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=== Anatomy and physiology === {{Main|Human body}} [[File:Anterior view of human female and male, with labels 2.png|thumb|upright=1.5|Basic anatomical features of female and male humans. These models have had [[body hair]] and male [[facial hair]] removed and head hair trimmed.]] Most aspects of human physiology are closely [[Homology (biology)|homologous]] to corresponding aspects of animal physiology. The [[dental formula]] of humans is: {{DentalFormula|upper=2.1.2.3|lower=2.1.2.3}}. Humans have proportionately shorter [[palate]]s and much smaller [[Human tooth|teeth]] than other primates. They are the only primates to have short, relatively flush [[canine teeth]]. Humans have characteristically crowded teeth, with gaps from lost teeth usually closing up quickly in young individuals. Humans are gradually losing their [[wisdom teeth|third molars]], with some individuals having them congenitally absent.<ref name="Revolution">{{cite book| vauthors = Collins D |url=https://archive.org/details/humanrevolutionf0000coll|title=The Human Revolution: From Ape to Artist|year=1976|isbn=978-0-7148-1676-0|page=[https://archive.org/details/humanrevolutionf0000coll/page/208 208]|publisher=Phaidon |url-access=registration}}</ref> Humans share with chimpanzees a [[Vestigiality|vestigial]] tail,<ref>{{cite news |last=Weisberger |first=Mindy |title=Why don't humans have tails? Scientists find answers in an unlikely place |url=https://www.cnn.com/2024/03/23/world/humans-tails-genetic-mutation-junk-dna-scn/index.html |date=23 March 2024 |work=[[CNN]] |url-status=live |archiveurl=https://archive.today/20240324031927/https://www.cnn.com/2024/03/23/world/humans-tails-genetic-mutation-junk-dna-scn/index.html |archivedate=24 March 2024 |accessdate=24 March 2024 }}</ref> [[Appendix (anatomy)|appendix]], flexible shoulder joints, grasping fingers and [[opposable thumb]]s.<ref>{{cite book| vauthors = Marks JM |title=Human Biodiversity: Genes, Race, and History|date=2001|publisher=Transaction Publishers|isbn=978-0-202-36656-2|page=16|language=en}}</ref> Humans also have a more barrel-shaped chest in contrast to the funnel shape of other apes, an adaptation for bipedal respiration.<ref>{{cite journal|last1=Gea|first1=J|year=2008|title=The Evolution of the Human Species: A Long Journey for the Respiratory System|journal=Archivos de Bronconeumología ((English Edition))|volume=44|issue=5|pages=263–270|doi=10.1016/S1579-2129(08)60042-7|pmid=18448018}}</ref> Apart from bipedalism and brain size, humans differ from chimpanzees mostly in [[smelling]], [[hearing]] and [[Digestion#Protein digestion|digesting proteins]].<ref name="O'Neil" /> While humans have a density of [[hair follicle]]s comparable to other apes, it is predominantly [[vellus hair]], most of which is so short and wispy as to be practically invisible.<ref>{{cite news|date=2017|title=How to be Human: The reason we are so scarily hairy|work=New Scientist|url=https://www.newscientist.com/article/mg23631460-700-why-are-humans-so-hairy/|access-date=29 April 2020|archive-date=25 February 2021|archive-url=https://web.archive.org/web/20210225235006/https://www.newscientist.com/article/mg23631460-700-why-are-humans-so-hairy/|url-status=live}}</ref><ref>{{cite journal | vauthors = Sandel AA | title = Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness | journal = American Journal of Physical Anthropology | volume = 152 | issue = 1 | pages = 145–150 | date = September 2013 | pmid = 23900811 | doi = 10.1002/ajpa.22333 | hdl-access = free | hdl = 2027.42/99654 }}</ref> Humans have about 2 million [[sweat gland]]s spread over their entire bodies, many more than chimpanzees, whose sweat glands are scarce and are mainly located on the palm of the hand and on the soles of the feet.<ref>{{cite web| vauthors = Kirchweger G |title=The Biology of Skin Color: Black and White|url=https://www.pbs.org/wgbh/evolution/library/07/3/text_pop/l_073_04.html|url-status=live|archive-url=https://web.archive.org/web/20130216070146/https://www.pbs.org/wgbh/evolution/library/07/3/text_pop/l_073_04.html|archive-date=16 February 2013|access-date=6 January 2013|date=2 February 2001|work=Evolution: Library|publisher=PBS}}</ref> It is estimated that the worldwide average [[Human height|height for an adult human]] male is about {{Height|cm=171|precision=0}}, while the worldwide average height for adult human females is about {{Height|cm=159|precision=0}}.<ref>{{cite journal|author1=Roser M| author1-link=Max Roser |author2=Appel C| author3=Ritchie H| author3-link=Hannah Ritchie |date=8 October 2013|title=Human Height|url=https://ourworldindata.org/human-height|journal=Our World in Data|access-date=30 July 2022|archive-date=30 January 2021|archive-url=https://web.archive.org/web/20210130203158/https://ourworldindata.org/human-height|url-status=live}}</ref> Shrinkage of stature may begin in middle age in some individuals but tends to be typical in the extremely [[Old age|aged]].