The endocrine system is instrumental in regulating mood, growth and development, tissue function, metabolism, as well as sexual function and reproductive processes. This system consists of a network of ductless glands that regulate and balance the body's hormones, PH, temperature and assimilation of light. The endocrine glands include the pineal, pituitary, thyroid, thymus, pancreas, gonads (ovaries and testes) and adrenals.