any structural anomaly of any of the glands of the exocrine system that secrete their essential product by way of a duct to some environment external to itself, either inside the body or on a surface of the body; the duct portion may be branched (compound) or unbranched (simple); the glandular portion may be tubular or acinar, or may be a mix of the two (tubuloacinar or tubuloalveolar); if the glandular portion branches, then the gland is called a branched gland Typical exocrine glands include sweat glands, salivary glands, mammary glands, stomach, liver, pancreas