Fungi A (EXAM IV) Flashcards
(106 cards)
1
Q
List three main characteristics of Fungi:
A
- Eukaryotes
- Spore-forming
- No chlorophyll
2
Q
List the oxygen requirements of most fungi:
A
Most are aerobic, some facultative & 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 such as 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 & branching
11
Q
Describe the cells of unicellular fungi such as 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 & spore formation
13
Q
Asexual reproduction of fungi can be by:
A
Cell division (budding or 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 may pathogenic fungi are dimorphic, _____ form is more typically at human body temp
What is an exception to this? Why?
A
Yeast; candida; both forms of candida exist inside & outside the body
22
Q
Both forms of _____ exist inside & outside the body:
A
Candida
23
Q
Candida forms ____ & ____
A
Pseudohyphae & Pseudomycelia
24
Q
Hyphal growth is a modified budding where newly budded cells remain attached to mother cell:
A
Pseudohyphae
25
Some pathogenic fungi such as Aspergillus & Cryptococcus neoformans are not:
Dimorphic
26
A pathogenic fungi that is not dimorphic as it exists as mold form only:
Asperfillus
27
A pathogenic fungi that is not dimorphic as it exists as 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:
1. Superficial
2. Cutaneous
3. Subcutaneous
4. Systemic
30
The primary mechanisms of the human body to fight fungi:
1. Neutrophil phagocytosis/killing
2. T-cell mediated immunity
31
Fungal infections of keratinized outer layers of skin, hair & nails:
Superficial mycoses
32
Superficial mycoses are typically ____ with _____
Mild infections with minimal inflammatory response
33
Describe the treatment of superficial mycosis:
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 beigelii may also be referred to as:
White piedra
37
Fungal infections involving outer layers of skin, hair & nails:
Tineas
38
Give examples of a tinea infection:
Malassezia furfur
39
Malassezia furur may also be referred to as:
Pityriasis versicolor
40
Most tineas & piedras occur in the:
Tropics
41
What are the most common superficial mycosis?
-Pityriasis versicolor
-White piedra
42
What type of disease is Pityriasis Versicolor?
Tinea
43
Where is Pityriasis Versicolor found?
World-wide
44
Describe Pityriasis Versicolor:
Pigmented macules- not elevated but altered color
45
Where is M. Furur (Pityriasis Versicolor) not found?
Environment
46
Discuss the transmission of Pityriasis Versicolor (M. Furfur)?
Human-to-human
47
Fungal infection of the keratinized outer layers of skin, hair & nails eliciting a more prominent host response:
Cutaneous mycoses
48
For cutaneous mycoses skin infections, describe the layers that are invaded:
No invasion beyond stratum corneum (outermost layer of epidermis)
49
What are the similarities between superficial mycoses & cutaneous mycoses? What are the differences?
Similarities: they both affect the keratinized outer layers of skin, hair & nails
Differences: Cutaneous mycoses elicit a more apparent immune response
50
List some common dermaphytes that may cause cutaneous mycoses:
1. Microsporum
2. Trichophyton
3. Epidermophyton
4. Keratinophilic & keratinolytic
51
Dermaphytes may cause:
Tineas (ringworm)
52
Tinea pedis is responsible for:
Athletes foot
53
Tinea cruris is responsible for:
Jocks 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 _______ others are _____
soil organisms; zoonoses
57
Dermaphytes are diagnosed by:
Microscopy of samples
58
Fungal infections of the dermis & subcutaneous tissue:
Subcutaneous mycoses
59
Subcutaneous mycoses do not response well to:
Antifungal chemotherapy
60
What is the proper treatment for subcutaneous mycoses?
Need to excise
61
Sporotrichosis is caused by the organism:
Sporothrix schenkii
62
Sporothrix shcenkii (causitive agent of sporotrichosis) comes from:
Thorns & splinters
63
What is the treatment for sporptrichosis & what are the downfalls to this?
