Lecture 7 - Lactation and Milk

Question 1

what are the functional units of the mammary gland

Answer 1

alveoli

Question 2

each alveoli has a cluster of cells called what

Answer 2

secretory cells

Question 3

what is in the centre of the cluster of secretory cells of the alveolus that secretes milk

Answer 3

a duct

Question 4

ducts are arranged how

Answer 4

like branches of a tree with each smaller duct leading to 6-10 larger collecting ducts, leading to the nipple

Question 5

what cells surround the secretory cells and what do they do

Answer 5

myoepithelial cells surround the secretory cells and contract under the influence of oxytocin and cause milk to be ejected into ducts

Question 6

the mammary gland is made up of what and how many

Answer 6

15-25 lobes

Question 7

each lobe of the mammary gland has how many lobules

Answer 7

20-40 lobules

Question 8

each lobule of the mammary gland is comprised of clusters of what and how many

Answer 8

40-100 alveoli

Question 9

each lobe drains into its own what and delivers what

Answer 9

each lobe drains into its own collecting duct, delivery milk through pores to the nipple

Question 10

alveoli are well what …. and what does this mean

Answer 10

alveoli are well vascularised so that oxytocin may reach them and cause surrounding myoepithelial cells to contract, squeezing milk out from lactocytes

Question 11

what is the mammary gland development in puberty

Answer 11

• 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

Question 12

what is the mammary gland development in pregnancy ( 2 hormones that allow for further preparation)

Answer 12

• human chorionic gonadotropin (HcG) and placental lactogen allow for further preparation

Question 13

what is the mammary gland development in pregnancy ( a hormone that stimulates development of glands that …)

Answer 13

oestrogen stimulates development of glands that will produce milk

Question 14

what is the ‘milk hormone’

Answer 14

prolactin

Question 15

what is the mammary gland development in pregnancy ( a hormone that allows tubules to ….)

Answer 15

progesterone allows the tubules to elongate and epithelial cells that line the tubules to duplicate

Question 16

what does prolactin stimulate

Answer 16

milk production via suckling (baby)

Question 17

what is prolactin suppressed by

Answer 17

prolactin-inhibiting factors released by the hypothalamus during the last 3 months of pregnancy to allow for the body to prepare for milk production

Question 18

what does oxytocin stimulate, what is this also known as

Answer 18

the ejection of milk from the milk gland into ducts via suckling (baby)

also known as letdown

Question 19

what does oxytocin do during delivery of the baby

Answer 19

acts on the uterus during and after delivery, causing to to contract

Question 20

what are the three stages of lactogenesis

Answer 20

lactogenesis 1 : colostrum

lactogenesis 2 : transitional milk

lactogenesis 3 : mature milk

Question 21

when is colostrum produced and what is the production like

Answer 21

produced in the first couple days, low milk production

Question 22

colostrum has high levels of :

Answer 22

white blood cells, immunoglobulin A, vitamin A

Question 23

colostrum is high in …. and low in ….

Answer 23

high protein , low fat

Question 24

when is transitional milk produced

Answer 24

1st couple days, up to 10 days

Question 25

what is the milk production like for transitional milk and what is it stimulated by

Answer 25

increased milk production, stimulated by maternal hormones

Question 26

what is the content of transitional milk like

Answer 26

higher protein and lower fat than mature milk

Question 27

when is mature milk produced

Answer 27

begins around 10 days postpartum

Question 28

what is the milk composition like of mature milk

Answer 28

more stable

Question 29

how much mature milk is consumed by an infant on average during exclusive breastfeeding from 0-6 months

Answer 29

~780ml

Question 30

when should breastfeeding initiation begin

Answer 30

within the first hour of birth

Question 31

healthy term infants are born with reflexes to feed, what are they

Answer 31

- suck and swallow in coordinated pattern - oral search reflex - rooting reflex

Question 32

what is the suck and swallow in coordinated pattern include

Answer 32

a gag reflex to prevent food and fluids into lungs

Question 33

what does the oral search reflex include

Answer 33

open mouth wide in proximity to breast and thrusting tongue forward

Question 34

what does the rooting reflex include

Answer 34

turn head to side when stimulated on side of upper or lower lip

Question 35

what is the mechanics of breastfeeding (suction)

