Simple Epithelial Tissue Notes

Essential Question:

• What are the characteristics, functions, and locations of each type of epithelium?
• Naming Convention:
  • First name: "Simple" indicates a single layer of cells.
  • Last name: Describes the shape of the cells.

Types of Simple Epithelium:

1. Simple Squamous Epithelium

• Characteristics:
  • Single layer of flat cells.
  • Disc-shaped or flat nuclei.
  • Very thin.
• Functions:
  • Diffusion (movement from high to low concentration).
  • Filtration (passage through a membrane).
• Locations:
  • Alveoli (air sacs of lungs) for gas exchange.
  • Lining of heart, blood, and lymphatic vessels (especially capillaries).
  • Lining body cavities.
• Structure Identification:
  • Apical Surface: Top layer not attached to anything.
  • Basement Membrane: Part attached to connective tissue.
  • Nuclei: Disc-shaped.

2. Simple Cuboidal Epithelium

• Characteristics:
  • Single layer of cube-shaped cells.
  • Round or spherical nuclei.
• Functions:
  • Secretion (production and release of substances).
  • Filtration (in kidneys).
• Locations:
  • Kidney tubules.
  • Surface of ovaries.
  • Common in glands.
• Structure Identification:
  • Lumen: Empty space inside the tube.
  • Apical Surface: Exposed side.
  • Basement Membrane: Attached to connective tissue.

3. Simple Columnar Epithelium

• Characteristics:
  • Single layer of tall, column-shaped cells.
  • Oval-shaped nuclei.
  • May have cilia or microvilli.
  • Contains goblet cells for mucus production.
• Functions:
  • Absorption.
  • Secretion of mucus.
  • Cilia aids in movement.
• Locations:
  • Small tubes in lungs.
  • Female reproductive organs (uterine tube, uterus).
  • Digestive tract.
• Structure Identification:
  • Cilia/Microvilli: On apical surface.
  • Goblet Cells: Produce mucus.
  • Basement Membrane: Attached to connective tissue.

4. Pseudostratified Columnar Epithelium

• Characteristics:
  • Appears layered ("false layer"), but is a single layer.
  • Column-shaped cells with staggered nuclei.
  • May have cilia and goblet cells.
• Functions:
  • Similar to simple columnar.
• Locations:
  • Male reproductive tubes.
  • Trachea and upper airways.
• Structure Identification:
  • Cilia: On apical surface.
  • Goblet Cells: Visible as lighter spaces.
  • Nuclei: Staggered.

Homework Questions:

1. Where in the body is ciliated pseudostratified columnar epithelium found?
2. What type of tissue is found in the digestive tract?
3. What is the most common tissue found in glands?