Chapter Five: Tissue Organization - VOCABULARY Flashcards

Vocabulary flashcards covering epithelial tissue and gland topics from Chapter 5.

Histologist

A professional who studies the microscopic anatomy of cells and tissues, using light and electron microscopy to prepare tissue sections for analysis.

Histology

The study of the microscopic structure of tissues.

Epithelial tissue (epithelium)

Tissue composed of closely packed cells with little extracellular matrix; avascular; lines body surfaces, cavities, and forms glands.

Cellularity

A characteristic of epithelia: tissues are made up almost entirely of tightly packed cells with minimal extracellular matrix.

Polarity

Epithelia have distinct apical, lateral, and basal surfaces.

Apical surface

The exposed surface of an epithelium facing a body cavity or the external environment; may have microvilli or cilia.

Basal surface

The bottom surface of an epithelium attached to the basement membrane.

Basement membrane

A thin, specialized extracellular matrix that anchors epithelium to connective tissue and acts as a selective barrier.

Avascularity

Epithelial tissues lack blood vessels; nutrients diffuse from underlying connective tissue.

Innervation

Epithelia are richly innervated, enabling sensory detection.

Regeneration capacity

Epithelial cells divide rapidly to replace damaged or lost cells.

Gland

A structure of epithelial origin that secretes substances; can be endocrine or exocrine.

Endocrine gland

Gland that releases hormones directly into the bloodstream without ducts.

Exocrine gland

Gland that secretes onto an epithelial surface via a duct; can be unicellular or multicellular.

Unicellular exocrine gland

Single-cell glands that secrete substances without a duct, such as goblet cells.

Goblet cell

Unicellular exocrine gland that secretes mucin to form mucus; common in intestinal and respiratory epithelia.

Mucin

Glycoprotein that forms mucus when hydrated.

Simple epithelium

Epithelium with a single cell layer; suited for absorption, filtration, or secretion.

Stratified epithelium

Epithelium with two or more cell layers; provides protection.

Simple squamous epithelium

Single layer of flat cells; thin barrier for rapid diffusion; lines alveoli and vessels.

Simple cuboidal epithelium

Single layer of cube-shaped cells; secretion and absorption; lines kidney tubules and glands.

Simple columnar epithelium

Single layer of tall cells; absorption and secretion; may be nonciliated with goblet cells or ciliated.

Pseudostratified columnar epithelium

Appears layered but all cells touch the basement membrane; nuclei at different levels; often has goblet cells and cilia.

Pseudostratified ciliated columnar epithelium

Pseudostratified epithelium with cilia and goblet cells; lines larger airways.

Pseudostratified nonciliated columnar epithelium

Rare form lacking cilia; found in parts of the male urethra and epididymis.

Stratified squamous epithelium

Multiple cell layers; basal cells are cuboidal; apical cells are squamous; provides protection.

Keratinized stratified squamous epithelium

Superficial cells are dead and filled with keratin; epidermis.

Nonkeratinized stratified squamous epithelium

All cells alive with visible nuclei; moist; lines mucous membranes.

Stratified cuboidal epithelium

Two or more layers; apical cells cuboidal; protects and secretes; ducts of glands.

Stratified columnar epithelium

Two or more layers; apical cells columnar; rare; protects and secretes; found in select ducts and conjunctiva.

Transitional epithelium

Epithelium of the urinary tract; stretchable; changes shape with urine volume; may be binucleated.

Endothelium

Simple squamous epithelium lining heart chambers, blood vessels, and lymph vessels.

Mesothelium

Simple squamous epithelium lining serous membranes of body cavities.

Acinus (acini)

Cluster of secretory cells forming the secretory portion of a multicellular exocrine gland.

Duct

Tube through which gland secretions are discharged onto the epithelial surface.

Multicellular exocrine gland

Gland composed of many cells with a duct system; often organized into lobes by connective tissue capsule.

Simple gland

Exocrine gland with a single unbranched duct.

Compound gland

Exocrine gland with branched ducts.

Tubular gland

Secretory portion is tubular.

Acinar (alveolar) gland

Secretory portion forms sacs or acini.

Tubuloacinar gland

Gland with both tubular and acinar secretory units.

Merocrine secretion

Secretion released via vesicles by exocytosis; gland cells remain intact.

Apocrine secretion

Apical portion of the cell pinches off to release secretions; the cell regenerates.

Holocrine secretion

Whole cell disintegrates to release its secretions; whole cells become part of the secretion.