Understanding Tissue Organization and Types

Sep 16, 2024

Tissue Level of Organization Lecture

Introduction

  • Presenter: Dr. Alita Partasadarsu
  • Focus: Differences between normal and abnormal cervical epithelium.
    • Normal Epithelium: Organized, structured.
    • Abnormal Epithelium: Irregular arrangement, cancerous.

Overview

  • Histology: Study of tissues.
  • Types of Tissues in Human Body:
    1. Epithelial Tissue
    2. Connective Tissue
    3. Muscle Tissue
    4. Nervous Tissue
  • Focus: Epithelial and Connective Tissue

Tissue Membranes

  • Definition: Thin layer or sheet of cells.
  • Types of Membranes:
    • Epithelial Membranes
      1. Mucous Membrane: Lines digestive, respiratory, urinary, and reproductive tracts.
      2. Serous Membrane: Lines body cavities (abdominal, pleural, pericardial).
      3. Cutaneous Membrane: Skin.
    • Connective Tissue Membranes
      • Synovial Membrane: Lines joints, produces fluid.

Epithelial Tissue

  • Properties:
    • Cells closely packed, avascular.
    • Capable of reproduction for wear and tear.
  • Functions:
    • Protection from injury and pathogens.
    • Sensory functions.
    • Secretion of hormones, mucus, digestive juices, sweat.
    • Barrier to control movement of substances.
  • Structure:
    • Organized into layers: Apical surface and basement membrane.
  • Types:
    • Covering/Membranous Epithelium
    • Glandular Epithelium: Endocrine (inside) and Exocrine (outside) glands.

Cell Junctions in Epithelial Tissue

  • Types:
    • Anchoring Junctions: Desmosomes, Hemidesmosomes, Adherens.
    • Tight Junctions: No space, prevent substance passage.
    • Gap Junctions: Channels for material exchange between cells.

Classification of Epithelial Tissue

  • Based on Layers:
    • Simple (one layer), Stratified (multiple layers), Pseudostratified, Transitional.
  • Based on Cell Shape:
    • Squamous (flat), Cuboidal (boxy), Columnar (tall).
  • Examples and Functions:
    • Simple Squamous: Absorption, secretion.
    • Stratified Squamous: Protection.
    • Simple Cuboidal, Columnar: Absorption, secretion.
    • Transitional: Found in urinary tract, stretches.

Glandular Epithelium

  • Exocrine: Out of body (mucus, sweat, saliva).
  • Endocrine: Into body (hormones).
  • Types of Exocrine Secretion:
    • Merocrine: Vesicle fusion, minimal damage.
    • Apocrine: Pinched off, some damage.
    • Holocrine: Cell destruction upon secretion.

Connective Tissue

  • Functions: Support, connect tissues.
  • Cells:
    • Fibroblasts/Fibrocytes: Produce fibers.
    • Adipocytes: Store fats.
    • Mesenchymal Cells: Stem cells.
    • Macrophages/Mast Cells: Immune response.
  • Fiber Types:
    • Collagen: Strength, flexibility.
    • Elastic: Returns to shape.
    • Reticular: Mesh-like support.

Types of Connective Tissue

  • Connective Tissue Proper:
    • Loose: Adipose, Areolar, Reticular.
    • Dense: Regular (tendons), Irregular (dermis).
  • Supportive Connective Tissue:
    • Cartilage: Avascular, types (Hyaline, Elastic, Fibrocartilage).
    • Bone: Hard, vascularized, supports body, calcium-rich.
  • Fluid Connective Tissue:
    • Blood: Vascular system.
    • Lymph: Lymphatic system.

Brief Overview of Muscle and Nervous Tissue

  • Muscle Tissue:
    • Types: Skeletal (voluntary), Cardiac (involuntary), Smooth (involuntary).
  • Nervous Tissue:
    • Cells: Neurons (signal transmission), Neuroglia (support).
    • Functions: Communication, response to stimuli.

Conclusion

  • Summary: Overview of tissue types, focusing on epithelial and connective tissue.
  • Note: Detailed exploration of muscle and nervous tissues in subsequent lectures.