breast Flashcards
Appocrine vs Eccrine sweat glands
Eccrine = sweat glands that open directly onto skin surface (Everywhere)
Appocrine = sweat glands that open onto a hair follicle (Armpits, groin, scalp)
What is the arterial supply of the breast
[LATERAL SIDE]:
Suclavian artery –> thoraco-acromial trunk –> Axillary artery –> lateral thoracic artery –> lateral mammary branches
[MEDIAL SIDE]:
Subclavian artery –> internal thoracic artery –> medial mammary branches
posterior intercostal arteries
What muscles does the breast lie on?
Pec major
serratus anterior
external oblique
rectus abdominis
Which lymph nodes drain the:
breast skin
breast tissue
nipple/ areola
skin:
-axillary nodes
-infraclavicular
-inferior deep cervical
tissue:
-axillary
-posterior intercostal
-parasternal
nipple/ areola:
-sub-areolar lymphatic plexus
where does the breast extend to/ from vertically/ horizontally
vertically = 2-6th ribs
horizontally= sternum - mid axillary line
which nerves supply the breast/ nipple
breast = 4-6th intercostal nerve
nipple = 4th IC nerve
What structure does the breast develop from and during which gestational week
From mammary ridge at 5th week of gestation
what effect does oestrogen have on breast
Oestrogen = proliferation of mammary ducts/ lobules
what effect does progesterone have on the breast
Progesterone = growth or dilation of ducts/ lobes
Describe the changes to the breast with hormonal changes in pregnancy
preg= sustained increase in oestrogen + progesterone = proliferation + growth of mammary ducts and stromal tissue + fat
Why does lactation NOT occur during pregnancy
High levels of oestrogen + progesterone inhibits lactation (inhibits prolactin)
Describe how lactation occurs postpartum
Post preg = drop in oestrogen + proges = production of prolactin in ANT pituitary = production of breast milk
What hormone is needed for milk ‘let down’ and how does it work
Oxytocin = contracts myoepithelial cells in breast
Where is oxytocin produced and how is it secreted
produced = POSTERIOR pituitary
secretion = baby suckling
What is the milk produced in the first 4 days called and what does it contain
Colostrum = high protein + IgA
What drugs can pass into breast milk
alcohol
metronidazole
tetracyclines
anticoagulants
How does menopause change the breast
Age >35 = reduced oestrogen = less stromal tissue = more fat + fibrotic tissue (less dense)
Where do the Coopers ligaments attach
Skin - deep fascia
What is a breast lobule
many alveoli (milk producing units) that drain into a lactiferous duct = lobule
What is a breast Lobe
many lobules that drain into a common lactiferous duct = Lobe
How many lobes can be present in the breast
12-20
Where do the lactiferous ducts drain
Each drains into a lactiferous sinus at the nipple
