Connective Tissue Microanatomy and Classification

Vocabulary flashcards based on lecture notes covering connective tissue functions, appearance, fixed and wandering cells, fiber types, loose/dense CT, cartilage classifications, bone composition, and blood.

Fixed Cells

Connective tissue cells that remain in the tissue for a long period of time, such as fibroblasts and adipocytes.

Wandering Cells

Cells that move through connective tissue and appear temporarily in response to injury or infection, such as macrophages and mast cells.

Fibroblasts

The most common fixed cells in connective tissue that produce protein fibers of the extracellular matrix (ECM), including collagen and elastin.

Adipocytes

Energy-storing fat cells containing large globules of fat known as lipid droplets surrounded by a structural network of fibers.

Macrophages

Bacteria and virus 'eaters' that originate as white blood cells (WBCs) and are almost as plentiful as fibroblasts in connective tissue.

Mast Cells

Large, circular, widely distributed cells usually located near blood vessels that release heparin and histamine.

Heparin

A substance released by mast cells that prevents blood clotting.

Histamine

A chemical released by mast cells that promotes reactions associated with inflammation and allergies.

Collagenous Fibers

Thick, cord-like threads of collagen produced by fibroblasts that are flexible, slightly elastic, have great tensile strength, and form important components of tendons and ligaments.

Tensile Strength

The resistance of a fiber or material to breaking under tension.

Elastic Fibers

Stringy, hair-like fibers made of elastin that are weaker than collagenous fibers, easily stretched or deformed, and located in structures subjected to stretching such as vocal cords.

Reticular Fibers

Thin, highly branched collagenous fibers that resemble a tree structure and form delicate supporting networks in tissues such as the spleen and liver.

Areolar Tissue

A delicate, thin loose connective tissue with a gel-like ground substance and spider-web appearance containing collagenous fibers, elastic fibers, blood vessels, mast cells, and macrophages.

Adipose Tissue

A tissue formed when adipocytes storing fat droplets in their cytoplasm crowd out other cell types; located beneath skin and muscles, around kidneys and eyeballs, on the heart, around certain joints, and in abdominal membranes.

Reticular Connective Tissue

Connective tissue consisting of thin, branched reticular fibers that provides the framework for internal organs like the liver and spleen.

Dense Connective Tissue

Connective tissue where fibers occupy more space than cells and ground substance, with poor blood supply resulting in slow healing; located in tendons, ligaments, sclera, and deeper skin.

Chondrocytes

Cartilage cells residing within small compartments in the matrix called lacunae.

Lacunae

Small compartments in the cartilage matrix that contain chondrocytes.

Hyaline Cartilage

The most common cartilage type, composed of very fine collagenous fibers and resembling white glass; located on the ends of bones, in joints, soft part of the nose, and trachea rings.

Fibrocartilage

A very tough cartilage containing many collagenous fibers that forms discs between vertebrae and cushions bones in the knees and pelvic girdle.

Elastic Cartilage

A highly flexible cartilage containing a dense network of elastic fibers that serves as the framework for the external ears and larynx.

Bone Tissue

The most rigid connective tissue with a solid ECM made hard by mineral salts such as calcium phosphate $Ca_3(PO_4)_2$ and calcium carbonate $CaCO_3$; contains marrow, is highly vascularized, and stores inorganic minerals.

Blood

A connective tissue consisting of a fluid extracellular matrix called blood plasma and formed elements (RBCs, WBCs, and platelets) that transports nutrients throughout the body.