The tissue composition ratios of the breast also vary among women. Some womens breasts have a higher proportion of glandular tissue than of adipose or connective tissues. The fat-to-connective-tissue ratio determines the density or firmness of the breast. During a womans life, her breasts change size, shape, and weight due to hormonal changes during puberty, the menstrual cycle, pregnancy, breastfeeding, and menopause. Glandular structure
The breast is an apocrine gland that produces the milk used to feed an infant. The nipple of the breast is surrounded by the areola (nipple-areola complex). The areola has many sebaceous glands, and the skin color varies from pink to dark brown. The basic units of the breast are the terminal duct lobular units (TDLUs), which produce the fatty breast milk. They give the breast its offspring-feeding functions as a mammary gland. They are distributed throughout the body of the breast. Approximately two-thirds of the lactiferous tissue is within 30 mm of the base of the nipple. The terminal lactiferous ducts drain the milk from TDLUs into 4–18 lactiferous ducts, which drain to the nipple. The milk-glands-to-fat ratio is 2:1 in a lactating woman, and 1:1 in a non-lactating woman. In addition to the milk glands, the breast is also composed of connective tissues (collagen, elastin), white fat, and the suspensory Coopers ligaments. Sensation in the breast is provided by the peripheral nervous system innervation by means of the front (anterior) and side (lateral) cutaneous branches of the fourth-, fifth-, and sixth intercostal nerves.
This pathogen and its associated syndrome (characterized by lethargy, fever, and pale mucous membranes) was previously observed in only wild sheep and goats in the region, and is the first observed occurrence of A. ovis in reindeer. In Australia, bovine anaplasmosis, caused by A. marginale, is found in only the northern and eastern parts of Australia where the cattle tick is present. It was probably introduced as early as 1829 by cattle from Indonesia infested with the cattle tick Boophilus microplus.The veterinarian George P. Broussard of New Iberia, Louisiana, conducted important research on anaplasmosis and brucellosis. References


== External links ==