Lactation Flashcards
Describe the functional morphological structures of mammary tissue.
Mammary tissue consists of glandular tissue, including lobules and alveoli, which are responsible for milk production. The lobules are connected by ducts that carry milk towards the nipple. Surrounding the glandular tissue are adipose (fat) tissue and connective tissue that provide support and protection to the mammary glands.
Compare and contrast mammary tissue in non-lactating and lactating women.
In non-lactating women, the mammary tissue is relatively quiescent. The lobules and alveoli are small and inactive. In lactating women, mammary tissue undergoes significant changes to support milk production. The lobules and alveoli enlarge, and there is increased branching of the milk ducts. Lactating women also have increased blood flow to the breast and may experience breast engorgement.
What are the roles of progesterone and prolactin in mammary gland development? What is the role of estrogen?
Progesterone and prolactin play essential roles in mammary gland development. Progesterone promotes the growth and branching of the mammary gland during puberty and pregnancy, preparing it for milk production. Prolactin stimulates the proliferation and differentiation of mammary epithelial cells, leading to milk synthesis. Estrogen supports the development of mammary ducts and the growth of stromal tissue, preparing the breast for potential milk production.
Describe the two major hormones involved in lactation.
The two major hormones involved in lactation are prolactin and oxytocin. Prolactin is responsible for milk production and is produced by the anterior pituitary gland. Oxytocin, produced by the posterior pituitary gland, stimulates the contraction of myoepithelial cells around the alveoli, leading to milk ejection (letdown) and promoting milk flow.
How does dopamine act to regulate prolactin secretion?
Dopamine acts as an inhibitory hormone to regulate prolactin secretion. It is produced by the hypothalamus and inhibits the release of prolactin from the anterior pituitary gland. Dopamine inhibits lactotroph cells, which produce prolactin, through a negative feedback loop. Decreased dopamine levels or dopamine receptor antagonists can lead to increased prolactin secretion.
Describe the cessation of lactation
The cessation of lactation typically occurs when breastfeeding frequency decreases or stops. Reduced stimulation of the nipple and breast, along with hormonal changes, leads to a decrease in prolactin levels. As prolactin decreases, milk production slows down and eventually ceases. The process of lactation cessation is called involution, during which the mammary tissue returns to its non-lactating state.
What is the structure/anatomy of the mammary gland/breast?
The mammary gland consists of lobes and lobules. Lobes contain clusters of milk-producing cells called alveoli. These alveoli are connected to ducts that transport milk towards the nipple. The breast is composed of adipose (fat) tissue, connective tissue, blood vessels, and nerves, providing support and protection to the mammary gland.
What are the functional units of the lactating breast?
The functional units of the lactating breast are the alveoli. Alveoli are small, spherical structures within the mammary gland where milk is produced. They are lined with milk-secreting epithelial cells that synthesize and secrete milk components.
How is mammary gland development regulated during puberty?
During puberty, estrogen, and progesterone play key roles in mammary gland development. Estrogen promotes the growth of ductal structures, leading to the development of a branched ductal system. Progesterone stimulates the growth and differentiation of the lobules, preparing the mammary gland for potential future milk production.
How is mammary gland development regulated during pregnancy?
During pregnancy, elevated levels of estrogen and progesterone, primarily from the placenta, promote further development of the mammary gland. Estrogen stimulates the growth and branching of the ductal system, while progesterone supports the growth and maturation of the alveoli. These hormonal changes prepare the mammary gland for milk production.
How is lactation hormonally regulated?
The primary hormones involved in lactation are prolactin and oxytocin. Prolactin, produced by the anterior pituitary gland, stimulates milk synthesis and secretion. Prolactin levels increase in response to suckling and nipple stimulation. Oxytocin, produced by the posterior pituitary gland, triggers milk ejection (letdown) in response to suckling. It stimulates the contraction of myoepithelial cells surrounding the alveoli, allowing milk to flow through the ducts.
