Glands

Glands

Epithelial cells that make and secrete a substance

Exocrine glands

Made of secretory cells derived from the surface epithelium

Localized effect

Secrete product onto external or internal epithelial surfaces

Have ducts (generally)

Endocrine glands

Hormones into blood stream travel to target organ

No ducts

Unicellular gland

Single secretory cell

No duct

Intestinal and respiratory epithelium (goblet cells)

Multicellular gland

Many secretory cells

Simple tubular

Large intestine

Simple branched tubular

Stomach

Simple coiled tubular

Sweat gland (foot pad)

Simple branched acinar

Enlarged spherical secretory unit opens to the surface by a duct

Sebaceous gland

Compound tubular

Seminiferous tubules of testis

Compound acinar

Mammary glands

Compound tubuloacinar

Salivary glands, exocrine pancreas

Serous Gland

Secrete watery product enriched with proteins (enzymes)

Exocrine pancreas (amylase, trypsin, lipase)

Parotid salivary gland, sweat gland (foot pad), lacrimal gland

Image: Serous acinar, stained dark → lots of protein, lots of RER

Mucous gland

Secrete thick and viscous substance rich in mucin (glycoprotein)

Lubricant - protects cell layers, traps foreign particles and bacteria

Goblet cells, sublingual salivary gland

Seromucous gland

Mixed gland - both mucous and serous segments/units

Mandibles salivary gland

Merocrine (Eccrine) gland

Exocytosis

Apocrine gland

Pinch off apical cell cytoplasm with cell product

Halocrine gland

Whole cells

Myoepithelial cells

Not present in all glands

In mammary glands, contraction for milk letdown

Share some properties with smooth muscle, especially contractility