Day 4.2.1 Flashcards
1
Q
What is the first step in the replicative cycle of viruses?
A
attachment through a receptor
2
Q
what are the specific receptors for hiv
A
cd4 on t cells
3
Q
what are the specific receptors for rhinoviruses
A
ICAM on upper respiratory epithelial cells
4
Q
what are the specific receptors for polio virus
A
immunoglobulin-like receptors
5
Q
how do viruses enter a cell
A
after binding to specific recpetors - 2 methods -
receptor mediated endocytosis
membrane fusion
6
Q
what method does influenza virus enter a cell with
A
receptor mediated endocytosis
7
Q
what method do paramyxoviruses enter cells with
A
membrane fusion
8
Q
name two viruses that enter cells through membrane fusion
A
herpesviruses
paramyxoviruses
9
Q
name two viruses that enter a cell by receptor mediated endocytosis
A
influenza
adenovirus
10
Q
how is uncoating of viruses triggered
A
by pH changes in endosomes
11
Q
name a virus that undergoes uncoating due to pH changes
A
influenza A virus
12
Q
name the processes by which viruses replicate and produce viral protein
A
transcription
translation
13
Q
where do all dna viruses replicate
A
nucleus
14
Q
what is the exception in dna viruses wrt site of replication
A
poxviruses (cytoplasm)
15
Q
what enzyme do dna viruses use to replicate
A
host cell rna polymerase
16
Q
where do all rna viruses replicate
A
in the cytoplasm of host cell
17
Q
what enzyme do rna viruses use to replicate
A
own rna polymerase
18
Q
what are the exceptions wrt site of replication in rna viruses
A
retroviruses
orthomyxoviruses
19
Q
what are the steps in replicative cycle of viruses
A
attachment entry uncoating replication and viral protein production asssembly release
20
Q
how are replicated viruses released from host cell?
A
2 methods
- budding
- host plasma membrane rupture
21
Q
phases of one step growth analysis
A
- adsorption of virus
- eclipse phase
- synthetic phase
- latent period
22
Q
how long does eclipse phase last
A
10-12 hours
23
Q
what does the eclipse phase correspond to
A
the period during which the input virus becomes uncoated
24
Q
what is the peculiar feature of the eclipse phase
A
no infectious virus can be detected during this time because it is undergoing uncoating
25
when does the synthetic phase start
around 12 hours post-infection
26
what does synthetic phase correspond to
the time during which new virus particles are assembled
27
during what period can no extracellular virus be detected?
latent period
28
what characteristics do orthomyxoviruses and paramyxoviruses share
spherical shape
single stranded rna
hemagglutinin
negative sense rna
29
what is the cytopathic effect of paramyxoviruses
syncytia formation
30
What virus doesn't cross placenta?
measles
31
list viruses that cross placenta
rubella
herpes
hiv
cmv
32
viruses that cause respi disease in children
respiratory syncytial virus
parainfluenza viruses 1-4
rhinoviruses
adenoviruses
33
common viral causes of pharyngitis
coxsackievirus a
adenoviruses
orthomyxoviruses (influenza viruses)
EBV
34
common causes of viral gastroenteritis
rotavirus
noroviruses
sapoviruses
adenoviruses and astroviruses
35
what is the most common cause of viral gastroenteritis in children
rotavirus
36
noroviruses aka
norwalk virus
37
common cause of viral gastroenteritis in adults
adenoviruses and astroviruses
38
viruses that cause common cold
rhinoviruses
coronaviruses
adenoviruses
coxsackieviruses
39
most common pediatric viral diseases with a rash
```
measles
rubella
roseola (hhv 6)
erythema infectiosum
vzv
```
40
most common causes of aseptic meningitis
coxsackievirus
echoviruses
mumps viruses
41
what are the only dsRNA viruses
reoviruses
42
what are the most common cause of infectious diarrhea in infants and young children
rotaviruses
43
most common human disease caused by an arbovirus
dengue fever
44
most common cause of epidemic encephalitis
Japanese encephalitis virus
45
most common viral cause of mental retardation in US
cmv
46
which family comprises the genera rubiviruses and alphaviruses?
