Breast Development and Physiology Flashcards
Breast feeding has been shown to lead to what benefits for the mother?
- Decreased postpartum bleeding
- More rapid uterine involution
- Earlier return to pre-pregnancy weight
The AAP recommends exclusive breast feeding for ______________.
all children for the first six months
Breast feeding has been shown to decrease what negative outcomes in neonates?
- Meningitis
- Diarrhea
- Bacteremia
- URIs
- UTIs
- Sepsis
- SIDS
- OM
- Diabetes
- Leukemia/lymphoma
Describe the structure or the breast.
Breasts are divided into lobes that contain milk-producing alveoli. These are surrounded by myoepithelium that pushes milk into the conducting ductules that ultimately lead to one duct.
The bumps on the areolae are called ______________.
glands of Montgomery
What changes in composition occur during lactation?
A much greater percentage of the breast becomes glandular and a much less percent of the breast is intraglandular fat
Prior to puberty, the ductules lead to __________.
terminal limb buds in the breast (that have not differentiated into glands)
What embryologic structures give rise to the breast?
The ectoderm dives into the underlying mesoderm
What protein induces differentiation of the mammary mesenchyme?
Parathyroid hormone-related protein (PTHrp)
Note: even the nipple is dependent on the development of the mesenchyme, so mutations in PTHrp can lead to agenesis of the nipple.
What is witch’s milk?
Elevated prolactin and progesterone levels in pregnancy can pass into neonates and cause transient neonatal lactation.
Which hormones stimulate the development of ducts and alveoli?
- Ducts: LH (terminal end buds)
* Alveoli: progesterone (side branching and TDLU development)
Increased _______________ during puberty induces the elongation and branching of the ductal network by increasing IGF-1 production by stromal cells.
estrogen and GH
_______________ regress at the end of the luteal phase unless pregnancy occurs.
TDLU
Milk secretion is initiated by _______________.
the fall in progesterone that occurs when the placenta is removed
Why does suckling induce milk secretion?
suckling inhibits hypothalamic dopamine release, this allows prolactin to be released from the anterior pituitary to cause milk secretion .
______________ stimulates the contraction of mammary myoepithelium.
Oxytocin
What can inhibit the release of oxytocin?
Stress
Obesity – and gaining too much weight during pregnancy –reduces ability to _____________.
initiate lactation
Also, lactation is an energy-intensive process and obesity seems to impact women’s ability to mobilize energy for lactation.
_____________ affects the terminal ducts and _____________ induces side-pouching.
Estrogen; progesterone
Milk secretion during pregnancy is held in check by _______________.
progesterone
The junctions start out os ____________.
open and then close
How much breast milk can a woman make in a day?
Up to one liter
what is Blomstrands chondroplasia?
also called amastia (no nipple or mammary glands), from a lack of PTHrP or its signaling
what two hormones work together to cause side branching?
prolactin and progesterone
what stimulates milk ejection?
oxytocin , suckling
what stimulates milk secretion?
prolactin, milk removal
what was once used to inhibit lactation?
bromocriptine - a dopamine agonist
what is colostrum and what does it contain
it is the milk secreted in the first 2 days postpartum, it contains a large amount of IgA and lactoferrin (bigger use = immunity)
5 pathways of milk secretion
1) apocrine
2) classical - exocytosis
3) transcytosis
4) membrane transport
5) paracellular
