1. Connective
and
Muscle Tissue

2. Connective Tissue

3. Where found?
Most abundant type of tissue
everywhere in the body

4. Purposes
1. Binds body parts together (tendons, ligaments) 2. Provide support and protection 3. Serve as frameworks (bone) 4. Fills spaces 5. Stores fat 6. Produces blood cells 7. Protects against infections (white blood cells) 8. Helps repair tissue damage

5. Characteristics
1. Cells are further apart than epithelial cells and have abundant
2. Major components:
a. cells b. Extracellular matrix (ECM)
extracellular matrix (ECM) is between the cells
Extracellular matrix is made of protein fibers and ground substance;
consistency varies from fluid to semisolid to solid
3. Most of this tissue is well vascularized = good blood supply
except tendons and ligaments (which means they heal slowly)
4. Most connective tissue cells can divide

6. Extracellular Matrix= fibers + ground substance
Ground Substance is made of:
Interstitial fluid
Cell adhesion proteins = glues cells to matrix
Proteoglycans= proteins + glycosaminoglycans (GAG)
= traps water and forms fluids of various viscocities
Fibers- 3 types
Collagen
Elastic
Reticular

7. Collagen
fiber
Actin filament
Proteoglycan

8. Major Cell Types of Connective Tissue
Fibroblasts:
Most common fixed cell
Large star-shaped cell
Secrete fibers into extracellular
matrix
Macrophages:
Usually attached to fibers, but
can detach and wander
Conduct phagocytosis
Defend against infection

9. Major Cell Types of Connective Tissue
Mast Cells:
Large, fixed cells
Release heparin to prevent
blood clotting
Release histamine, which causes
inflammatory response

10. Connective Tissue Fibers
Fibroblasts produce 3 types of fibers in connective tissue:
Collagen Fibers:
Thick, bundled, tough threads, the body’s main structural protein
Provide high tensile strength to the matrix; flexible, slightly elastic
Found in ligaments and tendons, bone, skin
Elastic (Yellow) Fibers:
Composed of branching elastin protein
Can stretch and return to original shape
Not as strong as collagen fibers
Found in skin, lungs, blood vessels
Reticular Fibers:
Short, branching fibers; collagen-like
Form delicate, supporting networks
Found in spleen, liver, basement membrane

12. Categories of Connective Tissue
Connective tissues can be classified in 2 major categories:
A. Connective Tissue Proper:
1. Loose connective tissues:
- Areolar
- Adipose
- Reticular
2. Dense connective tissues:
- Dense Regular
- Dense Irregular
- Elastic
B. Specialized connective tissues:
Cartilage
Bone
Blood

13. Adipocytes (white adipose cells)
Areolar Tissue
LOCATIONS: Within and deep to the dermis of skin, and covered by the epithelial lining of the digestive, respiratory, and urinary tracts;
between muscles; around joints,
blood vessels, and nerves
Fibrocytes
Macrophage
Collagen fibers
FUNCTIONS: Cushions organs; provides support but permits independent movement; phagocytic cells provide defense against pathogens
Mast cell
Loose
Connective
Tissue
Elastic fibers
Areolar tissue from pleura
LM × 380 a
Areolar tissue
Adipose Tissue
LOCATIONS: Deep to the skin, especially at sides, buttocks, and breasts; padding around eyes and kidneys
FUNCTIONS: Provides padding and cushions shocks; insulates (reduces heat loss); stores energy
Adipocytes (white adipose cells)
LM × 300 b
Adipose tissue
Reticular Tissue
LOCATIONS: Liver, kidney, spleen, lymph nodes, and bone marrow
FUNCTIONS: Provides supporting framework
Reticular fibers
Reticular tissue from liver
LM × 375 c
Reticular tissue

14. Collagen fiber bundles
Dense Regular Connective Tissue
LOCATIONS: Between skeletal muscles and skeleton (tendons and aponeuroses); between bones or stabilizing positions of internal organs (ligaments); covering skeletal muscles; deep fasciae
Dense
Connective
Tissue
Collagen fibers
FUNCTIONS: Provides firm attachment; conducts pull of muscles; reduces friction between muscles; stabilizes positions of bones
Fibroblast nuclei a
Tendon
LM × 440
Dense Irregular Connective Tissue
LOCATIONS: Capsules of visceral organs; periostea and perichondria; nerve and muscle sheaths; dermis
FUNCTIONS: Provides strength to resist forces from many directions;
helps prevent overexpansion of organs, such as the urinary bladder
Collagen fiber bundles b
Deep dermis
LM × 111
Elastic Tissue
LOCATIONS: Between vertebrae of the spinal column (ligamentum flavum and ligamentum nuchae); ligaments supporting penis; ligaments supporting transitional epithelia; in blood vessel walls
Elastic fibers
FUNCTIONS: Stabilizes positions of vertebrae and penis; cushions shocks; permits expansion and contraction of organs
Fibroblast nuclei c
Elastic ligament
LM × 887

15. Human Skin

16. Specialized Connective Tissue
Bone (Osseous Tissue):
Most rigid connective tissue
Solid matrix, composed of mineral (calcium) salts & collagen
Contain osteocytes (bone cells) in lacunae (chambers)

17. Specialized Connective Tissue
Blood:
Cells suspended in fluid matrix called plasma

18. Specialized Connective Tissue
Cartilage
Made of:
Chondrocytes (cartilage cells) in lacunae (chambers),
surrounded by the extracellular matrix
Covered by perichondrium (connective tissue), which contains blood vessels and provides some nutrients to the cartilage
3 types of cartilage: Hyaline, Elastic, and Fibrocartilage

19. Types of cartilage

20. Muscles

21. Where found? attached to skeleton in the heart
in the walls of hollow organs

22. Purpose
contract and shorten to produce movement

23. Types and Characteristics

24. Skeletal
1. Voluntary
2. Multinucleate
3. contains many striations

25. Skeletal Muscle

26. Cardiac 1. involuntary 2. uninucleate 3. branching fibers
4. many striations with intercalated discs

27. Cardiac Muscle

28. Smooth 1. involuntary 2. uninucleate 3. no striations
4. spindle-like appearance

29. Smooth Muscle