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The nipple is a raised region of tissue on the surface of the breast from which, in lactating females, breast milk from the mammary gland leaves the body through the to Breastfeeding an infant. The milk can flow through the nipple passively, or it can be ejected by smooth muscles muscle contractions that occur along with the ductal system. The nipple is surrounded by the areola, which is often a darker colour than the surrounding skin.
Male mammals also have nipples but without the same level of function or prominence. A nipple is often called a teat when referring to non-humans. "Nipple" or "teat" can also be used to describe the flexible mouthpiece of a baby bottle.
In humans, the nipples of both males and females can be sexually stimulated as part of sexual arousal. In many cultures, female nipples are , or regarded as sex objects and evaluated in terms of their physical characteristics and sex appeal.
The skin of the nipple is rich in a supply of special that are sensitive to certain stimuli: these are slowly-adapting and rapidly-adapting integumentary . Mechanoreceptors are identified respectively by Type I slowly-adapting with multiple Merkel corpuscle end-organs and Type II slowly-adapting with single Ruffini corpuscle end-organs, as well as Type I rapidly-adapting with multiple Meissner corpuscle end-organs and Type II rapidly-adapting with single Pacinian corpuscle end-organs. The dominant nerve supply to the nipple comes from the lateral cutaneous branches of fourth intercostal nerve.Grabb & Smith's Plastic Surgery 6th edition. Chapter 59 page 593 The nipple is also used as an anatomical landmark. It marks the T4 (fourth thoracic vertebra) dermatome and rests over the approximate level of the diaphragm.
The arterial supply to the nipple and breast originates from the anterior intercostal branches of the internal thoracic (mammary) arteries; lateral thoracic artery; and thoracodorsal arteries. The venous vessels parallel the arteries. The lymphatic ducts that drain the nipple are the same for the breast. The axillary nodes are the apical axillary nodes, the lateral group and the anterior group. 75% of the lymph is drained through the axillary lymph nodes located near the armpit. The rest of the drainage leaves the nipple and breast through infroclavicular, pectoral, or parasternal nodes.
Since nipples change throughout the life span in men and women, the anatomy of the nipple can change and this change may be expected and considered normal.
In humans, the nipples are often surrounded by body hair.
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". 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 and a reluctance of the mother to continue to breastfeed. 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.
Some cases of nipple discharge will clear on their own without treatment. Nipple discharge is most often not cancer (benign), but rarely, it can be a sign of breast cancer. It is important to determine what is causing the discharge and to get treatment. Reasons for nipple discharge include:
Sometimes, babies can have nipple discharge. This is caused by hormones from the mother before birth. It usually goes away in two weeks. Cancers such as Paget's disease (a rare type of cancer involving the skin of the nipple) can also cause nipple discharge.
Nipple discharge that is not normal is bloody, comes from only one nipple, or comes out on its own without squeezing or touching the nipple. Nipple discharge is more likely to be normal if it comes out of both nipples or happens when the nipples are squeezed. Squeezing the nipple to check for discharge can make it worse. Leaving the nipple alone may make the discharge stop.
Nipple discharge in a male is usually of more concern. Most of the time a mammogram and an examination of the fluid is done. A biopsy is often performed. A fine needle aspiration (FNA) biopsy can be fast and least painful. A very thin, hollow needle and slight suction will be used to remove a small sample from under the nipple. Using a local anesthetic to numb the skin may not be necessary since a thin needle is used for the biopsy. Receiving an injection to prevent pain from the biopsy may be more painful than the biopsy itself.
Some men develop a condition known as gynecomastia, in which the breast tissue under the nipple develops and grows. Discharge from the nipple can occur. The nipple may swell in some men possibly due to increased levels of estrogen.
Changes in the nipple are not necessarily symptoms or signs of breast cancer. Other conditions of the nipple can mimic the signs and symptoms of breast cancer.
Herpes infection of the nipple can go unnoticed because the lesions are small but usually are quite painful. Herpes in the newborn is a serious and sometimes fatal infection. Transmission of Hepatitis C and B to the infant can occur if the nipples are cracked.
Other infections can be transmitted through a break of the skin of the nipple and can infect the infant.
A case in Erie, Pennsylvania, concerning the exposure of breasts and nipple proceeded to the United States Supreme Court. The Erie ordinance was regulating the nipple in public as an act that is committed when a person "knowingly or intentionally, ... appears in a state of nudity commits Public Indecency." Later in the statute, nudity is further described as an uncovered female nipple. But nipple exposure of a man was not regulated. An opinion column credited to Cecil Adams noted: "Ponder the significance of that. A man walks around bare-chested and the worst that happens is he won't get served in restaurants. But a woman who goes topless is legally in the same boat as if she'd had sex in public. That may seem crazy, but in the US it's a permissible law."
