Fungi: A- Exam IV Flashcards
(105 cards)
1
Q
What are three main characteristics of fungi?
A
- Eukaryotes
- Spore-forming
- No chlorophyll
2
Q
List the oxygen requirements of fungi:
A
most are aerobic, some facultative and strict anaerobes
3
Q
The cell wall of fungi usually contains:
A
chitin
4
Q
polysaccharide containing N-acetyl glucosamine (NAG)
A
chitin
5
Q
What are the two growth forms of fungi?
A
- filamentous (molds)
- unicellular (yeasts)
6
Q
Filamentous fungi (molds), have threadlike filaments called:
A
hyphae
7
Q
Mass of hyphae:
A
mycelium
8
Q
What are the two categories of hyphae found in filamentous fungi?
A
septate vs. coenocytic
9
Q
Septate vs. coenocytic hyphae describe:
A
the crosswalls
10
Q
Filamentous fungi grow by:
A
extension of tip and branching
11
Q
Describe the cells of unicellular fungi (yeasts):
A
single ovoid or spherical cells
12
Q
How do unicellular fungi (yeasts) reproduce?
A
asexually by cell division (budding) or sexually by cell fusion and spore formation
13
Q
Asexual reproduction of fungi can be by:
A
cell division (budding) (transverse division), or spore formation
14
Q
Some yeast-forms of fungi perform asexual cell division by ____, others by ___.
A
budding; transverse division (fission)
15
Q
sexual reproduction of fungi involves production of:
A
sexual spores
16
Q
sexual reproduction of fungi involves production of sexual spores by:
A
meiosis of a diploid cell
17
Q
Form producing asexual spores, often mold-like growth form:
A
anamorph
18
Q
Form producing sexual spores, typically a fruiting body:
A
teleomorph
19
Q
ability to grow as yeast form or mold form:
A
dimorphism
20
Q
Many pathogenic fungi are:
A
dimorphic
21
Q
Although many pathogenic fungi are dimorphic, ___ form more typical at human body temp
What is an exception to this? Why?
A
yeast
candida; both forms of candida exist inside and outside the body
22
Q
Both forms of ____ exist inside and outside the body
A
candida
23
Q
Candida forms ___ & ___
A
psuedohyphae & pseydomycelia
24
Q
Hyphal growth is a modified budding where newly budded cells remain attached to mother cell
A
psuedohyphae
25
Some pathogenic fungi such as aspergillum and cryptococcus neoformans are not:
dimorphic
26
A pathogenic fungi that is not dimorphic as it exists in mold form only:
aspergillus
27
A pathogenic fungi that is not dimorphic as it exists in yeast form only:
cryptococcus neoformans
28
Diseases caused by fungus or mold:
mycoses
29
Fungal infections are classified by affected area of body such as:
- superficial
- cutaneous
- subcutaneous
- systemic
30
The primary mechanisms for the human body to fight fungi:
1. neutrophil phagocytosis and killing
2. T-cell mediated immunity
31
Fungal infections of keratinized outer layers of skin, hair, and nails:
superficial mycoses
32
Superficial mycoses are typically ___ with ___
mild infections with minimal inflammatory repsonse
33
Describe the treatment for superficial mycoses:
easy to treat or clears without treatment
34
Fungal infections of the hair shaft:
piedras
35
Give an example of a piedra:
trichosporon beigelii
36
Trichosporon beigelli may also be referred to as:
shite peidra
37
Fungal infections involving outer layer of skins, hair, and nails:
tineas
38
Give examples of a tinea infection:
Malassezia furfur
39
Malassezia furfur may also be referred to as:
pityriasis versicolor
40
Most tineas and piedras occur in the:
tropics
41
What are the most common superficial mycoses?
- pityriasis versicolor
- white piedra
42
What type of disease is pityriasis versicolor?
tinea
43
Where is pityriasis versicolor found?
worldwide
44
describe pityriasis versicolor:
pigmented macules- not elevated but altered color
45
Where is M. furfur (pityriasis versicolor) NOT found?
not in the environment
46
What is the transmission of M. furfur (pityriasis versicolor):
human-to-human
47
Fungal infections of the keratinized outer layers of skin, hair, and nails eliciting a more prominent host repose:
cutaneous mycoses
48
For cutaneous mycoses skin infections, describe what layers are invaded:
No invasion beyond stratum corneum (outermost layer of epidermis)
49
What are the similarities between superficial mycoses and cutaneous mycoses?
