9.1c Anatomy and Physiology of Lactation

Question 1

Anatomy of Lactation

Answer 1

• Alveoli is the milk producing cells
• 2:1 ratio of glandular to adipose tissue (1:1 in non-lactating mothers)
• Size and shape of breast is not accurate indicator of milk production
• Colostrum is prepartum milk
• Sebaceous glands protect nipple from mechanical stress of sucking and pathogens

Question 2

Lactogenesis

Answer 2

• Fall of progesterone stimulates release of prolactin from anterior pituitary
• Prolactin is highest in the first 10 days of birth
• Prolactin is produced in response to infant suckling (supply-meets-demand)
• Oxytocin - Important in milk ejection reflex (MER) or “Let down reflex”
• MER is triggered by suckling or sights, sounds, odors that mom associates with baby (baby cry)
• “pins and needles” feeling as milk is ejected
• Oxytocin is also released during orgasm
• Fear, Stress, Alcohol can inhibit MER

Question 3

AfterPains

Answer 3

• Uterine contractions that occur with breastfeeding are painful during first 3-5 days
• Afterpains are more common in multiparous women and resolve in 1 week

Question 4

Mothering Hormones

Answer 4

• Prolactin and Oxytocin
• Affect mothers emotions and physical state in postpartum women
• Women may feel thirsty and relaxed during breastfeeding
• Nipple-Erection Reflex is important for breastfeeding for effective latch

Question 5

Human Milk

Answer 5

• Ideal food for infants
• Composition changes to meet nutritional and immunologic needs of growing infant
  (Milk of pre-term mother is different from milk of term mother due to different nutritional needs)
• Contains immunologic protection
• Promotes colonization of intestinal bacteria

Question 6

Lactogenesis Stage 1

Answer 6

• Begins at 16-18 weeks of pregnancy

- Starts producing colostrum

Question 7

Lactogenesis Stage 2

Answer 7

• Begins with birth as progesterone drops and placenta is removed
• First 2-3 days is colostrum
  (Clear, yellow liquid with antibodies, high protein, low fat)
  (High protein helps binding of bilirubin)
  (Laxative properties to excrete first meconium)
  (Establishes Lactobacillus Bifidus - GI Flora)

Question 8

Lactogenesis Stage 3

Answer 8

• Transitional Milk (3-5 days)
• Transition from colostrum to normal milk
• Milk is fully mature by 10 days

Question 9

Composition of Breastmilk

Answer 9

• Changes over time as infant grows and develops
• Fat is the most variable component of breastmilk (gradually increases after each feeding)
  GROWTH SPURTS
• 10 days, 3 weeks, 6 weeks, 3 months, 6 months
• More frequent feedings required lasts about 24-48 hours