togaviruses
47
example of rubiviruses
rubella virus
48
example of alphavirus
arthropod borne viruses
49
how is rubella virus different from other togaviruses?
respiratory virus
| does not cause readily detectable cytopathologic effects
50
five classic childhood exanthems
```
rubella
measles
roseola
fifth disease
chickenpox
```
51
typical picture of rubella
maculopapular rash that appears first on face and neck then quickly spreads to trunk and upper extremities then to legs
52
what disease shows first distinct then flushed appearance of lesions
rubella
53
what is the onset of rash accompanied by in rubella
low grade fever
54
how long does the rash in rubella last
3-5 days
55
rubella aka
3 day measles
56
how long does fever persist
not more than 24 hours
57
most prominent and characteristic symptom of rubella
lymphadenopathy of postauricular, occipital and posterior cervical lymph nodes
58
can lymphadenopathy in rubella occur in absence of rash
yes
59
what can be the effects of rubella infection during pregnancy
stillbirth
spontaneous abortion
congenital rubella syndrome
60
congenital rubella syndrome classical triad
cataracts
heart defects
deafness
61
how is staph aureus different from other staph
coagulase positive
62
how does s aureus infection begin
by traumatic inoculation of organism
63
what kinds of skin lesions do s aureus cause
boils
carbuncles
impetigo
scalded skin syndrome
64
what other than skin lesions do s aureus cause
```
abscesses
sepsis
osteomyelitis
pneumonia
endocarditis
food poisoning
toxic shock syndrome
```
65
what kind of toxins does s aureus produce
cytolytic
exfoliative
enterotoxins
toxic shock syndrome toxin
66
name the cytolytic toxins produced by s aureus
```
alpha
beta
delta
gamma
Panton-Valentine leukocidin
```
67
name the exfoliative toxins produced by s aureus
A
| B
68
name the enterotoxins produced by s aureus
A - E, G, I.
69
superantigens
toxins (polypeptides) that bind to class ii MHC molecules on macrophages --- interact with specific T cell receptors --- massive release of cytokines by both macrophages and T cells
70
name 3 superantigens
Exfoliative toxin A
enterotoxins
TSST 1
71
what forms of coagulase do s aureus strains contain
2 - bound and free
72
function of bound coagulase
it is bound to the cell wall and can directly convert fibrinogen to insoluble fibrin and cause staph to clump
73
how does cell-free coagulase cause staph clumping
cell-free coagulase + globulin plasma factor (coagulase-reacting factor) = staphylothrombin (thrombin-like factor) ---> catalyses conversion of fibrinogen to fibrin
74
how does staph clumping help staph
it helps them from phagocytosis
75
what other enzymes do staph produce
hyaluronidase
fibrinolysin
lipases
nuclease
76
hyaluronidase
hydrolyses hyaluronic acids
77
fibrinolysin aka
staphylokinase
78
what staph produce lipases
all s aureus strains
| more than 30% coagulase negative staph
79
what is the function of lipases with staph
they hydrolyze lipids and ensure the survival of staph in sebaceous areas of the body
80
function of nuclease with staph
it is thermostable and hydrolyzes viscous dna
81
what is s aureus unable to do
invade through intact skin or mucous membranes
82
what does the cell wall of s aureus contain
ribitol phosphate teichoic acid
83
what kind of clusters do s aureus form
like bunches of grapes
84
what are s aureus
pyogenic gram positive cocci
85
predominant type of bacteria on skin
staph
| corynebacteria
86
predominant bacteria on conjunctiva
sparse - gram positive cocci and gram negative rods
87
predominant bacteria on teeth
strep
| lactobacilli
88
