Histology & Bone Anatomy – Vocabulary Flashcards

A comprehensive set of vocabulary flashcards covering key concepts in epithelial tissue, intercellular junctions, bone types, structure, blood supply, and ossification processes.

Tissue

A group of similar cells and their extracellular products that perform a common function.

Extracellular Matrix (ECM)

Material produced by cells, composed of protein fibers and ground substance, surrounding and supporting the cells.

Epithelial Tissue

One of the four tissue types; covers exposed surfaces, lines cavities, and forms glands.

Connective Tissue

Tissue type that protects, supports, and interconnects body parts and organs.

Muscle Tissue

Tissue specialized for contraction to produce movement.

Nervous Tissue

Tissue specialized for conducting electrical impulses and information processing.

Avascular

Lacking blood vessels; describes epithelial tissue which receives nutrients by diffusion.

Polarity (in epithelia)

Presence of structural and functional differences between the apical, lateral, and basal surfaces of epithelial cells.

High Regenerative Capacity (epithelium)

Rapid cell division that replaces damaged or lost epithelial cells, maintaining barrier integrity.

Apical Surface

The free surface of an epithelial cell that faces the body exterior or lumen.

Lateral Surface

The side surfaces of epithelial cells that contact adjacent cells.

Basal Surface

The surface of an epithelial cell attached to the basement membrane.

Basement Membrane

Thin extracellular layer anchoring epithelium to underlying connective tissue.

Tight Junction

Intercellular junction that forms a seal to prevent passage of molecules between cells.

Adhering (Adherens) Junction

Junction with actin microfilaments that strengthens the apical surface and stabilizes tight junctions.

Desmosome

Button-like junction with intermediate filaments providing strong cell-to-cell adhesion.

Hemidesmosome

Half-desmosome anchoring basal cells to the basement membrane.

Gap Junction

Intercellular channel (connexon) that allows ions and small molecules to pass between cells for communication.

Goblet Cell

Unicellular mucous-secreting epithelial gland found in the digestive and respiratory tracts.

Keratinized Stratified Squamous Epithelium

Epithelia with surface layers of dead, keratin-filled cells; forms the epidermis of skin for protection and water resistance.

Non-keratinized Stratified Squamous Epithelium

Moist surface epithelium lacking surface keratin; lines oral cavity, esophagus, vagina.

Long Bone

Bone longer than wide (e.g., femur); has a shaft and two ends.

Short Bone

Nearly equal length and width (e.g., carpals, tarsals).

Flat Bone

Thin, flattened bones (e.g., sternum, cranial bones) providing protection and surface for muscle attachment.

Irregular Bone

Complex-shaped bones (e.g., vertebrae) that don’t fit other categories.

Diaphysis

Shaft of a long bone; provides leverage and houses the medullary cavity.

Metaphysis

Region between diaphysis and epiphysis; contains epiphyseal plate/line where growth in length occurs.

Epiphysis

Expanded end of a long bone; forms joints and contains spongy bone with red marrow.

Articular (Hyaline) Cartilage

Hyaline cartilage covering joint surfaces of bones; reduces friction and absorbs shock.

Medullary Cavity

Central cavity of long bones containing yellow (fatty) marrow in adults.

Nutrient Foramen

Opening in bone shaft through which the nutrient artery enters to supply bone tissue.

Periosteum

Tough membrane covering outer bone surface except at articular cartilage; has outer fibrous layer and inner cellular (osteogenic) layer.

Endosteum

Thin membrane lining medullary cavities, canals, and trabeculae inside bone; contains osteogenic cells.

Periosteal Arteries

Small vessels in periosteum that supply the outer compact bone.

Epiphyseal Artery

Blood vessel supplying the epiphysis of a long bone.

Metaphyseal Artery

Artery supplying the metaphysis and epiphyseal plate region.

Tensile Strength (Bone)

Resistance to stretching forces, provided mainly by collagen fibers.

Compression Resistance (Bone)

Ability to resist crushing forces, provided by mineral salts (hydroxyapatite).

Ossification Center

Localized area where bone forms; mesenchymal cells differentiate into osteoblasts during intramembranous ossification.

Intramembranous Ossification

Bone formation directly from mesenchyme; produces flat bones of skull, clavicle, some facial bones.

Endochondral Ossification

Bone formation that replaces a hyaline cartilage model; responsible for forming most bones of the body.

Secondary Ossification Center

Center of bone formation in the epiphysis that appears after the primary center; often associated with tubercles and condyles.

Tubercles

Small, rounded bone projections that may develop their own secondary ossification centers.

Condyles

Rounded articular bone surfaces that can have secondary ossification centers.

Appositional Bone Growth

Growth in bone thickness through addition of new bone at the periosteal surface while osteoclasts enlarge the medullary cavity.

Fibrous Layer (Periosteum)

Outer dense irregular connective tissue layer of periosteum providing attachment for tendons and ligaments.

Cellular (Osteogenic) Layer

Inner periosteal layer containing osteoprogenitor cells, osteoblasts, and osteoclasts for bone growth and repair.