Final answer:
The lobule's shape and definition in the mammary gland are provided by supportive connective tissue, which includes suspensory ligaments made of collagenous and adipose tissue.
Step-by-step explanation:
The specialized tissue that gives the lobule its shape and definition in the mammary gland is the supportive connective tissue. This tissue is primarily composed of suspensory ligaments made of collagenous and adipose tissue. The lobules themselves are key functional structures in milk production and are comprised of clusters of alveoli that secrete milk into the lactiferous ducts.
The fat tissue surrounding the lobes mainly determines the size of the breast but is not indicative of the amount of milk produced. During lactation, stimulated myoepithelial cells contract to push the milk through the ducts, and then, the baby can draw milk through the suckling process.