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A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring.Mammals get their name from the Latin word mamma, "breast".The mammary glands are arranged in organs such as the breasts in primates (for example, humans and chimpanzees), the udder in ruminants (for example, cows, goats, sheep, and deer), and the dugs of other animals (for example, dogs ...
Lactiferous ducts are ducts that converge and form a branched system connecting the nipple to the lobules of the mammary gland.When lactogenesis occurs, under the influence of hormones, the milk is moved to the nipple by the action of smooth muscle contractions along the ductal system to the tip of the nipple.
A mammary alveolus (pl.: alveoli, from Latin alveolus, "little cavity") is a small cavity or sac found in the mammary gland. [1] [2] Mammary alveoli are the site of milk production and storage in the mammary gland. [1] [2] Mammary alveoli cluster into groups called mammary lobules, and each breast may contain 15 to 20 of these lobules.
The female adult breast contains 14–18 irregular lactiferous lobes that converge at the nipple. The 2.0–4.5 mm milk ducts are immediately surrounded with dense connective tissue that support the glands. Milk exits the breast through the nipple, which is surrounded by a pigmented area of skin called the areola.
The mammary ridge is primordial for the mammary glands on the chest in humans, and is associated with mammary gland and breast development.. In human embryogenesis, the mammary ridge usually appears as a narrow, microscopic ectodermal thickening during the first seven weeks of pregnancy and grows caudally as a narrow, linear ridge. [1]
A poor milk ejection reflex can be due to sore or cracked nipples, separation from the infant, a history of breast surgery, or tissue damage from prior breast trauma. If a mother has trouble breastfeeding, different methods of assisting the milk ejection reflex may help.
The suckling stimulus also triggers the release of oxytocin from the posterior pituitary gland, which triggers milk let-down: Prolactin controls milk production (lactogenesis) but not the milk-ejection reflex; the rise in prolactin fills the breast with milk in preparation for the next feed. The posterior pituitary produces a yet-unidentified ...
[59] [60] Accordingly, overexpression of COX-2 in mammary gland tissue produces mammary gland hyperplasia as well as precocious mammary gland development in female mice, mirroring the phenotype of VDR knockout mice, and demonstrating a strong stimulatory effect of COX-2, which is downregulated by VDR activation, on the growth of the mammary glands.