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Parasitology [LEC] > MODULE 2 UNIT 1 > Flashcards

MODULE 2 UNIT 1 Flashcards

1
Q

one of the three major groups of parasites that are of medical importance to man

A

Protozoa

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2
Q

performs all the functions of life, i.e., reproduction, respiration, excretion, etc.

A

single cell unit

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3
Q

carried on by specialized cells

A

higher organisms

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4
Q

They have remarkable range in size and form, some visible to the naked eye, while others require magnification up to a thousand fold before they can be seen. INTRODUCTION

A

Protozoa

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5
Q

Some are spherical or ovoidal, while others have bizarre contours.

A

Protozoa

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6
Q

are found in all moist habitats

A

Protozoa

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7
Q

Protozoa are common in

A

sea, in soil and in fresh water.

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8
Q

“first animal”

A

‘protos’ and ‘zoon’

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9
Q

they often possess animal-like behaviors, such as motility at some stage of their life cycle

A

“one-celled animals”

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10
Q

three phyla of protozoa of medical interest in humans

A

• Phylum Sarcomastigophora • Phylum Ciliophora •Phylum Apicomplexa

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11
Q

includes subphylum Sarcodina, and, subphylum Mastigophora

A

Phylum Sarcomastigophora

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12
Q

T or F: Although, protozoa exhibit marked diversity in size, shape, and other characteristics, there are fundamental characteristics common to the entire group.

A

TRUE

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13
Q

The structure of a protozoan cell is composed of

A

(1) cytoplasmic body, and (2) a nucleus

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14
Q

The various life functions are carried out by specialized intracellular structures known as

A

organelles

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15
Q

consists of a thin outer ectoplasm and a voluminous inner endoplasm

A

cytoplasm

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16
Q

very complex in electron microscope

A

cytoplasm

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17
Q

appears more transparent, less granular, and more homogeneous

A

Ectoplasm

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18
Q

It is covered with plasma membrane that is like those found in all cells.

A

Ectoplasm

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19
Q

functions of cytoplasm

A

movement, respiration, procurement of food, discharge of metabolic wastes, and protection

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20
Q

The locomotory organelles of protozoa arise from the

A

ectoplasm

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21
Q

are temporary extensions of the ectoplasm and are found in amoebas under the subphylum Sarcodina

A

Pseudopodia

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22
Q

are long, slender, whiplike structures seen in subphylum Mastigophora

A

Flagella

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23
Q

subphylum Mastigophora are also called

A

flagellates

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24
Q

T or F: They may have one or more than one flagellum, and these may be inserted into the cell at different angles.

A

TRUE

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25
Q

structurally similar to flagella but shorter and covering the entire surface of the body

A

Cilia

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26
Q

seen in phylum Ciliophora (locomotory structure)

A

Cilia

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27
Q

do not exhibit an obvious mode of mobility but can glide nonetheless

A

Protozoa in phylum Apicomplexa

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28
Q

is a lateral expansion of the plasma membrane with a flagellar rim extending out like a fin along the outer edge of the body of certain flagellates

A

Undulating membrane

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29
Q

Food may be taken in at any place in the [?] or ingested at a particular point.

A

cytoplasm

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30
Q

function for feeding by phagocytosis

A

Pseudopodia in amoebas

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31
Q

a ciliate; food passes directly into a specialized “cell mouth” structure which is located near the anterior end of the body

A

Balantidium coli

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32
Q

specialized “cell mouth” structure which is located near the anterior end of the body

A

cytostome

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33
Q

excretion of undigested particles are discharged at the general surface or through a specialized “ cell anus”

A

cytopyge

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34
Q

Certain protozoa at times enter an inactive cystic state, in which they secrete a membranous

A

cyst wall

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35
Q

It is necessary for the protection and survival outside the body and against the acidic digestive juices of the gastrointestinal tract.

A

cyst wall

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36
Q

consists of a moderately dense granular protoplasm that immediately surrounds the nucleus

A

endoplasm

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37
Q

functions of endoplasm

A

metabolism and nutrition, and storage of food

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38
Q

endoplasm contains which organelles?