Oral potassium iodide; downfalls include adverse side effects such as nausea & salivary gland enlargement
64
Fungal infections that invade internal organs:
Systemic mycosis
65
Systemic mycosis are caused by:
Endemic dimorphic fungal pathogens
66
A fungal organisms living on dead or decaying matter:
Saprobe
67
Histoplasma capsulatum is responsible for:
Histoplasmosis
68
Blastomyces dermatitis is responsible for:
Blastomycosis
69
Coccidioides immitis is responsible for:
Coccidiodomycosis
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 sap robes involves what form of fungus?
Yeast form
72
A spherule can be described as:
100s of endospores
73
Fungus from bird or bat droppings:
Histoplasma capsulatum
74
Histoplasma capsulatum has a high _____ content
Nitrogen
75
How is histoplasma capsulatum acquired?
Inhalation of conidia
76
With histoplasma capsulatum the organisms remains:
Viable within macrophages
77
How does histoplasma capsulatum remain viable within macrophages?
Modulate pH of 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 & activated macrophages
80
Describe primary infections with histoplasma capsulatum:
Primary infections are most often asymptomatic
81
What may develop in cases of histoplasma capsulatum?
Granulomas
82
Describe the granulomas that may develop in a histoplasma capsulatum infection:
Granulomas develop in the lung with caseous necrosis (plus calcification)
83
Can reactivation occur with histoplasma capsulatun infections?
Yes- years later
84
What is the treatment for fungal infections of histoplasma capsulatum:
3-12 months of anti-fungal agen
85
Fungal species found in decaying matter (such as leave litter):
Blastomyces dermatiditis
86
How might one acquire blastomyces dermatiditis?
Acquire by inhalation of conidia
87
What are important for the immunity against blastomyces dermatiditis?
Cell-mediated immune system of CD4 T-cells, lymphocytes & activated macrophages
88
What percent of primary infections are accompanied by symptoms with fungal infection of blastomyces dermatiditis:
Less than 50%
89
What may develop in fungal infection of blastomyces dermatiditis:
Granulomas (plus calcification)
90
Can reactivation occur with blastomyces dermatiditis fungal infection?
Yes- years later
91
What is the hallmark for disease caused by blastomyces dermatiditis?
Cutaneous lesions (heaped up orders & small central microabscesses)
92
Describe the cutaneous lesions that are the hallmark for blastomyces dermatiditis fungal infection:
Heaped up borders & small central microabcscesses
93
Describe the cutaneous lesions that are the hallmark for blastomyces dermatiditis fungal infection:
Heaped up borders & small central microabcscesses
94
How is blastomyces dermatiditis fungal infection diagnosed?
Histopathological examination (looking for thick-walled yeasts with single broad-based bud)
95
What is the treamtment for fungal infection with blastomyces dermatiditis:
3-12 months of antifungal agent
96
What region of the US can coccidioides immitis be found?
Southwestern USA (lower sonaran life zone)
97
Coccidioides immitis is characterized by:
Huge blooms
98
What is the primary target for coccidioides immitis?
Lung
99
The primary target for coccidioides immitis is the lungs, but the fungus spreads:
Through the circulatory system & infects many organs
100
Discuss the symptoms caused by fungal infection with coccidioides immitis:
Usually no symptoms
101
Why are their typically no symptoms accompanied by infection with coccidioides immitis?
Because of cell-mediated immunity
102
If symptoms are present with coccidioides immitis, what might present?
1. Acute pulmonary infections
2. Arthralgias & skin lesions
3. Desert rheumatism or valley fever
4. Disseminated coccidiomycosis
5. Chronic meningitis (if not treated = fatal)
103
Acute pulmonary infections
Arthralgias & skin lesions
Desert rheumatism or valley fever
Disseminated coccidiomycosis
Chronic meningitis (if not treated = fatal)
These conditions may all clinically present in cases of fungal infection with:
coccidioides immitis
104
Desert rheumatism & valley fever are characteristic of:
coccidioides immitis fungal infection
105
What is the histopathology of coccidioides immitis?
Presence of spherules
106
What is the treatment for coccidioides immitis?
Antifungal for 12-24 months
