breastfeeding

Question 1

how many lobes are in the breast and how are they arranged?

Answer 1

~20, radiating around areola.

have a duct system that drains down to the nipple.

Question 2

how is the lactating and nonlactating breast divided?

Answer 2

non lactating breast is more fat (50%)
lactating breast (30%) as the lactating breast has hyperplasia of glandular tissue that takes up the space

Question 3

what are the characteristics of ducts that emerge at the nipple

Answer 3

~9 ducts.

ducts are torturous and branch near the nipple

Question 4

what is the structure of the mammary gland

Answer 4

• basic secretory units with an alveoli structure that is siting within connective tissue
• alveoli structure is lined by mammary epithelilal cells and myoepithelilal cells

Question 5

where are myoepithelilal cells and what is their role

Answer 5

surround/line the alveoli.

are contractile and responsible for milk ejection

Question 6

what is lactogenesis

Answer 6

where the breast is converted from a nonsecretory state to a secretory state

Question 7

what hormones promote development of the breast during pregnancy

Answer 7

• inc in human placental lactogen and prolactin thus get hyperplasia of the glandular tissue within the breast.

Question 8

how does progesterone and oestrogen change during pregnancy and what is the effect of this

Answer 8

• progesterone and oestrogen released from placenta .’. high levels
• inhibit actual milk production (although breast is still growing in size)

Question 9

how does progesterone and oestrogen change after birth and what is the effect of this

Answer 9

• fall in progesterone and oestrogen. stops the inhibition of milk production.

Question 10

what is lactogenesis postpartum

Answer 10

milk production after birth due to fall in progesterone and oestrogen

Question 11

how is the breast stimulated to produce milk?

Answer 11

• 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.

Question 12

what is the autocrine inhibition of milk production

Answer 12

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

Question 13

how is milk synthesis controlled

Answer 13

• mechanical stimulation stimulates release of prolactin from ant. pituitary.
• prolactin to cuboidal cells of milk producing alveoli to inc. milk synthesis

Question 14

what is the ‘let down reflex’

Answer 14

• 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)

Question 15

how can we augment lactation

Answer 15

encourage lactation using dopamine antagonists
- doperidone
- metoclopramide
these are galactagogues.

Question 16

what is a galactagogue

Answer 16

a food or drug that promotes or increases the flow of a mother’s milk.

Question 17

how may we suppress lactation

Answer 17

decreasing prolactin secretion by giving dopamine agonists

• bromocriptine
• cabergoline

Question 18

what are the 5 secretory pathways that get components of milk into the lumen of the milk-producing alveoli?

Answer 18

• exocytosis
• MGF (milk fat globule)
• osmosis
• Ig secretion
• paracellular route

Question 19

role of exocytosis in getting the components of milk into the lumen of the milk-producing alveoli.

Answer 19

• 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.

Question 20

role of milk fat globule (MFG) in getting the components of milk into the lumen of the milk-producing alveoli.

Answer 20

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.

Question 21

role of osmosis in getting the components of milk into the lumen of the milk-producing alveoli.

Answer 21

Secretion of certain ions, water, Na+ and K+ can freely move out of the cell into the lumen

Question 22

role of Ig Secretion in getting the components of milk into the lumen of the milk-producing alveoli.

Answer 22

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

Question 23

Paracellular route in getting the components of milk into the lumen of the milk-producing alveoli.

Answer 23

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.

Question 24

what are the components of breast milk

Answer 24

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

Question 25

difference between macronutrients in breastmilk and formula milk

Answer 25

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

Question 26

how does volume of breast milk change over time, post partum?

Answer 26

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

Question 27

how does composition of breast milk change over time, post partum

Answer 27

- inititally milk has lower levels of lactose and icreases over time - initially high salt, decreases over time

Question 28

how does composition of breast milk change during a single feed

Answer 28

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

Question 29

what are the gastrointestinal benefits of breastfeeding

Answer 29

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).

Question 30

what is necrotizing enterocolitis (NEC),

Answer 30

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)

Question 31

what are nutritional benefits of breastmilk for the baby

Answer 31

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

Question 32

what are the immunological benefits of breastfeeding for the baby

Answer 32

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.

Question 33

what immune factors are contained in breast milk

Answer 33

* 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

Question 34

what is the enteromammary axis

Answer 34

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.

Question 35

short term benefits of breastfeeding for the infant

Answer 35

- Improved immunity, less infections and infectious morbidity - Reduces GI infections - Reduced respiratory infections - Reduced urinary tract infections - reduced risk of SIDS

Question 36

long term benefits of breastfeeding for the infant

Answer 36

- 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(?)

Question 37

benefits of breastfeeding for the mother

Answer 37

- 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

Question 38

signs of good attachment to the breast

Answer 38

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

Question 39

what is the non-nuteritive sucking

Answer 39

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.

Question 40

what is nutritive sucking

Answer 40

once the let down reflex occurs there is slower paced sucking and this is nutritive sucking.