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TISSUES
Lesson 1 - Page 1

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transmitted light microscope

prepared slides

tissues

 

Early in the development of multicellular plants and animals cells divide and differentiate into various specialized types in order to meet the needs of these complex organisms. Similar cells group together to perform similar functions faster and more efficiently. A group of similar cells working together to perform similar functions is called a tissue.

Epithelial tissue is characterized by having many cells with little intercellular substances. Muscular tissue comes in three kinds: smooth, striated, and heart (cardiac). Connective tissue in contrast to epithelium has a large amount of non-living, intercellular substance which is secreted by the connective tissue cells. Nervous tissue consists primarily of heavily branched cells (neurons) which are modified for conduction.

Plant tissue also comes in many types. Meristematic tissue is found at the growing tips of roots and stems. Epidermal tissue is the protective outer layer. Parenchymal tissue is composed of rather generalized cells with thin walls and large vacuoles. Its main function is storage of water and food. Vascular tissue is differentiated rather early in the root and serves to circulate food, water, and minerals in the plant body. In this activity students will look at various tissues and try to differentiate the characteristics of each of the cells. In the next lab students will look at the organs that are made up of these tissues.

Using prepared slides have the students try to distinguish as many different tissues as they can find. They do not need to know the name of the tissues, just distinguish that there is a difference.

Have students record their findings.

BIOLOGICAL SCIENCES-MICROSCOPE/TISSUES

PROBLEM: How many different types of tissues can be found on a plant and animal?

HYPOTHESIS: ___________________________________________________________________

MATERIALS: transmitted light microscope, prepared slides of plant and animal tissues

Draw what you see under medium to high power. Differentiate on the drawing the different types of cells.

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