Anatomy Lecture 1

Cell Division and Epithelial Tissue

• Anaphase: Sister chromatids separate and move toward opposite centrosomes.
• Telophase:
  • Chromosomes revert to an uncondensed state as spindle fibers break apart.
  • Cleavage furrow formation occurs at the equator.

Interphase Characteristics

• Interphase is distinguished from Prophase by the presence of a nuclear envelope.

Epithelial Tissue Overview

• Epithelial tissue covers and lines organs and body cavities.
• Functions of epithelial tissue include:
  • Protection against external factors.
  • Permeability regulation allowing substance passage.
  • Sensation through nerve endings.
  • Secretion of various substances.

Epithelial Locations and Types

• Found on body surfaces, lining cavities, and tubular structures.
• The pancreas consists of glands made of epithelium.

Epithelial Tissue Characteristics

• Characteristics include:
  • High cellularity with minimal extracellular matrix (ECM).
  • Polarity with distinct apical and basal layers.
  • Attachment to the basement membrane.
  • Avascularity, lacking blood vessels.
  • High regeneration capacity.

Poles of Epithelial Tissue

• Apical Pole: Free surface exposed to the external environment.
• Basal Pole: Attached to the underlying basement membrane.

Exocrine Glands

• Multicellular Exocrine Glands: Include pancreas, mammary glands, and salivary glands.
• Unicellular Exocrine Glands: Mucous and goblet cells, located close to epithelial surfaces.

Exocrine Secretion Types

• Two main types of exocrine secretions:
  • Serous: Thin, watery fluids (e.g., sweat, milk, tears) with a dark stain.
  • Mucous: Thick fluids consisting of mucin and water, stained light.

Secretory Methods

• Three Types:
  • Merocrine: Secretion occurs via exocytosis without damaging cells.
  • Holocrine: Cells rupture releasing the product, damaging the cells.
  • Apocrine: Product accumulates in the apical portion, leading to cell decapitation.

Functions and Components of Connective Tissue

• Functions include:
  • Protection of organs.
  • Structural support.
  • Binding tissues.
  • Storage of energy.
  • Transportation of materials.
  • Immune defense.
• Components consist of cells, protein fibers, and ground substance.

Protein Fibers in Connective Tissue

• Types of protein fibers include collagen, elastic, and reticular fibers.
• Connective tissue types categorized as fibrous, supportive, and fluid.

Key Cell Types in Connective Tissue

• Fibroblasts: Most common cells, synthesize fibers and ground substance.
• Adipocytes: Specialized in fat storage.
• Mesenchymal Cells: Embryonic stem cells involved in healing.
• Immune Cells: Include macrophages, mast cells, and leukocytes.

Areolar Connective Tissue

• Loose, diverse structure with a watery ECM.
• Functions include cushioning organs, phagocytosis of bacteria, roles in inflammation, and fluid management.

Types of Connective Tissue

• Loose Connective Tissue: Includes areolar, adipose, and reticular.
• Dense Connective Tissue: Comprises dense regular, dense irregular, and elastic.

Dense Regular and Irregular Connective Tissue

• Dense Regular:
  • Structure: Tight, dense arrangement for limited stretch in one direction.
  • Location: Tendons, ligaments, and fascia.
• Dense Irregular:
  • Structure: Irregular arrangement, withstands tension in multiple directions.
  • Location: Fibrous capsules of organs, dermis, and submucosa of the digestive tract.

Elastic Connective Tissue

• Function: Facilitates recoil following stretching; maintains blood flow; assists lung function post-inspiration.
• Location: Present in large arteries, ligaments of the vertebral column, and bronchial tubes.

Protein Fiber in Elastic Connective Tissue

• Composed primarily of elastic fibers.

Test your knowledge on the processes of cell division, specifically anaphase and telophase, as well as the characteristics and functions of epithelial tissue. This quiz covers the general features of interphase and various types of epithelial tissues in the body.