Phase 2 KPH - Week 3 (Breastfeeding) Flashcards
(135 cards)
Breasts
- Accessory organs of the female reproductive system
- Develop during puberty
- Mounds of variable size and shape
- Lie on the front of the thorax, superficial to pectoralis major, extend up to axilla
- Contain glandular, fatty and connective tissues
List the structures of the breast
- Alveoli
- Mammary glands
- Lobes
- Lobules
- Lactiferous ducts
- Lactiferous sinuses
- Nipple
- Lymphatic vessels
Describe the structure and function of mammary glands
- Composed of alveoli
- Enlarge during pregnancy, atrophy when breast-feeding ceases
- Form 15-20 lobes that radiate around the nipple
- Each lobe contains many smaller lobules, which end in dozens of tiny bulbs called acini
What is the function of the alveoli of the breast?
To produce milk (initially colostrum)
Describe the function of the lactiferous ducts
Drain the milk (or colostrum) from the lobes to the centre of the nipple where they open at the lactiferous sinuses
Describe the path taken by milk in the breast
Alveoli -> lobes -> lactiferous ducts -> lactiferous sinuses -> nipple
Describe the structure of the nipple
- In centre
- Mostly composed of smooth muscle fibres
- Surrounded by pigmented area of skin = areola
- Almost unpigmented before first menstruation, pigmentation increases around puberty then turns pink -> brown during pregnancy
- Numerous sebaceous glands in areolae (independent of hair follicles except at periphery of areolae) = Montgomery tubercles
- Secretion of areolar glands prevent irritation of nipple during nursing
Retromammary space
Layer of loose connective tissue between breast and pectoral fascia, potential space, often used in reconstructive plastic surgery
Describe the connective tissue stroma of the breast
- Supporting structure which surrounds the mammary glands
- Fibrous and fatty component
- Fibrous stroma condenses to form suspensory ligaments (of Cooper)
What is the function of the suspensory ligaments (of Cooper)
- Attach and secure breast to dermis and underlying pectoral fascia
- Separate the secretory lobules of the breast
Describe the lymphatic drainage of the breasts. Why is this significant?
- Drain into axillary lymph nodes
- Form a route for breast cancer to spread
Describe the vasculature of the breasts
- Arterial supply to medial part = internal thoracic artery
- Arterial supply to lateral part = lateral thoracic and thoracoacromial branches and lateral mammary branches
- Veins drain into axillary and internal thoracic veins
Describe the nerve supply of the breasts
- Innervated by anterior and lateral cutaneous branches of the 4th to 6th intercostal nerves
- Contain sensory and autonomic nerve fibres (autonomic regulate smooth muscle and blood vessel tone)
Describe the histology of the breast
- Ducts are lined by inner layer of cuboidal to columnar epithelial cells and an outer layer of myoepithelial cells
- Connective tissue within lobules is composed of fibroblasts in a background of collagen and acid muscins with histiocytes and occasional lymphocytes
- Interlobular stroma is hypocellular and composed of fibroadipose tissue
Define lactation
Secretion of milk from mammary glands and period of time that a mother lactates to feed her young
Define galactopoiesis
Maintenance of milk production, requires prolactin
Why is oxytocin needed in lactation?
Triggers milk let-down (ejection) reflex in response to suckling
When does development of breasts for lactation begin during pregnancy?
From week 18
Role of progesterone in lactation
- Influences growth in size of alveoli ad lobes
- High levels inhibit lactation before birth
- Levels drop after birth, triggers the onset of copious milk production
Role of oestrogen in lactation
- Stimulates milk duct system to grow and differentiate
- High levels inhibit lactation
- Levels drop at delivery, remain low for first several months of breastfeeding
Which type of contraception should be avoided by breastfeeding women and why?
- Oestrogen-based contraception should be avoided
- Spike in oestrogen could reduce mother’s milk supply
Describe the role of prolactin in lactation
- Contributes to increased growth and differentiation of alveoli
- Influences differentiation of ductal structures
- High levels during pregnancy and breastfeeding also increase insulin resistances, increased growth factors levels (e.g. IGF-1) + modify lipid metabolism in preparation for breastfeeding
- During lactation, is the main factor in maintaining tight junctions of ductal epithelium and regulating milk production through osmotic balance
Describe the role of human chorionic sommatomammotropin in lactation
- From month two, placenta releases large amounts of HCS
- Closely associated with prolactin
- Instrumental in breast, nipple and areola growth before birth
Describe the role of follicle stimulating hormone (FSH), lutenising hormone (LH) and human chorionic gonadotrophin in lactation
- Control oestrogen and progesterone secretion
- Also control prolactin and growth hormone