199b breast

Question 1

embryology of the breast

Answer 1

5th week: 15-20 buds from ectodermal ridge from axilla to inguinal region

apoptosis except primary mammary buds –> penetrate into mesoderm + secondary buds; can have some accessory nipples

2nd and 3rd trimester - glands, mammary buds, nipple

post birth - protrusion of nipple + development of terminal ducts

Question 2

post birth breast development

Answer 2

normal milky discharge for 4-7 days

birth to 2 years : further branching and terminal lobule development

puberty - E causes mammary ductul epi and stroma proliferation (terminal duct lobules, collecting ducts, breast buds proliferate)

stops 2 years after onset of menarche

Question 3

breast anatomy

Answer 3

tail of spence goes into axilla - most tissue with most pathology

cooper’s ligaments (suspensory ligaments)

mostly subcutanous fat (80%)

Question 4

breast blood supply

Answer 4

arteries - both off subclavian/axillary artery
IMA 60%
lateral thoracic artery 30%

veins
towards axilla
circulus venosus - circle of veins under nipple-areolar complex

Question 5

breast sensory

Answer 5

3-6 intercostal nerves - lateral and anterior cutanous branches (majority)

supraclavicular nerve (upper)

intercostocrachial lateraal from 2nd intercostal

Question 6

breast lymph draining

Answer 6

axillary lymph (75%)
internal mammary lymph nodes on medial aspect

Question 7

breast physo - menstrual cycle

Answer 7

E peaks prior to mid chcyel - enlarges ducts

P peaks at day 21 - growth of breast lobules

increased in tissue – tenderness
volume increases 25 mL due to increased blood flow and water retention

post menses - normalizes breast size and tenderness due to drop in hormones

Question 8

breast - pregnancy

Answer 8

prolactin increase during preg

E, P, and prolactin cause new ducts, branching, and alveolar proliferation (along with palcental lactogen)

Question 9

breast - lactation

Answer 9

Prolactin - anterior pituitary; stimulates milk production within alveolar cells

oxytocin - posterior pit; stimulates myoepithelial cells to eject milk

P and E - high during preg, inhibit lactation by blocking prolactin binding at alveolar cells; drop with delivery

initially, colostrum is made (thick, sticky, high WBCs and IgA to coat intestines)

milk beings 3-4 days postpartum

suckling increases prolactin and oxytocin

Question 10

breastfeeding benefits

Answer 10

good for kids in all realms

maternal - lowers blood loss (uterine involution), increased child spacing, lowers depression and cancer)

should breastfeed exclusively for 6 months with at least another month

Question 11

contraception and lactation

Answer 11

high prolactin blocks GnRH pulses

lasts for ~6 months
otherwise need contraception b/w 3-6 weeks

Question 12

mastitis

Answer 12

pain and inflammation of breast from breastfeeding

unilateral pain, red, fever, aches

antibiotics + frequency feeding/pumping