What are the differences?
similarities- they both effect the keratinized outer layers of skin, hair, and nails
Differences- more apparent host response elicited with cutaneous mycoses
50
List some common dermpahytes that may cause cutaneous mycoses:
1. microsporum
2. trichophytdon
3. epidermophyton
4. keratiophilic & keratinolytic
51
Dermaphytes may cause:
tineas (ringworm)
52
Tinea pedis is responsible for:
athletes foot
53
Tinea cruris is responsible for:
jock's itch
54
Ringworm is characterized by:
ring of inflammatory scaling
55
What is the transmission of ringworm/tinea:
person-to-person
56
Some dermaphytes are ____ while others are ___
soil organisms; zoonosis
57
Dermaphytes are diagnosed by:
microscopy of samples
58
Fungal infection of the dermis and subcutaneous tissue:
subcutaneous mycoses
59
Subcutaneous mycoses do not respond well to:
anti fungal chemotherapy
60
What is the proper treatment for subcutaneous mycoses?
Need to excise
61
Sporotrichosis is caused by what organism?
sporothrix schenkii
62
Sporothrix shcenkii (causative agent of sportrichosis) comes from:
thorns and splinters
63
What is the treatment for sporotrichosis and what are the downfalls?
treatment - oral potassium iodide
downfalls- adverse side effects such s nausea and salivary gland enlargement
64
fungal infections that invade internal organs:
systemic mycoses
65
Systemic mycoses are caused by:
endemic dimorphic fungal pathogesn
66
A fungal organism living on dead or decaying matter:
saprobe
67
Histoplasma capsulate is responsible for:
histoplasmosis
68
Blastomyces dermatitis is responsible for:
blasomycosis
69
Coccidiodes immitis is responsible for:
coccidiomycosis
70
The saprobic phase at 25 degrees Celsius involves what form of fungus?
mold or mycelial form
71
The parasitic phase at 37 degrees Celsius (of saprobes) involves what form of fungus?
yeast form
72
A spherule can be described as:
100s of endospores
73
fungus from bird or bat droppings:
histoplasmosis capsulatum
74
Histopasma capsulatum has a high ___ content
nitrogen
75
How is histoplasma capsulate acquired?
inhalation of conidia
76
With histoplasma capsulatum, the organism remains:
viable within macrophages
77
How does histoplasma capsulatum remain viable within macrophages?
modulates the pH of the phagolysosome
78
Describe the role of antibodies in histoplasma capsulatum:
antibodies play no role in resolution
79
What is important for the immunity against histoplasma capsulatum?
cell-mediated immune system of CD4 T-lymphocytes and activated macrophages
80
Describe primary infections with histoplasma capsulatum:
primary infection most often asymptomatic
81
What may develop in cases of histoplasma capsulatum?
granulomas
82
Describe the granulomas that may develop in a histplasma capsulatum infection:
develop in the lung with caseous necrosis (plus calcification)
83
Can reactivation occur with histoplasma capsulatum infections?
Yes- years later
84
What is the treatment for infection of histoplasma capsulatum?
3-12 months of antifungal agent
85
Fungal species found in decaying matter (such as leave litter)
blastomyces dermatiditis
86
How might once acquire blastomyces dermatiditis?
acquired by inhalation of conidia
87
What are important for the immunity against blastomyces dermatiditis?
cell-mediated immune system of CD4 T-cells, lymphocytes and activated macropahges
88
What percent of primary infections are accompanied by symptoms with fungal infection of blastomyces dermatiditis?
less than 50%
89
What may develop with infection of blastomyces dermatiditis?
granulomas + calcification
90
Can reactivation occur with blastomyces dermatiditis infection?
Yes- years later
91
What are the hallmark for disease caused by blastomyces dermatiditis?
cutaneous lesions (heaped up borders and small, central micro abscesses)
92
Describe the cutaneous lesions that are the hallmark forblastomyces dermatiditis:
heaped up borders and small, central microabscesses
93
How is blastomyces dermatiditis diagnosed?
histopathological examination (they're looking for thick-walled yeasts with single broad-based bud)
94
What is the treatment for fungal infection with blastomyces dermatiditis?
6-12 months of anti fungal agent
95
What region of the US can coccidioides immitis be found?
Southwestern USA (lower Sonoran life zone)
96
coccidioides immitis is characterized by huge:
blooms
97
What is the primary target for coccidioides immitis?
lungs
98
The primary target for coccidioides immitis is the lungs but the fungus spreads:
through the circulatory system and infects many organs
99
Discuss the symptoms for fungal infection of coccidioides immitis:
usually no symptoms
100
Why are there typically no symptoms with coccidioides immitis?
cell-mediated immunity
101
If symptoms are present with coccidioides immitis, what might present?
1. acute pulmonary infection
2. arthralgias and skin lesions
3. desert rheumatism or valley fever
4. disseminated coccidiomycosis
5. chronic meningitis (ion to treated=fatal)
102
acute pulmonary infection
arthralgias and skin lesions
desert rheumatism or valley fever
disseminated coccidiomycosis
chronic meningitis (ion to treated=fatal)
These conditions may all clinically present in cases with fungal infection with:
coccidioides immitis
103
Desert rheumatism and valley fever are characteristic of:
coccidioides immitis
104
What is the histopathology of coccidioides immitis?
presence of spherules
105
What is the treatment for coccidioides immitis?
anti-fungal for 12-24 months
