Breast feeding Flashcards
What are the two non invasive types of breast cancer
Ductal carcinoma in situ (cancer cells are found in the lining of the duct)
Lobular carcinoma in situ (cancer cells are found in the lobules)
What are the two types of invasive breast cancer
Infiltrating ductal carcinoma (penetrates the wall of the duct and travels to area outside of it)
Infiltrating lobular carcinoma (spreads through the wall of the lobule and also travels to areas outside of it)
What is the most common type of breast cancer
Infiltrating ductal carcinoma
What exists between lobes in the breast
Septa
What attaches glands in breast to dermis of overlaying skin
Suspensory ligaments (of Cooper)
What hormones cause lactation
Prolactin and oxytocin
What hormones cause breast changes in pregnancy
Progesterone
Estrogens
Prolactin
What changes occur in pregnancy in breasts
Increase in vascularity and melanin pigmentation in nipple and areola
HYperplastic proliferation of terminal ductile epithelium, vacuoles in luminal epithelial cells, formation of true alveoli (because of prolactin and progesterone)
2+3rd trimester: increasing lipid rich proteinaceous secretion )(not true milk) into alveoli
Increase in support tissue (loose lobular tissues)
How does alveolar switch occur
receptors for oestrogen and progesterone are present on epithelium of the ductules; prolactin receptor expression in alveoli are inhibited by high levels of progesterone during pregnancy
After birth, progesterone levels drop. Prolactin receptors are now expressed on surface of breast alveolar cells and true milk production can begin.
What leads to the non-secreting state of female breasts
Alveolar distension, capillary occlusion and alveolar hypoxia. The ductule system rather than the alveolar system predominates
What is full milk production like in pregnancy and wh
Inhibited
Inhibition of expression of prolactin preceptors by pregnancy levels of oestrogen and progesterone makes placental prolactin ineffective
How does lactogenssis start
After birth
Drop in levels of oestrogen and progesterone after expulsion of placenta allows dominance of mother’s pituitary prolactin and this activates alveolar prolactin receptors. Breast now fully responsive to prolactin and so lactogenesis starts
Where is the prolactin that stimulates alveolar cells to produce milk come from
Anterior pituitary. NOT the placenta
What is the suckling-induced reflex
When baby suckles, sensory information causes release of the neuropeptide prolactin from anterior lobe of pituitary gland. Causes more milk production. Nipple stimulation by suckling is essential for keeping prolactin levels high. Strength and duration of suckling influences amount of prolactin released. Cessation of breast feeding results in inhibition of lactation
What is the milk ejection reflex
Sensory information via the spinal cord and brainstem activates oxytocin neurone In the hypothalamus
There is signalling between hypothalamus and posterior pituitary. Oxytocin is synthesised and released from posterior pituitary into bloodstream. On reaching the mammary gland, oxytocin causes contraction of my-epithelial cells surrounding alveoli to induce expulsion of milk into ductal system and lactiferous sinus
A build up of intra-mammary pressure or milk let down then occurs, causing milk to spurt from nipple
