MEDA

MEDA, qismi vasei nai hozima, ki dar on khurok hazm meshavad. Medai hayvonot du khel ast: Medai gadudi yo hozima va Medai mushaki yo jovanda. Medai gadudi dar devoraash gadudhoi hozima dorad. Devorai Medai mushakiro kutikula faro giriftaast. Medai yak qator hayvonhoi bemuhra (baze rudakovokho, pahnkirmho, halqakirmho va g.) ba qismi ruda tabdil yoftaast. Medai hayvonhoi muhrador dar qafoi surkhruda joygir shudaast. Medai nokhiho az yakchand qismho iborat ast. Qisme, ki az surkhruda cap meshavad kardiali va qisme, ki ba rudai duvozdahangushta medaroyad, pilori nomida meshavad. Qismi khaltashakli bayni qismhoi kardiali va pilori khobidai Meda asri M, nom dorad. Meda bo epiteliyai yakqabata pushida shuda, dar on gadudhoi naychashakl joy giriftand. Dar beshtari mohiho, obkhokiho, khazandaho va parrandaho gadudhoi zeri Meda va gadudhoi pilorii Meda az ham farq mekunand. Aksari shirkhurkho (ba gayr az darrandaho va primatho) gadudhoi kardiali niz dorand. Gadudi Meda luob va shirai Meda judo mekunad. Medai shirkhurho ba surkhruda va qismhoi kardialiyu pilori judo meshavad. Medai baze hayvonhoi jovanda nisbatan murakkab va az 4 qism iborat ast: shikamba, tur, hazorkhona va shirdon (rasmi 1). Az onho tanho shirdon gadud dorad. Dar ushtur devorai shikamba chuqurchahoi ziyod dorad, ki dar onho ob zakhira meshavad.

Rasmi 1. Medai gusfand . (taogrekh shudaast): 1 — surkhruda- 2—shikamba; 3 — tur, —hazorkhona; 5— shirdon; 6 — rudai davozdahangushga; 7 — tarnovcha.

Medai odam (rasmi 2) qismi vasei nai hozima buda, shaklan ba khaltachai darozruya monand ast. Qismi ziyodi on dar tarafi chapi boloi kovokii shikam va yak qismi on dar tarafi rost joygir shudaast.

Rasmi 2. Medai odam: A — namud az pesh (1 —asri meda; 2 — khaiiya kalon; 3 — charbui kalon (buridagi); 4 — qismi darbon; 5 — rudai duvozdahangushta; 6—khami khurd; 7—charbui khurd (buridagi); 8 — daromadgohi meda; 9 — surkhruda); V — pardai luobi.

Medai odam az qismhoi zerin iborat ast: devorai pesh va qafoi Meda, zeri Meda, daromadgoh va baromadgoh. Devorai Meda az pardai serozi yo shikamparda va pardai luobi tarkib yoftaast. Dar asri pardai luobi gadudhoi luobjudokunanda va fermentjudokunanda, ki safedaro tajziya mekunand, joygir shudaand. Gadudhoi asri Meda pepsin va kislotar drogenkhlorid judo mekunand. Dar bayni Meda va rudai duvozdahangushta sfinkteri pilori joygir shudaast, ki vay halshavii khurokro ba tanzim medarorad. Shokhchai toqai sistemai zortai shikam Medaro az khun tamin mekunad. Shokhchai asabi gumroh va bofti asabhoi simpatikii shikam boshand, Medaro bo asab tamin mekunand. Judoshavii fermentho, tirai Meda va kislotai gidrogeikhlorid, ba miqdoru sifati khurok vobasta buda, ba vositai omilhoi neyrogumorali tanzim meyoband. Meda ba gayr az funksiyahoi asosii khud (korkardi khimiyavi, mekhaniki va ba ruda darovardani khurok) funksiyai muhofizat (bakterisidi, tasiri bakteriostatii kislotai gidrogeikhlorid va lizosim) va jabbishro niz ado mekunad. Faoliyati Meda bo nigohdorii gomeostaz dar organizm, mubodizai obu namak, funksiyai gurda, gadudhoi sekresiyai daruni, gardishi khun va g. aloqai zich dorad. Signalhoe, ki hangomi angezishi reseptorhoi Meda ba sistemai asabi markazi dokhil meshavand, boisi hissi gurusnagi, tashnagi va g. megardand.

Oid ba bemorihoi M. nig. Gastrit, Zajmi meda va Pudai duvozdahangushta va g.

Ad.: Raaenkov I. P., Novie dannie po fiziologii i patologii pnshevareviya (Leksii), M., 1948; Ugolev A. M., Pishevarenie i ego prisposobitelnaya evolyusiya. M., 1961.