BE 02 Flashcards
(115 cards)
0
Q
Breast development: First month of gestation
A
Breast development commences - two lines of glandular tissue (milk lines or mammary ridges) along ventral service from axilla to medial thigh develop in both male and female embryos
1
Q
Three major phases of growth that impact latctation
A
Embryological and infancy
Puberty
Pregnancy and lactation
2
Q
Breast development: 5th week gestation
A
Milk lines in thorax region develop into ridge which will become breasts
3
Q
Breast development: 2nd and 3rd month of fetal development
A
Nipples and areolae formed that overlie a bud of breast tissue composed of both the primary mammary ducts and a loose fibrous stroma
4
Q
Breast development: Mid-pregnancy
A
Secondary buds develop and bifurcate into tubules that form the basis of the duct system. Each duct system opens separately into the nipple.
5
Q
Breast development: Birth to puberty
A
At birth newborn’s breasts have formed mammary ducts and areola and nipple is present. Nipple usually inverted, everting shortly after birth.
Mammary glands of both male and female children remain inactive until puberty.
6
Q
What is “witch’s milk”??
A
Breasts of babies soon after birth may release a milk-like substance, called witch’s milk. This is a result of maternal hormones crossing placental barrier, for which treatment is not usually required. This milk should not be expressed!
7
Q
Breast development: Puberty to pre-conception
A
Breast develop (thelarche) usually first sign of puberty in girls. Avg age is 9.5 to 10.3 years.
Initially estrogen, then progesterone, influence growth of breasts in female…. Estrogen - increased growth, branching in duct system. Progesterone - (during luteal phase of menstrual cycle) causes ducts and alveolar buds to continue to proliferate. Other hormones (incl. prolactin, FSH, LH, growth hormone, somatotropin, TSH, ACTH also have roles in breast develop.
Most growth completed by 16yo.
8
Q
Define lactogenesis 1 (secretory differentiation)?
A
the period in pregnancy when mammary epithelial cells differentiate into lactocytes with the capacity to synthesize unique milk constituents such as lactose
9
Q
What hormone correlates with breast growth?
A
Increasing levels during pregnancy of human placental lactogen
10
Q
Breast function is correlated with which hormone?
A
During pregnancy increasing levels of prolactin.
11
Q
What hormone holds the secretory process in check?
A
High circulating plasma [progesterone]
12
Q
Relation between pre-conception breast size and degree of increase of breast size during pregnancy?
A
NONE
13
Q
Note: There is a wide variation in timing and degree of glandular growth.
A
Some women have extensive 1st trimester growth, some have gradual growth through pregnancy, some have NO growth until just before and/or after birth
14
Q
The two components of the mammary gland (corpus mammae)
A
Parenchyma: ducts, lobes, alveolar structures
Stroma: connective tissue, adipose tissue (fat), blood vessels, lymphatics and nerves
15
Q
Parenchyma components
A
Ducts
Lobes
Alveolar Structures
16
Q
Stroma components
A
Connective tissue Adipose tissue (fat) Blood vessels Lymphatics Nerves
17
Q
See Anatomy of the Human Breast Illustration
A
Pg. 6 BE 02
18
Q
Define breast capacity
A
The maximum volume of milk able to be stored in the breast at any one time
19
Q
Where is milk stored in the breasts?
A
Alveoli
20
Q
NOTE: there is huge variation in breast capacity, and it is not related to breast size.
A
May also be different for each breast
21
Q
Breast descriptors (quadrants)
A
Upper outer quadrant (closest to armpit) Upper inner quadrant (close to sternum) Lower outer quadrant (below upper outer) Lower inner quadrant (below upper inner) *AKA outer: lateral, inner: medial
22
Q
Blood supply to the breast comes from….
A
Two arteries:
- Internal mammary artery: supplying 62-70% of blood to breast. Comes down on medial side of each breast.
-Lateral thoracic artery: supplying 30-40% of breast’s needs
23
Q
Rate of blood flow to the breast.
