4 线虫概论种类和生活史

线虫概论和种类

General Information about

Nematodes

一、线虫特点

（一）线形或圆柱形，体表光滑不分节，外被角皮层

（二）♀♂异体

（三）大小1cm—1m＋，因种而异

（四）有原体腔（假体腔）

（五）消化道完全口→咽管→肠→直肠→肛门

（六）生殖系统为管状

二、常见种类：属于线形动物门

自由生活大多数(8000+)

寄生生活少数寄生人体：已报道30多种

常见的：蛔虫Ascaris lumbricoides

钩虫Ancylostoma duodenale

Necator americanus(hookworm)

蛲虫Enterobius vermicularis(pinworm)

丝虫Wuchereria bancrofti

Brugi malayi(Filaria)

鞭虫Trichuris trichiura(whipworm)

旋毛虫Trichinella spiralis

粪类圆线虫Strogyloides stercoralis

Nematodes: relative size

线虫体表与内部结构

侧索

角皮层cuticle

皮下层hypodermis

消化道

肌层usculature

生殖器官

The arrangement of the somatic muscles is of value in the systematic grouping of nematodes

Polymyarian

多肌型

Holomyarian

细肌型Meromyarian

少肌型

Ascaride Hookworm Whipworm

Reproductive system ?Separate

female

Procoele

uterus oviduct ovary

testis

male

Vas deferens Seminal vesticle

Digestive System

?Complete

Process mouth, oesophagus, intestine, rectum and anus

三、生活史

线虫生活史模式：Egg→Larva→♀♂Adult

↖蜕皮4次↗

?Under favorable conditions larvae undergo several molts (蜕皮)（four times)

?Two types of roundworms

soil-transmitted nematodes: 不需中间宿主(土源性线虫)

Ascaris,hookworm,pinworm,whipworm,肠道线虫多属此型

bio-transmitted nematodes(生物源性线虫):Filaria,

Trichinella spiralis(intermediate host), 组织线虫多属此型