BIOL 441 LEC SLIDES 4 (Epithelial Tissue and Glands)

Vocabulary flashcards covering epithelial tissue types, exocrine and endocrine gland classifications, specialized epithelia, and tissue distribution across the human body.

Exocrine Gland

A gland that secretes chemical products through ducts directly onto an epithelial surface.

Endocrine Gland

A ductless gland that secretes hormones directly into surrounding connective tissue and capillaries to enter the bloodstream.

Secretory Unit

A group of secretory epithelial cells enclosing a small lumen in an exocrine gland.

Duct

An epithelial-lined tube with a relatively large lumen that conveys secretions from a secretory unit to an epithelial surface.

Simple Exocrine Gland

An exocrine gland possessing an unbranched duct system.

Compound Exocrine Gland

An exocrine gland possessing a branched duct system.

Tubular Secretory Unit

A secretory unit shaped like a uniform tube.

Acinar Secretory Unit

A berry-shaped or alveolar secretory unit enclosing a lumen.

Serous Secretion

A watery, enzyme-containing secretion produced by exocrine gland cells.

Mucous Secretion

A viscous glycoprotein secretion produced by glandular epithelial cells.

Mixed Secretion

A glandular release composed of both watery serous fluid and viscous mucous secretion.

Merocrine Gland

An exocrine gland that releases its secretory product via exocytosis without loss of cell membrane or cytoplasm.

Holocrine Gland

An exocrine gland whose cells accumulate secretory products, die, and completely degenerate to release the secretion, such as a sebaceous gland.

Apocrine Gland

An exocrine gland where the apical portion of the secretory cell is lost or pinched off to form the secretion.

Composite Glands

Glands that perform both exocrine and endocrine functions, such as the liver and pancreas.

Myoepithelial Cells

Contractile cells containing actin and myosin microfilaments located between secretory epithelial cells and the basal lamina that help eject secretions from glands.

Exchange Epithelium

Simple squamous epithelium specialized for rapid passage and exchange of gases and fluid.

Protective Epithelium

Stratified squamous epithelium designed to protect underlying tissues from mechanical wear and environmental exposure.

Ciliated Epithelium

Columnar epithelial tissue bearing apical cilia that beat rhythmically to move fluid and particles across surfaces.

Transporting Epithelium

Cuboidal or columnar epithelium that actively and selectively regulates the exchange of nongaseous materials across membrane barriers.

Secretory Epithelium

Cuboidal or columnar epithelium specialized for secreting substances, forming endocrine and exocrine glands including goblet cells.

Mesothelium

A specialized epithelium of simple squamous cells on a thin basement membrane lining body cavities like the pleura, peritoneum, and pericardium that secretes serous fluid.

Serous Membrane

A membrane composed of two mesothelial layers—an inner visceral layer and an outer parietal layer—that produces serous fluid.

Visceral Layer

The inner layer of a serous membrane directly covering internal organs.

Parietal Layer

The outer layer of a serous membrane lining the internal walls of body cavities.

Endothelium

Simple squamous cell epithelium that lines the interior surface of blood vessels and lymphatic vessels, providing a semi-selective barrier and non-thrombogenic surface.

Vasomotion

The active control of blood vessel caliber and vascular tone mediated by endothelial cells to regulate blood pressure.

Carcinoma

Any malignant tumor or cancer originating from epithelial tissue cells.

Simple Cuboidal Epithelium

A single layer of cube-shaped cells with central round nuclei lining renal tubules and thyroid follicles.

Simple Columnar Epithelium with Microvilli

A single layer of tall rectangular cells with an apical brush border of microvilli and interspersed goblet cells for enhanced nutrient absorption.

Simple Columnar Epithelium with Cilia

A single layer of tall cells bearing surface cilia that beat in unison to transport mucus or fluids.

Keratinized Stratified Squamous Epithelium

Multi-layered epithelial tissue covered by a cornified layer of flattened, fused cell remnants over a basement membrane and dermis with a $50\,\mu\text{m}$ scale reference.

Pseudostratified Columnar Epithelium

A single layer of column-like cells attached to the basement membrane at different levels, creating a stratified appearance; often ciliated with goblet cells.

Transitional Epithelium

A specialized stratified epithelium in the urinary system that can stretch and change shape in response to fluid volume changes.