predominant bacteria on oral mucosa
strep
| lactic acid bacteria
89
predominant bacteria in nares (nasal membranes(
staph
corynebacteria
(same as skin)
90
predominant bacteria in pharynx
strep
neisseria
gram negative rods
cocci
91
predominant bacteria in lower respiratory tract
none
92
predominant bacteria in stomach
H pylori
93
what % of stomach bacteria is H pylori
50%
94
predominant bacteria in in small intestine
lactics
enterics
enterococci
bifidobacteria
95
predominant bacteria in colon
```
bacteroides
lactics
enterics
enterococci
clostridia
```
96
difference between colon and small intestinal dominant bacteria
bifidobacteria exclusive to small intestine and bacteroides and clostridia exclusive to colon
97
predominant bacteria in anterior urethra
sparse - staph, corynebacteria, enterics (similar to skin, and enterics)
98
predominant bacteria in vagina during child-bearing years
lactic acid bacteria
99
predominant bacteria in vagina during non-child-bearing years
mixed
100
Main pathogenic Lancefield groupings for humans
```
A
B
C
D
G
```
101
what are lancefield groupings based on
antigenic characteristics of cell wall carb - C substance
102
common characteristics of streptococci
```
gram positive
cocci
arranged in pairs or chains
most are facultative anaerobes
catalase negative
```
103
schemes used to classify strep
serologic properties
hemolytic patterns
biochemical properties
104
serologic classification of strep
Lancefield groupings:
| a, b, c, d, g
105
hemolytic patterns classification of strep
complete (beta [b])
incomplete (alpha [a])
no hemolysis (gamma [g])
106
what strains of strep are pathogenic for humans
group A
107
90 % of strep disease in humans is caused by
group A beta hemolytic strep - S pyogenes
108
what defines the virulence of the bacteria - strep
M protein
109
important components in the cell wall of S pyogenes
M protein
lipoteichoic acid
F protein
110
Toxins produced by Group A beta hemolytic strep
Streptococcal pyrogenic exptoxins (Spe) A, B, C,F
DNases A to D
Streptolysins O, S
Hyaluronidase
Streptokinase A, B
111
superantigens produced by Strep pyogenes
SpeA
SpeB
Spe = Streptococcal pyrogenic exotoxin
112
what are SpeA and SpeB associated with
severe infections characterised by:
rash
hypotension
multiorgan failure
high mortality rate
113
most common organisms to cause subacute endocarditis
oral streptococci
why? Alpha-hemolytic
114
what strep are alpha-hemolytic (oral strep)?
S viridans
S mutans
S sanguis
S salivarius
115
characteristic phases of population growth in bacteria
A - lag
B - log
C - maximum stationary
D - decline
116
decline phase aka
death phase
117
log phase aka
exponential phase
118
what happens to bacterial cells in lag phase
they are metabolically active but not dividing
119
what is the cellular activity during lag phase
resynthesis of enzymes, coenzymes etc necessary for growth
120
what happens to bacterial cells in log phase
bacteria are growing and dividing at an exponential (logarithmic) rate
121
What is the period of fastest growth in the bacterial growth curve?
log phase
122
what is the generation time in log phase
maximal and constant
123
what works best in log phase?
cidal antibiotics
124
what is the best phase to stain bacteria culture to study them?
log phase
125
why does total number of viable cells remain constant in maximum stationary phase
medium getting depleted in nutrients and toxic quantities of waste materials lead to reduction in number of new cells produced and increase in number of dying cells
126
what kind of bacteria contain endotoxins in their outer membrane of the cell wall?