The legality around the exposure of nipples is inconsistently regulated throughout the US. Some states do not allow the visualization of any part of the breast. Other jurisdictions prohibit any female chest anatomy by banning anatomical structures that lie below the top of the areola or nipple. Such is the case in West Virginia and Massachusetts. West Virginia's regulation is very specific and is not likely to be misinterpreted, stating: "The display of 'any portion of the cleavage of the human female breast exhibited by a dress, blouse, skirt, leotard, bathing suit, or other wearing apparel is provided the areola is not exposed, in whole or in part.
The social media site Instagram has a "no nipples" policy with exceptions: material that is not allowed includes "some photos of female nipples, but photos of post-mastectomy scarring and women actively breastfeeding are allowed. Nudity in photos of paintings and sculptures is OK, too". Previously, Instagram had removed images of nursing mothers. Instagram removed images of Rihanna and had her account cancelled in 2014 when she posted selfies with nipples. This was incentive for the Twitter campaign #FreeTheNipple. In 2016, the Instagram page @genderless_nipples invited users to post images of nipples from both sexes, displaying close-ups of the nipples of both men and women for the purpose of spotlighting what may be inconsistency. Some contributors have circumvented the policy. Facebook has also been struggling to define its nipple policy.
Filmmaker Lina Esco made a film entitled Free the Nipple, which is about "laws against female toplessness or restrictions on images of female, but not male, nipples", which Esco states is an example of sexism in society.
Citations
Bibliography
Appearance
Changes in appearance may be normal or related to disease.
The average projection and size of human female nipples is slightly more than .M. Hussain, L. Rynn, C. Riordan and P. J. Regan, "Nipple-areola reconstruction: outcome assessment"; European Journal of Plastic Surgery, Vol. 26, Num. 7, December, 2003
Breast cancer
Symptoms of breast cancer can often be seen first by changes of the nipple and areola, although not all women have the same symptoms, and some people do not have any signs or symptoms at all. A person may find out they have breast cancer after a routine mammogram.
Warning signs can include:
Vertical transmission
Some infections are transmitted through the nipple, especially if irritation or injury to the nipple has occurred. In these circumstances, the nipple itself can become infected with Candidiasis that is present in the mouth of the breastfeeding infant. The infant will transmit the infection to the mother. Most of the time, this infection is localized to the area of the nipple. In some cases, the infection can progress to become a full-blown case of mastitis or breast infection. In some cases, if the mother has an infection with no nipple cracks or ulcerations, it is still safe to breastfeed the infant.
Other disorders
Surgery
A Nipple delay is a surgical procedure where breast tissue is removed, but the nipple and areola are preserved. This procedure was historically done only prophylactically or with mastectomy for the benign disease over the fear of increased cancer development in retained areolar ductal tissue. Recent series suggest that it may be an oncologically sound procedure for tumours not in the subareolar position.
Society and culture
Exposure
The cultural tendency to hide the female nipple under clothing has existed in Western culture since the 1800s. As female nipples are often perceived an intimate part, covering them might have originated under Victorian morality as with riding side saddle. Exposing the entire breast and nipple is a form of protest for some and a crime for others. The exposure of nipples is usually considered Modesty and in some instances is viewed as lewd or indecent behavior.D. Leder, The Body in Medical Thought and Practice, page 223, Springer Science & Business Media, 1992,
Sexuality
Nipples can be sensitive to touch, and nipple stimulation can incite sexual arousal. Few women report experiencing orgasm from nipple stimulation. Before Komisaruk et al.'s functional magnetic resonance (fMRI) research on nipple stimulation in 2011, reports of women achieving orgasm from nipple stimulation relied solely on anecdotal evidence. Komisaruk's study was the first to map the female genitals onto the sensory portion of the brain; it indicates that sensation from the nipples travels to the same part of the brain as sensations from the vagina, clitoris and cervix, and that these reported orgasms are genital orgasms caused by nipple stimulation, and may be directly linked to the genital sensory cortex ("the genital area of the brain").
Piercings
In business
Some companies and non-profit organisations have used the word nipple or images of nipples to draw attention to their product or cause.
See also
(2015). 9780323394208, Elsevier Health Sciences. ISBN 9780323394208
External links
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