Lecture 7 - Lactation and Milk Flashcards
what are the functional units of the mammary gland
alveoli
each alveoli has a cluster of cells called what
secretory cells
what is in the centre of the cluster of secretory cells of the alveolus that secretes milk
a duct
ducts are arranged how
like branches of a tree with each smaller duct leading to 6-10 larger collecting ducts, leading to the nipple
what cells surround the secretory cells and what do they do
myoepithelial cells surround the secretory cells and contract under the influence of oxytocin and cause milk to be ejected into ducts
the mammary gland is made up of what and how many
15-25 lobes
each lobe of the mammary gland has how many lobules
20-40 lobules
each lobule of the mammary gland is comprised of clusters of what and how many
40-100 alveoli
each lobe drains into its own what and delivers what
each lobe drains into its own collecting duct, delivery milk through pores to the nipple
alveoli are well what …. and what does this mean
alveoli are well vascularised so that oxytocin may reach them and cause surrounding myoepithelial cells to contract, squeezing milk out from lactocytes
what is the mammary gland development in puberty
- ovaries mature and increase in oestrogen and progesterone initiates mammary lobular structure (lobes)
- ductal system matures and nipple grows with pigmentation change
- fibrous and fatty tissue increase around the duct
what is the mammary gland development in pregnancy ( 2 hormones that allow for further preparation)
- human chorionic gonadotropin (HcG) and placental lactogen allow for further preparation
what is the mammary gland development in pregnancy ( a hormone that stimulates development of glands that …)
oestrogen stimulates development of glands that will produce milk
what is the ‘milk hormone’
prolactin
what is the mammary gland development in pregnancy ( a hormone that allows tubules to ….)
progesterone allows the tubules to elongate and epithelial cells that line the tubules to duplicate
what does prolactin stimulate
milk production via suckling (baby)
what is prolactin suppressed by
prolactin-inhibiting factors released by the hypothalamus during the last 3 months of pregnancy to allow for the body to prepare for milk production
what does oxytocin stimulate, what is this also known as
the ejection of milk from the milk gland into ducts via suckling (baby)
also known as letdown
what does oxytocin do during delivery of the baby
acts on the uterus during and after delivery, causing to to contract
what are the three stages of lactogenesis
lactogenesis 1 : colostrum
lactogenesis 2 : transitional milk
lactogenesis 3 : mature milk
when is colostrum produced and what is the production like
produced in the first couple days, low milk production
colostrum has high levels of :
white blood cells, immunoglobulin A, vitamin A
colostrum is high in …. and low in ….
high protein , low fat
when is transitional milk produced
1st couple days, up to 10 days
what is the milk production like for transitional milk and what is it stimulated by
increased milk production, stimulated by maternal hormones
what is the content of transitional milk like
higher protein and lower fat than mature milk
when is mature milk produced
begins around 10 days postpartum
what is the milk composition like of mature milk
more stable
how much mature milk is consumed by an infant on average during exclusive breastfeeding from 0-6 months
~780ml
when should breastfeeding initiation begin
within the first hour of birth
healthy term infants are born with reflexes to feed, what are they
- suck and swallow in coordinated pattern
- oral search reflex
- rooting reflex
what is the suck and swallow in coordinated pattern include
a gag reflex to prevent food and fluids into lungs
what does the oral search reflex include
open mouth wide in proximity to breast and thrusting tongue forward
what does the rooting reflex include
turn head to side when stimulated on side of upper or lower lip
what is the mechanics of breastfeeding (suction)
suction created within baby’s mouth causes the mothers nipple and areola to elongate and form a teat
what is the mechanics of breastfeeding (jaw and tongue)
baby’s jaw moves her tongue toward the areola, compressing it and causing milk to travel from the milk ducts to babys mouth
what is the mechanics of breastfeeding (tongue, anterior and posterior) = what type of movement is this
baby raises anterior portion of tongue and depresses and retracts posterior portion of tongue = peristaltic motions forming a grove in the tongue that channels milk to back of oral cavity
what initiates the swallow reflex in a baby
receptors in back of babys oral cavity
what is the key to success of breastfeeding
proper latch and positioning
what is meant by responsive breastfeeding
if the baby is left too long before being fed, it will become agitated and be very hard to feed
what % of breast milk is water
about 88%
what % of breast milk is fat
about 3.8%
what % of breast milk is protein
about 0.9%
what is the energy of breast milk
0.65-0.70kcal/ml
what is the second largest component of breast milk and how much energy does this provide
fat is the second largest component and provide half the energy
per feed : fat is what at the beginning and what at the end, and what are these called
fat is low in the beginning (foremilk) and high at the end (hindmilk)
breastmilk contains cholesterol, what is this important for ?
essential component of cell membranes
protein content of mature milk is … and what are the classes
relatively low
classes : whey, casein and non protein nitrogen
what is the main carbohydrate in breastmilk and what does this enhance
lactose, enhances calcium absorption
what are Human milk Oligosaccharides (HMOs)
- complex, indigestible, medium length CHO with lactose on one end
prebiotic is a functional ingredient of human milk, what does this stimulate
stimulate growth of Bifidus bacteria and inhibits Escherichia coli
what do prebiotics in breast milk prevent
prevent binding of pathogenic microorganisms to the surface receptors of their target cells : preventing infection
what are the two groups of vitamins and minerals
group 1 and group 2
what are group 1 vitamins and minerals
affected by maternal status
what are group 2 vitamins and minerals
not affected by maternal status
in group 1 nutrients low maternal intake or stores means what for the breast milk and therefore the infant
reduces the amount in breast milk, affects infant development
what is the iron concentration of breastmilk like
iron concentration is low but it is highly bioavailable
what is the absorption of iron from breastmilk like, compared to cows milk based formulas
50% of iron in BM compared to 10% iron from cow’s milk based formulas
what is a major determinant of anaemia risk during infancy
infant reserves at birth
what is the vitamin D content of breast milk like
low
why is supplementation of vitamin D in the mother not really helpful to increase vitamin D content of breast milk
doesn’t increase the breast milk concentrations enough
what is the recommendation for vitamin D and breastfed infants and when would this be appropriate
exclusively or partially breastfed infants may benefit from vitamin D supplementation, would be appropriate from 4 weeks of age until the infant is mobile or up to 12 months of age
what are prebiotics
oligosaccharides
what are examples of group 1 nutrients
- thiamin
- riboflavin
- vitamin B6
- vitamin B12
- iodine
- selenium
where is prolactin released from
the anterior pituitary
examples of group 2 nutrients
- vitamin D
- folic acid
- calcium
- iron
- copper
- zinc
