Lactation Flashcards
Purpose of the breasts
Nutrition for baby
Spacing of pregnancies (lactational amenorrhea)
What are breasts derived from
embryology
The ___ ___ arising from ___ to groin.They are modified ____ glands. (can get extra entire breasts developing or nipples on this line, or lactiferous ducts exiting on other parts)
Primary ___ ___ a downgrowth into dermis. Then become _____ buds. These become the _____ glands.
As gestation develops, buds undergo _____ induced by placental progesterone and ____. (15-20 at birth)
The milk crests arising from axilla to groin.They are modified sweat glands. (can get extra entire breasts developing or nipples on this line, or lactiferous ducts exiting on other parts)
Primary breast bud a downgrowth into dermis. Then become secondary buds. These become the lactiferous glands.
As gestation develops, buds undergo canalisation induced by placental progesterone and oestrogen. (15-20 at birth)
Can newborns make milk?
Due to hormonal stimulation, some babies make a colostrum like substance called witch’s milk
External breast structure other than breast body
Nipple: Pigmented raised structure where lactiferous ducts join the skin
Areola: Contains sebaceous glands that give texture to surface
Internal breast structures
Pectoral fat pads that gives most of the breast its shape and texture
Suspensory/Cooper’s ligaments provide support. Are affected by age and hormones
15-20 lobes made up of milk secreting lobules (alveoli) which join into a single lactiferous duct. These ducts expand into a lactiferous sinus that open into nipple
Development of the breast: Formation of alveoli by? Menstrual cycle change?
There are no ____ present until puberty and form under the influence of _____.
During each menstrual cycle under _____and progesterone cause alveolar bud growth. (Can measure for breasts tenderness)
In pregnancy further alveolar growth (doubles in weight)
There are no alveoli present until puberty and form under the influence of oestrogen.
During each menstrual cycle under oestrogen and progesterone cause alveolar bud growth. (Can measure for breasts tenderness)
In pregnancy further alveolar growth (doubles in weight)
What hormones are involved in breast developmet?
Oestrogen: needed for breast growth (mitogen)
Progesterone: Induces branching of ducts
Prolactin: Necessary for development, but also stimulates casein and alpha lactalbumin mRNA’s
GH: can be important
Insulin and cortisol: Stimulate alveolar epithelial cell division
Why does lactation occur after birth, despite high levels of circulation PRL in mother?
Upon placental removal, progesterone diminishes. It is an inhibitor milk production and SM relaxant
What is the endocrine response to lactation?
note is needed because placental PRL falls at birth, and is needed for milk production
Nipple suckling (if nerve is cut, reflex is lost) causes reduced production of prolactin inhibiting factor (PIF/dopamine) into the portal system, and vasoactive intestinal peptide (VIP) is made
These act on lactotrophs to form prolactin in the AP.
Prolactin induces milk production, duration and extent increases amount of prolactin made. (baby gets what it wants)
What else does suckling induce?
The milk ejection response
Suckling causes oxytocin release from PP.
Oxytocin stimulates myoepithelial cell contraction causing milk ejection.
Can also occur when female tract is stimulated, baby crying or smell
How does lactation effect fertility?
Prolactin can suppress FSH and particulalrly LH, meaning no ovulation occurs. (via kisspeptin neurons)
Lactational amenorrhea, not the most effective form, but a way of contraception. Useful for spacing pregnancies
What is colostrum
Normal milk is not made straight after birth
Colostrum has less sugar and fat, but more proteins.
Particularly rich in antibodies, IgA predominantly
Major components of human milk
- Phagocytes, leuckocytes, T cells: _____ ____
- Small soluble signalling molecules, e.g ____,_____ etc: Immunomodulators and EGF
- Enzymes like ____ and ___ to aid baby digestion
- Lipids: DHA with visual acuity and energy storage (TG)
- ____: energy source and ____ synthesis, promotes lactobacilus bifidus
- ______ for protection
- ____: antibacterial
- lysozyme: “
- ______
- water
- Phagocytes, leuckocytes, T cells: Immunological protection
- Small soluble signalling molecules, e.g prostaglandins,cytokines etc: Immunomodulators and EGF
- Enzymes like lipase and amylase to aid baby digestion
- Lipids: DHA with visual acuity and energy storage (TG)
- Lactose: energy source and myelin synthesis, promotes lactobacilus bifidus
- Immunoglobulins for protection
- Lactoferrin: antibacterial
- lysozyme: “
- vitamins
- water
Differences between human and bovine milk?
important as all formula derivatives are bovine, can never replicate what human milk is
Lactose: 1.5x higher in humans
Casein: Lactalbumin ratio: 1:2 humans, 3:1 cows
Linoleic acid (fatty acid): 8% of fat, 2% in bovine
Does breast size matter?
Larger breasts can store more but does not alter milk production capacity.
Also right yield on average more than left
