浙江大学医学院：《人体寄生虫学 Human Parasitology》课程教学资源（PPT课件讲稿）线虫 Nematode

Nematode(线虫)

Nematode(线虫) 3

Round worms 线虫 Nematode 似蚓蛔线虫(蛔虫) 毛首鞭形线虫〔鞭虫)蠕形住肠线虫(蛲虫) Ascaris lumbricoides Trichuris trichiura Enterobius vermicularis 钩虫 旋毛形线虫(旋毛虫) 丝虫 Hookworm Trichinella spiralis Fil laria e

Round Worms 4

Introduction .o Among the commonest of all parasites and responsible for diseases of major importance in humans os Non-segmented roundworms belonging to the phylum Nemathelminthes, class nematoda s The sexes are usually separate(Dioecious) the male which is smaller than the female commonly has a curved posterior end

Introduction ❖ Among the commonest of all parasites and responsible for diseases of major importance in humans ❖ Non-segmented roundworms belonging to the phylum Nemathelminthes, class nematoda ❖ The sexes are usually separate (Dioecious), the male which is smaller than the female commonly has a curved posterior end 5

Morphology 冷 Cylindrical and slender &s Bilaterally symmetrical ☆Sex- diferentiated . o Coelomic cavity: protocole os The supporting body wall consists of cuticle layer, syncytial layer(subcutical layer) and longitudinal muscular layer %s The alimentary tract is a simple tube extending from the mouth to the anus

Morphology ❖ Cylindrical and slender ❖ Bilaterally symmetrical ❖ Sex-differentiated ❖ Coelomic cavity: protocoele ❖ The supporting body wall consists of cuticle layer, syncytial layer (subcutical layer) and longitudinal muscular layer ❖ The alimentary tract is a simple tube extending from the mouth to the anus 6

dorsal nerve cuticle一 ovary intestine hypodermIs lateral nerve contractIle longI tudI nal muscle @ pseudocoelom uterus subventral nerve noncontractIle ventral nerve longI tudInal muscle

Morphology 令 No circulatory system s The reproductive system is in tubular form with dioecious(sex-differentiation) Digestive system cR The male reproductive organs are situated in the posterior third of the body 象/)交合 as a single coiled tube, the various parts 射精雪重殖腔 of which are differentiated as testis, vas male reproductive system deferens, seminal vesicle, and ejaculatory duct, also cloaca and spicule 受精 子宫 ca The female reproductive system may be 阴门阴遭 卵腐输所管 either a single or a bifurcated tube female reproductive system differentiated into ovary oviduct, seminal receptacle, uterus, ovejector and vagina

Morphology ❖ No circulatory system ❖ The reproductive system is in tubular form with dioecious (sex-differentiation):  The male reproductive organs are situated in the posterior third of the body as a single coiled tube, the various parts of which are differentiated as testis, vas deferens, seminal vesicle, and ejaculatory duct, also cloaca and spicule  The female reproductive system may be either a single or a bifurcated tube, differentiated into ovary, oviduct, seminal receptacle, uterus, ovejector and vagina 8 Digestive system female reproductive system male reproductive system

Physiology oo The methods of obtaining food may be classified as c& Sucking with ingestion of blood(Ancylostoma) cR Ingestion of lysed tissues and blood (trichuris c& Feeding on the intestinal contents(Ascaris) c& Ingestion of nourishment from the body fluids(filarial worms) .o Metabolism: mainly aerobic metabolism, and most species need free-living periods for larvae, which are capable of withstanding a wide range of environmental condition oo During larval development, nematodes pass through several molts or ecdysis, both inside and outside the host

Physiology ❖ The methods of obtaining food may be classified as  Sucking with ingestion of blood (Ancylostoma)  Ingestion of lysed tissues and blood (Trichuris)  Feeding on the intestinal contents (Ascaris)  Ingestion of nourishment from the body fluids (filarial worms) ❖ Metabolism: mainly aerobic metabolism, and most species need free-living periods for larvae, which are capable of withstanding a wide range of environmental condition ❖ During larval development, nematodes pass through several molts or ecdysis, both inside and outside the host 9

Life cycle ☆Geo- helminths cR Only one host: the larvae pass from host to host directly or after a free-living existence c& Transmission to a new host depends upon 'o the ingestion of the mature infectious eggs with larvae(Ascaris, Pinworm) .o the penetration of the skin or mucous membranes by the larvae(Hookworm) ☆Bio- helminths oR Have an intermediate host c& Transmission to a new definitive host is intermediated by the arthropod---(filarial worm) 10

Life cycle ❖ Geo-helminths Only one host: the larvae pass from host to host directly or after a free-living existence Transmission to a new host depends upon ❖ the ingestion of the mature infectious eggs with larvae (Ascaris, Pinworm) ❖ the penetration of the skin or mucous membranes by the larvae (Hookworm) ❖ Bio-helminths  Have an intermediate host Transmission to a new definitive host is intermediated by the arthropod--- (filarial worm) 10

Common medical nematodes species go Intestinal lumen residing nematodes cR Ascaris, Hookworm, Whip worm, Pinworm----the adult parasite inhabit in human intestinal tract o Blood and tissue residing nematodes c& Filaria, Thichinella----the location of the adult parasite is blood or tissue

Common medical nematodes species ❖ Intestinal lumen residing nematodes: Ascaris, Hookworm, Whip worm, Pinworm----the adult parasite inhabit in human intestinal tract ❖ Blood and tissue residing nematodes: Filaria, Thichinella----the location of the adult parasite is blood or tissue 11

Ascaris lumbricoides (似蚓蛔线虫,蛔虫) 12

Ascaris lumbricoides (似蚓蛔线虫,蛔虫) 12