A

mitochondria, Golgi apparatus, microbodies, and endoplasmic reticulum

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39
Q

endoplasm may also contain:

A

contractile vacuoles, food vacuoles, food reserves, and foreign bodies

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40
Q

acts as osmoregulators

A

contractile vacuoles

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41
Q

hypertonic to their environment; they imbibe water continuously by osmosis

A

Freshwater protozoa

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42
Q

collects excess water in their cytoplasm and pumps them out of the cell

A

contractile vacuoles

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43
Q

these species maintain a reserve food supply such as glycogen vacuole and chromatoidal bodies

A

immature amoebic cysts

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44
Q

represents the main storage form of glucose

A

Glycogen vacuole

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45
Q

n wet mount preparation, they are demonstrated by staining a brown color with iodine solution.

A

Glycogen vacuole

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46
Q

are dense structures which are made up of crystalline RNA and RNA-binding proteins

A

Chromatoidal bodies (or bars)

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47
Q

has chromatoid bodies with blunt, rounded ends in an unstained concentrated wet mount of stool

A

Cyst of Entamoeba histolytica/dispar

48
Q

may show food vacuoles or inclusions such such as red blood cells , bacteria, or other ingested materials

A

Endoplasm of some protozoa

49
Q

ingestes erythrocytes (arrow), under differential interference contrast (DIC) microscopy

A

Trophozoite of Entamoeba histolytica

50
Q

contains the chromosomes that are essential for life, reproduction, and genetic composition of the organism

A

nucleus

51
Q

It is bounded externally by a well-defined nuclear membrane similar to that of most eukaryotic cells.

A

nucleus

52
Q

two types of nucleus among the protozoa

A

a. Vesicular nucleus; b. Compact nucleus

53
Q

is found in most protozoa

A

Vesicular nucleus

54
Q

characterized by an irregular distribution of chromatin materials that clear areas are apparent in the nucleoplasm

A

Vesicular nucleus

55
Q

The chromatin granules may line the inner side of the nuclear membrane forming the

A

peripheral chromatin or linin
network of fibrils

56
Q

radiating towards the periphery of the nucleus

A

linin network of fibrils

57
Q

Inside the nucleus is a single mass or aggregate of dense chromatin

A

karyosome (AKA endosome),

58
Q

may be located centrally or eccentrically

A

karyosome (AKA endosome),

59
Q

may be surrounded by chromatin particles that appear to be arranged in an achromatic network

A

karyosome (AKA endosome),

60
Q

found in a few protozoa only, primarily in ciliates

A

Compact nucleus

61
Q

chromatin granules are dense so that there are no clear areas of nucleoplasm observed in light microscopy, although present

A

Compact nucleus

62
Q

ingestes erythrocytes stained with trichrome

A

Trophozoite of Entamoeba histolytica

63
Q

The ingested erythrocytes appear as

A

dark inclusions

64
Q

central nuclei

A

typical small, centrally located karyosome

65
Q

peripheral nuclei

A

thin, uniform peripheral chromatin

66
Q

The space between the karyosome and the nuclear membrane is traversed by a fine thread of linin network having a specific arrangement

A

“spokes wheel”

67
Q

two developmental stages commonly encountered in protozoa

A

(1) trophozoite; (2) cyst

68
Q

are the motile forms

A

Trophozoites

69
Q

are the nonmotile forms; resting

A

Cysts

70
Q

They are the vegetative stage, i.e, they have reproductive powers, and the feeding stage, some feeding on host cells

A

Trophozoites

71
Q

responsible for the pathogenic effects in the host

A

Trophozoites

72
Q

they are delicate and do not survive long outside the host

A

Trophozoites

73
Q

They are bounded by tough cell wall so they show considerable resistance in unfavorable environment.

A

Cysts

74
Q

closely associated with transfer from host to host and constitutes the infective stage of most of the protozoa

A

Cysts

75
Q

In apicomplexans, the cystic form is an

A

oocyst

76
Q

The protozoa possess the property of being transformed from the active trophozoite stage to an inactive cyst stage, losing its:

A

power of motility, growth and reproduction, and enclosing itself in a tough wall

77
Q

Conditions favoring encystment, in most cases, involve some adverse environmental events such as:

A

• nutritional deficiency • desiccation • pH or temperature changes • increased tonicity • decreased oxygen concentration • overpopulation

78
Q

When the condition becomes favorable again, the organism leaves the [?] and continues its life cycle in the [?]

