Tissues - Part 2

This lecture discusses the types of tissues in the body, focusing on connective tissues and giving an introduction to muscle and nervous tissues.

Types of Tissues

• Epithelial Tissue
• Connective Tissue
• Nervous Tissue
• Muscle Tissue

Connective Tissue

Connective tissue serves to bind and support other tissues in the body.

Types of Connective Tissue

1. Connective Tissue Proper
   • Adipose Tissue
   • Reticular Tissue
   • Areolar Connective Tissue
   • Dense Regular, Dense Irregular, Dense Elastic
   • Cells: Fibroblasts, Fibrocytes
2. Cartilage
   • Watery matrix, resistant to compressive and tensile forces
   • Cells: Chondroblasts, Chondrocytes
3. Osseous (Bone) Tissue
   • Solid, protective, supportive
   • Cells: Osteoblasts, Osteocytes
4. Blood (Hematopoietic) Tissue
   • Liquid, atypical connective tissue
   • Cells: Red Blood Cells, White Blood Cells, Platelets

Characteristics

• All derived from mesenchyme (embryonic tissue)
• Generally well vascularized
• Composed of diverse cell types and extracellular matrix

Extracellular Matrix

• Ground Substance: Holds interstitial fluid
• Fibers: Collagen, Elastic, Reticular

Areolar Connective Tissue

• Prototypical connective tissue
• Functions:
  1. Supports and binds other tissues
  2. Holds body fluids
  3. Defends against infection
  4. Stores nutrients as fat

Classes of Connective Tissue

Loose Connective Tissue

• Areolar: Supports and binds, holds fluids, defends
• Adipose: Stores energy, highly vascularized
• Reticular: Supports other tissues

Dense Connective Tissue

• Dense Regular: Collagen fibers in parallel arrangement, found in tendons
• Dense Irregular: Collagen fibers in different directions, found in dermis
• Dense Elastic: Elastic fibers, allows stretch and recoil

Cartilage

• Hyaline: Most abundant, supports and reinforces
• Fibrocartilage: Thick collagen fibers, resists compressive and tensile forces
• Elastic Cartilage: More elastic fibers, allows flexibility

Bone

• Compact and spongy bone, solid matrix
• Supports, protects, stores
• Red marrow: site of blood cell production

Blood

• Atypical connective tissue
• Functions in transport
• Plasma: fluid matrix, lacks fibers

Muscle Tissue

• Specialized for movement
• Types:
  1. Skeletal Muscle: Long fibers, striated, voluntary control
  2. Cardiac Muscle: Striated, involuntary, heart walls
  3. Smooth Muscle: Non-striated, involuntary, walls of hollow organs

Nervous Tissue

• Main component of nervous system
• Neurons: Excitable, send electrical impulses
• Supporting Cells: Non-excitable, support neurons

Conclusion

This overview of tissues highlights the complexities of connective, muscle, and nervous tissues, setting the stage for more detailed study in future lectures on the skeletal, muscular, and nervous systems.