Final answer:
Higher breast density refers to a larger amount of fibroglandular tissue compared to fatty tissue. This tissue includes the mammary glands which are responsible for milk production. Breast size, determined by fat deposition, does not affect milk production capabilities.
Step-by-step explanation:
Higher breast density is indicative of a greater proportion of fibroglandular tissue relative to fatty tissue within the breast. This fibroglandular tissue is comprised of the mammary glands, which include lobes, lobules, and ducts, primarily involved in milk production and delivery. The mammary glands consist of 15 to 25 lobes that have ducts emptying at the nipple and these lobes are surrounded by adipose and collagenous tissue. The size of the breast itself is determined by the amount of fat deposited around these glands, with variations not affecting the capability for milk production. During lactation, milk produced in the alveoli is transferred via the lactiferous ducts to the nipple, where it becomes available for the nursing child.