Unit 2- Cells and Tissues

Levels of Organization  Cells – Building blocks of the body Tissues – A group of similar cells that combine to perform a certain function (4 - muscle, nervous, connective, epithelial) Organs – Two or more different types of tissue – combined to perform a certain function – (kidney, liver, lung) System – organization of > 2 or more organs perform a more general function

Histology-study of tissues  4 types of tissue in the body epithelial connective muscular nervous

Epithelial Tissue Arrangements: Simple- Cells are found in a single layer attached to the basement membrane Stratified- Cells are found in 2 or more layers stacked atop each other Pseudostratified- a single layer of cells that appears to be multiple layers due to variance in height and location of the nuclei in the cells.

Pseudo stratified

Epithelial Tissue Shapes: Squamous- (Latin, squama- scale)- flat, thin, scale-like cells Cuboidal- cells that have a basic cube shape. Typically the cell's height and width are about equal. Columnar- tall, rectangular or column-shaped cells. Typically taller than they are wide.

Epithelial characteristics: major tissue of glands inner lining of body cavities inner lining of hollow organs anchored to connective tissue by a basement membrane lacks blood vessels

Connective Tissue functions: Binds structures Provides support Protection Stores fat Produces blood cells

Connective Tissue characteristics: Cells farther apart Intercellular material/matrix between them FIBROBLAST- major cell creates fibers

Muscular Tissue * MOVEMENT of structures or materials 3 Types: SKELETAL/STRIATED SMOOTH CARDIAC

NERVOUS TISSUE Transmit electrical impulses throughout the body Includes- brain, spinal cord, nerves Neurons- basic unit of nervous system, TRANSMIT impulses NeuroGLIA- supporting cells, no impulses