© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Low Resolution © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION CHAPTER 5 © Jones & Bartlett Learning, LLC Science © Jones & Bartlett OF SCIENCE Learning, LLC NOT FOR SALE OR DISTRIBUTIONof Lactation NOT FOR SALE OR DISTRIBUTION L ACTATION © Jones & Bartlett Learning, LLCIn This Chapter © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONBreast Anatomy . .NOT . .FOR . SALE. .OR . DISTRIBUTION Breast Physiology . Physiology of Milk Transfer . Human Milk . © JonesArtificial & Bartlett Baby Milk Learning, . .LLC . © Jones & Bartlett Learning, LLC NOT FORMaternal SALE Nutrition OR DISTRIBUTION . NOT FOR SALE OR DISTRIBUTION Breast Anatomy External Features © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC • Skin layers NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION The dermis (inner layer) contains nerve endings, capillaries, hair follicles, lymph channels, and other cells . The epidermis (outer layer) contains epithelial cells that cover and protect deeper skin layers from drying out and from invasion by bacteria . The germinating layer (transitional layer) contains basal cells that continu- ally divide . New cells constantly push older ones up toward the surface of © Jones & Bartlett Learning, LLCthe skin . © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Keratin (the surface layer) containsNOT tough, FOR protective SALE protein OR . It DISTRIBUTIONis dead skin . • Nipple There are an average of 5 to 9 nipple duct openings . ª Smooth muscle fibers function as a closing mechanism for the milk ducts . © Jonesª Sensory& Bartlett nerve endings Learning, in the nipple LLC trigger milk release when the baby© Jones & Bartlett Learning, LLC NOT FORsuckles SALE . OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 57 © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 9781284111972_CH05_Pass02.indd 57 09/08/16 9:15 PM © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Low Resolution © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 58 Chapter 5: Science of Lactation An inverted nipple appears inverted or inverts when stimulated . © Jones & Bartlett ªLearning, It will respond LLC to correction during the last trimester© ofJones pregnancy & . Bartlett Learning, LLC ª Nipple stimulation should be avoided when there is increased risk for NOT FOR SALE OR DISTRIBUTIONpreterm labor . NOT FOR SALE OR DISTRIBUTION ª Inversion is usually not a problem if the areola is pliable enough for the baby to grasp a large portion . Areola ª The areola enlarges and becomes darker during puberty, menstruation, © Jones & Bartlett Learning, LLCand pregnancy . © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONª The baby’s mouth needs to encloseNOT a largeFOR portion SALE to compress OR DISTRIBUTIONsufficient breast tissue . Montgomery glands (Montgomery’s tubercles) ª Sebaceous glands are located around the areola and are pimply in appearance . © Jonesª They & Bartlett secrete an oily Learning, substance to lubricate LLC and protect the nipple . © Jones & Bartlett Learning, LLC NOT FORª They SALE are rudimentary OR DISTRIBUTION mammary glands and may secrete a small amountNOT FOR SALE OR DISTRIBUTION of milk . Internal Features • Connective tissues support the breast, and subcutaneous fatty tissues give it © Jones & Bartlettshape Learning, . LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR Fibrous DISTRIBUTION bands (Cooper’s ligaments) support the breastNOT . FOR SALE OR DISTRIBUTION Fibrous tissue holds the breast together and supports the ducts as they fill with milk . • Nerves trigger milk synthesis and release . Sensory fibers innervate smooth muscle in the nipple and blood vessels © Jones & Bartlett Learning, LLCfrom the fourth, fifth, and sixth intercostal© Jones nerves & . Bartlett Learning, LLC The nipple and areola are composed of autonomic and sensory nerves . NOT FOR SALE OR DISTRIBUTION The epidermis of the nipple andNOT areola hasFOR few nerves SALE . OR DISTRIBUTION The dermis is highly innervated and responsive to suckling stimulation . • Blood and lymph systems The bloodstream transports proteins, fats, carbohydrates, and other © Jones substances & Bartlett to the cells Learning, for milk production LLC . © Jones & Bartlett Learning, LLC The lymphatic system absorbs excess blood fluids and returns them to NOT FORthe heart SALE . OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 9781284111972_CH05_Pass02.indd 58 09/08/16 9:15 PM © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Low Resolution © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Breast Anatomy 59 Lymph nodes filter and trap bacteria and cast-off cell parts . Swelling of a lymph node in the armpit could suggest an infection in the © Jones & Bartlett Learning,breast, arm, or handLLC . © Jones & Bartlett OF SCIENCE Learning, LLC NOT FOR SALE OR EngorgementDISTRIBUTION decreases the flow of blood and lymph,NOT increasing FOR the SALErisk OR DISTRIBUTION of local infection . • Fatty tissue There is very little fat immediately beneath the areola and nipple . L Fatty tissue does not contribute to milk synthesis or transport . ACTATION © Jones & Bartlett Learning, LLC Larger breasts may have a larger© storageJones capacity, & Bartlett though size Learning,is not a LLC NOT FOR SALE OR DISTRIBUTION predictor of milk production . NOT FOR SALE OR DISTRIBUTION • Glandular tissue is the functional part of the breast that produces and trans- ports milk . Milk production takes place in tiny individual glands called alveoli or acini . ª Alveoli consist of epithelial cells (lactocytes) encased by myoepithelial © Jones &cells Bartlett and are clustered Learning, together to LLCform lobuli . © Jones & Bartlett Learning, LLC NOT FORª Capillaries SALE surrounding OR DISTRIBUTION the alveoli bring nutrient-rich blood to make NOT FOR SALE OR DISTRIBUTION milk . ª Release of oxytocin and prolactin signals myoepithelial cells to contract the alveoli to release and produce more milk . ª The normal lactating breast is lumpy due to enlarged milk-filled alveoli . ª Alveoli multiply and increase in size during pregnancy and lactation, © Jones & Bartlett Learning,then decrease LLC in size and number when breastfeeding© Jones ends . & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONThe Tail of Spence is breast tissue that extends intoNOT the axilla FOR . SALE OR DISTRIBUTION • Milk-transporting tissue (see Figure 5-1) Milk flows through a system of lactiferous ductules, secondary ducts, and nipple pores . Ducts grow lengthwise as alveoli and lobuli develop . © Jones & Bartlett Learning, LLC Sprouting and growth of ducts© and Jones alveolar development & Bartlett intensify Learning, during LLC the first 4 to 5 months of pregnancy . NOT FOR SALE OR DISTRIBUTION Duct and alveolar tissues becomeNOT more FOR specialized SALE in the secondOR DISTRIBUTION half of pregnancy in preparation for milk-related functions . Ducts widen throughout the breast and in the area beneath the areola during passage of milk . Milk beneath the areola that is not removed flows backward into the breast . © Jones Milk & ducts,Bartlett once labeled Learning, as “lactiferous LLC sinuses,” have been shown to be © Jones & Bartlett Learning, LLC NOT FORducts SALE that transiently OR DISTRIBUTIONfill and drain, not sinuses . NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 9781284111972_CH05_Pass02.indd 59 09/08/16 9:15 PM © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Low Resolution © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 60 Chapter 5: Science of Lactation Milk-lled alveoli in Rib © Jones & Bartlettthe Learning, lactating breast. LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOTFat FOR SALE OR DISTRIBUTION Suspensory ligaments of breast Lactiferous © Jones & Bartlett Learning, LLC © Jones & Bartlettducts Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Constriction of © Jones & Bartlett Learning, LLCmyoepithelial cells © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONto force milk from NOT FOR SALE OR DISTRIBUTION the alveolus.