Exam 3: Lect 1

Question 1

Obligate parasite

Answer 1

A parasite that must always live in contact with a host

Question 2

Facultative parasite

Answer 2

A parasite that can complete its life cycle in a free-living environment or, alternatively, that lives during part or all of its cycle within a host

Question 3

Endoparasite

Answer 3

Living within a host (ex. tape worms, malaria)

Question 4

Ectoparasite

Answer 4

Living outside the host (body surface) (ex. Fleas, lice, mites)

Question 5

Adult Helminthic Replication

Dioecious

Answer 5

• Male reproductive organs are in one individual, and female reproductive organs are in another.
• Reproduction occurs only when two adults of teh opposite sex are present in the same host

Question 6

Adult Helminthic Replication

Monoecious or hermaphroditic

Answer 6

• One worm has both male and female reproductive organs and may self-fertilize
• Two hermaphrodites may copulate and simultaneously fertilize each other

Question 7

Classification of human parasites

Sucker

Answer 7

Attachment organ, adhesion to host tissue

Question 8

Classification of human parasites

Scolex

Answer 8

The head or attachment portion of a tapeworm; suckers or hooklets are present

Question 9

Classification of human parasites

Hooklet or rostellum

Answer 9

Top of the head portion of the tapeworm bearing hooks

Question 10

Classification of human parasites

Operculum

Answer 10

Egg cap of parasitic larvae

Question 11

Classification of human parasites

Proglottid

Answer 11

Tapeworm segments containing male and felmale reproductive systems; may be immature, mature, or gravid

Question 12

Classification of human parasites: Proglottid

Definition of “Gravid”

Answer 12

uterine branches filled with eggs

Question 13

Classification of human parasites

Ventral

Answer 13

Pertaining to the front or anterior

Question 14

Classification of human parasites

Dorsal

Answer 14

Back side

Question 15

Classification of parasitic worms

Trematodes (flukes): Intestinal

Answer 15

Fasciolopsis

Question 16

Classification of parasitic worms

Trematodes (flukes): Liver and lung

Answer 16

Clonorchis (Opisthorchis) Paragonimus

Question 17

Classification of parasitic worms

Trematodes (flukes): Blood

Answer 17

Schistosoma

Question 18

Classification of parasitic worms

Cestodes (tapeworms): Intestinal

Answer 18

Diphyllobothrium, Taenia

Question 19

Classification of parasitic worms

Cestodes (tapeworms): Tissue (larval form)

Answer 19

Taenia, Echinococcus

Question 20

Classification of parasitic worms

Nematodes (roundworms): Intestinal

Answer 20

Ascaris, Enterobius

Question 21

Classification of parasitic worms

Nematodes (roundworms): Tissue

Answer 21

Trichinella, Toxocara

Question 22

Classification of parasitic worms

Nematodes (roundworms): Blood and Tissue

Answer 22

Wucheria, Loa

Question 23

Antihemintic treatment

Class: Benzimdazoles

Answer 23

• Albendazole, mebendazole
• Oral administration
• Mode of action: Binds to nematode beta-tubulin, inhibiting polymerization and preventing the formation of microtubules, stopping cell division. Impaired uptake of glucose, leading to depletion of glycogen, and reduced stores of ATP
• Can stimulate Ascaris worms to emerge from mouth and nostrils, patients should be forewarned

Question 24

Mode of action: Bezimidazoles

Answer 24

• Binds to nematode beta-tubulin, inhibiting polymerization and preventing the formation of microtubules, stopping cell division. Impaired uptake of glucose, leading to depletion of glycogen, and reduced stores of ATP
• Can stimulate Ascaris worms to emerge from mouth and nostrils, patients should be forewarned

Question 25

Antihelmintic treatment

Class: Pyrazinosoquinolones

Answer 25

• Praziquantel
• Oral
• Mode of action: Disrupts calcium ion homeostasis in the worm, antagonizing voltage-gated calcium channels resulting in uncontrolled calcium ion influx leading to uncontrolled muscle contraction and paralysis exposing schistosome antigens at the parasite surface
• The binding site for the drug remains to be identified

Question 26

Mode of action: Pyrazinosoquinolones

Answer 26

• Disrupts calcium ion homeostasis in the worm, antagonizing voltage-gated calcium channels resulting in uncontrolled calcium ion influx leading to uncontrolled muscle contraction and paralysis exposing schistosome antigens at the parasite surface
• The binding site for the drug remains to be identified

Question 27

Antihelminitic treament

Class: Macrocyclic lactones

Answer 27

• Ivermectin, doramectin
• Topical, oral or possible
• Mode of action: Binds to glutamate-activated chloride channels existing in nerve or muscle cells of nematode causing hyperpolarization of nerve or muscle cells by increasing permeability of chloride ion through the cell membrane, parasites are paralyzed to death
• Toxicity: May cause neurotoxicity