Info

Component

Characteristic

Function

Fibroblasts Macrophages

Widely distributed, large, star-shaped cells Motile cells sometimes attached to fibers

Secrete proteins that become fibers Clear foreign particles from tissues by phagocytosis Release substances that may help prevent blood clotting and promote inflammation Hold structures together

Fibroblasts Macrophages

Mast cells

Collagenous fibers (white fibers)

Elastic fibers (yellow fibers) Reticular fibers

Widely distributed, large, star-shaped cells Motile cells sometimes attached to fibers

Large cells, usually located near blood vessels

Thick, threadlike fibers of collagen with great tensile strength Bundles of microfibrils embedded in elastin Thin fibers of collagen

Secrete proteins that become fibers Clear foreign particles from tissues by phagocytosis Release substances that may help prevent blood clotting and promote inflammation Hold structures together

Provide elastic quality to parts that stretch Form supportive networks within tissues

Ground substance

Fibroblast

Collagenous fiber

Figure 5.18

Ground substance

Fibroblast

Elastic fiber

Collagenous fiber

Figure 5.18

Elastic fiber

Loose connective tissue, or areolar tissue, contains numerous fibroblasts that produce collagenous and elastic fibers (250x micrograph enlarged to 1,000x).

located some distance apart and are separated by a gellike ground substance that contains many collagenous and elastic fibers that fibroblasts secrete (fig. 5.18).

Loose connective tissue binds the skin to the underlying organs and fills spaces between muscles. It lies beneath most layers of epithelium, where its many blood vessels nourish nearby epithelial cells.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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