Which one is part of the endocrine system?

A. sweat gland

B. tear gland

C. pituitary gland

D. all of the above

For the given question, the right option is option "D". The sweat gland, the tear gland and the pituitary gland are all part of the endocrine system. Some of the glands release their secretion in certain specific areas onlym while other glands release secretion for different types of purposes. The tear gland and the sweat gland are perfect examples of exocrine glands that release sweat through the skin and saliva in the mouth respectively. Endocrine glands are glands that are capable of releasing about 20 different types of hormones directly in the bloodstream.