Covering and Glandular Epithelia

Vocabulary practice flashcards covering the classification, histology, morphological characteristics, and glandular types of covering and glandular epithelia.

Simple cuboidal epithelium

An epithelial tissue consisting of a single layer of cells where $\text{height} = \text{width} = \text{depth}$, commonly lining structures such as renal collecting tubules and thyroid follicles.

Simple squamous epithelium

A single layer of flattened cells lining surfaces such as Bowman's capsule layer and blood and lymphatic vessels (where it is termed endothelium).

Simple columnar epithelium

A single layer of epithelial cells whose $\text{height} > \text{width}$, lining organs such as the stomach and intestine.

Brush border

A specialized border of densely packed microvilli located on the apical surface of simple columnar epithelial cells to increase absorption surface area.

Respiratory type epithelium

A simple or pseudostratified columnar epithelium equipped with cilia, typical of the respiratory tract lining.

Stratified squamous epithelium (keratinized)

A multi-layered, waterproof protective epithelium found in the epidermis, organized into basal, spinous, granular, transparent, and keratin layers.

Stratified squamous epithelium (non-keratinized)

A moist, multi-layered protective epithelium featuring living cells in its superficial squamous layer and a basal layer, found lining moist cavities such as the vagina.

Transitional epithelium (Urothelium)

A stratified epithelium with variable thickness that lines most of the urinary tract (from kidney to proximal urethra) and features large, protective umbrella cells on its luminal surface.

Umbrella cells

Large, dome-shaped superficial cells found at the outermost layer of transitional epithelium (urothelium) that adapt to changes in epithelial stretching.

Glands

Secretory structures that originate embryologically from epithelial cells invading the underlying connective tissue.

Exocrine glands

Glands equipped with ducts that transport and discharge their secretory products directly onto an epithelial surface.

Endocrine glands

Ductless glands whose secretory cells discharge hormones and products directly through the blood or lymphatic circulatory system.

Goblet cells

Unicellular exocrine glands consisting of single specialized secretory cells that produce and secrete mucus in the lining epithelium of the small intestine and respiratory tract.

Serous secretory gland acini

Acini composed of serous secreting cells that produce a thin, watery, protein-rich secretion.

Mucus secretory gland acini

Acini composed of mucus secreting cells that synthesize and release thick, viscous mucus.

Mucoserous gland acini

Mixed-type glandular secretory units containing both serous and mucus secreting cells, such as those present in the bronchus.

Sweat gland

An exocrine skin gland consisting of secretory acini and ducts located within the subcutaneous connective tissue alongside adipocytes.

Sebaceous gland

A lipid-secreting cutaneous gland found in thin skin composed of peripheral basal regenerative cells and central lipid-filled secretory cells bounded by a connective tissue layer.

Thyroid follicles

Cystic spherical units in the thyroid gland lined by simple cuboidal epithelium and filled with a viscous liquid called colloid.

Colloid

The viscous proteinaceous liquid stored inside the lumen of thyroid follicles.

Parathyroid gland

An endocrine gland where glandular cells are organized into linear sequences (rows) or clusters (nests/aggregates), intimately associated with capillaries and adipocytes.