The breast (lactation anatomy and physiology) Flashcards
Prolactin is formed in the
Anterior pituitary gland
LH is released from
Anterior pituitary gland
hPL =
Human placental lactogen
Oestrogens role in mammary growth:
Growth of ductal system.
Progesterone role in mammary growth:
Full development of lobule-alveolar system.
The process of growth and development of the mammary gland in perparation for milk production
Mammogenesis
When does mammogenesis begin?
When mammary gland is exposed to oestrogen at puberty
Structures of the breast continue to bud until what age?
35 years
Mammogenesis at 4 weeks gestation =
2 milk lines form axilla to groin
Secretory units of glandular tissue/mammary gland =
Alveoli
Colostrum =
First milk, high in immunological factors and low volume
Colostrum can stimulate baby to do what?
Pass first stool (myconium)
At birth, baby’s breast tissue is…
Confined to the nipple area
During childhood the mammary gland
Undergoes limited general growth in line with size and stature of child
Mammary gland at puberty:
Alveoli mature
Fat deposition
Buds branch into acini/alveoli system
During pregnancy, what hormones are involved with the development of breast?
Progesterone
Oestrogen
Prolactin
hPL
What inhibits prolactin during pregnancy?
High levels of oestrogen and progesterone - stop milk let down
Serum placental lactogen role in mammogenesis =
Areola growth
Breast is located between which ribs?
2-6
Breast lies superiorly to what muscles?
Pectoralis major
Serratus anterior
Tissue extending towards the axilla =
Axillary tail of Spence
Function of tubercles of Montgomery =
Sebaceous glands attach to milk glands. Provide olfactory stimulus to help baby find breast
Mammary gland is an adapted
Sweat/eccrine gland
What opens into the nipple?
Lactiferous ducts
Ligment which attaches to dermis and pectroal fascia to secure breast
Cooper’s ligaments/Suspensory ligaments
What surrounds alveoli to allow milk let down?
Myoepithelial cells (smooth muscle)
What line alveoli and form milk?
Lactocytes
Blood supply to breast:
Internal mammary from perforating branches
Lateral thoracic from axillary artery
Breast lymphatics mainly drain into:
Axillary nodes
Innervation of breast:
Intercostal nerves (4-6)
When in pregnancy do women begin to secrete?
Late T1 early T2
Transition from pregnancy to lactation
Lactogenesis
Lactogenesis stage one time frame
Mid/late pregnancy –> 24/48 hrs
Lactogenesis 1 is characterised by:
Production of colostrum
Why is colostrum low volume?
Baby has immature kidneys, don’t want to fluid overload
Lactogenesis 2 timeframe:
Day 3 –> Day 8
Lactogenesis 2 is characterised by:
Copious volume of milk production
Lactogenesis 3 timeframe
Day 9 –> Involution
Involution occurs how long after last feed?
40 days
Lactogenesis one is under what control?
Endocrine: prolactin
What rises in lactogenesis 1?
Plasma concentration of lactose and lactaalbumin
Lactogenesis 2 is triggered by what?
3rd stage of labour
What occurs after 3rd stage of pregnancy:
Sudden decrease in progesterone, oestrogen and hPL. Increase prolactin from APG
What has a supportive role in lactogenesis 2?
Thyroxin
Insulin
Cortisol
In the absence of … lactation won’t commence
TSH
Ex of reasons lactation doesn’t occur:
Absence of TSH
Retained products of conception
Milk in lactogenesis 2 is:
Copious
High fat content
Maintenance of milk production =
Galactoporesis
Milk production becomes what during galactoporesis?
Autocrine process
2 hormones involved in milk letdown reflex:
Oxytocin
Prolactin
Oxytocin stimulus:
Baby suckling
Sensory: sound, smell, tactile stimulus
Oxytocin is made in…
Hypothalamus
Oxytocin is secreted from
Posterior pituitary gland
Oxytocin function:
Contraction of myoepithelium
Prolactin is made by:
Lactotroph cells in anterior pituitary gland
What inhibits formation of prolactin?
Dopamine
Dopamine analogues:
Reduce lactational ability
Dopamine agonists
Increase milk production
Prolactin acts on:
Lactocytes
Theories for how removal of milk increases milk production:
- Prolactin receptor theory
- Feedback inhibitor of lactation
- Prolactin inhibitory factor (dopamine?)
What is in formula milk:
- Vitamins
- Minerals
- Water
- Proteins
- Carbohydrates
- Fats
- Water
What is in breast milk:
- Enzymes
- Anti-inflammatory molecules
- Transfer factors (assist absorbtion)
- Viral fragments, WBCs, bifidus factor, antibodies
- Horones
- Water, vitamines, minerals, proteins, carbohydrates, fats, water
Antibodies in maternal milk:
sIGA
Bifidus factor:
Makes is more acidic (bacteria better in high pH)
Hormones in breast milk:
Insulin
TSH
Growth hormone
Epidermal growth factor
Problems with formula milk:
- Sertilisation issues
- First processed food
- Atopic probelms: asthma, eczema
- Cows milk allergy
- Difficult to process
Breast feeding pathology is related to what:
- Poor positioning and attachment
- Nipple tissue and trauma
- Breastfeeding management
Mastitis =
Inflammation of breast tissue
2 types of mastitis =
Infective
Non-infective
Most common type of mastitis =
Non-infective
Cause of non-infective mastitis =
Poor positioning and attachment - inadequate milk removal - milk stasis - back pressure - inflammatory response
Symptoms of non-infective mastits =
Swelling Warmth Flu-like Pyrexia Unilateral Sudden onset More painful before feed
Treatment of non-infective mastitis =
Treat cause - support positioning and attachment
- increase feed frequency
- analgesics
- gentle breast massage during feed
Common causes of infective mastitis =
Staphlococcus aureus
Streptococcal
E.coli
Signs and symptoms of infective mastitis:
Pain, swelling, heat More severe flu-like Pyrexia (more than 40) Rigors Discharge of pus or blood from nipple
Management of infective mastitis =
- Warm, moist compress
- increase feed
- positioning and attachment
- analgesia
- antibiotics
- increase fluid intake
Antibiotics effective against infective mastits =
Penicillins
Cephalosporins
