Lactation

Question 1

What are two functions of the breasts?

Answer 1

• Nutrition of the young

- Spacing of pregnancies

Question 2

Where do the lactiferous ducts join the skin?

Answer 2

At the nipple

Question 3

What causes the granular texture on the surface of the areola?

Answer 3

Sebaceous glands

Question 4

What comprises the majority of breast tissue?

Answer 4

Adipose tissue from the pectoral fat pad

Question 5

What is the function of Cooper’s ligaments?

Answer 5

Lift and support to the breasts

Question 6

Breasts are modified ____ glands and are derived from _____ that arise between the axilla, armpit and groin

Answer 6

Sweat glands

Milk crests

Question 7

Describe the embryological development of the breast.

Answer 7

• Development starts ~6wks gestational age
• Primary bud is a downgrowth of the dermis
• Secondary bud develops into primary buds and form the lactiferous ducts
• Breast bud lumen develops as gestation progresses
• Canalisation induced by placental steroids

Question 8

What is witch’s milk and why does it form?

Answer 8

• Breasts are fully developed at birth and could produce milk
• Exposure to placental steroids and maternal hormones can cause production of witch’s milk

Question 9

What effect does oestrogen and progesterone have on the breast during puberty?

Answer 9

• Promote growth of alveolar buds during menstrual cycle

- Successive cycles cause increased growth

Question 10

What effect do the following hormones have on breast development and lactation?

• Oestrogen
• Progesterone
• Prolactin
• Growth hormone
• Insulin and cortisol

Answer 10

• Oestrogen: mitogen, essential for growth
• Progesterone: branching of ducts
• Prolactin: milk prod., alveolar development
• Growth hormone: same family as prolactin
• Insulin and cortisol: alveolar cell growth

Question 11

What prevents milk production from occurring during pregnancy?

Answer 11

Inhibition by progesterone

• Prevents production
• Prevents milk ejection (smooth muscle relaxant)

Question 12

What effect does baby suckling on the nipple have on hormone production?

• Prolactin
• Dopamine
• VIP
• Oxytocin

Answer 12

• Induces secretion of prolactin by anterior pituitary
• Decreases dopamine secretion
• Induces secretion of VIP (vasoactive intestinal peptide), acts on lactotrophs
• Synthesis and secretion of oxytocin from the posterior pituitary

Question 13

What is the effect of oxytocin on the breast?

Answer 13

Induces contraction of myoepithelial cells of alveoli, causing injection of milk into ducts

Question 14

What is the effect of prolactin on the breast?

Answer 14

Induces production of milk proteins

Question 15

Through what mechanism does prolactin suppress FSH and LH?

Answer 15

Thought to be through effect on kisspeptin neurons in the hypothalamus

Question 16

Where do supernumeroury nipples/breasts usually form?

Answer 16

On the embryonic milk ridge

Question 17

What are the four stages of lactation?

Answer 17

1. Lactogenesis stage I
2. Lactogenesis stage II
3. Galactopoesis
4. Involution

Question 18

What occurs in lactogenesis stage II?

Answer 18

• PP 3-8 days is the start of large scale milk production

- Increase in a-lactalbumin, decreased Na and Cl in milk

Question 19

What causes dec. Na and Cl in milk in lactogenesis stage Ii?

Answer 19

Tight junctions in alveolar epithelium - reduce passage of salts

Question 20

What is galactopoesis?

Lactation

Answer 20

Maintenance of established milk secretion

Question 21

What is involution?

Lactation

Answer 21

• Cessation of breast milk production approx 40 days after last feed

Question 22

How does the composition of colostrum compare to mature milk?

Answer 22

• Less fat and sugar
• More protein
• Rich in antibodies, mainly IgA

Question 23

How dose lactose content in breast milk compare to cows’ milk? What is the significance of this?

Answer 23

• 6.8g vs 3.3g

- Lactose is an energy source and used for myelination

Question 24

How does the casein:lactalbumin ratio compare in human and cows milk? What is the significance of this?

Answer 24

• 1:2 vs 3:1

- A-lactalbumin increases production of lactose (enzyme inducer)

Question 25

How does the linoleic acid content compare in human and cows milk? What is the significance of this?

Answer 25

- 8.3% of fat vs 1.6% of fat | - Obtained exclusively by diet

Question 26

Water comprises ___% of breast milk volume

Answer 26

87.5%

Question 27

Which components of breast milk help protect baby from infection?

Answer 27

- IgA - Lactoferrin - Lysozyme - Small signalling molecules - Phagocytes/lymphocytes/T cells

Question 28

Humans take approx. ___ months to double birth weight

Answer 28

4-6 months

Question 29

Does breast size affect milk production?

Answer 29

No, just milk storage

Question 30

What are 3 benefits of breastfeeding for the mother?

Answer 30

• Spacing of offspring • Bonding to offspring • Enhances involution of the uterus • Protection against diabetes • Protection against post-partum depression • May protect against breast cancer May protect against ovarian cancer (esp. if feeding for longer than 12 months)

Question 31

During the first ___ months of life the infant intestinal mucosa is permeable to proteins

Answer 31

6-9

Question 32

Breast feeding reduces risk of the baby developing asthma to ___

Answer 32

0.7

Question 33

What are some benefits of breastfeeding for the baby?

Answer 33

Protects against: - Childhood obesity - Infectious disease - GI infection - Otitis media - Atopy - Asthma - Adult obesity - Increases cognitive ability

Question 34

Which infectious diseases can be transmitted via breast feeding?

Answer 34

- HIV - Mastitis - Hepatitis B

Question 35

How does the concentration of alcohol in maternal plasma relate to that in maternal milk?

Answer 35

Similar in milk and maternal plasma

Question 36

How does alcohol affect breast feeding?

Answer 36

- Babies do not suck as well | - May lead to feeding problems

Question 37

What effect does excess caffeine consumption have on babies?

Answer 37

Sleeplessness and irritability

Question 38

What is mastitis?

Answer 38

Inflammation of a lactiferous lobe