Is there any correlation between blood flow and milk production?
A
Rate of blood flow: appx. 150-160 ml per minute.
No correlation between blood flow and milk production
24
Discuss lymphatic drainage in the breasts
Each breast has extensive lymphatic drainage.
Subareolar plexus and other superficial and deep nodes drain lymph primarily to lymphatic nodes in axilla, though some goes to interpectoral and internal mammary nodes
25
What characterizes breast engorgement?`
Stasis of milk in the alveoli and increased interstitial fluid (lymph)
26
What nerves supply the breast?
Nerves arising from branches of the 4, 5 and 6 intercostal nerves
27
What is the most sensitive part of the breast?
Areola. Sensitivity increases at birth.
28
What is significant about the lowermost branch of the 4th intercostal nerve?
It becomes more superficial close to the areola in the lower outer quadrant - at about 5 o'clock on left breast and 7 o'clock
29
What controls milk release from the breast, which is essential to establishing and maintaining milk production?
A neuro-hormonal reflex that causes the Milk Ejection Reflex (MER) AKA the let-down reflex
30
How is the MER initiated (flow of activities)
Initiated PHYSICALLY by stimulation of nipple and areola --> Nerve impulses travel to the HYPOTHALAMUS --> Causes release of OXYTOCIN from the posterior pituitary gland --> and PROLACTIN from the anterior pituitary gland --> Oxytocin travels through blood stream to breasts --> Causes myoepithelial cells surrounding each alveolus to CONTRACT --> Forces milk into ductal system and toward nipple.
31
What happens after MER to the remaining milk?
Milk flow reverses, returning milk to alveoli when MER subsides.
Minimal residual breastmilk only remains in ductal system when there is no MER
32
What surgical injury could prevent functioning of MER?
Eg reduction mammoplasty, prei-areolar incisions that sever the 4th intercostal nerve.
33
How is oxytocin released?
Pulsastile fashion
| Each release effective for 1.5-2 mins *Assoc w duration of MER
34
Avg # MERs per BF session
3-8
35
MER:
- are both breasts affected?
- What is infant milk intake assoc with?
- BOTH are affected at once
| - Infant milk intake assoc w # and duration of milk ejections
36
Simulatory factors in oxytocin release (4)
hearing a baby cry
thinking about baby
preparing to BF
being usual time baby feeds
37
Inhibitory factors in oxytocin release (4)
fear
pain
embarrassment
anxiety
38
What all does oxytocin do? (7)
- causes myoepithelial cells surrounding alveoli to contract, initiating MER
- causes increased uterine activity, reducing risk of hemorrhage
- causes skin temp of breasts to rise, providing warmth to infant
- exhibits flight-fight antagonist fx, decreasing maternal anxiety
- increases calmness and social responsiveness
- during early hours after birth enhances parenting behaviors
- causes thirst
39
In what three areas of the body is fatty tissue found?
1. Subcutaneous: directly beneath skin. Minimal near nipple, increasing in thickness farther from nipple.
2. Intraglandular: intermingles with the glandular tissue and is difficult to separate.
3. Retromammary
* Amt of fatty tissue present varies between women, but similar between breasts of same woman.
40
Define Coopers Ligaments
Loose structure of connective tissue which provides suppot for the glandular and fatty tissues.
41
How does accessory tissue in breast develop? What might the accessory tissue be composed of?
Incomplete regression of milk line, which stretches from the axilla to groin during embryological development. May develop anywhere along milk line.
May include glandular tissue, areola and/or nipple.
42
What is hyperadenia?
Where is it commonly found?
What happens to it during pregnancy?
How is it distinguished from the tail of Spence?
Def: presence of addiitonal mammary tissue w/ or w/o nipples.
Found commonly: axilla
Preg: Undergoes similar changes to normal breast during menstrual cycles, pregnancy and lactation.
