Lab 3: Tissues II and Integumentary system
Connective, muscle, and nervous tissues; the integumentary system
When you are prepared for the Test on Week 3 Learning Objectives in Week 4, you will be able to:
- Review from Week 2: Differentiate between the general functions of epithelial, connective, muscle, and nervous tissues.
- Review from Week 2: Identify epithelial tissue types, their features, and their basic functions.
- Identify connective tissue types, their features, and their basic functions.
- Identify muscle tissue types.
- Identify nervous tissue.
- Identify layers of the skin, layers within the epidermis, and their functions.
- Identify accessory structures in the skin and explain their functions.
Last week we looked at the four different categories of tissue in the body: epithelial, connective, muscle, and nervous. We then observed different types of epithelial tissue and learned how to differentiate between them. This week we will look at examples of the remaining three tissue categories and learn how to differentiate between specific types of connective tissue and muscle tissue. We will then look at the first organ system of the class, the Integumentary system. This consists of the skin and its accessory structures.
Tissues II
Connective tissue
General structure of connective tissue
As may be obvious from its name, one of the major functions of connective tissue is to connect tissues and organs. Unlike epithelial tissue, which is composed of cells closely packed with little or no extracellular space in between, connective tissue cells are dispersed in a matrix. The matrix usually includes a large amount of extracellular material produced by the connective tissue cells that are embedded within it. The matrix plays a major role in the functioning of this tissue. The major component of the matrix is a ground substance often crisscrossed by protein fibers. This ground substance is usually a fluid, but it can also be mineralized and solid, as in bones. Connective tissues come in a vast variety of forms, yet they typically have in common three characteristic components: cells, large amounts of amorphous ground substance, and protein fibers. The amount and structure of each component correlates with the function of the tissue, from the rigid ground substance in bones supporting the body to the inclusion of specialized cells; for example, a phagocytic cell that engulfs pathogens and also rids tissue of cellular debris.
Functions of Connective Tissues
Connective tissues perform many functions in the body, but most importantly, they support and connect other tissues; from the connective tissue sheath that surrounds muscle cells, to the tendons that attach muscles to bones, and to the skeleton that supports the positions of the body. Protection is another major function of connective tissue, in the form of fibrous capsules and bones that protect delicate organs and, of course, the skeletal system. Specialized cells in connective tissue defend