Class Notes (839,091)
United States (325,774)
Boston College (3,572)
Biology (481)
BIOL 2000 (49)
Gubbels (1)

Cestodes Intro.docx

3 Pages

Course Code
BIOL 2000

This preview shows page 1. Sign up to view the full 3 pages of the document.
Cestodes Intro: • Anchored in gut wall with scolex, absorb food through tegument, shedding body segments (proglottids) filled with eggs • Scolex with arms is hooked, w/o arms is unhooked o Bothria = slit like grooves (2 per scolex) o Acetabulum = suckers (4 per scolex) • Proglottid are egg producing units budded from head and neck • Strobila is linear series of proglottids (hermaphroditic) o Strobilation = asexual production of segments • No digestive tract, specialized microvillie for nutrient uptake • Excretion and Osmoregulation = protonephredial excretion system (flame cells) • Developmental Stages o Zygote develops into oncosphere, contains larvae that will penetrate intestinal wall o Intermediate Host = immature form of parasite (egg eating) o Definitive Host = mature form (larvae eating) o Always two hosts • Two classes o Pseudophyllidea – acquatic intermediate host (SCOLEX WITH BOTHRIA) (ciliated oncosphere, allow swimming in water)  Coracidium has cilia and develops into procercoid -> plerocercoid o Cyclophyllidea – herb/omnivorous intermediate host  All intermediate stages have scolex inside out  Larvae are usually liquid filled bladder with invaginated scolex, cause pathogenesis usually not adults because well adapted  Dipylidium  Taenoid • Metacestode Stages o Pseudophyllidea – procercoid in first host, then plerocercoid in second host o Cyclophyllidea – cysticercoid, cysticercus, hydatid Nematodes Intro • Provide powerful genetic models to study basis of development, aging and many diseases • Molt 4 times to become adult • Stiff motility using sinuous undulations of bodies, lack circular muscles depend on longitudinal muscles • Musculature tightly attached to hypodermis and cuticle • Coordinated muscle contraction in different quadrants along length of worm results in bending of cuticula • Muscle contains striated fiber made of actin and myosin • Brain consists of single ring around phanyx • Have complete digestive system with mout at very tip o Food pumped against pressure by muscular esophagus • Reproduction: most are dioecious but hermaphrodites occur to, males smaller than females (use pheromones) o SPERM: rely on amoeboid movement rather than flagellum, actin has no role  Small highly basic protein (Major Sperm Protein [MSP])  MSP forms dimers which assemble into subfilaments, two fest form a helical filament, cells move by fiber growth through addition of subunits • Development: small number of cell
More Less
Unlock Document

Only page 1 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.