The breast

Question 1

Mammary growth requires multiple hormones, name them.

Answer 1

1. LH and prolactin - from the ant. pituitary
2. Human placental lactogen - from the placenta
3. Oestrogen and progesterone - steroid sex hormones: ovarian, adrenal and placental
4. Adenocorticotrophic hormone and human growth hormone

Question 2

Role of oestrogen in mammary growth?

Answer 2

Produce ductal growth and proliferation

Question 3

Role of prolactin in mammary growth?

Answer 3

Influences growth of nipple

Question 4

Role of progesterone in mammary growth?

Answer 4

Produces lobes and lobules in the alveoli, causing other structures to grow and bud, and they lead to further development and enlargement of the ducts, widening them to make them better for their secretory function and for them to conduct milk in the mature lactating breasts

Question 5

At gestational week 4, what do the breasts develop from?

Answer 5

Two milk lines/streaks which extend from the axilla to the groin

Question 6

At gestational weeks 7-8 we have the milk hills stage, what is this?

Answer 6

Thickening and inward growth of the breasts into the chest wall

Question 7

By which week do we have primary milk ducts?

Answer 7

wk 32

Question 8

By which week do our alveolar structures contain colostrum?

Answer 8

wk 32-40

Question 9

Which hormones strongly effect breast growth in girls? What do they do?

Answer 9

Oestrogen and human growth hormone

• They cause budding and branching of glandular tissue, and small ductules of areolar buds are developed
• The alveoli, which are the sacs aligned with milk secreting cells, develop AKA acini

Question 10

A lactiferous tubule feeding into several alveoli is called a…

Answer 10

lobule

Question 11

Several of the lobules which feed into a lactiferous duct is called a…

Answer 11

lobe in the breast

Question 12

Lactiferous tubules feed into…

Answer 12

Alveoli (acini)

Question 13

Why do women have hot breasts during pregnancy?

Answer 13

Because there is a higher metabolic rate in women during pregnancy and lactation

Question 14

Blood supply to the breasts?

Answer 14

60% from internal mammary artery AKA internal thoracic artery
30% from lateral thoracic artery

Question 15

Nerve supply to the breasts?

Answer 15

branches of the 2nd to 6th IC nerves

- Mainly 4th, 5th and 6th

Question 16

The areola has openings that penetrate it, these are connected to tubercles of Montgomery, which contain true mammary lobules, a milk-secreting glandular structure but also attached is a sebaceous gland, what has the presence of >tubercles of Montgomery shown to do?

Answer 16

It has been demonstrated to allow babies to attach to the breast more quickly. Some sort of olfactory stimulation is said to be produced to help the newborn find and attach to the breast

Question 17

What is the role of feedback inhibitor of lactation (FIL)?

Answer 17

It is removed with milk, so if FIL is not removed, the secretion of milk slows down
- This is why frequent breastfeeding is recommended, so that milk secretion does not stop

Question 18

Prolactin vs oxytocin in breastfeeding

Answer 18

Prolactin:

1. Responsible for milk production
2. Resposive to touch and stimulation
3. Levels higher at night
4. Frequent contact/feeds sets up long term production

Oxytocin:

1. Responsible for milk delivery
2. Acts on muscle cells in pulsatile action
3. Levels higher when baby is near
4. Stress can temporarily delay ‘let down’