Cestodes Introduction

Question 1

In what phylum are tapeworms classified?

Answer 1

platyhelminthes (flatworms)

Question 2

In what 2 orders are human tapeworms found?

Answer 2

1. cyclophyllidea 2. pseudophyllidea

Question 3

What is the scolex?

Answer 3

chief neural ganglia w physical and chemical sensory endings

Question 4

What cestodes have an acetabulate scolex?

Answer 4

(4 muscular cups) cyclophyllidea

Question 5

What tapeworms have a bothraite scolex?

Answer 5

( shallow grooves) pseudophyllidea

Question 6

Where is the neck?

Answer 6

immediately posterior to scolex

Question 7

What is strobilation?

Answer 7

formation of proglottids

Question 8

What does PZQ do to cestodes?

Answer 8

damages tegument of neck

Question 9

The strobila is made up of

Answer 9

proglottids.

Question 10

What is inside the gravid?

Answer 10

egg

Question 11

What is a rostellum scolex?

Answer 11

muscular, armed -> has hooks, unarmed -> no hooks

Question 12

Are tapeworms monoecious or dioecious?

Answer 12

monoecious

Question 13

Why is the cestode tegument described as a syncytium?

Answer 13

has no cell boundaries

Question 14

Which is the outermost layer of the tegument?

Answer 14

glycocalyx

Question 15

What is the microtrix?

Answer 15

increase SA & maintain position in the glycocalyx

Question 16

What is the function of the function of the distal cytoplasm?

Answer 16

no nuclei. vesicles maintain glycocalyx

Question 17

What is found between the distal cytoplasm & proximal cytoplasm?

Answer 17

tegumental muscle (longitudinal & circular)

Question 18

How are the distal cytoplasm and proximal cytoplasm connected

Answer 18

cytoplasmic connective (channels)

Question 19

How do cestodes acquire nutrients?

Answer 19

no digestive tract -> all nutrients absorbed

Question 20

Give an example of diffusion across the tegument?

Answer 20

proxidine (vit B6) - high to low [] in worm no E required

Question 21

How is glucose taken up by the tegument?

Answer 21

active transport (low to high gradient so requires E)

Question 22

What are intrinsic enzymes?

Answer 22

produced by worm & embedded in tegument part of contact digestion

Question 23

What is contact digestion? Give an example.

Answer 23

digest molecules in host gut. small molecules taken up by active transport. ex: amylase (starch -> glucose)

Question 24

What is protandry?

Answer 24

male 1st sperm stored

Question 25

How does the uterine structure differ in Cyclophyllideans & Pseudophyllideans?

Answer 25

cyclo: end blindly vs. pseudo: ends in uterine pore

Question 26

What are apolysis and anapolysis? In which order does each occur?

Answer 26

apolysis - gravid proglottid breaks off & disperses eggs in cyclo vs. anapolysis - uterine pore in pseudo

Question 27

How do the vitelline glands differ in the two orders?

Answer 27

cyclo: single, compact vs. pseudo: scattered

Question 28

What is an oncosphere?

Answer 28

larva

Question 29

Why is the called a hexacanth embryo?

Answer 29

has 6 hooks

Question 30

How many hosts do most cestodes need to complete their life cycle?

Answer 30

2

Question 31

What stage develops inside the egg?

Answer 31

onchosphere

Question 32

Where does the egg hatch?

Answer 32

IH or outside of IH and larva gets eaten by IH

Question 33

What happens once the larva gets inside the intermediate host?

Answer 33

migrates to parenteral site & develops to metacestode (juvenile)

Question 34

In which host is the metacestode found?

Answer 34

DH

Question 35

What stimulates the development of the metacestode to the adult?

Answer 35

digest enzymes

Question 36

What are the treatments for most cestode infections?

Answer 36

niclosamide & PZQ