Glands: Structure and Classification

Vocabulary flashcards covering the structure, classification, secretory methods, and examples of glands as described in the lecture notes.

Merocrine glands

Secretions released by exocytosis with no damage to the secretory cell; vesicles fuse with the membrane to release the product (e.g., salivary glands, eccrine sweat glands).

Apocrine glands

Secretions formed by pinching off a portion of the apical cell; the cell repairs and continues, examples include mammary glands and some sweat glands.

Holocrine glands

Secretory products released when the entire cell ruptures and dies; secretory cells are replaced by division (e.g., sebaceous glands).

Endocrine glands

Glands that secrete hormones directly into the bloodstream or surrounding interstitial fluid; examples include adrenal, thyroid, and pituitary glands.

Exocrine glands

Glands that secrete into ducts or onto surfaces (skin, mucosal surfaces); can be unicellular or multicellular. Secretions include mucin, enzymes, electrolytes, etc.

Goblet cell

Unicellular exocrine gland that secretes mucin to form mucus; located in epithelial tissue such as airways and trachea.

Unicellular exocrine gland

A single-cell gland (no duct system); goblet cells are classic examples. Secretes directly onto surfaces or into ducts if present.

Multicellular exocrine gland

Glands composed of many cells with a duct system; secretory portions can be tubular or alveolar and can be simple or compound.

Simple gland

Gland with a single duct (unbranched); secretory portions can be tubular or alveolar.

Compound gland

Gland with multiple ducts (branched); secretory portions may be tubular, acinar (alveolar), or tubuloacinar.

Tubular gland

Secretory portion is tube-shaped.

Alveolar (acinar) gland

Secretory portion forms a sac-like acinus.

Simple tubular

A simple gland with a straight tubular secretory portion and a single duct.

Simple coiled tubular

A simple gland with a coiled secretory portion; often exemplified by certain sweat glands.

Simple branched tubular

A simple gland with a branched secretory portion but a single duct.

Compound tubular

A compound gland with tubular secretory units and multiple ducts.

Compound acinar (alveolar)

A compound gland with sac-like acinar secretory units and multiple ducts.

Compound tubuloacinar

A compound gland with both tubular and acinar secretory units and multiple ducts.

Merocrine secretion

Secretions released by exocytosis without damaging the secretory cell.

Apocrine secretion

Secretions released by pinching off a portion of the cell’s apical cytoplasm; the cell regenerates and continues secreting.

Holocrine secretion

Secretions produced by rupture and release of the entire secretory cell; cell is replaced by division.

Mucoid secretion

Thick, viscous mucus produced by goblet cells (mucin-rich).

Serous secretion

Watery, enzyme-rich secretion produced by some glands.

Eccrine sweat glands

Merocrine glands that secrete watery sweat for thermoregulation via exocytosis.

Sebaceous glands

Holocrine glands that secrete sebum; the entire secretory cell ruptures to release the product.

Gastric pits

Simple tubular glands in the stomach that contain diverse cells (parietal, chief, mucous, etc.) for digestion.