Getting my breastfeeding geek on…
(October 2015)
I was inspired by a recent study day to refresh myself on breastfeeding A&P and this is the result. I am bowled over time and again by the cleverness of breastfeeding and I am working on a piece about colostrum (honest to goodness the cleverest food ever) which I hope to share at some point but today it’s all about the breast and supply.
We will start on the outside with the nipple, or papilla which is a projected part of the breast where the lactiferous ducts end their journey (more on those later!) and the milk comes out. The nipple is surrounded by an areola of varying size, it isn’t important how big it is. It is generally darker than the surrounding breast tissue and this helps the baby to locate the nipple on its first expedition to the breast. The areola has a number of oil secreting glands called (brilliantly I might add) Montgomery’s Tubercles and these help to protect and lubricate the areola.
The breast tissue which started to develop in puberty has been developing in earnest throughout pregnancy (known as stage 2 Mammogenesis) and the milk producing cells are functional from around 20 weeks of pregnancy when colostrum starts to be produced. The structure of the breast is made up of fat and connective tissue and is in front of the pectoral muscles (Pectoralis Major). Breast milk is produced in the ‘acini’ cells which are within the ‘alveolus’, a collection of acini cells at the top of the many lactiferous ducts which lead down toward the nipple. Visually it is quite like a bunch of grapes, imagine the many ducts leading into one another until you have a smaller number leading to the nipple. Though there are still quite a few, some women having as many as 14 and as few as 5.
Back to the acini cells though because this is where the magic happens. The cell is lined like a kind of patchy crazy paving with ‘prolactin receptors’. They need to be primed, or fired up by prolactin.
When the baby goes to the breast a nerve impulse is sent to the anterior lobe of the pituitary gland which then secretes prolactin into the blood stream and then acts on the acini cels to produce breastmilk.
Oxytocin also plays its part in breastfeeding as it acts on the tiny muscles which are around the acini cells. This muscle is made up of myo-epithelials cell and is smooth muscle, which is the same sort of muscle as the uterus… and that, as we know is also stimulated to contract by oxytocin. So… the baby goes to the breast and this stimulates the posterior lobe of the pituitary gland to release oxytocin which causes the myo-epithelial cells to contract and move the milk down the duct toward the baby.
So it is important that the baby is put to the breast regularly in the early days to prime the prolactin receptor sites. If prolactin is not stimulated then the receptor sites may not be adequately primed and this will affect milk production. Put very simply, the more the baby feeds, the more milk will be produced. Milk is therefore continually produced and there are no reservoirs of milk in the breast.
The baby stimulating the breast is key – oxytocin is stimulating the milk for the current feed and prolactin is stimulating the milk for the subsequent feeds.
Now to ensure the breasts don’t continue to produce milk until they explode there is another clever mechanism and it is called the ‘Feedback Inhibitor of Lactation’ (FIL). This protein is always present in the milk but when the milk is not moving through the breast then it kind of ‘backs up’ in the acini cell and so the FIL is higher and this slows the production of breastmilk. When there is less milk in the breast, FIL is lower so breastmilk production is higher and this is why frequent feeding stimulates higher breastmilk production as it keeps FIL low. Allowing the baby to set the pace allows a natural balance to occur.
Having a good knowledge of the delicate balance of hormones necessary for the establishment of breastfeeding is vital to properly support mothers in the early days. It is even more important when supplements are given for any reason that the role of skin to skin is promoted as this stimulates the hormonal response and helps to protect breastfeeding.
References
http://www.ncbi.nlm.nih.gov/books/NBK148970/
http://www.unicef.org.uk/BabyFriendly/Health-Professionals/Care-Pathways/Breastfeeding/
http://kellymom.com/hot-topics/milkproduction/
Picture credits
https://doodledailyblog.wordpress.com/2011/01/05/get-your-geek-on/
http://www.mchip.net/sites/default/files/mchipfiles/Anatomy%20of%20the%20breast.JPG
We will start on the outside with the nipple, or papilla which is a projected part of the breast where the lactiferous ducts end their journey (more on those later!) and the milk comes out. The nipple is surrounded by an areola of varying size, it isn’t important how big it is. It is generally darker than the surrounding breast tissue and this helps the baby to locate the nipple on its first expedition to the breast. The areola has a number of oil secreting glands called (brilliantly I might add) Montgomery’s Tubercles and these help to protect and lubricate the areola.
The breast tissue which started to develop in puberty has been developing in earnest throughout pregnancy (known as stage 2 Mammogenesis) and the milk producing cells are functional from around 20 weeks of pregnancy when colostrum starts to be produced. The structure of the breast is made up of fat and connective tissue and is in front of the pectoral muscles (Pectoralis Major). Breast milk is produced in the ‘acini’ cells which are within the ‘alveolus’, a collection of acini cells at the top of the many lactiferous ducts which lead down toward the nipple. Visually it is quite like a bunch of grapes, imagine the many ducts leading into one another until you have a smaller number leading to the nipple. Though there are still quite a few, some women having as many as 14 and as few as 5.
Back to the acini cells though because this is where the magic happens. The cell is lined like a kind of patchy crazy paving with ‘prolactin receptors’. They need to be primed, or fired up by prolactin.
When the baby goes to the breast a nerve impulse is sent to the anterior lobe of the pituitary gland which then secretes prolactin into the blood stream and then acts on the acini cels to produce breastmilk.
Oxytocin also plays its part in breastfeeding as it acts on the tiny muscles which are around the acini cells. This muscle is made up of myo-epithelials cell and is smooth muscle, which is the same sort of muscle as the uterus… and that, as we know is also stimulated to contract by oxytocin. So… the baby goes to the breast and this stimulates the posterior lobe of the pituitary gland to release oxytocin which causes the myo-epithelial cells to contract and move the milk down the duct toward the baby.
So it is important that the baby is put to the breast regularly in the early days to prime the prolactin receptor sites. If prolactin is not stimulated then the receptor sites may not be adequately primed and this will affect milk production. Put very simply, the more the baby feeds, the more milk will be produced. Milk is therefore continually produced and there are no reservoirs of milk in the breast.
The baby stimulating the breast is key – oxytocin is stimulating the milk for the current feed and prolactin is stimulating the milk for the subsequent feeds.
Now to ensure the breasts don’t continue to produce milk until they explode there is another clever mechanism and it is called the ‘Feedback Inhibitor of Lactation’ (FIL). This protein is always present in the milk but when the milk is not moving through the breast then it kind of ‘backs up’ in the acini cell and so the FIL is higher and this slows the production of breastmilk. When there is less milk in the breast, FIL is lower so breastmilk production is higher and this is why frequent feeding stimulates higher breastmilk production as it keeps FIL low. Allowing the baby to set the pace allows a natural balance to occur.
Having a good knowledge of the delicate balance of hormones necessary for the establishment of breastfeeding is vital to properly support mothers in the early days. It is even more important when supplements are given for any reason that the role of skin to skin is promoted as this stimulates the hormonal response and helps to protect breastfeeding.
References
http://www.ncbi.nlm.nih.gov/books/NBK148970/
http://www.unicef.org.uk/BabyFriendly/Health-Professionals/Care-Pathways/Breastfeeding/
http://kellymom.com/hot-topics/milkproduction/
Picture credits
https://doodledailyblog.wordpress.com/2011/01/05/get-your-geek-on/
http://www.mchip.net/sites/default/files/mchipfiles/Anatomy%20of%20the%20breast.JPG
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