Sans

For alternative betydninger, seSans (flertydig).(Se også artikler, som begynder med Sans)

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Sansernesørger for at levende organismer registrerer indtryk fra omverdenen. Afhængig af definition og kontekst tales der om et varierende antal sanser, men almindeligvis ansesmenneskerfor at have fem sanser:synet,hørelsen,smagen,lugtesansen,ogfølesansen.De fleste vil også anerkende at mennesker har bådekropssansogbalancesans.^[1]

Alle levende organismers sanser gør dem følsomme overfor deres omgivelser, f.eks. forandringer i lys, lyd og kemisk opbygning. Følsomheden gør, at organismerne kan reagere hensigtsmæssigt snarere end tilfældigt på deres omgivelser, og dermed øge deres chancer for at overleve.

Definition af sans

Sanserne hører videnskabeligt underfysiologienog klinisk underneurologien.Neurologer taler i klinisk patologisk sammenhæng om ni sanser.^{[kilde mangler]}Andredyrearterkan have andre sanser, se nedenfor.

Den videnskabelige definition af en sans er: "Et system som består af en sansecelle eller en gruppe af sanseceller som giver respons på en bestemt fysisk type energi og som svarer til et bestemt område (eller en gruppe af områder) ihjernen,hvor signalerne bliver modtaget og fortolket ". Der er generelt enighed om denne definition blandt lægerne.

Nogle mener at mennesker også har sans for fx

Det har intet med fysiologi at gøre, men medpsykologi.

Der skelnes imellem sansning ogperception.Perception er behandling af sansedata på et højere niveau.

Liste af sanser i organismer

Synssansen(elektromagnetisk stråling på nethinden).
Høresansen(mekaniske vibrationer i luften rammer det indre øre).
Smagssansen(neurokemisk reaktion på tungen)
Lugtesansen(neurokemisk reaktion i næsen)
Følesansensom kan underopdeles i nedenstående modaliteter:
- Balancesansen (væske i øret som måler din balance)
- Kropsansen (viden om feks om din mund er lukket eller åbnet)
- Tactitioner evnen til at opfattetryk.
- Thermoceptioner evnen til at opfattevarmeog fraværet af varme = (kulde).
- Nociceptioner evnen til at opfattesmerte.
- Equilibrioceptioneller deVestibulare sanserer evnen til at opfattebalance.Er fysisk lokaliseret i ørerne og giver information om hovedets bevægelser.
- ProprioceptionellerKinæsteseer opfattelse af kroppens og kropsdelenes placering i rummet (eks. er din pegefinger strakt eller bøjet nu).

Næsten alle sanser kan underopdeles, men grundlæggende er der fem sanser, med underopdelinger. Visse smertekvaliteter opstår også som kemisk medierede og derfor er smag og lugt ikke de eneste kemiske sanser.

Sanser, andre dyrearter

Elektroception(eller "elektroreception" ) – Mangedyrsom f.eks.næbdyret,hajerogmallerer følsomme og har derfor ensansforelektriske felter.Denne sans kan anvendes til at finde byttedyr.^[2]^[3]^[4]^[5]
Magnetoception(eller "magnetoreception" ) er evnen til at opfattefluktuationerimagnetfelterog er observeret hosfugle.Det er et ikke særlig forståetfænomen^[6].
Ekkolokaliseringer evnen til atorientere sig i rummetvha. lyd (græsk: echo, lyd), dvs. bruge lyden som "ekkolod"ellersonar.Flagermusogtandhvalerhar denne sans.

