Sokht va inkishofi ustukhono

Vazifai sistemai takyagoh va harakat. Skeletu mushakho takyagohi badani inson va azoi harakat meboshand. Onho ba ham payvast shuda, kovokihoi makhsusro hosil mekunand (rasmi 4). Dar in kovokiho uzvho joygir va himoya karda meshavand. Masalan, dil va shushro ustukhonhoi qafasi sina va mushakhoi sinayu takhtapusht, uzvhoi kholigii shikam (meda, ruda, gurdaho) –ro qismi poyonii sutunmuhra, ustukhonhoi kos, mushakhoi takhtapusht va shikam muhofizat mekunand. Magzi sar dar kosakhonai sar, harommagz dar kovokii sutunmuhra, uzvhoi tanosul dar kholigii ustukhonhoi kos joy giriftaand.

Boftai ustukhon. Ustukhoni (skeleti) badani odam az boftai ustukhonii vaslkunanda tarkib yoftaast.
Boftai ustukhoni doroi tori asab, raghoi khungard va hujayrahoi shokhador meboshad. Hujayrahoi ustukhon va shokhahoi onho bo juychahoi boriktarini pur az moei baynihujayragi ihota shudaand. In hujayraho tavassuti in juychaho gizo va nafas megirand. Sokhti ustukhonho. Andoza va shakli ustukhoni (skeleti) badani odam gunogun ast. Asosan se namudi ustukhonhoro farq kardan mumkin ast:

1) nayshakl;
2) sufta (hamvor);
3) kutoh (nohamvor).

Ustukhonhoi darozro inchunin nayshakl menomand, baroi on ki daruni onho kholi meboshad. CHunin sokhti ustukhonhoi daroz dar yak vaqt boisi mustahkami va sabukii onho megardad. Kanali ustukhoni nayshaklro boftai payvastkunandai sercharb – magzi zard yo iliki zard pur kardaast. Ustukhoni badan az ustukhonparda, moddai zich va moddai isfanjmonand iborat ast. Tanai ustukhoni nayshakl az moddai sakhtu mustahkam va saraki on az moddai isfanjmonand iborat meboshad.
Dar kholigii in modda magzi surkh joygir shudaast. Dar in magz hujayrahoi surkhro uzvi khunofar menomand. Ustukhonhoi kutoh bisyortar az moddai isfanji tarkib yoftaand. Ustukhonhoi sufta az moddai zich va isfanji iboratand.

Inkishofi ustukhonho. Ustukhoni odam dar bachagi va navrasi mesabzad, yane daroz va gafs meshavad. Tashakkuli skelet dar sinni 22-25-solagi anjom meyobad. Gafsshavii ustukhon az hisobi taqsimshavii hujayrahoi sathi darunii ustukhonparda ba amal meoyad. Dar natija, dar rui ustukhon qabathoi navi hujayra ba vujud omada, dar atrofi in hujayraho moddai baynihujayravi hosil meshavad. Darozshavii ustukhonho az hisobi taqsimshavii hujayrahoi boftahoi tagoyaki, ki nugi ustukhonhoro mepushonand, ba amal meoyad. Inkishofyobii ustukhonho az tarafi hormoni sabzish tanzim karda meshavad. Ba hormoni inkishof hormoni qismi peshi hipofiz, ki hormoni qadkashi menomand, dokhil meshavad. Dar holati ziyod shudani in hormon tez darozshavii ustukhonho mushohida karda meshavad.
Qadi inkhel odamon khele baland meshavad, ki onro «gigantizm» menomand. Dar holati kam judo shudani in hormon inkishofi ustukhon sust meshavad va qadi in khel odamon past buda, onhoro «karlik» menomand.

Tarkibi khimiyavii ustukhon.

Tarkibi ustukhonro ob, moddahoi organiki – osein va oseomukoidho, ravganho va moddahoi gayriorganiki tashkil medihand. In moddaho ba ustukhon sakhti mebakhshand. Baroi aniq kardani in agar ustukhonro dar yak shabonaruz dar mahluli 10-foizai kislotai sulfat (H2SO4) yo gidrogenkhlorid HCl nigoh dorem, on goh, namakhoi kalsiy va fosfor hal meshavand va ustukhon khosiyati sakhtii khudro gum karda, khele narm megardad, ba darajae, ki onro gireh bastan mumkin meshavad.
Payvastagihoi organiki ustukhonro chandiru mustahkam mekunand. Vobasta ba sinnu sol tarkibi khimiyavii ustukhon ham tagyir meyobad. Tarkibi ustukhoni javonon va miyonasolon beshtar az moddahoi organiki boy meboshad. Tarkibi ustukhoni pironsolon bisyortar moddahoi gayriorganiki dorad.

Savolho

1. Sistemai takyagoh va harakat chi ahamiyat dorad?
2. Sokhti boftai ustukhoni chi khel ast?
3. Kadom namudhoi ustukhonhoro medoned?
4. Sabuki va mustahkamii ustukhonhoi bozu ba chi vobasta ast?
5. Az chi sabab ustukhonho gafs va daroz meshavand?
6. Vobasta ba sinnu sol tarkibi khimiyavii ustukhon chi khel tagyir meyobad?