Earlobe

From Infogalactic: the planetary knowledge core
Jump to: navigation, search
Earlobe
Gray904.png
Details
Latin lobulus auriculae (singular), lobuli auricularum (plural)
System Auditory system
Identifiers
Dorlands
/Elsevier		 l_13/12500813
TA Lua error in Module:Wikidata at line 744: attempt to index field 'wikibase' (a nil value).
TH {{#property:P1694}}
TE {{#property:P1693}}
FMA {{#property:P1402}}
Anatomical terminology
[[[d:Lua error in Module:Wikidata at line 863: attempt to index field 'wikibase' (a nil value).|edit on Wikidata]]]

The human earlobe (lobulus auriculae) is composed of tough areolar and adipose connective tissues, lacking the firmness and elasticity of the rest of the auricle (the external structure of the ear). In some cases the lower lobe is connected to the side of the face. Since the earlobe does not contain cartilage[1] it has a large blood supply and may help to warm the ears and maintain balance. The zoologist Desmond Morris in his book The Naked Ape (1967) conjectured that the lobes developed as an additional erogenous zone to facilitate the extended sexuality necessary in the evolution of human monogamous pair bonding.[2] However, earlobes are not generally considered to have any major biological function.[3] The earlobe contains many nerve endings, and for some people is an erogenous zone.

A free earlobe
An attached earlobe, with piercing.

Genetics

Extreme form of attached ear lobe
Clint Eastwood
File:Earlobe.jpg
Hypothetical model of earlobe types inheritance
(After Mader, 2000)[4]

Earlobes average about 2 centimeters long, and elongate slightly with age.[5] Although the "free" vs. "attached" appearance of earlobes is often presented as an example of a simple "one gene - two alleles" Mendelian trait in humans, earlobes do not all fall neatly into either category; there is a continuous range from one extreme to the other, suggesting the influence of several genes.[4][6][7]

Recessive gene frequency in the selected worldwide populations
Population N Recessive gene frequency
(for attached ear lobes)
 Source
Africans ? 0.60 Messeri (1976)[8]
Afroamericans 242 0.56 Glass et al. (1952)[9]
Ainu ? 0.49 Messeri (1967)[8]
Babinga ? 0.87 Messeri (1967)[8]
Bavaria ? 0.84 Messeri (1967)[8]
Bosna i Hercegovina 7,325 0.55 Hadžiselimović (1981)[10]
Brazil ? 0.34 Saldanha (1960)[11]
Cameroon ? 0.83 Messeri (1967)[8]
China ? 0.62 Messeri (1967)[8]
Hong Kong 70 0.80 Lai, Walsh (1966)[12]
India: Bengal 100 0.49 Dutta (1963)[13]
Indians (Canada) 532 0.68 Chaison (1963)[14]
Japan 70 0.82 Lai, Walsh (1966)[12]
Laponia ? 0.71 Messeri (1967)[8]
Micronesia ? 0.52 Messeri (1967)[8]
Nepal 169 0.66 Bhasin (1969)[15]
New Guinea 399 0.80 Lai, Walsh (1966)[12]
Nicobar 813 0.81 Gabel (1958)[16]
Papuans ? 0.54 Messeri (1967)[8]
Polynesia  ? 0.39 Messeri (1967)[8]
Russia ? 0.59 Messeri (1967)[8]
Sardinia 403 0.53 Messeri (1967)[8]
Scotland 500 0.48 Chattopadhyay (1968)[17]
Somalia ? 0.42 Messeri (1967)[8]
Sweden 247 0.59 Wiener (1937)[18]
Tibet ? 0.68 Tiwari, Bhasin (1969)[19]
USA: Baltimore 380 0.63 Glass et al. (1952)[9]
USA: Brooklin 248 0.92 Wiener (1937)[18]
USA: Buffalo 381 0.43 Dronamraju (1966) [20]
USA: Pennsylvania 241 0.50 Glass et al. (1952)[9]

Clinical significance

Earlobes are normally smooth, but occasionally exhibit creases. Creased earlobes are sometimes associated with genetic disorders in children, including Beckwith-Wiedemann syndrome.[21] In some early studies, earlobe creases were thought to be associated with an increased risk of heart attack and coronary heart disease; however, more recent studies have concluded that since earlobes become more creased with age, and older people are more likely to experience heart disease than younger people, age may account for the findings linking heart attack to earlobe creases.[21] The earlobe crease is also called Frank's Sign.

Society and culture

Stretched earlobe piercing, Ethiopia

Earlobe piercing and stretching

Piercing the earlobes is a commonplace activity in many cultures in many historical eras; no other location on the body is as commonly pierced. Consequently, injury to the earlobe due to the weight of heavy earrings is also common.[22] Some cultures practice earlobe stretching, using piercing ornaments to stretch and enlarge the earlobes to accommodate plugs.

