Biology · Structural Organisation in Animals · NEET
| Duct | Present (secretion goes through duct) | Absent (ductless) |
| Where secretion goes | Onto a surface or into a cavity | Directly into the blood |
| Product | Enzymes, mucus, sweat, saliva, oil, earwax, milk | Hormones |
| Range of action | Local | Distant target organs |
| Examples | Salivary, sweat, sebaceous, mammary, goblet cells | Pituitary, thyroid, adrenal, islets of Langerhans |
Both. The pancreas is a mixed (heterocrine) gland. Its acinar cells act as an EXOCRINE gland, sending digestive enzymes through the pancreatic duct into the duodenum. Its Islets of Langerhans act as an ENDOCRINE gland, releasing insulin and glucagon straight into the blood. In NEET matching questions, 'endocrine glandular epithelium' is matched to the pancreas because of the islets. This exact match came in NEET 2024.
Exocrine. Goblet cells are unicellular glands that release mucus onto the surface of the alimentary canal and airways. Because the mucus goes out onto a surface (not into blood), they are exocrine. They are also the classic example of a UNICELLULAR gland, while most exocrine glands (salivary, sweat) are multicellular.
Earwax (cerumen) is made by ceruminous glands in the ear canal and released through a duct onto the skin surface. Any secretion that leaves the body through a duct onto a surface is exocrine. NEET 2023 tested exactly this: 'Earwax is the secretion of exocrine gland' is a TRUE statement. Other exocrine products to remember: saliva, sweat, milk, oil (sebum) and digestive enzymes.
No. Endocrine glands are ductless. They release hormones directly into the surrounding tissue fluid, from where the hormones enter the blood and reach distant target organs. Examples: pituitary, thyroid, adrenal and the islets of the pancreas. 'Ductless' is the single word NTA uses to mean endocrine.
A duct gland is exocrine: it has a tube (duct) that carries the secretion to a surface or cavity, so the secretion is delivered locally. A ductless gland is endocrine: it has no tube, so the hormone is delivered widely through the blood. Same glandular epithelium origin, different delivery route.
Exocrine. Salivary glands are multicellular exocrine glands that send saliva through ducts into the mouth. In NEET 2024 they were the example of 'multicellular glandular epithelium'. Do not confuse the exocrine/endocrine split (mode of secretion) with the unicellular/multicellular split (number of cells) — a gland is described on both axes.
Given below are two statements: Statement I: Goblet cells are unicellular glands. Statement II: Earwax is the secretion of exocrine gland. In the light of the above statements, choose the correct answer:
Match List I with List II. A. Unicellular glandular epithelium, B. Compound epithelium, C. Multicellular glandular epithelium, D. Endocrine glandular epithelium — with I. Salivary Glands, II. Pancreas, III. Goblet cells of alimentary canal, IV. Moist surface of buccal cavity.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Exocrine glands have ducts and release their product onto a surface or into a cavity; endocrine glands are ductless and release hormones directly into the blood.
Exocrine: salivary glands, sweat glands, sebaceous (oil) glands, mammary glands, ceruminous (earwax) glands, goblet cells, and exocrine pancreas. Endocrine: pituitary, thyroid, parathyroid, adrenal, pineal, and the islets of Langerhans of the pancreas.
A gland that is both exocrine and endocrine. The pancreas is the standard example: acinar cells are exocrine (enzymes via duct) and islets of Langerhans are endocrine (hormones into blood).
No. Glands can be unicellular (a single cell, like a goblet cell) or multicellular (a cluster, like a salivary gland). This is separate from the exocrine/endocrine classification.
Glands develop from glandular epithelium — columnar or cuboidal epithelial cells that become specialised for secretion.
