Repro: Lactation Flashcards
What are the components of the mammary glands?
15-24 lobules of tissue with fibrous and adipose tissue in between.
The lobes contain alveoli, lactiferous ducts which come together just before the nipple.
NB mammary tissue and breast tissue are not the same.
How do the breasts change during pregnancy?
There is hypertrophy of the duct-lobule-alveolar system
Prominent lobules form
The areola enlarges and darkens so the baby can see it.
Montgomery tubercles form which r bumps in the areolar that secrete sebum to prevent cracking of the nipple and pheromones so bab can detect it
Why does the breast not produce milk during pregnancy?
There is a high progesterone to oestrogen ratio which favours growth of the breast (angiogenesis and adipose deposition) but inhibits prolactin receptors
What is the role of hemidesmosomes?
Ensure the cells remain healthy during lactogenesis. In the second half of pregnancy they move out of the way so neutrophils and macrophages can get it. Babies first feed inc lots of neutrophils an macrophages which go into their gut
What is colostrum?
Produced day 0-3.
Appears yellow in colour and smelly due to high protein content.
Contains less water, fat and sugar than milk and a huge amount of protein - particular IgA IgM IgG, also white cells.
How much milk is produced each day?
800ml per day or 1.5L if twins
What stimulates prolactin release?
Suckling at one feed promotes production of the next feed.
Need to feed every 1.5-2.5 hours during the day and 3 hours at night.
Why does milk production cease if there is no suckling?
The milk builds up and is not released so the increased turgor causes the secretory cells to become damaged
Outline the let-down reflex
Mechanoreceptors in the nipple detect baby suckling.
This is sent to the dorsal root ganglion via the intercostal nerves and the hypothalamus via the spinal cord.
The hypothalamus inhibits dopamine release so prolactin is released, as well as oxytocin from the post pituitary.
Prolactin causes milk production in the alveoli and oxytocin causes myoepithelial cells to contract
NB baby crying also stimulates the hypothalamus
What can cause lactation to cease?
- lost feedback, not enough suckling
- pain eg mastitis
- menstruation may reduce quantity of milk produced
- suppression of prolactin eg heinz cream of tomato soup contains ergot
- age, mammary glands begin to shrink after 35
When is it advised to stop breast feeding?
When the baby grows teeth
What are the advantages of breast feeding?
- babies have fewer infections
- bonding through release of oxytocin
- reduces risk of breast and ovarian cancer
- causes further contraction of uterus
- aids weight loss gained during pregnancy (~5kg)
