breastfeeding Flashcards
how many lobes are in the breast and how are they arranged?
~20, radiating around areola.
have a duct system that drains down to the nipple.
how is the lactating and nonlactating breast divided?
non lactating breast is more fat (50%) lactating breast (30%) as the lactating breast has hyperplasia of glandular tissue that takes up the space
what are the characteristics of ducts that emerge at the nipple
~9 ducts.
ducts are torturous and branch near the nipple
what is the structure of the mammary gland
- basic secretory units with an alveoli structure that is siting within connective tissue
- alveoli structure is lined by mammary epithelilal cells and myoepithelilal cells
where are myoepithelilal cells and what is their role
surround/line the alveoli.
are contractile and responsible for milk ejection
what is lactogenesis
where the breast is converted from a nonsecretory state to a secretory state
what hormones promote development of the breast during pregnancy
- inc in human placental lactogen and prolactin thus get hyperplasia of the glandular tissue within the breast.
how does progesterone and oestrogen change during pregnancy and what is the effect of this
- progesterone and oestrogen released from placenta .’. high levels
- inhibit actual milk production (although breast is still growing in size)
how does progesterone and oestrogen change after birth and what is the effect of this
- fall in progesterone and oestrogen. stops the inhibition of milk production.
what is lactogenesis postpartum
milk production after birth due to fall in progesterone and oestrogen
how is the breast stimulated to produce milk?
- Suckling of the infant on the breast will stimulate prolactin release driving milk synthesis
- also causes release of oxytocin that drives milk ejection in a positive feedback manner.
what is the autocrine inhibition of milk production
duct cells will inhibit further milk production if there is already lots there. if milk isnt removed from breast, woman will not produce more milk
how is milk synthesis controlled
- mechanical stimulation stimulates release of prolactin from ant. pituitary.
- prolactin to cuboidal cells of milk producing alveoli to inc. milk synthesis
what is the ‘let down reflex’
- suckling stimulates nerve pathways that signal to the hypothalamus to cause release of oxytocin from the posterior pituitary gland.
- oxytocin causes the myoepithelial cells to contract and secrete milk (down the duct and out of nipple)
how can we augment lactation
encourage lactation using dopamine antagonists
- doperidone
- metoclopramide
these are galactagogues.
what is a galactagogue
a food or drug that promotes or increases the flow of a mother’s milk.
how may we suppress lactation
decreasing prolactin secretion by giving dopamine agonists
- bromocriptine
- cabergoline
what are the 5 secretory pathways that get components of milk into the lumen of the milk-producing alveoli?
- exocytosis
- MGF (milk fat globule)
- osmosis
- Ig secretion
- paracellular route
role of exocytosis in getting the components of milk into the lumen of the milk-producing alveoli.
- milk proteins, lactose, calcium and phosphate are packaged into secretory vesicles and exocytosed
- milk proteins synthesised in RER -> golgi, where Ca and phosphate are added.
Lactose synthesised @ golgi. as it cannot move out, water is drawn in osmotically. Vesicle fuses with apical membrane and contents transferred to alveolar lumen.
role of milk fat globule (MFG) in getting the components of milk into the lumen of the milk-producing alveoli.
Lipids are produced on the smooth endoplasmic reticulum, packaged into milk fat globules and these fat globules then get surrounded by a thin membrane. These are then found in the milk.
role of osmosis in getting the components of milk into the lumen of the milk-producing alveoli.
Secretion of certain ions, water, Na+ and K+ can freely move out of the cell into the lumen
role of Ig Secretion in getting the components of milk into the lumen of the milk-producing alveoli.
Secretory IgA binds to a receptor on the basolateral cellular wall. The receptor and IgA are transported in an endocytotic vesicle and emptied to the Golgi body or apical membrane
Paracellular route in getting the components of milk into the lumen of the milk-producing alveoli.
These are normally closed, but can be open in pregnancy as well as in conditions like mastitis and involuting breasts.