A

cyst stage; trophozoite stage

79
Q

Mechanisms for excystation may include:

A

• absorption of water with consequent swelling of the cyst • secretion of lytic enzymes by the protozoan • action of host digestive enzymes on the cyst wall

80
Q

T or F: Note, however, that both processes, encystation and excystation, occur only within the host.

A

TRUE

81
Q

Trophozoites that are passed in feces during diarrhea, in unfavorable condition outside the host, do NOT encyst but [?], thus must be examined or preserved within a short time after passage.

A

disintegrate

82
Q

Cysts are passed in [?] stool.

A

semi-formed or formed

83
Q

[?] to another susceptible host is required so that they can continue their life cycle and grow as trophozoite stage.

A

Transference

84
Q

Protozoan reproduction may be either [?], or alternate the two types in their life cycles.

A

asexual or sexual

85
Q

Most often asexual reproduction is by

A

binary fission

86
Q

one individual divides into two of more or less equal parts

A

binary fission

87
Q

The plane of fission in amoebas

A

random

88
Q

The plane of fission in flagellates

A

longitudinal

89
Q

The plane of fission in ciliates

A

transverse

90
Q

occurs in Apicomplexa, as in the malaria parasite in the genus Plasmodium

A

Multiple fission

91
Q

the nucleus and other essential organelles divide repeatedly followed by cytokinesis (cytoplasmic division)

A

Multiple fission

92
Q

a large number of daughter cells are produced almost simultaneously

A

Multiple fission

93
Q

A type of multiple fission is

A

schizogony

94
Q

Cells undergoing schizogony are called

A

schizonts or meronts

95
Q

When the multiplication is completed, the schizont ruptures and liberates daughter cells called merozoites, to initiate another phase of

A

merogony or gametogony

96
Q

schizogony producing more asexually reproducing merozoites

A

merogony

97
Q

gametocyte formation

A

gametogony

98
Q

Another type of multiple fission often recognized is

A

sporogony

99
Q

Another type of multiple fission often recognized is

A

sporogony

100
Q

products of sporogony are

A

sporozoites in resistant oocysts

101
Q

sexually differentiated cells, called gametes unite permanently and a complete fusion of the nuclear material takes place

A

Syngamy

102
Q

gametes

A

female macrogamete, and male microgamete

103
Q

The resulting product of Syngamy

A

zygote

104
Q

Cells that produce macrogametes and microgametes are the gametocytes or gamonts formed by

A

gametogony

105
Q

only the nuclei unite, is found only among ciliates

A

Conjugation

106
Q

Later on, the two organisms separate, each being rejuvenated during the process, although probably not essential for perpetuation of the species.

A

Conjugation

107
Q

two major methods of transmission of protozoal infection:

A

through ingestion of the infective stage of the protozoa or via an arthropod vector

108
Q

few transmission of protozoal infection involve

A

sexual contact

109
Q

T or F: The mode of transmission is non-specific for each species.

A

FALSE = specific

110
Q

T or F: Protozoa, similar to worms, multiply in their hosts, so disease can result from infection initiated by only a few organisms.

A

FALSE = in contrast

111
Q

Pathologic changes are due to [?] by the parasite itself or its products.

A

invasion and destruction of cells or tissues

112
Q

T or F: Tissue damage primary to immune response, or immunopathology, may occur.

A

FALSE = secondary

113
Q

Generalized systemic symptoms are common. Give examples.

A

fever, and signs like splenomegaly and lymphadenopathy

114
Q

The early stage of infection may be asymptomatic or it may be severe, leading to death or into a chronic latent stage, with relapses at times before eventual recovery.

A

FALSE = subclinical

115
Q

The diagnosis of some diseases, may be strongly suspected on clinical grounds from characteristic signs and symptoms. Give examples.

A

malaria or leishmaniasis

116
Q

clinical impressions should always be confirmed by [?] that identified the parasite in the specimen

A

laboratory diagnosis

Parasitology [LEC] (23 decks)

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