Dense Connective Tissue

Dense Connective Tissue

1. Two main types of protein

   • Elastic
     • Fibers responsible for the flexibility of the tissue
   • Reticular
     • Consist of collagen fibrils, which are composed of type III collagen. Supports the resident cells of LCT and provide early mechanical strength

2. Celullar components

   • Fibroblasts
     • They synthesize both types of fibers and the complex carbohydrates of the ground substance.
   • Macrophages
     • Macrophages are phagocytes and they protect the LCT by ingesting potential pathogens and cell debris.
   • Mast cells
     • These vasoactive mediators are important in mounting an immune response, but they can also cause the typical symptoms of allergic reactions.
   • Adipocytes
     • Adipocytes are specialized cells that gradually accumulate fat, in the form of triglycerides.Adipose tissue can be of two types: brown and white. Brown adipose tissue is present during fetal life but diminishes in the first 10 years of life. White adipose tissue is the predominant one in adults.

3. Ground Substance

   • Ground substance is a clear and viscous gel with a high water content. Ground substance occupies the greatest proportion in LCT, being responsible for the flexible consistency of this tissue type. It consists of proteoglycans.

4. Found beneath the dermis layer and is also underneath the epithelial tissue of all the body systems that have external openings. It is also a component of the lamina propria of the digestive and respiratory tracts, the mucous membranes of reproductive and urinary system, the stroma of glands, and the hypodermis of the skin. It is also found in the mesentery which is surrounding the intestine

5. Dense Irregular CT

   • The type I collagen fibers of the dense irregular connective tissue are surrounded by small amounts of ground substance. Among the collagen fibers there is a network of elastic fibers as well, to limit the distensibility of the tissue. Ground substance is amorphous and gel-like in texture that surrounds cells. It can be found in a number of locations within the body, including the dermis of the skin, in glandular tissue, in the walls of organs, and in the whites of the eyes.

6. Dense Regular CT

   • Dense regular connective tissue is mainly made up of type I collagen fibers. It is found in areas of the body where large amounts of tensile strength are required, like in ligaments, tendons and aponeurosis. The collagen fibers are densely packed together and arranged in parallel to each other. This arrangement allows the fibers to have a good resistance to forces pulling along a single axis, but also gives some ability to stretch. A small amount of ground substance is present around dense regular connective tissue fibers and cells.

7. Fibroblasts

   • They are responsible for the synthesis of collagen and extracellular matrix. They are present close to the collagen fibers and appear as flattened, fusiform or spindle shaped cells.

8. Collagen fibers

   • Collagen fibers are tough, thick fibrous proteins found in dense connective tissues. It has many types but in dense connective tissue mainly type I collagen is present.