Tissues grade 11
Epithelial tissue forms protective coverings and linings for all body surfaces, cavities, and organs, also making up glands, functioning in absorption, secretion, filtration, protection, and sensation . Characterized by tightly packed cells with little space between them, it has a free surface and attaches to underlying connective tissue via a basement membrane , lacking its own blood vessels but receiving nutrients via diffusion. Tissues are classified by cell shape (squamous, cuboidal, columnar) and layers (simple, stratified, pseudostratified). Key Characteristics Covering/Lining: Forms skin (epidermis) and lines internal structures like the digestive tract, blood vessels, and respiratory system. Cellularity: Cells are tightly packed with minimal extracellular matrix . Polarity: Has a free (apical) surface and a basal surface attached to the basement membrane. Avascularity: No direct blood supply; relies on diffusion from unde...