Dominican Universisty A&P 1 - Lesson 4 - The Tissues(1) (1)

Principles of Anatomy & Physiology

  • Focus: The Tissue Level of Organization

History of Pathology

  • Giovanni Maria Lancisi (Morgagni): Established pathological anatomy (1761).

  • Marie François Xavier Bichat: Known as the father of pathological histology (1800).

  • Rudolph Virchow (1821-1902): Known as the father of modern pathology; stated "All diseases are results of visible cell abnormalities" (histopathology).

Father of Histology

  • Marie François Xavier Bichat: Introduced histology; focused on gross dissection rather than microscopy.

  • Marcello Malpighi: First to observe capillaries, considered 'Father of Histology'.

  • Mayer (1819): Coined the term "Histology" (Greek: histos = tissues, logos = study).

Introduction to Tissues

  • Purpose:

    • Understanding types of tissues and their origins.

    • Discussing cell cohesion in tissues.

    • Comparing and contrasting epithelial, connective, muscular, and nervous tissues.

    • Learning about structure/function of membranes and tissue repair.

Types of Tissues

  • Definition of Tissue: A group of cells with a common embryonic origin functioning together in specialized activities.

  • Four Basic Types:

    1. Epithelial

    2. Connective

    3. Muscular

    4. Nervous

Epithelial Tissue

  • Types and Features:

    • Epithelial tissue forms protective barriers and is involved in secretion/absorption.

    • Types:

      • Simple Squamous: Allows diffusion/filtration; found in lungs and blood vessels.

      • Simple Cuboidal: Secretion/absorption; found in kidney tubules.

      • Nonciliated Simple Columnar: Secretion and absorption; lines GI tract.

      • Ciliated Simple Columnar: Propels mucus/particles; found in respiratory tract.

      • Stratified Squamous: Protects against abrasion; found in skin, esophagus.

      • Transitional: Allows stretching; found in urinary bladder.

Connective Tissue

  • General Characteristics:

    • Consists of cells and extracellular matrix (fiber and ground substance).

    • Highly vascularized with various cell types: fibroblasts, macrophages, mast cells, adipocytes.

  • Classification:

    • Loose Connective Tissue: Soft matrix, provides padding.

    • Dense Connective Tissue: Fibrous matrix, stronger connections.

    • Cartilage, Bone, Blood: Specialized types each with unique functions.

Muscular Tissue

  • Types:

    • Skeletal Muscle: Voluntary control; striated; attached to bones.

    • Cardiac Muscle: Involuntary; striated; found in the heart.

    • Smooth Muscle: Involuntary; non-striated; found in walls of hollow organs.

Nervous Tissue

  • Components:

    • Neurons: Conduct impulses; consist of dendrites, axons, and cell body.

    • Neuroglia: Support neurons; do not conduct impulses.

Tissue Repair

  • Process of replacing damaged or dead cells;

    • Epithelial cells renewed through stem cell division.

    • Connective tissue has varied repair capacities;

    • Muscle cells have limited repair abilities;

    • Some nervous cells can repair, others cannot (fibrosis leads to scar formation).

Signs of Inflammation

  • Cardinal Signs:

    • Redness, heat, swelling, pain, loss of function.

Aging and Tissues

  • Effects of Aging:

    • Slower tissue repair, reduction in blood supply, and metabolic rate.

    • Increased stiffness and loss of elasticity in tissues.

Homeostatic Imbalances

  • Disorders:

    • Epithelial disorders (ulcers), autoimmune connective tissue disorders (e.g., lupus), muscular/nervous tissue pathology discussed in future courses.