Spence: distinguishable from axillary tail of Spence d/t lack of anatomical connection to breast.
43
How to treat engorged hyperadenic tissue, as may happen at lactation initiation.
Symptomatic tx: cold packs/cold cabbage leaves; oral analgesics/NSAIDs for relief until tissue involutes, usually in a few days. Sometimes this process can take more than a week.
44
Define Polythelia (AKA x2)
How common?
What do they look like?
Occasionally associated with...
Presence of nipple w/ no associated breast tissue, and is additional to normal breasts. AKA hyperthelia or accessory nipples.
Fairly common - 2-6% of adult women.
Found anywhere along embryonic milk line. Often mistaken for moles.
While rarely require tx, occ assoc w/ congenital urogenital abnormalities.
45
Define hyperplasia
| When does this become an issue for most women?
Over-develop of breast. Often defined as greater than 400mm^3 = moderate hypertrophy.
80% of cases start in adolescence.
46
```
Define gigantomastia
Why might this condition occur?
How serious is it?
Intervention?
Symptoms:
```
Def: breast growth greater than 1500mm^3
Why: cause unknown, may represent abnormal response of breast to normal serum estrogen levels, or to excess hormonal production, or hormonal imbalance.
Serious: very. Also very rare.
No success w/ medical interventions, surgery often required (ie bilateral total mastectomy).
Sx: extreme pain, ulceration of breasts, breast necrosis, hemorrhage, sepsis.
47
Define hypoplasia.
| Types 1-4, define.
Def: restricted breast development
Type 1: round breasts, normal lower and medial and lateral quadrants
Type 2: hypoplasia of lower medial quadrant.
Type 3: hypoplasia of the lower medial and lateral quadrants
Type 4: severe constrictions, minimal breast base.
48
Hypoplasia:
Causes
Adequate milk supply?
Causes: abnormalities of estrogen and preogesterone production during puberty and adolescence affecting breast development. If a young woman has many anovular cycles (progestone being secreted by the corpus luteum after ovulation) breast develop of lobular-alveolar system may be very restricted.
Supply: often inadequate, depends on type.
49
Challenges in nipples for latching baby (4)
inverted nipples
flat nipples
large and broad nipples
---- difficult but not impossible!
50
How do inverted nipples develop?
| Any changes during pregnancy?
Nipple develop occurs in embryological stage
Inverted nipple is failure of mammary pit to elevate. *Mammary pit is the shallow depression into which lactiferous ducts open.
Inverted nipples may be uni- or bi-lateral.
Preg: further nipple develop during preg. Nipple inverte in early preg may evert well by end of preg.
51
Can inverted nipples be 'sucked out'? How?
- By baby during feed (if well latched)
- Mechanically (hand pump, 'nipple everting' apparatus, modified disposable syringe) just prior to feeding
- Nipple shield used during feeds
52
How to tell if a normal-looking nipple is inverted?
Compress areola between thumb and forefinger. Inverted nipple retracts into breasts whereas normal nipple remains everted.
53
Some flat nipples are composed of..... which becomes erect with manipulation.
erectile fibromuscular tissue
54
How to condition nipples to be erect when needed....
Gentle stimulation of nipples in shower during pregnancy and immediately prior to BF after baby is born
55
Define galactorrhea
milk secretion not assoc w BF: response to increase in prolactin (secondary to pregnancy, post-abortion, pituitary adenomas, or hypothyroidism). Some medications may also cause (eg OCP, hormone replacement tx, phenothiazines, etc).
56
Define Montgomery's tubercles
May form from sebaceous glands assoc w a milk duct from an underlying mammary lobule. When this occurs a thin, clear to brown nipple discharge may occur. During lactation small droplets of milk may be secreted from the tubercle.
57
Define intraductal papillomatosis
Arises in mammary ducts from abnormal proliferation of cells supported by a vascular stalk. Stalk can rupture with slight trauma, leading to bloody discharge. Intraductal papillomas are often multiple and located in ducts toward periphery of breast. They are benign.
