Life Cycle - Human Biology (4A)
Post Lab 

   
OBJECTIVES:
  • Exploring four types of tissues. 
  • Comparing nervous, connective, epithelial, and muscular tissues.  
VOCABULARY:
  • connective
  • epithelial
  • muscular
  • nervous
MATERIALS:

Students try to find tissue cells on their skin.

 

BACKGROUND:

A tissue is a group of cells that have a similar shape and function.  Different types of tissues can be found in different organs.  In humans, there are four basic types of tissue:  epithelial, connective, muscular, and nervous tissue.  There may be various sub-tissues within each of the primary tissues.  

Epithelial tissue covers the body surface and forms the lining for most internal cavities.  The major function of epithelial tissue includes protection, secretion, absorption, and filtration.  The skin is an organ made up of epithelial tissue which protects the body from dirt, dust, bacteria and other microbes that may be harmful.   Cells of the epithelial tissue have different shapes as shown on the student's worksheet.  Cells can be thin, flat to cubic to elongated.  

Connective tissue is the most abundant and the most widely distributed of the tissues.  Connective tissues perform a variety of functions including support and protection.  The following tissues are found in the human body, ordinary loose connective tissue, fat tissue, dense fibrous tissue, cartilage, bone, blood, and lymph, which are all considered connective tissue.  

There are three types of muscle tissue: skeletal, smooth, and cardiac.  Skeletal muscle is a voluntary type of muscle tissue that is used in the contraction of skeletal parts.  Smooth muscle is found in the walls of internal organs and blood vessels.  It is an involuntary type.  The cardiac muscle is found only in the walls of the heart and is involuntary in nature. 

Nerve tissue is composed of specialized cells which not only receive stimuli but also conduct impulses to and from all parts of the body.  Nerve cells or neurons are long and string-like.

In tissues the simplest combination is called a membrane, or a sheet of tissues which cover or line the body surface or divide organs into parts.  Examples include the mucous membrane which lines body cavities.  Tissues combine to form organs.  An organ is a part of the body which performs a definite function.  The final units of organization in the body are called systems.  A system is a group of organs each of which contributes its share to the function of the body as a whole.

PROCEDURE:
  1. Use the worksheet to go over the four tissues of the Human Body.  Make them take notes about each of the tissues and have them research where these tissues may be in the human body.
      
  2. Make sure that the students realize that tissue is made up of cells.  
      
  3. Students should look at their own cells of their skin, and ask them if they can see the entire tissue.  Remember the skin is epithelial tissue.  Students should use a Swift-GH  microscope to focus on the different parts of their skin.  They can look at their leg, hand, arm, or palm.  They will notice that the shape of the cells vary considerable from one area of the body to another. 

    Make them think they may find some tissue, so they look at different parts of their skin.  Review with them that there are different skin cells at different locations.  They cannot find tissue because they are just look at the surface part of the skin.

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