Higher Order Structures

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Tissues

tissue - group of cells with similar shape and function

organs are comprised of tissues

component cells of a tissue are a specific cell type (although a tissue's cells are not necessarily identical)

4 broad tissue types:

muscle tissue (skeletal, smooth, and cardiac) - contractile; allows movement of body and contractions of organs

nerve tissue - conducts signals between nervous system and various organs

connective tissue (fibrous, fatty, loose, cartilage, blood, bone, lymph) - holds body together; anchors organs to skeleton and other organs

epithelial tissue (skin) - protection against the outside environment; monitors and controls temp, resists abrasion, foreign bodies, and damaging chemicals; lines most internal cavities, secreting or absorbing nutrients

stem cells differentiate into various cell types; genes turn on or off, resulting in production of proteins that characterize a cell's structure and function

early in embryonic growth, cells migrate to the appropriate location in the body and then proliferate to create tissues

Organs

organ - made up of tissues that work together to perform a specific function for the body as a whole

organ system - a group of organs that performs related functions (perform more general functions)