58
Define duct ectasia
Most common cause of multi-colored sticky discharge. Dilation of teh terminal ducts. An irritating lipid forms producing an inflammatory reaction and nipple discharge
59
In general, milky, green, gray or black discharges, either uni- or bi-lateral and can eb expressed from several ducts ARE or ARE NOT suggestive of cancer?
ARE NOT
60
Breastmilk color changes throughout cycle of lactation, which may be over months or years!
Describe colors and consistencies in colostrum, transitional milk, and mature milk.
Colostrum: thick fluid ranging from clear to bright orange, depending on amt of beta-carotene in mom's diet.
Transitional milk: thick and creamy
Mature milk: ranges from thin bluish shade to whiter, depending on amt of fat in that sample of milk.
61
Colors of breastmilk can change with what mom is eating! Examples include...
```
strong natural or artificial colorants in foods
eg orange when eating lots of carrots
pink from beetroot
green from some sports drinks
khaki from licorice.
```
62
Other, non-food causes of colored milk (3)
Old blood discoloring colostrum and transitional milk to look rusty. Sometimes called Rusty Pipe Syndrome.
Fresh blood colors milk pink. Intraductal papillomas or tiny cracks in nipple are most common cause of this.
Pus in breastmilk from the adenitis form of mastitis, or a breast abscess, may change milk to green/yellow and if expressed, pus will separate from milk.
63
Name the two stages in initiation of lactation
```
Secretory differentiation (previously lactogenesis I)
Secretory activation (previously lactogenesis II)
```
64
Define secretory differentiation
when the mammary epithelial cells of the alveoli differentiate into lactocytes with the capacity to synthesize unique milk constituents.
65
Define secretory activation
Initiation of copious milk secretion associated with major changes in the concentrations of many milk constiuents
66
Define lactogenesis III
the maintenance of lactation, and is an autocrine function that is controlled independently in each breast.
67
Lactation cycle:
Conception --> Puberty -->
| Pregnancy --> Lactation --> Weaning --> Involution --> Quiescence --> Pregnancy --> repeat
68
See Sequencing of Lactogenesis image
Pg. 25/47 BE 02
69
When does lactation become under autocrine (local) control [shifting from endocrine (hormonal) control?
About 30-40 hours after birth
70
When does secretory differentiatoin commence and how does this look for lactating women?
Commences mid pregnancy (normal individual variations exist)
Some women able to express small amts of colostral fluid fr breasts from thisi time, while others may see no sign of milk production until after infant is born.
71
Hormonal control and secretory differentiation
Prolactin stimulates functional development
| Progesterone inhibits onset of copious milk secretion
72
Colostrum contains relatively high concentrations of (4)...
| There is no .... present, and .... concentration is low.
```
Sodium
Chloride
Immunoglobulins
Lactoferrin
There is no casein present and lactose concentration is low.
```
73
Can lactose escape from milk secretion into blood stream during pregnancy? Why?
YES. Because paracellular pathway between lactocytes remains open during pregnancy.
74
How do we measure the onset of secretory differentiation?
By measuring urinary lactose
| Also can ID the rise in hormone prolactin identified with its beginning
75
Why do babies need increased immune protection in the first 2 days after birth? What two components of breastmilk provide this protection?
Because the kidneys need to clear the excess fluid most babies are born with. Secretory IgA and lactoferrin provide this.
76
What biochemically characterizes secretory activation?
A decrease in sodium and total protein
| An increase in lactose and citrate in the milk
77
```
When does secretory activation occur?
What happens (3)
```
Occurs biochemically about 30-40 hours after brith of infant and removal of placenta.
What happens: progesterone levels fall rapidly d/t removal of placenta - no longer inhibiting milk secretion; serum prolactin levels very high at birthing - essential for initiation of lactation; lactose secretion by lactocyte into colostrum increases - extra fluid drawn into alveolus with it (osmotic transfer)
78
One reason that lactation is unexpectedly delayed or poorly established, consider the possibility that....
