Mammary glands Flashcards
Describe the function and structure of mammary glands
mammary glands are modified sweat glands. they consist of a series of ducts and secretory lobules (15-20). each lobule has many alveoli.
lobe > lactiferous duct > lactiferous sinus > nipple
Describe the function and structure of the connective tissue stroma and the pectorial fascia surrounding the mammary glands.
Connective tissue stroma:
has a fibrous and fatty component. fibrous component condenses to form suspensory ligaments of cooper. function is to:
• Attach and secure the breast to the dermis and underlying pectoral fascia.
• Separate the secretory lobules of the breast.
Pectoral fascia: flat sheet of connective tissue associated with pectoralis major.
There is a layer of loose connective tissue between the breast and pectoral fascia – known as the retromammary space
What hormones are responsible for breast milk production
prolactin and oxytocin
What produces prolactin and when does it steadily increase
anterior pituitary gland
It steadily increases in the blood from pregnancy Week 5 to term.
what controls prolactin levels in the plasma
the dopaminergic system
How does prolactin acts on the human breast to produce milk
binding to mammary epithelial cell receptors, which stimulates synthesis of mRNA of milk proteins.
what does prolactin inhibit
ovulation
what produces oxytocin and how is it initiated
posterior pituitary gland
Suckling at the breast stimulates the PPG to produce and release oxytocin in an intermittent manner.
How does oxytocin acts on the human breast to produce milk
It is responsible for milk ‘let down’ or milk ejection
What is the milk produced for the first several days after delivery
Colostrum
What are Colostrum contents
increased concentration of calcium, potassium, proteins, fat-soluble vitamins, minerals and antibodies.
High conc. of proteins, but low conc. of carbohydrate, lipids and potassium compared to mature milk.
Why is colostrum particularly valuable for infants
Due to its high concentration of antibodies, this milk prevents infection (passive immunity against bacteria/viruses)
when does colostrum transition to mature milk
between day 3 and 7 postpartum
What are the anti-infective agents that colostrum possesses
macrophages, lymphocytes, immunoglobulins (especially IgA), lactoferrin, lysozyme, complement, interferon, oligosaccharides, growth factors, and enzymes.
What does it not provide
Vitamin K- babies get supplement
When does mature milk terminate
until termination of breastfeeding
What is the main carbohydrate in mature milk
Lactose- increases over the duration of breastfeeding
what is the protein present in mature milk
Casein is present but lower than formula milk
what are the lipids present in mature milks
triacyglycerols, phospholipids, fatty acids (including essential fatty acids).
what is an extra molecule that mature milk posesses
energy
what are the differences between formula and breast milk
- Breast milk is microbiologically clean
- Only breast milk provides a range of anti-infective components (e.g. antibodies) to help prevent the baby from infection.
- Breast feeding reduces the risk of GI, respiratory and other infections (otitis media, meningitis, UTIs), SIDS (cot death), childhood lymphomas, early allergic diseases and type1 diabetes.
- Breast milk is always at the right temperature. Whereas bottle feeding requires careful sterilising (cleaning by heat) and temperature control before feeding to the baby.
- Breast milk is more easily digested than formula milk, so the baby is often less constipated and gassy.
What can soy milk cause
it can cause teeth deficiencies due to high glucose levels
What is weaning
the process of getting babies used to eating foods other than milk and using a spoon and cup.
when should the weaning transition occur
4-6 months.
once introduced, solid foods should be given regularly and in increasing quantities.
What is the macronutrient composition of breast milk
• Sugars 7% - mainly lactose • Fat 4% • Protein 1.3% - (main)Casein 0.4% • Minerals 0.2% Exact composition varies: • First milk = Colostrum – High in protein, low in fat and sugar • Mature milk content varies with the age of baby and time of day
How does breast milk provide immunity?
• Macrophages, T cells, stem cells, and lymphocytes
• Secretory immunoglobulin A – passive immunity
• Hundreds of biologically active substances, many
with multiple roles acting in gut, for example:
– α-lactalbumin: antibacterial and immunostimulatory properties
– Lactoferrin binds iron in competition with bacterial pathogens
– Oligosccharides: selectively encourage the growth
of beneficial (probiotic) organisms
How does breast milk promote maturation of the gut?
• Epidermal growth factor
– promotes healing
• Neuronal growth factors
– promotes development of peristalsis
How long should infants be breast
fed for? and why is this important
exclusive breastfeeding up to 6 months
infants have less morbidity and mortality
• Breast milk provides all nutritional needs up to
age 6 months
• WHO recommends continued breast feeding for 2
years and beyond
• Continues to provide immune protection
Describe the hormonal control of lactation
Prolactin:
- Secreted in anterior pituitary gland in response to nipple stimulation
- binds to mammary epithelial cell receptors, which stimulates synthesis of mRNA of milk proteins.
- highest levels at night
Oxytocin:
- Secreted in posterior pituitary gland in response to nipple stimulation
- stimulates smooth muscle in alveoli to eject milk/ ‘milk let down’
What hormone is responsible for the local control of lactation
- Feedback Inhibitor of Lactation (FIL) is secreted
into milk
• As milk volume increases, FIL blocks milk
production
• Removing FIL allows further milk production
Why is good positioning and attachment important?
Good positioning is essential to ensure that the baby can correctly attach at the breast
• Correct attachment essential to
– ensure effective milk removal
– prevent nipple damage
What is the breast feeding culture like?
• Many families have no member who has ever
breast fed
• Formula milk advertisements (follow on) on TV,
bus shelters etc
• Media, toys, TV, films all portray bottle not breast feeding
• Breast feeding in public still frowned on
– Breast are for sexual display and not feeding
What are the pros and cons of bottle feeding?
Pros:
Large volumes available at all times
• Enables separation from mother and for father to give feeds
• Bottle fed babies tend to sleep longer through night
Cons
• Formula milk is expensive
• Bottles have to be cleaned and sterilised and milk made up
– Warm milk in bottles act as aculture medium
• Lacks all the biologically activeelements of breast milk
• Places child at risk of infection, SID, reduced cognition etc
