Endocrine system in a 5 year old child, endocrine glands. This illustration represents the anatomy of the endocrine system in a silhouette of a 5 year old child. The endocrine system is made up of the endocrine glands. we find there the pineal gland, the hypothalamus and the pituitary gland in the brain. Then there is the thyroid gland, larger in children and the thymus, which has become almost nonexistent in adults. And finally, there is the pancreas, adrenal glands and gonads. In boys, the gonads represent the testes while in girls, they are the ovaries. But this system also consists of organs endowed with endocrine cells as in the digestive tract.