic
Can extend and return to original length
Lungs, arteries

19. Connective Tissue Types
Bone (osseous tissue)
Composed of:
Bone cells in cavities
Hard matrix of calcium salts
Large numbers of collagen fibers
Used to protect and support the body

20. Connective Tissue Types
Hyaline cartilage
Most common cartilage
Composed of:
Abundant collagen fibers
Rubbery matrix
Entire fetal skeleton is hyaline cartilage
Figure 3.19b

21. Connective Tissue Types
Elastic cartilage
Provides elasticity
Example: supports the external ear

22. Connective Tissue Types
Fibrocartilage
Highly compressible
Example: forms cushion-like discs between vertebrae
Figure 3.19c

23. Connective Tissue Types
Blood
Blood cells surrounded by fluid matrix
Functions as the transport vehicle for materials
Figure 3.19h