Life Cycle - Human Biology (4A)Post Lab
|OBJECTIVES: Exploring four types of tissues. Comparing nervous, connective, epithelial, and musculartissues. VOCABULARY: connective epithelial muscular worried MATERIALS: worksheet|
Students try to find tissue cells on theirskin.
| BACKGROUND: A tissue is a group of cells that have a similar shapeand function. Different types of tissues can be found in differentorgans. In humans, there are four basic types of tissue: epithelial,connective, muscular, and nervous tissue. There may be various sub-tissueswithin each of the primary tissues. |
Epithelial tissue covers the body surface and forms the liningfor most internal cavities. The major function of epithelial tissueincludes protection, secretion, absorption, and filtration. The skinis an organ made up of epithelial tissue which protects the body from dirt,dust, bacteria and other microbes that may be harmful. Cellsof the epithelial tissue have different shapes as shown on the student"sworksheet. Cells can be thin, flat to cubic to elongated.
Connective tissue is the most abundant and the most widely distributedof the tissues. Connective tissues perform a variety of functionsincluding support and protection. The following tissues are foundin the human body, ordinary loose connective tissue, fat tissue, densefibrous tissue, cartilage, bone, blood, and lymph, which are all consideredconnective tissue.
There are three types of muscle tissue: skeletal, smooth, and cardiac. Skeletal muscle is a voluntary type of muscle tissue thatis used in the contraction of skeletal parts. Smooth muscle is foundin the walls of internal organs and blood vessels. It is an involuntarytype. The cardiac muscle is found only in the walls of the heartand is involuntary in nature.
Nerve tissue is composed of specialized cells which not onlyreceive stimuli but also conduct impulses to and from all parts of thebody. Nerve cells or neurons are long and string-like.
In tissues the simplest combination is called a membrane, ora sheet of tissues which cover or line the body surface or divide organsinto parts. Examples include the mucous membrane which lines bodycavities. Tissues combine to form organs. An organ is a partof the body which performs a definite function. The final units oforganization in the body are called systems. A system is a groupof organs each of which contributes its share to the function of the bodyas a whole.PROCEDURE: Use the worksheet to go over the four tissuesof the Human Body. Make them take notes about each of the tissuesand have them research where these tissues may be in the human body. Make sure that the students realize that tissue is madeup of cells. Students should look at their own cells of their skin, andask them if they can see the entire tissue. Remember the skin isepithelial tissue. Students should use a Swift-GH microscopeto focus on the different parts of their skin. They can look at theirleg, hand, arm, or palm. They will notice that the shape of the cellsvary considerable from one area of the body to another. Make them think they may find some tissue, so they look at differentparts of their skin. Review with them that there are different skincells at different locations. They cannot find tissue because theyare just look at the surface part of the skin.