There is some function placental tissue remaining after birth. This inhibits lactation d/t progesterone being emitted from this tissue.
79
What are three other hormones involved in successful initiation of lactation whose mechanisms are not yet clear?
Insulin
Thyroxine
Glucocorticoids
80
Immediately following birth, and before the volume of breastmilk increases.... (3)
sodium and chloride concentration begins to decrease
lactose levels increase
protective components in breastmilk are also very high: sIgA, lactoferrin, oligosaccharides
81
INTO or OUT OF
| Sodium and chloride are able to move .... breastmilk, while lactose is able to move .... breastmilk into the bloodstream
INTO breastmilk
| OUT OF breastmilk and into bloodstream
82
Why do tight junctions close?
| When this occurs....
Withdrawal of progesterone in the presence of prolactin and glucocorticoids. When this occurs, stable milk composition is maintained.
83
After day X, milk composition is similar to that of mature human milk.
DAY 4
84
Average daily milk production:
- Day 1
- Established lactation
- Day 1: 15 to 30 mls (1/2 to 1 oz) (range 7-123ml)
| - Established lactation: 750-800ml (17 to 25 oz) (range 500-1200ml/day)
85
An ongoing raised sodium concentration (at Day 5 and beyond) is likely to indicate...
Lactation problems such as delayed onset of secretory activation, low supply or early involution.
86
About how soon after birth does milk 'come in' usually?
About 70 hours pp (av range 50-73 hours)
87
Mothers perceive secretory activation as (6)
- breast swelling,
- milk leakage,
- change in physical appearance of milk,
- change in infant cues,
- breast fullness, and/or
- breast tingling
88
When secretory activation begins, what happens to mom's metabolism and mammary bloodflow?
BOTH INCREASE
| Along with the increased blood flow to GI tract and liver to meet increased demand for nutrients
89
While milk production occurs initially as a result of endocrine (hormonal) control, it continues based on...
continuing removal of milk from breast, which is driven by infant appetite [AUTOCRINE control]
90
Define Feedback Inhibitor of Lactation (FIL) and how it works.
FIL is the name of a small whey protein that provides a local negative feedback mechanism. When it is present in large quantities (ie when lot of breastmilk in breast) slows synthesis of breastmilk. Likewise, when little is present in breast (ie minimal breastmilk in breast) breast will synthesize milk rapidly.
91
Where are prolactin receptors found?
On the basement membrane of the alveolus.
92
How do prolactin receptors influence milk being made?
| A note about prolactin and milk production.
As alveoli become increasingly distended, as breast fills, less prolactin is found on basement membranes, suggesting that prolactin xfer into lactocyte slows w increasing breast fullness, and eventually stops.
*PROLACTIN MUST be present in order for milk to be made, but the degree to which prolactin is able to apss into alveolus (via prolactin receptor control) is more relevant than levels of prolactin in blood stream.
93
Describe the prolactin receptor theory.
| What recommendation does this theory bring?
Increased suckling in early lactation stimulates develop of MORE receptors for prolactin. This increase may be significant when basal prolactin level are reached from about 80 days pp - more receptors permitting transfer or more of the reduced amount of serum prolactin.
RECOMMEND: lots of BF in early pp days to create these add'l receptors.
94
MYTH: serum (blood) prolactin levels control milk synthesis.
THIS IS NOT TRUE but many texts still contain this old information.
95
Why can a mother continue to BF when pregnant, or when taking progestin-only birth control?
Because rising blood levels of progesterone from the pregnancy do not inhibit milk secretion when it is under autocrine control.
96
Serum prolactin levels rise throughout pregnancy from (preconception) to (peak at term)
pre-conception levels of 10ng/mL
| to peak at about 200ng/mL at term
97
Which nerve is stimulated by suckling, and what does this cause?
