BODY TISSUES TISSUES – groups of cells that work together ORGANS- groups of tissues working together

4 Primary tissue types 1. EPITHELIUM- overall role is “covering” 2. CONNECTIVE- overall role is “support” 3. NERVOUS- overall role is “control” 4. MUSCLE- overall role is “movement”

EPITHELIAL TISSUE the lining, covering, and glandular tissue of the body nearly all substances given off or received by the body must pass through epithelium functions- protection, absorption, filtration and secretion

Characteristics of Epithelium -fit closely together to form a continuous sheet -always has one surface exposed called the APICAL SURFACE -lower surface rests on the BASEMENT MEMBRANE- a structureless material secreted by the cells -depend on diffusion from capillaries in the underlying tissue for food and oxygen—NO DIRECT BLOOD SUPPLY - regenerate easily if well nourished

2 types of layer classification SIMPLE- a single layer of epithelial cells STRATIFIED- more than one cell layer of epithelial

3 classifications of shape 1. SQUAMOUS- flattened 2. CUBOIDAL- cube shaped 3. COLUMNAR- column shaped

TYPES OF EPITHELIA Types of epithelium Description/function Examples in the body Simple Squamous Simple cuboidal Simple Columnar Pseudostratified columnar (ciliated)

TYPES OF EPITHELIA Types of epithelium Description/function Examples in the body Stratified Squamous Stratified Cuboidal/ columnar Transitional Glandular

Simple squamous

Simple Cuboidal

Simple Columnar

Pseudostratified columnar

Stratified Squamous