Reproduction and the Growing Child - (General) Flashcards
What happens at 4 weeks of mammogenesis?
Two milk lines (Streaks) form from the axilla to the groin.
What happens by 8 weeks of mammogenesis?
‘Milk hills’
Thickening and inward growth- invagination into chest wall
What happens from 12-16 weeks of mammogenesis?
Differentiation
Epithelial cells -> mammary buds in an alveolar pattern.
What happens from 28-32 weeks of mammogenesis?
Canalization (formation of channels) of branched epithelial tissue
Primary milk ducts
What happens by 40 weeks of mammogenesis?
Lobular-alveolar structures containing colostrum develop
Ducts open into nipple
Nipple and areola develop and become pigmented
What hormones are responsible for breast growth at puberty?
Oestrogen
Human growth hormone
With reproductive cycles, is the proliferation and active growth reversible?
No
What hormone is responsible for areolar growth during pregnancy?
Serum placental lactose
What is oestrogen’s effect on the breast during pregnancy?
Stimulates ductal system proliferation and differentiation
What cells line each alveolus of the breast?
Lactocytes- secretory epithelial cells
What is the role of myoepithelial cells in the breast?
Contract around the alveoli to eject milk into the ductules
Where is milk produced in the breast?
Alveolar glandular tissue
What stops liquid from dripping out of the breast?
Surface tension
Closure of tight junctions between lactocytes
When do changes to the nipple and areola occur in pregnancy?
Around 12 weeks
When does colostrum begin to be secreted in pregnancy?
12-16 weeks
When does involution occur?
40 days after last breastfeed
What is lactogenesis?
The transition from pregnancy to lactation