Lecture Notes on Types of Tissue

Overview of Animal Tissues

• Animals consist of four main types of tissue:
  1. Epithelial Tissue
  2. Muscular Tissue
  3. Connective Tissue
  4. Nervous Tissue

Epithelial Tissue

• Definition: The covering and protecting tissues of the body.
• Examples: Skin, lining of the mouth, blood vessels, lung alveoli, kidney tubules.
• Functions:
  • Covers organs and cavities
  • Forms barriers between different body systems

Classification of Epithelial Tissue

• Number of Layers:

  • Simple: One layer of cells
  • Stratified: Multiple layers of cells

• Shape of Cells:

  • Squamous: Flat and scale-like (Latin: "Squama" means scale)
  • Cuboidal: Cube-shaped
  • Columnar: Column-shaped

Types of Epithelial Cells

1. Simple Squamous
2. Simple Cuboidal
3. Simple Columnar
4. Stratified Squamous
5. Stratified Cuboidal
6. Stratified Columnar
7. Pseudostratified:
   • Appears stratified but is not
   • Found in lungs with cilia
   • Full name: Pseudostratified Ciliated Columnar Epithelial Cells

Functions of Epithelial Tissue Shapes

• Squamous Epithelium:

  • Locations: Lining blood vessels, lung alveoli, esophagus, lining of the mouth
  • Purpose: Allows for transportation of substances through a permeable surface
  • Skin: Made of multiple layers of squamous epithelium to withstand wear and tear

• Cuboidal Epithelium:

  • Locations: Lining kidney tubules, ducts of salivary glands
  • Purpose: Provides mechanical support

Glandular Epithelium

• Definition: Specialized epithelial tissue that forms glands
• Function:
  • Glands secrete substances either inside or outside the body
  • Examples:
    • Salivary glands (secrete saliva)
    • Sweat glands (secrete sweat)

Conclusion

• Understanding epithelial tissue is crucial for recognizing how body systems function and interact.
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