In these instances there will be higher NaCl and lower concentrations of lactose and K in breast milk.
what are the components of breast milk
Nutrients – Macronutrients (major component, protein, carb, fat) and trace elements (low solute load, good for neonate kidneys) Immunoglobulin – Secretory IgA Cells – Macrophages and lymophocytes Non-specific immune components Growth factors
difference between macronutrients in breastmilk and formula milk
human milk has 70kcal of energy per 100ml in mature milk, 7.3g of lactose, 0.9g protein and 4.2g fat.
slightly higher than formular milk
formular milk made from cows milk, which has v different composition
how does volume of breast milk change over time, post partum?
nitially on days 1-2, very little milk is produced. However by day 3 milk production increases a lot and continues to increase to meet the infants demand. You can fully breastfeed in this way up to 6 months of age
how does composition of breast milk change over time, post partum
- inititally milk has lower levels of lactose and icreases over time
- initially high salt, decreases over time
how does composition of breast milk change during a single feed
As time goes on during the course of a feed the amount of fat increases in the milk, this is called the hindmilk and is fat rich
what are the gastrointestinal benefits of breastfeeding
breastmilk contains inc. whey (70%) to casin (30%) fraction. whey = more soluble in acid .’, more soluble in stomach .’. promotes gastric emptying.
breastmilk also contains bile salt activated lipase, which helps to activate the fat component.
important in preventing necrotizing enterocolitis (NEC).
what is necrotizing enterocolitis (NEC),
The wall of the intestine is invaded by bacteria, which cause local infection and inflammation that can ultimately destroy the wall of the bowel (intestine)
what are nutritional benefits of breastmilk for the baby
Human milk: higher whey70%: casein30% fraction.
Lactoferrin, lysozyme and sIgA are whey proteins important in host defence.
breastmilk has LCPUFA important for brain/retinal development
what are the immunological benefits of breastfeeding for the baby
term babies - IgG transferred from placenta to baby in third trimester so have inbuilt passive immunity.
preterm babies will not have this so immunity from BM is vital.
what immune factors are contained in breast milk
- sIgA is a specific immune response
- Complement – high complement 3 (C3)
- Lactoferrin – Inhibits bacterial growth by binding iron
- Lysozyme – cleaves peptidoglycans of bacterial walls
- Cytokines – Predominantly anti-inflammatory cytokines are found, this allows human milk to protect but not injure the GIT
- PAF acetylhydrolase – Inhibits platelet activating factor (may be why helps NEC)
- Oligosaccharides – Act as food for bacterial flora in colon, this inhibits binding of enteric/respiratory pathogens to epithelial cells
- Epidermal growth factors – Enhance development of gastrointestinal epithelium
- Cellular elements – Neutrophils and macrophages
what is the enteromammary axis
Pathogens in the mother recognised in intestine stimulate immune response in Peyers Patches.
Lymphocyte starts secreting IgA for that pathogen.
These sIgA will get into the breast milk and therefore the infant will receive sIgA for the pathogen that had infected the mother.
short term benefits of breastfeeding for the infant
- Improved immunity, less infections and infectious morbidity
- Reduces GI infections
- Reduced respiratory infections
- Reduced urinary tract infections
- reduced risk of SIDS
long term benefits of breastfeeding for the infant
- Lower risk of T1DM and T2DM
- Reduced risk of childhood obesity
- Prevention/delay of allergies
- Reduced risk of childhood leukaemia
- Reduced adolescent cholesterol levels
- Lower BP
- better cognitive development(?)
benefits of breastfeeding for the mother
- stimulates release of oxytocin causes the uterus to contract and reduces risk of postpartum haemorrhage
- Breast cancer due to reduced oestrogen exposure
- Ovarian cancer (suggestive evidence)
- Lose baby weight
signs of good attachment to the breast
mouth being wide open, being full, the chin should be close to the breast and lower lip everted.
Also more of the areola should be visible above the baby’s mouth than below. Should also hear sucking and swallowing as the milk goes in
what is the non-nuteritive sucking
occurs in short fast bursts at a rate of up to 2 sucks a second.
when initially put on the breast there is little or no milk in order to try get the milk let down reflex activated through the mechanical stimulation.
what is nutritive sucking
once the let down reflex occurs there is slower paced sucking and this is nutritive sucking.
