University:
American Career College
Course:
MA700 | Clinical Procedures and Pharmacology
Academic year:

2021
Views:

488

Pages:

21
Author:

VNever

Nematodes (Roundworms) General morphology:  Body elongate, cylindrical, tapered at both ends, unsegmented (not divided into segments) and bilaterally symmetric (body is identical on each side)  Body design is a tube within a tube, the outer tube being the body wall and underlying muscles and the inner tube being the digestive tract  Between the tubes is the fluid-filled pseudocoelom, in which the reproductive system and other structures are found; the pseudocoelom is filled with hemolymph 4 Nematodes from outside to inside  Cuticle  An elastic cuticle covers the body surface of nematodes; it is periodically molted  Cuticle has sensory and locomotion structures: spines, bristles, warts, papillae, and ridges  Cuticle covers the entire external and internal surface  Hypodermis  Cellular structure  Produce cuticle  Musculature  Longitudinal rows of muscle cells  Cuticle, hypodermis, and musculature make up the Nematodes’ body wall  Pseudocoelom  Hemolymph Digestive system  They have a complete digestive tract  The digestive system is complete nematodes, with mouth, gut, and anus in most Mouth and Esophagus in Nematoda  Mouth is usually a circular opening surrounded by a maximum of six lips  Three lips in Ascaris  Buccal cavity or buccal capsule in Hook worms  Used for identification of different nematode  Tow important type of Es.:  Fillariform Cylindrical  Rabditiform Posterior bulb Intestine Simple, tube-like structure extending from esophagus to anus In females: anus and rectum In males: anus and rectum combine and create cloaca Nervous system  The nervous system of nematodes is relatively simple  No brain  There are two main concentrations of nerve elements in nematodes, one in the esophageal region and one in the anal area, connected by longitudinal nerve trunks  The most prominent feature of the anterior concentration is the nerve ring, or circumesophageal commissure Reproduction in nematoda  Most nematodes are dioecious (separate male and female worms)  Male reproductive System:  Testes, Vas deferens, Seminal vesicle, Ejaculatory duct  Copulatory spicules:  needle-like mating structures  open the vulva of females, and facilitate the transmission of sperm  Gubernaculum (telamon):  guides exertion of the spicules from the cloaca at copulation  Female Reproductive System     Oviduct Seminal receptacle (sperm storage area) Uterus Ovejector (for ejecting egg through the female genital pore)  Vagina  Vulva  Nematoda life cycle  L1 or L2 (Rabtidiform larva)  L3 (Filariform larva) Females are: - ViViparous (produce larva) - Larviparous (deposit larva) - Ovoviviparous: (Discharging living young rather than eggs such as: Dracunculus, filariae, Strongyloides and Trichinella) - Oviparous (Producing and laying eggs) In nematode life cycle: - A parasite exhibits monoxenous, when its development is restricted to a single host species - Heteroxenous: two different types of host (typically as part of a complex life cycle) Intestinal Nematodes 1- Ascaris lumbricoides 2- Enterobius vemicularis 3- Trichuris trichiura 4- Trichostrongylus 5- Hookworms (Necator and Ancylostoma) 6- Strongyloides stercoralis Geohelminths (soil-transmitted helminths or STH) 1- Ascaris lumbricoides 2- Trichuris trichiura 3- Hookworms (Necator and Ancylostoma) 4- Strongyloides stercoralis

Introduction to Nematodes

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