BIOL 441 LEC SLIDES 5 (Connective Tissue Vocabulary)

Vocabulary practice flashcards generated from lecture notes covering Connective Tissue components, cell types, fibers, ECM molecules, pathologies, and classification.

Connective Tissue

The most abundant tissue in the body, distinguished from other tissues by its abundant extracellular matrix (ECM) which carries the mechanical load.

Mesenchyme

The common embryonic tissue from which all classes of connective tissue originate.

Fibroblasts

The most common active cell type in connective tissue proper; elongated cells with cytoplasmic processes, large ovoid nuclei, and prominent nucleoli that synthesize and secrete ECM components.

Fibrocytes

The inactive form of fibroblasts characterized by a small spindle-shaped cell structure with condensed chromatin, capable of reactivating during injury.

Myofibroblast

A connective tissue cell exhibiting features of both fibroblasts and smooth muscle, plays a key role during wound contraction.

Hypertrophic Scar

A raised scar containing nerves and blood vessels that results when myofibroblasts persist and continuously remodel tissue during wound healing.

Fibromatosis

A group of contractive connective tissue diseases characterized by the presence of excessive numbers of myofibroblasts.

Fibrosis

The formation of excessive, stiff collagenous ECM contractures resulting from the inappropriate activation of myofibroblasts by chronic inflammation or mechanical stress.

Structural Proteins

A class of ECM molecules, such as collagens and elastin, that provide strength and flexibility to connective tissue.

Proteoglycans

Protein-polysaccharide complexes in the ECM that function as matrix material or filler.

Adhesive Glycoproteins

Molecules in the ECM, such as fibronectins and laminins, that enable cells to attach to the matrix.

Collagen Fibers

Tough, flexible fibers comprising a family of over $20$ related proteins; forms the most abundant protein in the body ($\text{approximately }30\text{\%}$ of dry weight).

Procollagen

A triple-stranded precursor collagen molecule synthesized with terminal peptide extensions that prevent premature self-assembly inside the cell.

Scurvy

A condition caused by vitamin C deficiency that disrupts the cofactor needed by cross-linking enzymes to stabilize collagen, resulting in impaired wound healing, abnormal capillary bleeding, and defective bone formation.

Keloid Scar

An abnormally large, reddish-purple scar containing excessive collagen that extends beyond the original wound boundary and frequently recurs after removal.

Glycation

The non-enzymatic covalent addition of sugar molecules to functional proteins like collagen or hemoglobin, resulting in reduced functionality.

Reticular Fibers

Extremely thin, highly glycosylated fibers composed of Type III collagen that crosslink to form fine supporting meshworks in soft tissues and lymphoid organs.

Ehlers-Danlos Syndrome

A genetic connective tissue disorder associated with mutations in the genes encoding collagen types III and IV.

Elastic Fibers

Rubber-like protein fibers that allow tissues to stretch or distend and then recoil back to their original shape.

Ground Substance

A complex, gel-like mixture of hydrated macromolecules ($90\text{\%}$ water) filling the space between cells and fibers; acts as a lubricant, compressive barrier, and growth factor binder.

Glycosaminoglycans (GAGs)

Negatively charged, hydrophilic polysaccharides that attract cations like $\text{Na}^+$ and absorb water within the ground substance.

Hyaluronic Acid

The simplest, non-sulfated, and very large GAG that serves as an efficient space-filler due to its size and water-binding capacity.

Loose Connective Tissue

A delicate, flexible packing tissue found beneath epithelium with widely separated protein fibers and a gel-like matrix that allows nutrient and gas diffusion.

White Adipose Tissue

The primary form of adipose tissue, consisting of unilocular cells with a single large lipid droplet used for long-term energy storage, insulation, and protection.

Brown Adipose Tissue

Adipose tissue common in newborns containing multilocular cells packed with mitochondria and thermogenin (UCP1) for non-shivering thermogenesis.

Reticular Connective Tissue

A specialized connective tissue composed purely of Type III collagen fibers that creates a delicate stroma for lymphoid organs such as lymph nodes, spleen, and bone marrow.

Dense Regular Connective Tissue

A strong, flexible tissue containing collagen fibers aligned parallel to the line of pull, providing high resistance to unidirectional stress as seen in tendons and ligaments.

Tendons

Tough, white, and elastic dense regular connective tissue structures containing continuous rows of fibroblasts that anchor muscle to bone.

Ligaments

Yellowish, elastic dense regular connective tissue structures containing scattered fibroblasts that connect bone to bone.

Dense Irregular Connective Tissue

A tissue made of collagen and elastic fibers interwoven in varied directions to resist multidirectional physical stress, found in the dermis and organ capsules.

Fascia

Dense irregular connective tissue that wraps and binds muscles together, fills intermuscular spaces, and houses nerves, blood, and lymph vessels.

Dense Elastic Connective Tissue

Connective tissue consisting of parallel, branching elastic fiber bundles capable of stretching $1\text{ to }1.5\times$ their length before recoiling; located in large arteries and bronchial tubes.