How do the exocrine and endocrine glands differ? What are heterocrine glands ?

Explanation

Exocrine glands have ducts to send their secretions to the sites of action, endocrine glands lack ducts, release their secretions into the blood stream stream that carries them to the target organs. Heterocrine glands have both exocrine and endocrine tissues, the former send their secretions via ducts and the latter through the blood.