Lab 3: Connective Tissues  
We will now be looking at the various kinds of connective tissue. All types will be examined except elastic connective tissue, bone and blood. These will be studied in other units.
 
A. Loose Connective Tissue 
 
Slide #8A (areolar connective tissue
Matrix (Not a distinct structure in this slide! You are only aware of its presence.) The matrix contains ground substance that is a diversity of large molecules including hyaluronic acid suspended in water that are not visible and fibers that you can see. There are two types of fibers: elastic fibers (thinner and black) and collagen fibers (thicker and pink).
 
Connective tissue cells that can be seen in this slide include fibroblasts or fibrocytes. As I will explain, I will not expect you to differentiate between these two cell types. Macrophages (I will not ask you to identify these cells.) and mast cells.
 
Slide #15A (adipose tissue)
Locate the fat vacuole (or where it was) and the nucleus. Is there much intercellular matrix?
 
Slide #10A (reticular connective tissue)
The stain used in this slide makes the fibers appear very dark. The reticular fibers form the stroma (framework) of this organ (lymph node) and of many other organs. The functional cells of the organ are called the parenchyma.
 
B. Dense Connective Tissue
 
Slide #9A (dense regular connective tissue)
This is a section of tendon. The collagen fibers look like smooth, wavy hair. Fibroblasts are scattered about in between the fibers but only the nuclei of these cells can be discerned.
 
Slide #20A (dense irregular connective tissue)
Dense irregular connective tissue is found in the dermis of the skin. The collagen fibers in this slide are arranged in various directions. We will be looking at this slide again in the next lab.
 
C. Cartilage
Cartilage is unique in being avascular. The matrix is a firm gel that contains chondroitin sulfate and other molecules. Chondrocytes are found within spaces called lacunae. Perichondrium is dense irregular connective tissue that surrounds the cartilage.
 
Slide # 11A (hyaline cartilage)
This cartilage has the smoothest looking matrix. Find the lacunae, chondrocytes and perichondrium.
 
Fibrocartilage
This cartilage has a "streaky" looking matrix due to the presence of extra collagen fibers. These fibers enhance the tensile strength of the cartilage.
 
Slide # 13A (elastic cartilage)
This is a section of the ear. The stain brings out the elastic fibers within the elastic cartilage. The matrix is dark and "messy" and has many large lacunae. The chondrocytes are often shriveled.