Editing Nipple (section)

==Function==
[[File:Breastfeeding infant.jpg|thumb|Infant [[Latch (breastfeeding)|latched on]] to a nipple to [[breastfeed]]]]
[[File:Smoczek od butelki.JPG|thumb|Silicone teat or nipple, used for [[Baby bottle|bottle feeding]] ]]
{{main|Breastfeeding}}

The physiological purpose of nipples is to deliver [[milk]], produced in the female [[mammary gland]]s during [[lactation]], to an [[infant]]. During breastfeeding, nipple stimulation by an infant will stimulate the release of [[oxytocin]] from the [[hypothalamus]]. Oxytocin is a [[hormone]] that increases during pregnancy and acts on the breast to help produce the [[milk ejection reflex|milk-ejection reflex]]. Oxytocin release from the nipple stimulation of the infant causes the uterus to contract even after childbirth.{{sfn|Henry|2016|p=117}}<ref>{{cite web|url=https://www.womenshealth.gov/glossary/#o|title=Glossary - womenshealth.gov|website=womenshealth.gov|access-date=12 August 2017|date=2017-01-10}}{{PD-notice}}</ref> The strong uterine contractions that are caused by the stimulation of the mother's nipples help the uterus contract to clamp down the uterine arteries. These contractions are necessary to prevent [[post-partum hemorrhage|post-partum haemorrhage]].<ref name=Abedi2016>{{cite journal|last1=Abedi|first1=P|last2=Jahanfar|first2=S|last3=Namvar|first3=F|last4=Lee|first4=J|title=Breastfeeding or nipple stimulation for reducing postpartum haemorrhage in the third stage of labour|journal=The Cochrane Database of Systematic Reviews|date=27 January 2016|volume=1|issue=1|pages=CD010845|pmid=26816300|doi=10.1002/14651858.CD010845.pub2|pmc=6718231}}</ref>

When the infant suckles or stimulates the nipple, oxytocin levels rise and small muscles in the breast contract, moving the milk through the milk ducts. The result of nipple stimulation by the infant helps to move breast milk out through the ducts and to the nipple. This contraction of milk is called the "let-down reflex".<ref>{{cite web |url=https://www.womenshealth.gov/files/documents/your-guide-to-breastfeeding.pdf |title=Guide to breastfeeding |website=www.womenshealth.gov |access-date=2017-08-12 |archive-date=2020-10-17 |archive-url=https://web.archive.org/web/20201017113931/https://www.womenshealth.gov/files/documents/your-guide-to-breastfeeding.pdf |url-status=dead }}</ref> Latching on refers to the infant fastening onto the nipple to breastfeed. A good attachment is when the bottom of the areola (the area around the nipple) is in the infant's mouth and the nipple is drawn back inside his or her mouth. A poor latch results in insufficient nipple stimulation to create the let down reflex. The nipple is poorly stimulated when the baby latches on too close to the tip of the nipple. This poor attachment can cause sore and [[cracked nipple]]s and a reluctance of the mother to continue to breastfeed.<ref name = whgov>{{cite web |url=https://www.womenshealth.gov/itsonlynatural/overcoming-challenges/breastfeeding-checklist-how-to-get-good-latch.html |title=Breastfeeding checklist: How to get a good latch |publisher=WomensHealth.gov |access-date=4 August 2017 |date=2017-06-09 |archive-date=2017-08-04 |archive-url=https://web.archive.org/web/20170804173646/https://www.womenshealth.gov/itsonlynatural/overcoming-challenges/breastfeeding-checklist-how-to-get-good-latch.html |url-status=dead }}{{PD-notice}}</ref><ref name = whgov2>{{cite web|url=https://www.womenshealth.gov/itsonlynatural/overcoming-challenges/common-questions-about-breastfeeding-pain.html|title=Common questions about breastfeeding and pain|publisher=womenshealth.gov|access-date=4 August 2017|date=2017-06-09|archive-date=2017-08-04|archive-url=https://web.archive.org/web/20170804173525/https://www.womenshealth.gov/itsonlynatural/overcoming-challenges/common-questions-about-breastfeeding-pain.html|url-status=dead}}{{PD-notice}}</ref> After birth, the milk supply increases based upon the continuous and increasing stimulation of the nipple by the infant. If the baby increases nursing time at the nipple, the mammary glands respond to this stimulation by increasing milk production.