Negative effects of wearing earrings

Some research has found that the most frequent complications connected with wearing earrings are:[23]

There was noticeable relationship between the piercing of young girls' earlobes and following development of allergy.[24][25][26] In the view of Professor Ewa Czarnobilska, the manager of the research team, the primary reason for the allergies connected to earrings is the presence of nickel, which is a common component of the alloys used in jewelry production.[25][26] The symptom seen is generally eczema, and is often misdiagnosed as a food allergy, for instance to milk. The specific mechanism in allergies caused by earrings is the contact of nickel ions with the Lymphatic system.[25][26]

The study noted that children who simply stopped wearing earrings did not see the disappearance of the allergic symptoms. The immune system remembers the presence of the nickel ions in the person's blood and lymph, so the child can still react to:[25][26]

  • metal parts of wardrobe,
  • Dental braces,
  • Dental prosthesis,
  • Orthotics,
  • meals cooked in pots with addition of nickel,
  • margarine (nickel is a catalyst in hydrogenation of unsaturated fats),
  • coins,
  • chocolate,
  • nuts,
  • leguminous vegetables,
  • wine, and
  • beer.

Research by allergists has found that in a sample of 428 pupils of ages 7–8 and 16–17 years old:[25][26]

  • 30% of the research population showed an allergy to nickel, and
  • the allergy occurred in girls who had started wearing earrings in early childhood.

Other symptoms of allergy to nickel are recurring infections, Asthma attacks and chronic larynxis.[25][25][26]

References

<templatestyles src="Reflist/styles.css" />

Cite error: Invalid <references> tag; parameter "group" is allowed only.

Use <references />, or <references group="..." />

de:Ohrmuschel#Ohrläppchen

  1. ↑ Steinberg, Avraham (2003). Encyclopedia of Jewish Medical Ethics: a Compilation of Jewish Medical Law on All Topics of Medical Interest. Jerusalem: Feldheim Publishers. p. 350. ISBN 1583305920.
  2. ↑ Desmond Morris The Naked Ape: A Zoologist's Study of the Human Animal (Hardback: ISBN 0-07-043174-4; Reprint: ISBN 0-385-33430-3) Jonathan Cape, 1967 . Chapter 2, page 59 of Corgi paperback ed
  3. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ 4.0 4.1 Mader S. S. (2000): Human Biology. McGraw–Hill, New York, ISBN 0-07-290584-0.
  5. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  6. ↑ Boaz N. T. (1999): Essentials of biological anthropology. Prentice Hall, New Jersey,ISBN 0-13-080793-1.
  7. ↑ Dutta P., Ganguly P. (1965): Further observations on ear lobe attachment. Acta Genet. Statist. Med. 15: 77-86, 1965. [PubMed: 14277139, related citations]
  8. ↑ 8.00 8.01 8.02 8.03 8.04 8.05 8.06 8.07 8.08 8.09 8.10 8.11 8.12 Messeri E. (1967): Variabilita morfologica del lobolo auricolare in Sardegna. Atti Soc. Peloritana, Sc. Fis. mat. nat., 13 (1/2): 89.
  9. ↑ 9.0 9.1 9.2 Glass B., Sacks M. S., John E. F., Hess C. (1952): Genetic Drift in a Religious Isolate: An Analysis of the Causes of Variation in Blood Group and Other Gene Frequencies in a Small Population .Phys. Anthrop, 144.
  10. ↑ Hadžiselimović R. (1981): Genetic distance among local human populations in Bosnia and Herzegovina (Yugoslavia). Coll. Antrop., 5. (Suppl.): 63-66.
  11. ↑ Saldanha P. H. (1960): Frequencies og consaguineous marriages in North-east of Sao Paolo, Brazil. Acta Genet., 10 (1): 71.
  12. ↑ 12.0 12.1 12.2 Lai Y. C., Walsh R. J. (!966): Observation on ear lobe types. Acta Genet. Statist. Med., 16 (3): 250.
  13. ↑ Dutta P. C. (1963): A note on the ear lobe. Acta Genet. Statist. Med., 15 (3): 290.
  14. ↑ Chaisson L. P. (1963): Gene frequencies in the Micmac Indians. J. Hered., 54 (2): 229.
  15. ↑ Bhasin M. K. (1969): Ear lobe attacment among Newars of Nepal. Hum. Hered., 19 (5): 506.
  16. ↑ Gabel N. E. (1958): A racial study of the Fijans. Anthrop Rec., 20 (1): 22.
  17. ↑ Chatopadhyay P. K. (1968): A note on the ear lobe attachment among the Jats and Ahirs. Acta Genet. Statist. Med., 18 (3): 277.
  18. ↑ 18.0 18.1 Wiener (1937): Complications in ear genetics. J. Hered., 28 (3): 425.
  19. ↑ Tiwari S. C., Bhasin M. K. (1969): Frequency of hand clasping and ear lobe attacment in Tibetians. J. Hered., 19 (4): 658.
  20. ↑ Dronamraju K. R. (1966): Ear lobe attacment in the Buffalo region. Acta Genet. Statist. Med., 16 (3): 258.
  21. ↑ 21.0 21.1 MedlinePlus Encyclopedia Earlobe creases
  22. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  23. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  24. ↑ Harmful earrings (pl. Szkodliwe kolczyki) Fizjointormator. Retrieved 2015-04-01
  25. ↑ 25.0 25.1 25.2 25.3 25.4 25.5 25.6 Polish Scientists wearn: earrings harm children (pl. Polscy naukowcy ostrzegają: kolczyki szkodzą dzieciom) Tvn24 Retrieved 2015-04-01
  26. ↑ 26.0 26.1 26.2 26.3 26.4 26.5 Lua error in package.lua at line 80: module 'strict' not found.
Retrieved from "https://infogalactic.com/w/index.php?title=Earlobe&oldid=722741364"