Se også

Eksterne henvisninger

Fænomenalt god, pædagogisk, interaktiv og populært orienteret:Tutis Vilis: Sensory Physiology Transformations for Perception and Action,bu Arkiveret15. september 2015 hosWayback Machine bu1 Arkiveret7. april 2011 hosWayback Machine(opleves bedst i enwebbrowsermedFlash-plug-in, men kan også downloades somPDF-fil)
Extra Sensory Perceptions. Aristotle missed the mark when he named only five. Harvard Medical School Arkiveret6. februar 2015 hosWayback Machine
Cognition and Perception Links Arkiveret18. december 2003 hosWayback Machine
2004-05-14, Sciencedaily: Following Earth's Magnetic Field: Chemical Reaction In Birds Provides Sense Of Direction During Migratory FlightsCitat: "...Migratory birds have long been known to possess a magnetic compass that helps them find the correct direction during their migratory flights...Now, our study points to what we need to look for a molecular substrate for certain chemical reactions. That is, we can rule out magnetic materials in birds’ beaks and elsewhere..."
- 24 November, 2004, BBC News: Pigeons 'sense magnetic field'Citat: "...The pigeons probably use tiny magnetic particles in their beaks to sense our planet's magnetic field, scientists say..."

Noter

^"The five (and more) human senses". Fra Live Science.
^University of Florida. (2006, February 6). Scientists Trace Origin Of Shark's Electric Sense. ScienceDailyCitat: "..."Sharkshave a network of electrosensory cells that allows them to hunt by detecting electrical signals generated by prey, "said Martin Cohn, a developmental biologist with the departments of zoology and anatomy and cell biology, and the UF Genetics Institute." That doesn't mean they can only detect electric fish. They can sense electricity generated by a muscle twitch, even if it's the weak signal of a flounder buried under sand. "..."
^Washington University School of Medicine. (2008, May 7). Platypus Genome Explains Animal's Peculiar Features; Holds Clues To Evolution Of Mammals. ScienceDailyCitat: "...theplatypusalso sports a duck-like bill that holds a sophisticated electrosensory system used to forage for food underwater... "
^University of Texas at Austin. (2009, September 29). Electric Fish Plug In To Communicate. ScienceDailyCitat: "...They do so at night, while trying to avoid predators such ascatfishthat sense the electric fields... "
^Washington University in St. Louis. (2015, August 4). Fish that have their own fish finders. ScienceDailyCitat: "...The fish with nuanced signal discrimination can glean a stunning amount of information from electric signals, including the signaler's species, sex, age, relative dominance status, and possibly even individual identity. They can also detect emotional states, such as aggression, submission, courtship and active exploration. The fish with the simpler communication system were less studied and less well understood..."
^The Magnetic Sense of Animals

[1] "The five (and more) human senses". Fra Live Science.

[2] University of Florida. (2006, February 6). Scientists Trace Origin Of Shark's Electric Sense. ScienceDailyCitat: "..."Sharkshave a network of electrosensory cells that allows them to hunt by detecting electrical signals generated by prey, "said Martin Cohn, a developmental biologist with the departments of zoology and anatomy and cell biology, and the UF Genetics Institute." That doesn't mean they can only detect electric fish. They can sense electricity generated by a muscle twitch, even if it's the weak signal of a flounder buried under sand. "..."

[3] Washington University School of Medicine. (2008, May 7). Platypus Genome Explains Animal's Peculiar Features; Holds Clues To Evolution Of Mammals. ScienceDailyCitat: "...theplatypusalso sports a duck-like bill that holds a sophisticated electrosensory system used to forage for food underwater... "

[4] University of Texas at Austin. (2009, September 29). Electric Fish Plug In To Communicate. ScienceDailyCitat: "...They do so at night, while trying to avoid predators such ascatfishthat sense the electric fields... "

[5] Washington University in St. Louis. (2015, August 4). Fish that have their own fish finders. ScienceDailyCitat: "...The fish with nuanced signal discrimination can glean a stunning amount of information from electric signals, including the signaler's species, sex, age, relative dominance status, and possibly even individual identity. They can also detect emotional states, such as aggression, submission, courtship and active exploration. The fish with the simpler communication system were less studied and less well understood..."

[6] The Magnetic Sense of Animals

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