Hosiyathoi umumiii sistemai asab

Ahamiyati sistemai asab. Sistemai asab dar tanzimi vazifai organizm roli muhim mebozad. Vay kori doimii hujayraho, boftaho, uzvho va sistemai onhoro tamin mekunad. Bo mavjudiyati in sistema organizm bo muhiti beruna aloqamand ast.

Faoliyati sistemai asab ba hissiyot, talim, khotir, nutq, tafakkur va ravandi ruhi asos yofta, odam bo yorii onho na tanho muhiti atrofro dark mekunad, balki metavonad onro faolona digargun sozad.

Boftai asab. Sistemai asabro hujayrahoe tashkil mekunand, ki onho neyron va hujayrahoi asosii boftai asab buda, kori sistemai asabro tamin mekunand. Hujayrahoi hamroh vazifai gizodihi, takyagohi va muhofizatiro ijro menamoyand. Miqdori hujayrahoi hamroh nazarba neyronho qarib 10 marotiba ziyodtar meboshad. Neyron az se qism iborat ast:

• Jasad (tana);
• Izofai kutoh (dendritho);
• Izofai daroz (akson).

Dendritho az kalimai yunonii dendron – darakht girifta shudaand. Onho kutoh va sershokhaand. Dar yak neyron metavonad yakchand dendrit mavjud boshad. Dendritho bo retseptorho payvast buda, impulshoi asabiro ba jasadi neyron mebarand va vazifai hissiyotqabulkuniro ijro mekunand. Akson (az kalimai yunoni aksis girifta shuda, manoyash shokha meboshad) bo mushakho payvast shuda, vazifai harakatro ijro mekunad. Har yak neyron az yak akson iborat ast. Akson bo qabati makhsusi tabiati lipididoshta pushonida shudaast, ki onro mielin (dila) menomand. Az jihati shokharoni neyronho se khel meshavand: 

1. neyronhoi yakshokhador (unipolyari);
2. neyronhoi dushokhador (bipolyari);
3. neyronhoi bisyorshokhador (multipolyari).

Torhoi asab ba tamomi organizm pahn shuda, impulshoro ba hamai uzvhoi badan mebarand. 

Qismhoi sistemai asab. Sistemai asab az qismhoi markazi va kanori iborat ast. Qismi markazi az magzi sar va harommagz tarkib yofta, bo limfai boftai vaslkunanda pushonida shudaast. Ba qismi kanori girehhoi asab dokhil meshavand. YAk qismi sistemai asab, ki kori mushakhoi skeletro tanzim mekunad, sistemai somatiki nom dorad. Odam tavassuti in sistemai asab metavonad harakathoro idora karda, onhoro ikhtiyoran ba vujud orad yo qat gardonad. 

1. Sistemai asab chi ahamiyat dorad?
2. Sokhti bofta va hujayrai asab chi khel ast?
3. Qismhoi asosii sistemai markazii asab kadomhoyand?
4. Sistemai somatikii asab kori kadom uzvhoro tanzim mekunad?