Lab 6 II Flashcards
Connective tissue
• most wide-ranging and abundant type of tissue in the human body.
•FUNCTION: mechanical binding and support, circulation of body fluids, insulation, storage of food reserves and the process of inflammation.
• variable degree of vascularization
• grouped based on the characteristics of the extracellular matrix:
-the consistency of the ground substance
-the types of fibers present
-the arrangement of the fibers.
All connective tissues have three structural features in common
cell
protein fibers
ground substance
fibers + ground substance = extracellular matrix
List:
Connective Tissue Proper - 4
Supporting Connective Tissues - 2
Connective Tissue Proper
- Areolar (Loose) Connective Tissue
- Adipose Connective Tissue
- Reticular Connective Tissue
- Dense Regular Connective Tissue
Supporting Connective Tissues
- Cartilage
- Bone
Components of the ground substance include
- glycosaminoglycans (GAG) such as chondroitin sulphate and hyaluronic acid
- proteoglycan
- adhesive glycoproteins.
Cell types ending: young and old
Immature = “-blasts”
- Fibroblasts are present in connective tissue proper and produce and secrete the matrix components, while in
- cartilage, chondroblasts
- osteoblasts are found in bone.
Mature = “-cytes”
- involved in maintaining the matrix and are less active
The fibers of connective tissue are of three types:
collagen, elastic and reticular fibers.
Areolar (Loose) Connective Tissue
• most widespread
• FUNCTION: used to attach the skin to the underlying tissue, to fill the spaces between various organs and thus hold them in place, and it surrounds and supports the blood vessels.
• Contains:
-Collagen fibers are the predominant fiber type, also elastic fibers.
-Fibroblasts, Mast cells, macrophages
Collagen fibers are the predominant fiber type.
- Constructed of the tough fibrous protein collagen and provide high tensile strength to the matrix.
- They usually appear as broad, pink bands in the slide.
Elastic fibers
- appear as thin, dark lines
* These fibers contain the rubber like protein elastin that allows them to stretch and recoil.
The fibroblast
is an actively mitotic cell that secretes the ground substance and fibers.
Mast Cell
- has coarse, dark-staining granules in the cytoplasm.
- Since the cell membrane of this cell is very delicate, it frequently ruptures in slide preparation, resulting in a number of granules free in the tissue surrounding the mast cells.
- The nucleus of the mast cell is small, oval and light-staining, and may be obscured by the cytoplasmic granules.
- FUNCTION: secrete heparin, a chemical that inhibits blood clotting, and histamine, a chemical that increases blood flow by dilating blood vessels.
Macrophages
- Large irregularly shaped phagocytic cells that arise from monocytes (type of white blood cell)
- Wander through connective tissue where they engulf and destroy bacteria, foreign particles and dead or dying body cells.
- Other types of white blood cells also can migrate from blood into connective tissue during infections
Reticular Connective Tissue
• forms the internal framework of the spleen, liver, bone marrow and lymph nodes. It is also closely associated with blood vessels and nerves.
•Contains:
- fibroblasts (called reticular cells), white blood cells and macrophages, reticular fiber
FUNCTION:
The fibers form a soft skeleton (stroma) to support the lymphoid organs (lymph node stromal cells, red bone marrow, and spleen).
LOCATION:
found around the kidney, liver, the spleen, and lymph nodes
Reticular fiber
- predominant in reticular connective tissue.
* short, thin branched networks of collagen-like fibers.
Adipose Connective Tissue
- FUNCTION: synthesis and storage of lipid, pads and protects certain regions of the body, acting as a shock absorber. As well, it forms an insulating layer in the integument which helps regulate body temperature.
- Locations for adipose tissue include under the skin, around kidneys, heart and eyeballs, within the abdomen and in the breasts.
- characterized by a large, internal lipid droplet.
- the cytoplasm is reduced to a thin layer and the nucleus is displaced to the edge of the cell.
- Adipose cells may appear singly but are more often present in groups
- When adipose cells accumulate in large numbers, they become the predominant cell type and form adipose tissue or fat.