State four difference between endocrine and exocrine gland with examples.

Type of Secretions: Endocrine glands secrete hormones directly into the bloodstream. These hormones are chemical messengers that regulate various body functions. For example, the pituitary gland secretes growth hormone which regulates body growth. On the other hand, exocrine glands secrete non-hormonal substances through ducts to the surface of an organ or tissue or into a vessel. For example, the salivary glands secrete saliva into the mouth.

Presence of Ducts: Endocrine glands are ductless. They release their secretions (hormones) directly into the blood. Exocrine glands, however, have ducts and they release their secretions through these ducts onto an epithelial surface. For example, sweat glands have ducts that carry sweat to the surface of the skin.

Target Site: The secretions of endocrine glands (hormones) are carried by the bloodstream to act on target sites which can be a considerable distance away from the gland. For example, insulin produced by the pancreas (an endocrine function) acts on cells throughout the body. In contrast, the secretions of exocrine glands act locally, close to the site of secretion. For example, the enzymes secreted by the pancreas (an exocrine function) act in the small intestine.

Nature of Secretions: The secretions of endocrine glands are usually slower and have long-lasting effects. For example, the thyroid gland secretes thyroid hormones that regulate metabolism over a long period. Exocrine gland secretions, on the other hand, have immediate and short-lived effects. For example, tear glands produce tears that lubricate the eyes immediately.