"Izwe kumele likwazi amaqhawe alo!" - lesi siqubulo singasetshenziselwa ukucela ulwazi oluthe xaxa mayelana ne "bait", okuyinto, ngokombono wabaningi, bavele bahlanganyele ekukhuliseni nasekuzalweni kwempilo entsha. Ngempela, bona, i-spermatozoa, bangamaqhawe ngempela. Ibutho lazo lezigidi lilungele ukufa ukuze lihlangabezane nomgomo wesosha elilodwa kuphela - umhlangano owamukelekile neqanda ...
I-Spermatozoon iyinhlangano yamagciwane emaduna (mobile) esetshenziswa ngamagciwane amancane we-testicle (ama-gamete) ayenziwe ngama-micini amancane angu-50-60, umsebenzi oyinhloko wokuletha izinto ezifuywayo zofuzo ngokuqeda isisu somzimba wesifazane. Ukugcwaliseka kwalokhu kukhishwa kungenzeka kuphela ngenxa yesakhiwo esithile esithile esiyinkimbinkimbi yesidoda.
Njengoba kuboniswe umdwebo wesakhiwo se-spermatozoon esithombeni esingezansi, naphezu kokuhluka kwamanye amangqamuzana emzimbeni, isakhiwo se-spermatozoon esivamile sabantu futhi sihlanganisa izakhiwo ezinjalo zeselula njengekhanda, intamo, umzimba nomsila (flagellum).
Ikhanda le-sperm yamadoda, elinalo, liqukethe i-nucleus encane kakhulu ye-haploid eneqoqo lama-chromosomes angu-23, okuthi ngemva kokuhlangana neqanda, ukwakha i-zygote, iba yisimo se-diploid enama-chromosomes omama kanye nobaba ngemva kokuqhathaniswa namanye amaseli.
Ngaphansi kwekhanda le-plasma elingaphambi kwekhanda, elihlanganisa isigamu se-nucleus ngesimo se "cap", i-acrosome ye-sperm ifakwa. Iqukethe ama-enzyme e-acrozine, lapho, uma uxhumane neqanda, akwazi ukuchithwa igobolondo lalo futhi avumele isidoda ukuba singene ngaphandle kobunzima. Futhi ekukhulisweni kweqanda, kuphela ikhanda ne-nucleus yesilisa ephuma kudivayisi ye-chromosomal yefa elihlala kuyo, zonke ezinye izitho zeseli lesilisa zihlala ngaphandle.
Ingxenye ephakathi ye-spermatozoon iboniswa intamo nomzimba, ngemuva kwalokho umsila - isitho sokuhamba kwe-gamete yesilisa. I-mitochondria enomoya engxenyeni ephakathi ihlanganisa i-cytoskeleton ye-flagellum esuka emitokhini yamancane futhi inesibopho samandla adingekayo ukuze kuqhume phambili inyoka. Isisindo sokuhamba kwesidoda singamamitha ayi-50 ngomzuzwana noma kufika ku-1.5 cm ngomzuzu. Uhlobo lwephethiloli yalokhu ukunyakaza yi-fructose, equkethe insimu.
Izinhlobo ze-spermatozoa kanye nobulili bomntwana ongakazalwa
Kunezinhlobo ezimbili zezidakamizwa ezithinta ubulili bomntwana: i-spermatozoa ene-X-chromosome - gynospermia, uma ihlangana neqanda, intombazane izalwa, futhi i-spermatozoa ene-Y-chromosome - androspermia, enesibopho sokuzalwa komfana. Kuye kwafakazelwa ngokwesayensi ukuthi kakade ekukhulelweni kunokwenzeka ukuthi kunqume ukuthi kungenzeka ukuthi ubulili besikhathi esizayo wengane. Ngakho-ke, okuhamba phambili, kodwa ukuphila isikhathi esifushane ne-androspermia ngesikhathi sokuvuthwa ngokushesha kunendlela ye-X-spermatozoa i-ovum, okwenza ukuba umfana akwazi ukukhulelwa. Ngakho-ke, ukukhulelwa kwentombazane kuzokwenzeka cishe esikhathini sokuphelelwa yisikhathi sokungena esikhathini, ngoba i-gynospermia encane yeselula inesikhathi eside sokuphila.
Ukukhula kwabo kwe-spermatozoa kufinyeleleke uma bechitha izinyanga ezingu-2.5 emasendeni kanye nenxenye yenyanga ku-appendages.
