Anatomy and Physiology - Tissues, Bone, and Joints

Homeostasis

A dynamic steady state characterised by narrow limits and fluctuations around a set point.

Intracellular Fluid (ICF)

Fluid located inside the body's cells, constituting $67\%$ of total body fluid.

Extracellular Fluid (ECF)

Fluid located outside cells, composed of interstitial fluid ($26\%$) and blood plasma ($7\%$).

Four Tissue Types

The four foundational tissue classifications in the human body: Epithelial, Connective, Muscle, and Nervous.

Epithelial Tissue

A primary tissue type that covers exposed surfaces, lines internal passageways, and forms glands.

Polar Covalent Bonds

The chemical bonds by which hydrogen and oxygen combine to form water molecules.

Hydrolysis

A chemical reaction that reverses the steps of dehydration synthesis.

Electrolytes

Ions formed when substances ionize in water, including Hydrogen ($H^+$), Sodium ($Na^+$), Potassium ($K^+$), Chlorine ($Cl^-$), Magnesium ($Mg^{2+}$), and Calcium ($Ca^{2+}$).

Basement Membrane

A structure that attaches epithelial tissue to underlying connective tissue.

Desmosomes

Cell-to-cell intracellular junctions that anchor adjacent cells together.

Hemidesmosomes

Intracellular junctions that anchor cells to the basement membrane.

Tight Junctions

Intracellular junctions that leave no space between adjacent cell membranes.

Gap Junctions

Intracellular junctions that contain space allowing communication between cells.

Epithelium Layers

Classification of epithelial tissue based on layer arrangement into Simple (single layer) or Stratified (multiple layers).

Epithelium Shapes

Classification of epithelial cell shapes into Squamos, Cuboidal, or Columnar.

Connective Tissue

Tissue composed of cells surrounded by a non-living extracellular matrix.

Fibroblasts

Specialized cells in connective tissue that produce protein fibers.

Collagenous Fibers

Stable triple-helix collagen fibers providing high tensile strength.

Elastic Fibers

Elastin fibers structured in random coils that confer extensibility.

Reticular Fibers

Delicate fiber networks (Reticulin = Type III Collagen) that support individual cells across various organs.

Ground Substance

Component of connective tissue matrix composed of interstitial fluid, adhesion proteins, and proteoglycans ("GAGs").

Areolar Connective Tissue

A loose connective tissue serving as "filler" made of a loose meshwork containing all three fiber types.

Dense Regular Connective Tissue

Dense connective tissue that forms ligaments and tendons.

Dense Irregular Connective Tissue

Dense connective tissue that makes up the dermis of the skin.

Cartilage

Supportive connective tissue composed of a semi-solid matrix.

Chondroblasts

Cartilage-forming cells that produce the extracellular matrix.

Chondrocytes

Mature cartilage cells situated within lacunae.

Hyaline Cartilage

Cartilage containing abundant dense, fine collagen; strong