Lecture 9.1: Breastfeeding and Human Lactation Flashcards
Mammary Gland Average Weight
150-200g
Mammary Gland Average Weight in Lactation
400-500g
Mammary Gland Structure
- 15-20 lobules
- 10 – 100 alveoli per lobule
- Alveolus – myoepithelial cells and lactocytes (secretory
cells) - Areola
- Montgomery’s Tubercles (mammary milk glands,
sebaceous glands, areolar glands)
Development of Breast Tissue (5 Stages)
- Mammogenesis
- Lactogenesis I
- Lactogenesis II
- Galactopoiesis
- Involution
When do the breasts develop in gestation?
4 weeks
Development of Breast Tissue: Mammogenesis
- Develops at 4 weeks gestation
- Born with only a few ducts
- Puberty: growth with each ovulation
- Ducts branch and develop buds
- Under influence of oestrogen and progesterone
Development of Breast Tissue: Lactogenesis I
- 1st phase (proliferation)
- Hypertrophy of the ductal-lobular-alveolar system
- 2nd phase (secretory)
- 16wks pregnancy alveoli accumulate colostrum
- Breast size increases
- Areola and nipple size increases
- Fat droplet accumulate in alveoli cells
- Plasma lactose and alpha-lactalbumin
Development of Breast Tissue: Lactogenesis II
- Day 3-8 postpartum
- Spaces between alveolar cells close
- Triggered by drop in progesterone
- Continuing presence of Prolactin
- Onset of copious milk production
- Endocrine to autocrine control
Development of Breast Tissue: Galactopoiesis
- Day 9 to Involution
- Maintenance of secretion
- Autocrine control – supply matches demand
- Breast size decrease 6-9 months
Development of Breast Tissue: Galactopoiesis
- Day 9 to Involution
- Maintenance of secretion
- Autocrine control – supply matches demand
- Breast size decrease 6-9 months
Development of Breast Tissue: Involution
- Decrease in milk secretion
- Apoptosis - programmed cell death
- High sodium levels
Synthesis of Milk: In Alveolar Cells
- Fat in smooth endoplasmic reticulum
- Protein secreted via golgi apparatus
- Sugar synthesised and secreted
Synthesis of Milk: Stages of Synthesis
- Early Colostrum
- Late Colostrum
- Early transitional
- Late transitional
- Mature Milk
GALT
Gastrointestinal Associated Immunocompetent Lymphoid Tissue
BALT
Bronchial Associated Immunocompetent Lymphoid Tissue
Name the Antibodies and Immunoglobulins
- IgA
- IgE
- IgG
- IgM
- IgD
Bio Active Components of Breastmilk (5 Categories)
- Enzymes
- Lipids
- Growth Factor and Hormones
- Whey
- Casein
Growth Factors and Hormones found in Breastmilk (5)
- Human Milk Growth Factors I II and III
- Cortisol, insulin, thyroxine, cholecystokinin (CCK)
- Prolactin
- Insulin-like Growth Factor
- Thyroxine and Thyroptropin-Releasing Hormone
Enzymes found in Breastmilk (2)
- Lipase
- Amylase
Lipids found in Breastmilk (2)
- Long Chain Polyunsaturated Fatty Acids
- Free Fatty Acids
- Triglycerides
What is the Roles of Casein in Breastmilk (2)
Inhibits microbial adhesion to mucosal membranes
What does Whey contain?
Immunological factors
Milk Secretion Axis
- Hypothalamus
- Pituitary Gland (prolactin, oxytocin)
- Oxytocin stimulates the uterus & myoepithelial cell
- Prolactin stimulates myoepithelial cells
- Lacteal
How many times does anterior pituitary release prolactin in 24 hours?
7 to 20 times
What is the Inhibitory Pathway of Prolactin?
- Dopamine agonist
- Prolactin-Inhibiting Factor (PIF) (antagonists)
Oxytocin is released in response to…?
suckling, and sight and smell of baby
What does Oxytocin stimulate?
- Milk Ejection Reflex
- Contraction of myoepithelial cells
- Pulsatile waves
- Forces milk from the alveoli down the ducts
- Key to lactation continuation
Why is Breastfeeding Important? (6)
- Nutrition
- Babies Fewer Infections
- Brain Growth
- Responsive Parenting
- Comfort
- Pain Relief
