Lecture 8 Flashcards
common features of ecdysozoans
many are diecous
males tend to be smaller and have a hook at the end of the tail
some have jaw like structures
complete digestive system
mouth - intestine - cloaca (opening for digestive, urinary and reproductive tracts)
layered, noncellular cuticle
lipid layer: provides resistance and water protection
outer cortex - inner cortex - matrix layer - basal layer - basal lamella
dorsal and ventral nerve
2 lateral epidermal cord 1 ventral epidermal cord
REPRODUCTION PARTS
female: ovary, oviduct, uterus, genital pore, vagina, seminal receptacle
male: testis, vas deferens, seminal vesicle , have a bursa; used to grasp onto the female during insemination
EXCRETION
Glandular system
- marine/aquatic organisms
- chemo sensory system at the end of the worm
- nerve ring
- renette gland
Tubular system
- couple of long ducts on either side
- secrete urinary product
describe the structure of the cuticle in nematodes + why is it important
layered, noncellular cuticle
lipid layer: provides resistance and water protection
outer cortex - inner cortex - matrix layer - basal layer - basal lamella
describe the filarial worm cycle
ecological importance of nematodes
C. elegans are model organisms (research)
decomposers
predators
parasites
regulate soil bacteria and fungal populations; associated with nutrient cycling
phylum Nematoda
roundworms (in X-section; no circular muscles in body wall - cant change shape)
- unsegmented, pseudocoelomate
- layered collagenous cuticle
- generally lack cilia
- excretorty system containing renette cells
- unsettled taxanomy
- ubiquitos and abundant
Nematoda - parasitic forms: Ascaris lumbricoides
lives in our small intestines
- produce eggs, released when we poo
- infect millions of us
- breath it in, crawls up your trachea, you swallow it and then it grows and lives in your small intestine
Nematoda - Parasitic Forms: Filarial Worms
mosquitos inject larval forms into humans
- develop in the thoracic musculature of the mosquito (1st and 2nd larvae stage)
- discharged into head and proboscis (3rd larval stage) and passed to host during feeding
- lymphatics
- blood circulation of parasite
- day time: microfilariae in lungs
- night time: perpheral circulation where the microfilariae are picked up by mosquito
