Final answer:
The two major classifications of glandular epithelium are endocrine and exocrine glands. Endocrine glands release hormones directly into the bloodstream, while exocrine glands secrete their substances through a duct that opens to the external environment.
Step-by-step explanation:
The two major classifications of glandular epithelium are endocrine and exocrine.
1) Endocrine glands are ductless glands that release their secretions directly into surrounding tissues and fluids. They release hormones into the bloodstream to regulate bodily functions.
2) Exocrine glands secrete their substances through a duct that opens either directly or indirectly to the external environment. Examples include sweat glands and salivary glands.