Histology and Epithelial Tissues

Flashcards covering body tissues, primary tissue categories, characteristics and junction types of epithelial tissue, and epithelial classifications based on shape and cell layers.

Body Tissues

Groups of cells that have structure and function, where cell specialization increases interdependence on other cells of the body.

Epithelial Tissue

A primary tissue type responsible for covering and lining body surfaces, forming boundaries with the outside world, and functioning in protection, absorption, filtration, and secretion.

Connective Tissue

A primary tissue type responsible for support, including protecting, supporting, and binding tissues together.

Muscle Tissue

A primary tissue type responsible for movement that is contractile (shortens).

Nervous Tissue

A primary tissue type that controls and regulates through electrical signals to receive, interpret, and respond to stimuli.

Endothelium

Specially designated epithelial tissue that lines vessels in the lymphatic and cardiovascular systems.

Avascular

Lacking a direct blood supply; epithelial tissues are avascular and rely on diffusion from underlying tissues.

Apical Surface

The surface of epithelial tissue exposed to the body surface or a body cavity, which is often slick, smooth, or has cell extensions.

Basal Surface

The lower attached surface of epithelial tissue that binds it to underlying connective tissue via the basement membrane.

Cell Junctions

Points of attachment between cells that allow epithelial tissues to form tightly fit, continuous sheets.

Tight Junctions

Cell junctions between you and the outside world that form an impenetrable barrier preventing the passage of material into the intercellular space.

Gap Junctions

Protein channels that connect the cytoplasm of adjacent cells for communication and coordination.

Anchoring Junctions

Cell junctions containing a variety of protein fibers that anchor into the cytoplasm for strength.

Adherens Junctions and Desmosomes

Anchoring junctions located between adjacent cells that hold cells together to form tissues.

Hemidesmosome

An anchoring junction that attaches the basal surface of epithelial cells to the underlying basement membrane.

Simple Epithelium

An epithelial classification consisting of a single layer of cells.

Stratified Epithelium

An epithelial classification consisting of multiple layers of cells.

Squamous Cells

Epithelial cells characterized by a flattened cell shape.

Cuboidal Cells

Epithelial cells characterized by a cube-like cell shape.

Columnar Cells

Epithelial cells characterized by a tall, column-like cell shape.

Simple Squamous Epithelium

Single layer of flat cells responsible for rapid diffusion; found in air sacs of lungs, capillary walls, lining of ventral body cavity, and covering organs.

Simple Cuboidal Epithelium

Single layer of cube-like cells involved in absorption and secretion; found in ducts of glands (salivary, pancreas) and walls of kidney tubules.

Simple Columnar Epithelium

Single layer of tall cells involved in absorption and secretion; lines parts of the digestive and respiratory systems.

Stratified Squamous Epithelium

Multi-layered epithelium that can withstand stress and friction; found on the skin, esophagus, and surface of the mouth.

Stratified Cuboidal Epithelium

Rare multi-layered epithelium in the body that lines the ducts of large glands such as the liver and pancreas.

Pseudostratified Columnar Epithelium

Epithelium consisting of heterogeneous cell types where all cells contact the basement membrane, and some feature membrane extensions such as cilia.

Transitional Epithelium

Epithelial tissue lining the urinary bladder, urethra, and ureters, whose cells modify their shape under stress from stretching.