Basic Tissue Types Epithelium The Anatomy Lecture of Dr. Nicolaes Tulp - Rembrandt (1632) The Cadaver belongs to Aris Kindt 1/16/1632 Hanged for burglary

Basic Tissue Types There are four basic tissue types –Epithelium –Muscle –Bone –Connective Tissue Today we will discuss the First type – Epithelium

Epithelial tissue consists of cells arranged in continuous sheets in either single or multiple layers. They are closely packed with little intracellular space

Epithelial Cells Provide an excellent protective barrier Separate and isolate substances within the body They have a very high rate of cell division, due to high rate of physical stress and injury

Epithelial cells have specialized areas Apical (free) surface - Faces the body surface, lines a body cavity or the open space of an internal organ

Epithelial cells have specialized areas Apical (free) surface - Faces the body surface, lines a body cavity or the open space of an internal organ Lateral surface - faces adjacent cells on either side and may contain gap junctions for communication

Gap Junction - used for communication

Epithelial cells have specialized areas Apical (free) surface - Faces the body surface, lines a body cavity or the open space of an internal organ Lateral surface - faces adjacent cells on either side and may contain gap junctions for communication Basal surface - opposite the apical end and adheres to the matrix

Epithelial tissue has a nerve supply but has no blood vessels going to it (avascular) these cells get all their nutrition through the process of diffusion

Epithelial cells are classified according to two characteristics: Layers and Shapes

Layer Classification Simple Epithelium - Single layer that functions in diffusion, filtration, secretion and absorption - These cells are found in the blood vessels, heart, air sacs and parts of the kidney

Simple Epithelium

Layer Classification Pseudostratified Epithelium - Multiple layers of cells with nuclei appearing at different levels. Not all cells reach the apical end, however all cells reach the matrix. These cell are found in the respiratory tract, glands and the male reproductive tract

Pseudostratified Epithelium Cilia

Layer Classification Stratified Epithelium - Contains two or more layers of cells, found in locations with considerable wear and tear. These cells are found in the tongue, esophagus, mouth and vagina

Stratified Squamous Epithelium

Shape Classification Squamous Epithelium - Flat cells, arranged like tiles, very thin and allow for the rapid movement of substances These cells may or may not have a keratinized surface (keratin protein) depending on location

Keratinized Stratified Squamous Epithelium Keratin

Shape Classification Cuboidal Epithelium - These cells are as tall as they are wide. They are shaped like cubes or hexagons. These cells often have microvilli on their apical surface

Cuboidal Epithelium

Shape Classification Columnar Epithelium - These cells are much taller than they are wide. Many of these cells have cilia, they are specialized for secretion and absorption

Columnar Epithelium

Shape Classification Transitional Epithelium - These cells can change shape cuboidal to flat (simple) as such organs as the bladder distend with urine

Transitional Epithelium Cuboidal Squamous

Practice Quiz The Anatomist - Gabriel Von Max (1869)

What Am I?