NS 431 EXAM 3 QUESTIONS AND
ANSWERS 100% PASS
Mammary gland anatomy - ANS -functional unit: alveoli
-secretory cells: secrete milk
-myoepithelial cells: stimulate release of milk via oxytocin
Lactation Hormones - ANS -estrogen: ductal growth, occurs during menstruation
-prolactin: alveolar development and milk secretion, 3rd trimester
-HGH: development of terminal buds, mammary gland development
-oxytocin: letdown, from onset of milk secretion to weaning
Stages of Lactogenesis - ANS 1) First few days PP, Milk formation begins, lactose/protein
content increases
2) 2-5 days PP, onset of copious milk secretion, delay of stage can cause breastfeeding failure
3) 10 days PP, milk composition is stable
Transportation of milk nutrients - ANS -exocytosis of lactose
-lipid vesicles; short/med from alveoli while long is from maternal blood
-active transport of ions (Na, K, H2O)
-transcytosis of proteins (immunoglobulins)
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,-paracellular transport of leukocytes
Letdown reflex feedback loop - ANS 1) suckling stimulates mechanoreceptors in nipple sends
signal to hypothalamus
2) Hypothalamus stimulates pituitary
-posterior: oxytocin stimulates milk ejection from myoepithelial cells
-anterior: prolactin stimulates milk production from secretory cells
Nutrients synthesized de nova in the mammary glands - ANS -lactose, requires a-lactalbumin
as cofactor
-casein
-short(<6) and medium (8-10) FA's
Nutrients transferred from maternal plasma - ANS -long chain FA's (>12); need adequate
consumption of Omega-3 and Omega-6
-majority of vitamins and minerals
Milk synthesis and secretion is most active during which period? - ANS -most active during
feeding, less active between feedings
Function of Prolactin during lactation - ANS -mammary glands: milk production
-reproductive organs: inhibit ovulation
Function of Oxytocin during lactation - ANS -mammary glands: milk ejection
-reproductive organs: promote uterine contraction, help get uterus to pre-pregnancy size
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, When should a woman begin pumping? - ANS -wait until breastfeeding is well established
and milk production is more stable because suckling is the primary stimulus of the letdown
reflex
Insufficient milk syndrome - ANS -milk synthesis is controlled by infant demand, breast-
emptying signals the breast to make more milk
-most women are capable of producing enough milk despite worry
-not very common; only 5%
The studies reported in the NEJM article were designed to test the hypothesis that Ca
supplementation: - ANS prevents bone loss during lactation and promotes bone gain after
weaning
Which of the following is correct regarding the design of the NEJM studies? - ANS -the study
was randomized, double-blind, and placebo controlled
-the same women who were studied for lactating were studied for weaning
In the NEJM studies, what were contained in the treatment pills and how long were the pills
given to the subjects? - ANS -500 mg of Ca2+, twice daily for 6 months
-400 IU of Vit-D
In the NEJM article, what methods were used to obtain data in the studies? - ANS -3-day food
records were used to estimate baseline dietary Ca2+ intake
-Pedometer were used to physical level
-Ca2+ content of breast milk was estimated from USDA's nutrient database
-DEXA (dual-energy-xray-absorptiometry) was used to measure bone density
In the NEJM article, the primary outcome in the study of lactation was - ANS bone density
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
ANSWERS 100% PASS
Mammary gland anatomy - ANS -functional unit: alveoli
-secretory cells: secrete milk
-myoepithelial cells: stimulate release of milk via oxytocin
Lactation Hormones - ANS -estrogen: ductal growth, occurs during menstruation
-prolactin: alveolar development and milk secretion, 3rd trimester
-HGH: development of terminal buds, mammary gland development
-oxytocin: letdown, from onset of milk secretion to weaning
Stages of Lactogenesis - ANS 1) First few days PP, Milk formation begins, lactose/protein
content increases
2) 2-5 days PP, onset of copious milk secretion, delay of stage can cause breastfeeding failure
3) 10 days PP, milk composition is stable
Transportation of milk nutrients - ANS -exocytosis of lactose
-lipid vesicles; short/med from alveoli while long is from maternal blood
-active transport of ions (Na, K, H2O)
-transcytosis of proteins (immunoglobulins)
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,-paracellular transport of leukocytes
Letdown reflex feedback loop - ANS 1) suckling stimulates mechanoreceptors in nipple sends
signal to hypothalamus
2) Hypothalamus stimulates pituitary
-posterior: oxytocin stimulates milk ejection from myoepithelial cells
-anterior: prolactin stimulates milk production from secretory cells
Nutrients synthesized de nova in the mammary glands - ANS -lactose, requires a-lactalbumin
as cofactor
-casein
-short(<6) and medium (8-10) FA's
Nutrients transferred from maternal plasma - ANS -long chain FA's (>12); need adequate
consumption of Omega-3 and Omega-6
-majority of vitamins and minerals
Milk synthesis and secretion is most active during which period? - ANS -most active during
feeding, less active between feedings
Function of Prolactin during lactation - ANS -mammary glands: milk production
-reproductive organs: inhibit ovulation
Function of Oxytocin during lactation - ANS -mammary glands: milk ejection
-reproductive organs: promote uterine contraction, help get uterus to pre-pregnancy size
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, When should a woman begin pumping? - ANS -wait until breastfeeding is well established
and milk production is more stable because suckling is the primary stimulus of the letdown
reflex
Insufficient milk syndrome - ANS -milk synthesis is controlled by infant demand, breast-
emptying signals the breast to make more milk
-most women are capable of producing enough milk despite worry
-not very common; only 5%
The studies reported in the NEJM article were designed to test the hypothesis that Ca
supplementation: - ANS prevents bone loss during lactation and promotes bone gain after
weaning
Which of the following is correct regarding the design of the NEJM studies? - ANS -the study
was randomized, double-blind, and placebo controlled
-the same women who were studied for lactating were studied for weaning
In the NEJM studies, what were contained in the treatment pills and how long were the pills
given to the subjects? - ANS -500 mg of Ca2+, twice daily for 6 months
-400 IU of Vit-D
In the NEJM article, what methods were used to obtain data in the studies? - ANS -3-day food
records were used to estimate baseline dietary Ca2+ intake
-Pedometer were used to physical level
-Ca2+ content of breast milk was estimated from USDA's nutrient database
-DEXA (dual-energy-xray-absorptiometry) was used to measure bone density
In the NEJM article, the primary outcome in the study of lactation was - ANS bone density
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
