Question

Structure that is ectodermal in origin is

• A. Pituitary gland
• B. Pineal body
• C. Lens of eye
• D. All of the above

Answer 1

The correct option is D All of the above

All secretory glands, whether exocrine or endocrine, develop from epithelia. Endocrine organs develop from the epithelia, that cover the outside of the embryo, that lines the digestive tract, and that lines the coelomic cavity. The hypothalamus, pituitary, and pineal gland develop from ectoderm. The pineal gland develops from the ectoderm of the diencephalon as an outgrowth between the thalamus and the superior and inferior colliculi. The adrenal cortex develops from mesoderm. The adrenal medulla develops from the neural crest. The thyroid gland, parathyroid glands, pancreas, and thymus develop from endoderm. Certain gastrointestinal cells, that develop from endoderm secrete hormones (e.g., stomach and intestinal gastrin, secretin, cholecystokinin (CCK), enterocrinin, and gastric inhibitory peptide (GIP) that aid digestion.

The surface ectoderm gives rise to the crystalline lens, the lacrimal gland, the meibomian glands, the corneal and conjunctival epithelium and the epidermis of the eyelids.