Stimulates 4th intercostal nerve
| Causes release of oxytocin and prolactin from anterior pituitary gland
98
```
Prolactin release following suckling:
- peaks
- returns to normal levels
- decreases over time
Intensity of suckling
```
- peaks about 45 mins after BF
- returns to pre-feed levels within 3 hours of BF
- decreases over time 0 from rise of up to 150ng/mL in early pp, to only about 5-10 ng/mL by 6 mos pp
Intensity of suckling influences degree of prolactin release, eg suckling twins simultaneously - 2x prolactin release!
99
There is a steady decline in breastmilk prolactin levels:
From 1 mo (amt) to 6 mos (amt),
despite daily milk production not changing significantly during this time.
- from 1 month pp (47-52 ng/mL) to
| - 6 mos pp (10-12 ng/mL)
100
Serum prolactin changes have no effect on...
Therefore, although prolactin is essential to the initiation of lactation after birth, during established lactation its role is.... rater than ....
regulation of rate of milk synthesis or milk production.
| Role is permissive rather than regulatory.
101
Describe variability in breastmilk storage capacity; generally and a specific range.
Is it a limiting factor to daily milk production??
What if a mother has small storage capacity?
Generally, storage capacity varies between each mom and each breast
Specifically, the range is 80ml - 600ml
NOT a limiting factor
This mother must feed infant more frequently.
102
Define involution
| When does it occur?
the reversal of mammary changes that occurred during pregnancy. Occurs when removal of milk fr breast ceases.
103
Describe process of involution
As milk is progressively left in breast for longer periods of time during weaning, FIL accumulates in breast and alveolar distention reduces transfer of prolactin into alveoli, slowing milk secretion. More than one feed/day is necessary to maintain milk secretion.
104
What changes occur to milk through involution process? At what threshold does this change occur?
With decreasing secretion of breastmilk, milk becomes more colostrum-like in composition with changes in milk proteins, lactose, chloride and sodium observed when milk volume fell below 400 mL/d.
105
Sequence of involution:
cessation of milk secretion --> apoptosis of lactocytes --> remodeling of gland to pre-pregnancy state/size.
This occurs gradually and explains why women can relactate fairly easily within the first month or so after weaning.
106
See The Process of Milk Production image on pg 40/47
BE 02
107
3 categories of lactation insufficiency and definitions
1. Pre-glandular (abnormality of hormonal functioning)
2. Glandular (an abnormality of breast structure)
3. Post-glandular (an abnormality of breastfeeding management)
108
For Lactogenesis to occur, a woman requires (2):
1. Adequate glandular tissue that is responsive to hormonal influences.
2. Correct balance of hormones to initiate lactogenesis.
109
Incidence of true lactation insufficiency (ie d/t it being physically impossible to establish lactation either because of diseased or malformed nipples, or because infant cannot suck on account of mental defect or of cleft palate or other physical default.)
About 5%
110
What is the hormone essential to breast function during pregnancy and immediately postpartum?
PROLACTIN
111
Why might prolactin levels be suppressed?
pharmacological inhibition (eg cabergoline or bromocriptine administration), Sheehan's syndrome, or rarely, genetic absence of prolactin. Will result in failure to lactate.
112
What conditions are thought to be associated with poor lactation? (5)
```
Hypothyroidism
Insulin-resistant PCOS
Irregular menstrual cycles
High androgen levels
Conditions treated with cranial radiation
```
113
Describe delayed onset of lactogenesis
Noticeable fullness/heaviness of breasts not occurring within 72 hours of birth.
114
3 factors that appear to delay onset of secretory activation:
Stress: serum levels of stress hormones high during pregnancy, parturition and lactation --> assoc w high cortisol levels. Cortisol is necessary to initiate secretory activation successfully, though unknown how.
Elevated glucose: high glucose in cord blood, from poorly controlled diabetes, eg.
Maternal obesity: high BMI assoc w/ lower prolactin response to suckling.