<ref>{{cite web|title=Senior Citizens Do Shrink – Just One of the Body Changes of Aging|url=https://seniorjournal.com/NEWS/Aging/5-11-28-SeniorsDoShrink.htm|url-status=dead|archive-url=https://web.archive.org/web/20130219004303/https://seniorjournal.com/NEWS/Aging/5-11-28-SeniorsDoShrink.htm|archive-date=19 February 2013|access-date=6 January 2013|work=News|publisher=Senior Journal}}</ref> Throughout history, human populations have universally become taller, probably as a consequence of better nutrition, healthcare, and living conditions.<ref>{{cite journal | vauthors = Bogin B, Rios L | title = Rapid morphological change in living humans: implications for modern human origins | journal = Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology | volume = 136 | issue = 1 | pages = 71–84 | date = September 2003 | pmid = 14527631 | doi = 10.1016/S1095-6433(02)00294-5 }}</ref> The average [[Body weight|mass]] of an adult human is {{Convert|59|kg|lb|abbr=on}} for females and {{Convert|77|kg|lb|abbr=on}} for males.<ref>{{cite web|title=Human weight|url=https://www.articleworld.org/index.php/Human_weight|url-status=live|archive-url=https://web.archive.org/web/20111208053451/https://articleworld.org/index.php/Human_weight|archive-date=8 December 2011|access-date=10 December 2011|publisher=Articleworld.org}}</ref><ref>{{cite web | vauthors = Schlessingerman A | date = 2003 |title=Mass Of An Adult|url=https://hypertextbook.com/facts/2003/AlexSchlessingerman.shtml|url-status=live|archive-url=https://web.archive.org/web/20180101030223/https://hypertextbook.com/facts/2003/AlexSchlessingerman.shtml|archive-date=1 January 2018|access-date=31 December 2017|publisher=The Physics Factbook: An Encyclopedia of Scientific Essays}}</ref> Like many other conditions, body weight and body type are influenced by both [[Genetic predisposition|genetic susceptibility]] and environment and varies greatly among individuals.<ref>{{cite book|vauthors=Kushner R|url={{GBurl|id=vWjK5etS7PMC|p=121}}|title=Treatment of the Obese Patient (Contemporary Endocrinology)|publisher=Humana Press|year=2007|isbn=978-1-59745-400-1|location=Totowa, NJ|page=158|access-date=5 April 2009}}</ref><ref>{{cite journal | vauthors = Adams JP, Murphy PG | title = Obesity in anaesthesia and intensive care | journal = British Journal of Anaesthesia | volume = 85 | issue = 1 | pages = 91–108 | date = July 2000 | pmid = 10927998 | doi = 10.1093/bja/85.1.91 | doi-access = free }}</ref> Humans have a far faster and more accurate [[throw]] than other animals.<ref>{{cite journal| vauthors = Lombardo MP, Deaner RO |date=March 2018|title=Born to Throw: The Ecological Causes that Shaped the Evolution of Throwing In Humans |journal=The Quarterly Review of Biology|language=en|volume=93|issue=1|pages=1–16|doi=10.1086/696721|s2cid=90757192|issn=0033-5770}}</ref> Humans are also among the best long-distance runners in the animal kingdom, but slower over short distances.<ref>{{cite news |url=https://www.nytimes.com/2009/10/27/health/27well.html |work=The New York Times |title=The Human Body Is Built for Distance | vauthors = Parker-Pope T |author-link1=Tara Parker-Pope |date=27 October 2009 |url-status=live |archive-url=https://web.archive.org/web/20151105211812/https://www.nytimes.com/2009/10/27/health/27well.html |archive-date=5 November 2015 }}</ref><ref name="O'Neil">{{cite web | vauthors = O'Neil D |title=Humans |url=https://anthro.palomar.edu/primate/prim_8.htm |work=Primates |publisher=Palomar College |access-date=6 January 2013 |url-status=live |archive-url=https://web.archive.org/web/20130111004211/https://anthro.palomar.edu/primate/prim_8.htm |archive-date=11 January 2013 }}</ref> Humans' thinner body hair and more productive sweat glands help avoid [[heat exhaustion]] while running for long distances.<ref>{{cite web | vauthors = John B |title=What is the role of sweating glands in balancing body temperature when running a marathon? |url=https://www.livestrong.com/article/514545-what-is-the-role-of-sweat-glands-in-balancing-body-temperature-when-running-a-marathon/ |publisher=Livestrong.com |access-date=6 January 2013 |url-status=live |archive-url=https://web.archive.org/web/20130131184339/https://www.livestrong.com/article/514545-what-is-the-role-of-sweat-glands-in-balancing-body-temperature-when-running-a-marathon/ |archive-date=31 January 2013 }}</ref> Compared to other apes, the human [[heart]] produces greater [[stroke volume]] and [[cardiac output]] and the [[aorta]] is proportionately larger.<ref>{{cite journal|last1=Shave|first1=R. E.|last2=Lieberman|first2=D. E.|last3=Drane|first3=A. L.|display-authors=etal|year=2019|title=Selection of endurance capabilities and the trade-off between pressure and volume in the evolution of the human heart|journal=PNAS|volume=116|issue=40|pages=19905–19910|doi=10.1073/pnas.1906902116|doi-access=free |pmid=31527253 |pmc=6778238|bibcode=2019PNAS..11619905S }}</ref><ref>{{cite journal|last1=Ríos|first1=L|last2=Sleeper|first2=M. M.|last3=Danforth|first3=M. D.|display-authors=etal|year=2023|title=The aorta in humans and African great apes, and cardiac output and metabolic levels in human evolution|journal=Scientific Reports|volume=13|issue=6841|page=6841|doi=10.1038/s41598-023-33675-1|pmid=37100851|pmc=10133235|bibcode=2023NatSR..13.6841R|hdl=10261/309357|hdl-access=free}}</ref>
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