d. Functions. According to its location, epithelial tissue has different functions.
As the skin, epithelial tissue protects the tissues beneath. In the small intestines, the
epithelial tissue absorbs. In the lungs, epithelial tissue is a membrane through which
the gases pass easily. In the glands, epithelial tissue secretes.
Section III. CONNECTIVE TISSUES
a. Connective tissue is tissue that supports other tissues, holds tissues together,
or fills spaces.
b. Among and outside the cells of the connective tissues, there is a material
called matrix. The matrix is manufactured by the connective tissue cells. Each type of
connective tissue has its own particular type of matrix.
2-8. TYPES OF CONNECTIVE TISSUE
There are several major types of connective tissue (CT). These include fibrous
CT (FCT), cartilage CT, bone CT, and fat CT. Blood is sometimes considered an
additional type of CT.
2-9. FIBROUS CONNECTIVE TISSUE (FCT)
a. Fibroblasts. The characteristic cells of FCT are fibroblasts. Fibroblasts are
able to form elongated fibers.
b. Matrix. These fibers make up the matrix of FCT.
c. Fibers. The fibers are either white or yellow.
(1) White fibers are made from a protein called collagen. White fibers tend to
have a fixed length. White fibers are not very easily stretched.
(2) Yellow fibers are made from a protein called elastin. Yellow fibers are
elastic. They can be stretched and then they can snap back (like a rubber band).
d. Types of FCT. The types of FCT are recognized by the arrangement of their
fibers. These types include:
(1) Loose areolar FCT. Loose areolar FCT has an open irregular
arrangement of its fibers.
AREOLAR = airy