Practical #1 Exam: Platyhelminthes

Question 1

What phylum do flatworms fall under?

Answer 1

Platyhelminthes

Question 2

Platyhelminthes Characteristics

Answer 2

-bilateral symmetry
-triploblastic
-have an excretory system w/ flame cells that aid in the removal of nitrogenous wastes (similar to our kidneys)
-have a nervous system with sense organs
-usually monoecious (hermaphroditic)
-acoelomate: (no true body cavity)

Question 3

Tripoblastic Tissue

Answer 3

-3 layers of tissue:
-epidermis
-mesoderm
-endoderm

Question 4

Class Turbellaria Characteristics

Answer 4

-free-living
-aquatic, usually under rocks or vegetation

Question 5

Dugesia Characteristics

Answer 5

-common name is “planaria”
-triangular head w/ earlike auricles that house many sensory cells used for touch and smell
-presence of simple eyes called ocelli (one eye: ocellus)
-locomotion performed in a gliding pattern via the glands in its ciliated epidermis.

Question 6

Dugesia Sexual Reproduction

Answer 6

reproductive system: monoecious (hermaphrodite) with a complex reproductive system.
-perform “penis fencing” in order to decide who will carry the eggs.
- planarians and other freshwater turbellarians also reproduce asexually by
transverse fission.

Question 7

What class are flukes in?

Answer 7

Trematoda

Question 8

Class Trematoda

Answer 8

-endoparastic
- have 2 hosts (Intermediate and definitive)
-life cycle is linked closely with water (can find snails easier)

Question 9

What is endoparasitic?

Answer 9

• parasites that live inside the host’s body

Question 10

What is intermediate host?

Answer 10

-invertebrate

Question 11

What is a definitive host?

Answer 11

-vertebrate

Question 12

Fasciola hepatica

Answer 12

-2 hosts: intermediate (snail), defentive (herbivorous vertebrate)
-spread to vertebrate by eating vegetation with metacercariae on it
-snail leaves metacercariae (like a cyst) on vegetation
- eaten by definitive host. Travels to the liver were it grows and reproduces
-eggs are released with the host’s feces
- definitive host feces comes in contact with water
-miracidia leave feces and swim to snail

Question 13

Local Trematodes

Answer 13

-there is a species of Schistosoma that infects birds, but the furcocercous
cercariae can accidently penetrate human skin which leads to swimmer’s itch

Question 14

What class do tapeworms fall under?

Answer 14

Cestoda

Question 15

Class Cestoda

Answer 15

-endoparasites
-life cycle is not directly linked to water
- 2 hosts:
- both are vertebrates Intermediate = pigs, cows, rabbits…(herbivores) Definitive = humans, dogs, wolves…
(carnivores)
-body composed of 2 major sections: scolex and strobillia

Question 16

What is the scolex?

Answer 16

-usually with hooks or lobes on
rostellum used to connect to host’s tissue

Question 17

What is the strobillia

Answer 17

-long chainof indivudal proglottids

Question 18

Cestoda Anatomy

Answer 18

-proglottids develop from the scolex and mature as they are pushed posteriorly
-proglottids fall off and stick into the host’s feces in order to infect the next hos

Question 19

Proglottid

Answer 19

• one segment that contains its own reproductive and
  digestive organs.

Question 20

Taenia saginata (Beef Tapeworm)

Answer 20

-most common in humans
- intermediate host = cattle
- definitive host = humans
- rostellum with no hooks, mature proglottids with many
branches

Question 21

Taenia saginata (Pork Tapeworm)

Answer 21

-intermediate host = usually pigs, but could be other vertebrates (even humans!)
-definitive host = humans
- rostellum with hooks, mature proglottid with no more than 13 branches

Question 23

Pharynx

Answer 23

-used for feeding, excreting, and mating

Question 24

Ocelli

Answer 24

-light sensitive pigment cups

Question 24

Auricles

Answer 24

-tactile (feeling) and olfactory (smelling) structures

Question 25

Class Turbellaria: Dugesia Whole Mount

Answer 25

• pharyx, ocelli, auricles

Question 26

Anatomical postions

Answer 26

-anterior (front)
-posterior (back)
-proximal (center)
-distal (away from center)

Question 27

Class Turbellaria: Dugesia Cross Section

Answer 27

• pharynx
• diverticula:
  -used like one giant, branching stomach that stretches throughout the organism.
• are found in all 3 cross sections, but there are fewer towards the
  posterior

Question 28

Class Trematoda: Fasciola hepatica Slides

Answer 28

-shoulders: a good feature to tell this species apart from
others
- oral sucker: used for attachment to the host
- branched intestine

Question 29

Class Cestoda: Taenia
Proglottid Slides

Answer 29

• scolex
• Immature and mature proglotid
  -mature has reproductive organs
• gravid proglottid
• strobillia (whole organism)