A woman with small breasts can produce the same amount of milk as a woman with larger breasts. The dark area around the nipple is called areola. On the areola you find the Montgomery glands, they look like small pimples. They produce an oil that lubricates the nipple and discourages the growth of bacteria. At the end of the nipple you'll find the nipple pores where your baby receives the milk through.
Milk is produced in the alveoli, grape like clusters of glandular tissue deep within the breast.
From the alveoli the milk is expelled in small milk ducts and they empty into larger ducts. These larger ducts widen underneath the nipple and areola and form reservoirs where milk collects. The milk collected in these reservoirs or sinuses is the milk the baby receives first when he starts to nurse. It is thirst quenching, high in volume, low in fat. While your baby nurses, new milk is being produced in the alveoli.