Tapeworms

Question 1

Like flukes, tapeworms are also:

Answer 1

hermaphroditic

Question 2

Tapeworms are ALWAYS_________, and the adult tape worms are always found in the ________ or in a connecting duct.

Answer 2

1) endoparasites

2) gastrointestinal tract

Question 3

What is the class of “true tapeworms”?

Answer 3

Eucestoda

Question 4

How do tapeworms take in their nutrients? This means that tape worms lack a _______ __________.

Answer 4

1) absorb through their body wall

2) body cavity

Question 5

What morphological trait varies greatly in tapeworms?

Answer 5

size (length)

Question 6

Three parts that make up the “body” of tapeworms:

Answer 6

1) scolex or “head”
2) short neck
3) strobila made up of segments called proglottids

Question 7

The four suckers on the scolex are known as _______. A scolex is said to be _______ if it has a __________.

Answer 7

1) acetabulum (vinegar cup)
2) armed (unarmed if there is no rostellum)
3) rostellum: “retractable nose” which may be covered with backward facing hooks

Question 8

The scolex serves as the ______ _______.

Answer 8

holdfast organ: anchor the adult tapeworm in the small intestine

Question 9

The neck is the ______ _______.

Answer 9

germinal region: the rest of the body of the tapeworm develops from the neck

Question 10

Each proglottid has ….

Answer 10

one or two sets of male AND female reproductive organs; formed at the neck and pushed farther down the body as new proglottids are formed

Question 11

3 basic types of proglottids:

Answer 11

immature: closest to neck and contain immature, nonfunctioning reproductive organs
mature: in the middle of the body with fully functioning reproductive organs (“teenagers” of proglottids)
gravid: farthest from neck and contain nonfunctioning reproductive organs; uterus is full of eggs

Question 12

The eggs of tapeworms are set free from the body of the tapeworm when:

Answer 12

gravid proglottids break away from the main body and the proglottid disintegrates and releases eggs; sometimes, single eggs released from uterus when pushed out by internal pressure

Question 13

An egg is also known as:

Answer 13

oncosphere

Question 14

Proglottids containing eggs are

Answer 14

voided in the feces of the definitive host.

Question 15

A larval tapeworm is a

Answer 15

mestacestode

Question 16

Life cycle of tapeworms:

Answer 16

1) Definitive host ingests intermediate host containing metacestode.
2) Scolices “excyst” and attach to the mucosa of the small intestine of the definitive host.
3) Scolex grows neck, neck grows proglottid, and adult tapeworm matures in intestine of definitive host.
4) Eggs are released from definitive host, and embryophore (envelope around oncosphere with 3 hooklets) is digested by intermediate host.
5) Oncosphere is released and travels to extraintestinal predilection site where the metacestode stage is formed

Question 17

What are the four different metacestode stages?

Answer 17

cysticercoid, cysticercus, coenurus, hydatid

Question 18

Cysticercoid stage:

Answer 18

single scolex; small, fluid filled cavity formed; found in mites and fleas

Question 19

Cysticercus stage:

Answer 19

found in vertebrates as a single “inside out” scolex in a large, fluid filled cavity

Question 20

Coenurus stage:

Answer 20

large, fluid filled cavity with many “inside out” (invaginated) scolices; “multi-headed” cysticercus

Question 21

Hydatid stage:

Answer 21

Large fluid filled cavity with brood capsules inside; brood capsules contain many protoscolices

Question 22

Brief illustration of tapeworm development stages:

Answer 22

oncosphere ——cysticercoid OR cysticercus OR coenurus OR hydatid metacestode stage—–ingestion—-adult tapeworm

Question 23

Describe morphological traits of Cysticercoide tapeworms:

Answer 23

No rostellum on suckers (unarmed)
Usually wider than they are long (“squatty body”)
Innermost oncosphere covering known as “pyriform apparatus” and is pear-shaped