WEEK 11 Flashcards
(159 cards)
What is the first milk produced?
colostrum
WHO/UN advises for women to breast feed exclusively for 6 months for optimal lifetime benefits. What are the advantages, to the BABY, of this?
- reduced incidence of GI, resp and middle ear infection
- decreased risk of childhood diabetes, asthma and eczema
- reduced risk of lactose intolerance
- improved intellectual and motor development
- decreased risk of obesity in later life
- possible reduced autoimmune diseases
- 27% reduced risk of sudden infant death syndrome
Why is breast feeding beneficial to the mother?
PROMOTES: - recovery from childbirth - return to 'normal' body weight - promotes period of infertility REDUCES risk of premenopausal breast cancer POSSIBLY: - reduces risk of ovarian cancer - improves bone mineralisation
What is the role of prolactin in lactational amenorrhoea?
- suppresses hypothalamic release of GnRH and therefore pituitary FSH and LH
- prevents follicular growth, ovulation and menstruation
Describe the development of the breast, from birth to after parturition.
- at birth breast consists of lactiferous ducts w/out any alveoli
- at puberty, under the influence of oestrogen, ducts proliferate and masses of alveoli form at ends of branches
- each cycle involves proliferative changes in alveoli and may be some secretory activity
- during pregnancy, due to oestrogen, progesterone and prolactin, glandular portion of breast undergoes hypertrophy replacing adipose tissue
- from wk 16, breast is fully developed for lactation but is awaiting activation
- atfer parturition breast produces colostrum before mature milk production begins
What happens to the alveoli during pregnancy?
- prior to pregnancy few alveoli exist
- in early pregnancy alveoli grow
- in mid-pregnancy, alveoli enlarge and acquire lumen
- during lactation, alveoli dilate
- after weaning, gland regresses
What do alveoli empty via?
Lactiferous ducts that are dilated to form lactiferous sinuses which open on the surface of the tissue
What are (i) secretory alveoli/acini (ii) contractile myo-epithelial cells surrounding stimulated by?
(i) prolactin
(ii) oxytocin
What is lactation initiated by? Explain the points when prolactin is increased, and then decreased.
Initiated by precipitous drop in oestrogen and progesterone after delivery
- prolactin surges each time mother nurses baby due to nerve impulses from nipples to hypothalamus
- when not nursing, hypothalamus produces prolactin inhibitory hormone
- lactation inhibits FSH and LH and thus lactation interferes with repro function
How is lactation inhibited during pregnancy?
- prolactin controls/promotes milk production
- prolactin is secreted during pregnancy but its action is inhibited by high progesterone and oestrogen levels in hPL
- these steroid levels fall after parturition and milk production begins
What is the role of prolactin in the sucking reflex?
- suckling stimulus inhibits hypothalamic release of dopamine (PIF) and prolactin released in proportion to the strength and duration of the suckling
What is the role of oxytocin in the milk ejection reflex?
- suckling stimulated neurones in hypothalamus to synthesise oxytocin which is carried to the posterior pituitary
- release of oxytocin into blood stream acts on myo-epithelial cells in alveoli, causing ‘let down’ of milk
- conditioned reflex: let down in response to cry of baby, oxytocin release inhibited by catecholamines and stress can inhibit this reflex
When does the coordination of suckling develop? What is the correct way for baby to suckle? Why is it important?
- between 32 to 35 eek gestation
- correct attachment important to suckle effectively to avoid engorgement/blocked ducts for mum and ensure sufficient intake for baby
What happens to (i) synthesised milk fat (ii) milk protein?
(i) moves through cell surface membrane. Enclosed droplet pinched off into duct lumen
(ii) passes through Golgi apparatus and released by endocytosis
What is the difference between colostrum and mature milk?
- colostrum has greater amounts of immunoglobulins (IgG, IgA) and a no. growth factors, conferring passive immunity
- relatively low protein and fat compared to other mammals means that human babies don’t grow as fast
What is the composition of mature milk?
- main energy source = fat
- lactose = main carb, it promotes growth of lactobacillus bifidus and provides galactose for myelin formation
- proteins casein and lactalbumin
- fat soluble vitamins A, D, E, K
- water soluble vitamins B6, B12, C, folate, niacin, riboflavin, thiamine
- gut is initially sterile and first feeds will contain acute dose of antigens and bacteria
What does benign breast disease consist of?
- a heterogeneous group of lesions including developmental abnormalities, inflammatory lesions, epithelial and stromal proliferations, and neoplasms
When in a womens life is it most common to acquire benign breast disease?
- increases in frequency towards menopause, then decreases
How is benign breast disease diagnosed?
with use of mammography, US, MRI and extensive use of needle biopsies
For BENIGN breast lumps, describe the (i) shape (ii) alignment (iii) margins (iv) lateral shadowing?
(i) oval/ellipsoid
(ii) wider than deep; alligned parallel to tissue planes
(iii) smooth/thin
(iv) present
For MALIGNANT breast lumps, describe the (i) shape (ii) alignment (iii) margins (iv) lateral shadowing?
(i) variable
(ii) deeper than wide
(iii) irregular or spiculated
(iv) absent
What is fibrocystic change (FCC)?
An exaggerates physiologic response
- nonproliferative change which induces gross and microscopic cysts, apocrine metaplasia, mild epithelial hyperplasia, adenosis and an increase in fibrous stroma
Who does FCC affect? What symptoms do women tend to have?
- over one third of women 20-50 years old, then declines after menopause
- most are asymptomatic but some present with nodularity and pain
Does FCC increase your risk of breast cancer? Explain/
- doesn’t increase risk of getting breast cancer but it can make it more difficult to identify potentially cancerous lumps during breast examination & on mammograms