Chapter 5 focuses on the tissue level of organizational hierarchy within the body. A tissue is a set of cells
with similar form and function. There are four major tissue types: the excitable tissues, muscular
(contractile and conducting action potentials); nervous (the neurons that conduct action potentials and those
that support, supply, and defend the neurons); connective (support, supply, defend, and bind); and epithelial
(coverings and secretion). The author of the text has provided a very useful introduction to understanding
tissue sections near the beginning of the chapter. Saladin also discusses germ layers, intercellular junctions,
glands, stem cells, repair of tissues, and tissue transformations.
Here are some concepts that students should have a better understanding of after reading this chapter:
the development from the germ layer to differentiated tissue and stem cells;
the appearances, attributes, and activities of significant epithelial tissues;
the characteristic functions and properties of connective tissue subtypes and their extracellular
the functions of neurons and glial cells in brief;
changes in membrane potential;
the major sub-types of muscle tissues, their locations within the body, and a basic understanding of
the differences in their forms and functions;
the types of and the significance of intercellular junctions;
endocrine and exocrine glands as well as the types of arrangement and secretions of exocrine
and growth, repair, regeneration, and death of tissues.
Topics for Discussion
Cloning and stem cells are very hot topics these days so your students will probably want to discuss the
ethical considerations a bit. Perhaps two teams can prepare arguments for and against their use. Just a
few hints: Try to assign people to the view opposite their own and mix up the teams so that you do not
have teams made up of groups of friends. If you chose to allow your students to use the Internet,
caution them to consult reputable educational and government sites—part of one’s education is related
to being able to sift the wheat from the chaff.
Stem cells can be derived from umbilical cords. Some students may have had this saved for them when
they were born—there are banks. Perhaps someone in the class could do a special report on this topic.
In addition, recently, there have been some successes with adult-derived stem cells.
The relationship of cell differentiation and cancer is something to challenge students with. The
biological supply houses can provide quite good slides of oat cell carcinoma, and these can be used as
a contrast with healthy lung tissue. Another more complex topic is the differentiation of blood cells.
Again, the biological supply houses have some well-prepared slides of various leukemias. Contrast