1. Connective Tissue
Includes the most abundant and widely distributed tissues
Functions:
Binds body tissues together
Supports the body
Provides protection

2. Connective Tissue Characteristics
Most tissue types are well vascularized (bone, adipose, reticular, areolar)
Some have poor blood supply or are avascular (cartilage, ligaments, tendons)
matrix
Non-living material that surrounds living cells

3. Extracellular Matrix (cont.)
Two main elements of matrix:
1. Ground substance – mostly water along with adhesion proteins and polysaccharide molecules
2. Fibers (3) – made by the cells
Collagen fibers (strongest)
Elastic fibers
Reticular fibers (delicate)

4. Connective Tissue Types
Bone (osseous tissue)
Composed of:
Bone cells-(osteocyte) in lacunae (cavities)
Hard matrix of calcium salts
Large numbers of collagen fibers
Used to protect and support the body
Figure 3.19a

5. Connective Tissue Types
Hyaline cartilage
Most common cartilage
Composed of:
Abundant collagen fibers
Rubbery matrix
Cells - chondrocyte
Examples: entire fetal skeleton, ends of long bones
Figure 3.19b

6. Connective Tissue Types
Elastic cartilage
Provides elasticity
Example: ear, wall of aorta

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

8. Connective Tissue Types
Dense 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

9. Connective Tissue Types
Areolar (loose) connective tissue
Most widely distributed connective tissue
Soft, pliable tissue
Contains all fiber types
Ex. packs most of our organs
Figure 3.19e

10. Connective Tissue Types
Adipose tissue (fat)
Matrix is an areolar tissue
Storage, cushions, protects, insulates
Examples?
Figure 3.19f

11. Connective Tissue Types
Reticular connective tissue
Delicate network of fibers
Examples:
Lymph nodes
Spleen
Bone marrow
Figure 3.19g

12. Connective Tissue Types
Blood
Blood cells surrounded by fluid matrix (plasma)
RBC’s, WBC’s and platelets
Figure 3.19h

13. Muscle Tissue Types (3) 1. Skeletal muscle voluntary striated
have more than one nucleus (multinucleate)
Figure 3.20a

14. Muscle Tissue Types 2. Cardiac muscle Found only in the heart
(involuntary)
Cells attached to each other at intercalated disks
striated
One nucleus per cell
Figure 3.20b

15. Muscle Tissue Types 3. Smooth muscle Involuntary
No visible striations (smooth)
One nucleus per cell
Ex. Lines hollow organs, blood vessels, reproductive tracts
Figure 3.20c

16. Nervous Tissue Neurons and nerve support cells
send impulses to other areas of the body
Figure 3.21

17. Tissue Repair (2 ways) 1. Regeneration 2. Fibrosis (scar tissue)
Replacement of destroyed tissue by the same kind of cells
2. Fibrosis (scar tissue)
Repair by dense fibrous connective tissue (scar tissue)
Tissues that are replaced largely with scar tissue:
Cardiac muscle
Nervous tissue within the brain and spinal cord
Joints (knee and elbow)

18. Developmental Aspects of Tissue
With old age there is a decrease in mass and viability in most tissues (atrophy)
Atrophy will also occur when tissues (muscles) are not used
Most prominent in muscles