Answer 35

suction created within baby's mouth causes the mothers nipple and areola to elongate and form a teat

Question 36

what is the mechanics of breastfeeding (jaw and tongue)

Answer 36

baby's jaw moves her tongue toward the areola, compressing it and causing milk to travel from the milk ducts to babys mouth

Question 37

what is the mechanics of breastfeeding (tongue, anterior and posterior) = what type of movement is this

Answer 37

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

Question 38

what initiates the swallow reflex in a baby

Answer 38

receptors in back of babys oral cavity

Question 39

what is the key to success of breastfeeding

Answer 39

proper latch and positioning

Question 40

what is meant by responsive breastfeeding

Answer 40

if the baby is left too long before being fed, it will become agitated and be very hard to feed

Question 41

what % of breast milk is water

Answer 41

about 88%

Question 42

what % of breast milk is fat

Answer 42

about 3.8%

Question 43

what % of breast milk is protein

Answer 43

about 0.9%

Question 44

what is the energy of breast milk

Answer 44

0.65-0.70kcal/ml

Question 45

what is the second largest component of breast milk and how much energy does this provide

Answer 45

fat is the second largest component and provide half the energy

Question 46

per feed : fat is what at the beginning and what at the end, and what are these called

Answer 46

fat is low in the beginning (foremilk) and high at the end (hindmilk)

Question 47

breastmilk contains cholesterol, what is this important for ?

Answer 47

essential component of cell membranes

Question 48

protein content of mature milk is ... and what are the classes

Answer 48

relatively low classes : whey, casein and non protein nitrogen

Question 49

what is the main carbohydrate in breastmilk and what does this enhance

Answer 49

lactose, enhances calcium absorption

Question 50

what are Human milk Oligosaccharides (HMOs)

Answer 50

- complex, indigestible, medium length CHO with lactose on one end

Question 51

prebiotic is a functional ingredient of human milk, what does this stimulate

Answer 51

stimulate growth of Bifidus bacteria and inhibits Escherichia coli

Question 52

what do prebiotics in breast milk prevent

Answer 52

prevent binding of pathogenic microorganisms to the surface receptors of their target cells : preventing infection

Question 53

what are the two groups of vitamins and minerals

Answer 53

group 1 and group 2

Question 54

what are group 1 vitamins and minerals

Answer 54

affected by maternal status

Question 55

what are group 2 vitamins and minerals

Answer 55

not affected by maternal status

Question 56

in group 1 nutrients low maternal intake or stores means what for the breast milk and therefore the infant

Answer 56

reduces the amount in breast milk, affects infant development

Question 57

what is the iron concentration of breastmilk like

Answer 57

iron concentration is low but it is highly bioavailable

Question 58

what is the absorption of iron from breastmilk like, compared to cows milk based formulas

Answer 58

50% of iron in BM compared to 10% iron from cow's milk based formulas

Question 59

what is a major determinant of anaemia risk during infancy

Answer 59

infant reserves at birth

Question 60

what is the vitamin D content of breast milk like

Answer 60

low

Question 61

why is supplementation of vitamin D in the mother not really helpful to increase vitamin D content of breast milk

Answer 61

doesn't increase the breast milk concentrations enough

Question 62

what is the recommendation for vitamin D and breastfed infants and when would this be appropriate

Answer 62

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

Question 63

what are prebiotics

Answer 63

oligosaccharides

Question 64

what are examples of group 1 nutrients

Answer 64

- thiamin - riboflavin - vitamin B6 - vitamin B12 - iodine - selenium

Question 65

where is prolactin released from

Answer 65

the anterior pituitary

Question 66

examples of group 2 nutrients

Answer 66

- vitamin D - folic acid - calcium - iron - copper - zinc