Tests to check level of knowledge

↑

▷ Содержание

⇐ ПредыдущаяСтр 4 из 7Следующая ⇒

Practical part

Students write down the basic terms and concepts in the workbook. Fill in the gaps:  

Parasitic system _______________________________________________________

Parasitocenosis_________________________________________________________________

Extensity of an invasion_________________________________________________

Intensity of an invasion _________________________________________________

Abiotic factors________________________________________________________

Biotic factors _________________________________________________________

Anthropogenic factors __________________________________________________

Vectors. Often the parasites cannot be transmitted from one host to another unless there is an organism that actively transports them. Arthropods (insects, ticks) that transfer the parasitic agents from one host to another are called vectors. Vectors are biological (specific) and mechanical.

The biological vector is a blood sucking insect or tick that is essential in the life cycle of parasite. It can be a definitive host (Anopheles mosquito for plasmodium) or an intermediate host (like the tse-tse fly for Trypanosoma brucei).

Mechanical vector is unessential in life cycle of the parasite, and the insect (non-bloodsucking) mechanically transfers it, e.g. flies can transport cysts of amoeba, or eggs of Ascaris, etc.

Task 1. Examples of simple and complex parasitic systems, fill out Table 1.

Example of a simple two members of the parasitic system – (Ascaris lumbricoides – man); simple three members – (rickettsia Provacek – louse – man); complex two members – (Balantidium sp. – man, pig); complex three members (Dirofilaria repens – mosquitoes genera Anopheles, Aedes, Culex – dog, man).

Table 1. Types of parasitic systems

Types of parasitic systems

Parasite(s)

Vector

Host/hosts

simple

two members

three members

complex

two members

three members

Task 2. Examples of highly specific and low specific parasites, Fill out Table 2.

Specificity of the parasite is degree of a historically formed adaptation to certain hosts. Its types are:

a) hostal specificity: monohostal parasites have one species of the host (Ascaris lumbricoides), polyhostal parasites have hosts of several species (trichinella);

b) topical specificity (a site of parasitizing): Ascaris lumbricoides lives in intestine, head louse ‒ on the hairy region of the head and etc.;

c) age specificity: enterobiasis in more common for children;

d) seasonal specificity: outbreaks of amebic dysentery are more typical for the end of spring and summer).

Table 2. Specificity of the parasite

Specificity of the parasite

Parasite(s)

Host/hosts

The name of the disease, its epidemiological characteristics

highly specific

low specific

1. The Parasitism ‒ such a cohabitation of different kinds of organisms, at which: a) organisms receive mutual benefit; b) the individual of one species uses the individual of other species only as habitation; c) the individual of one species uses the individual of other species as habitation and the source of nutrition, not causing any harm; d) the individual of one species uses the individual of other species as dwelling and the source of nutrition and harms her; e) none of the organisms receive any benefit.

2. Examples of parasites progressive morpho-physiological adaptation are: a) the presence of organs of bracing and special integuments of a body (the cuticle, tegument); b) simplification of the nervous system a constitution and sense organs; c) molecular «mimicry» and anti-enzymes discharge; d) a reduction of the tape worms alimentary system; e) a high fertility and intricit development of cycles.

3. The vectors can be the following types: a) temporary; b) specific; c) obligate; d) facultative; e) mechanical.

4. The adaptation of parasite to parasitism is expressed by: a) behavioral changes of host; b) sexual reproduction; c) synchronization of life cycles; d) toxic effect; e) high fertility.

5. The parasite cannot have the following effect on the host organism: a) mechanical; b) hypervitaminosis; c) anemia; d) toxic.

6. In which level the host organism cannot response to parasite? a) humoral; b) neural; c) cellular; d) tissue.

7. Which of the followings is not a strategy against host immune response? a) intracellular location of parasite; b) cellular reaction of host; c) antigenic masking; d) different morphological stages of parasite in host organism.

8. What kind of relationship of organisms, one feeds on the remains of the other's food? a) parasitism; b) predation; c) commensalism; d) mutualism.

9. Antigenic variation is exhibited by: a) Entamoeba; b) Schistosoma; c) Trypanosoma; d) Leishmania.

10. Pathogenicity of a parasite does not depend on: a) host’s genotype and environmental factors; b) parasite’s genotype; c) host’s education and social status; d) body height of the host; e) presence of other parasites in the host.

Познавательные статьи:



Техника прыжка в длину с разбега

Организация работы процедурного кабинета

Области применения синхронных машин

Оптимизация по Винеру и Калману