Adrenal gland. Fluorescence deconvolution micrograph of a section through an adrenal gland, showing subcapsular zona glomerulosa and zona fasciculata. Endothelial nitric oxide synthase enzymes are red, smooth muscle actin proteins of blood vessels are blue, connective tissue actin is green. . The adrenal glands are found on top of the kidneys. They are part of the endocrine system, producing stress hormones and releasing them into the bloodstream.