Isikhonkwane

Isikhonkwane yinto eyinkcenkce enentloko esibaca kunye nomphambili wayo omde nocwejileyo. Isando okanye isibetheleli sikhonkwane sisetyenziswa ngokubekwa kwenye into. sisoloko sisetyenziswa ukudibanisa izinto ezimbini.

 __LEAD_SECTION__ 

Isikhonkwane sisakhiwo esicacileyo semi-transparent apho iziphelo zeminwe yezilwanyana ezininzi, ngokubanzi ziyingxenye yeklasi ye - tetrapods, kuquka nabantu, isiphelo. Izikhonkwane zibonisa iindidi ezirhubuluzayo, iintaka kunye nezilwanyana ezanyisayo ; Ulwakhiwo lwazo luye lwavela kwi-phylogenetically ukususela kwizilwanyana ezirhubuluzayo, ngaphandle kwe -pipid amphibians eziye zavela kwizakhiwo ezizimeleyo ngokuzimeleyo. 

Izikhonkwane zinomsebenzi wokuququzelela ukubamba, ukufaka isandla ekuzinzeni kwesakhiwo seminwe kunye nokunciphisa ukugqoka iziphelo ezidibana nomhlaba. Iintlobo ezahlukeneyo zezikhonkwane zinamagama ahlukeneyo ngokuxhomekeke kwiingcali ezisebenzayo, ezifana neenzipho okanye iimpuphu: i-claw inambuzane echazwe kwi-tarsomere yokugqibela, nokuba imvelaphi eyahlukileyo ngokupheleleyo, ibizwa ngokuba yi-nail ngenxa yobudlelwane obusebenzayo, kwaye iqulunqwe ngokukodwa. ukusuka kwi -chitin .

Izikhonkwane ngokuyinhloko zenziwe ngamacandelo amaninzi e-keratin. Elona candelo lingaphandle kwaye linzima yi unguis, eyenziwe yimicu ethe ngqo kwicala lokukhula. Inxalenye engaphantsi ayinzima kakhulu kwaye inesakhiwo se-lamellar. Izikhonkwane zenkawu kunye nezinye izilwanyana ezininzi zenziwe kuphela ngu-unguis (eswele isikhonkwane esincinci), ngelixa amanye amaqela, afana ne -cebids ezininzi, enezinzipho.