Question

define endocrine glands and exocrine glands and heterocrine gland

Answer 1

Exocrine glands are glands that produce and secrete substances onto an epithelial surface by way of a duct. Examples of exocrine glands include sweat, salivary, mammary, ceruminous, lacrimal, sebaceous, and mucous.
endocrine glands are glands of the endocrine system that secrete their products, hormones, directly into the blood rather than through a duct. The major glands of the endocrine system include the pineal gland, pituitary gland, pancreas, ovaries, testes, thyroid gland, parathyroid gland, hypothalamus and adrenal glands.
Heterocrine glands are those glands which have both exocrine and endocrine characteristics. Pancreas, testis and ovaries are examples of the same.

Answer 2

``Exo'' means external or outside and ``crine''means secretions.These glands secrete their product external to itself,either in the body.it secrete ``sweat'',``oil''etc .Example  ``sweat gland,salivary gland                                      ``endo''means``within and ``crine''means secrtions.These gland have no duct.they secrete hormones.Examples``pituitary gland''and ``thyroid galnd''