Mammary glands

Question 1

Describe the function and structure of mammary glands

Answer 1

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

Question 2

Describe the function and structure of the connective tissue stroma and the pectorial fascia surrounding the mammary glands.

Answer 2

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

Question 3

What hormones are responsible for breast milk production

Answer 3

prolactin and oxytocin

Question 4

What produces prolactin and when does it steadily increase

Answer 4

anterior pituitary gland

It steadily increases in the blood from pregnancy Week 5 to term.

Question 5

what controls prolactin levels in the plasma

Answer 5

the dopaminergic system

Question 6

How does prolactin acts on the human breast to produce milk

Answer 6

binding to mammary epithelial cell receptors, which stimulates synthesis of mRNA of milk proteins.

Question 7

what does prolactin inhibit

Answer 7

ovulation

Question 8

what produces oxytocin and how is it initiated

Answer 8

posterior pituitary gland

Suckling at the breast stimulates the PPG to produce and release oxytocin in an intermittent manner.

Question 9

How does oxytocin acts on the human breast to produce milk

Answer 9

It is responsible for milk ‘let down’ or milk ejection

Question 10

What is the milk produced for the first several days after delivery

Answer 10

Colostrum

Question 11

What are Colostrum contents

Answer 11

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.

Question 12

Why is colostrum particularly valuable for infants

Answer 12

Due to its high concentration of antibodies, this milk prevents infection (passive immunity against bacteria/viruses)

Question 13

when does colostrum transition to mature milk

Answer 13

between day 3 and 7 postpartum

Question 14

What are the anti-infective agents that colostrum possesses

Answer 14

macrophages, lymphocytes, immunoglobulins (especially IgA), lactoferrin, lysozyme, complement, interferon, oligosaccharides, growth factors, and enzymes.

Question 15

What does it not provide

Answer 15

Vitamin K- babies get supplement

Question 16

When does mature milk terminate

Answer 16

until termination of breastfeeding

Question 17

What is the main carbohydrate in mature milk

Answer 17

Lactose- increases over the duration of breastfeeding

Question 18

what is the protein present in mature milk

Answer 18

Casein is present but lower than formula milk

Question 19

what are the lipids present in mature milks

Answer 19

triacyglycerols, phospholipids, fatty acids (including essential fatty acids).

Question 20

what is an extra molecule that mature milk posesses

Answer 20

energy

Question 21

what are the differences between formula and breast milk

Answer 21

• 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.

Question 22

What can soy milk cause

Answer 22

it can cause teeth deficiencies due to high glucose levels

Question 23

What is weaning

Answer 23

the process of getting babies used to eating foods other than milk and using a spoon and cup.

Question 24

when should the weaning transition occur

Answer 24

4-6 months.

once introduced, solid foods should be given regularly and in increasing quantities.

Question 25

What is the macronutrient composition of breast milk

Answer 25

• 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

Question 26

How does breast milk provide immunity?

Answer 26

• 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

Question 27

How does breast milk promote maturation of the gut?

Answer 27

• Epidermal growth factor
– promotes healing
• Neuronal growth factors
– promotes development of peristalsis

Question 28

How long should infants be breast

fed for? and why is this important

Answer 28

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

Question 29

Describe the hormonal control of lactation

Answer 29

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’

Question 30

What hormone is responsible for the local control of lactation

Answer 30

• Feedback Inhibitor of Lactation (FIL) is secreted
  into milk
  • As milk volume increases, FIL blocks milk
  production
  • Removing FIL allows further milk production

Question 31

Why is good positioning and attachment important?

Answer 31

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

Question 32

What is the breast feeding culture like?

Answer 32

• 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

Question 33

What are the pros and cons of bottle feeding?

Answer 33

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