gram negative bacteria
127
what is the biological activity of endotoxin associated with
lipopolysaccharide
128
what is the toxicity of endotoxin associated with
lipid component
129
what is the lipid component of endotoxin
Lipid A
130
what is the immunogenicity of endotoxin associated with
polysaccharide components
131
how does lipopolysaccharide activate complement
by alternative (properdin) pathway
132
which one is more potent - endo or exotoxin
endotoxin
133
which one is more specific - endo or exotoxin
exotoxin
134
which one has enzymatic activity - endo or exotoxin
exotoxin - often
135
which one is released by organisms - endo or exotoxin
exotoxin
136
which one is denatured by boiling - endo or exotoxin
exotoxin - usually
137
which one is antigenic - endo or exotoxin
both
138
which one forms toxoid - endo or exotoxin
exotoxin
139
which one is more pyrogenic - endo or exotoxin
endotoxin
140
which one is part of outer membrane - endo or exotoxin
endotoxin
141
which one is diffusible - endo or exotoxin
exotoxin
142
what is the difference in structure between endo and exotoxin
endo is lipopolysaccharide, exo is protein
143
which one is expressed by gram positive organisms only - endo or exotoxin
exotoxin
144
what is essential to function of outer membrane of gram negative bacteria
lipopolysaccharide
145
what is the function of the outer membrane of gram negative bacteria
to act as a protective permeability barrier
146
outer membrane of gram negative bacteria permeability
impermeable to:
large molecules
hydrophobic compounds from the environment
147
how are endotoxins released into bloodstream
not secreted - death of bacterial cell and breakdown of outer membrane leads to its release into bloodstream
148
host responses to endotoxins
chills
fever
weakness
generalised aches
severe cases - shock and death
149
potency of endotoxins
very high
150
action of endotoxins in oral mucosa
minute amounts cause
inflammation
resorption
of adjacent bone
151
effect of endotoxin on granulocytes
chemotactic effect on neutrophilic granulocytes - it induces phagocytosis by these cells
152
what do plaque bacteria produce other than endotoxin that may initiate perio disease
enzymes
- hyaluronidase
- collagenase
- chondroitin sulfatase
- elastase
- proteases
153
where do you find free endotoxin
dental plaque
| inflamed gingiva
154
most likely source of bacteria in diseased perio tissue
subgingival plaque
155
collagenase is a part of the component system of which bacteria
Porphyromonas spp
Clostridium spp
Bacteroides spp
Actinobacillus actinomycetemcomitans
156
how is endotoxin different from most bacterial exotoxins
it is a LPS complex instead of a protein, composed of
- lipid A
- core polysaccharide
- O antigenic side chain
157
which is the portion of endotoxin most responsible for toxic activity
lipid A
158
how does endotoxin affect complement system
it activates C3 in the absence of preceding activation of C1, 4, 2.
Various complement components are consumed and then their activity disappears or is reduced from serum
159
detection of protein A is used as a specific identification test for
staph aureus
160
name a major cause of nosocomial infections associated with indwelling medical devices
s aureus
161
how does s aureus cause food poisoning
releasing enterotoxins
162
how does s aureus cause tss?
release of superantigens in blood stream
163
the surface of which s aureus strains are coated with protein A?
the strains that are not coagulase negative staph
164
where is protein A bound in s aureus?
peptidoglycan layer or
| cytoplasmic membrane
165
what does protein A have a unique affinity for
binding to the Fc receptor of IgG and inhibiting complement fixation
166
what are the important human pathogens in genus Neisseria
N gonorrhoeae
| N meningitidis
167
what is the difference in prevalence and mortality levels of N menigitidis and N gonorrhoeae
N gonorrhoeae infections have high prevalence and low mortality
N menigitidis have low prevalence and high mortality
168
Describe salmonella
Gram negative
facultative
rod-shaped
169
what bacterium does Salmonella share its proteobacterial family with
E coli - family Enterobacteriaceae - aka enteric bacteria
170
what diseases does Salmonella cause in humans
Salmonellosis
| acute gastroenteritis
171
salmonellosis aka
enteric fever (typhoid)
172
what is the cause of typhoid
Salmonella
173
how does typhoid occur
it results from bacterial (salmonella) invasion of the bloodstream
174
what does acute gastroenteritis result from
foodborne infection or intoxication
175
which are the most numerous group of microbes that occur in the oral cavity
Streptococci
176
what do streptococci cause in oral cavity
dental caries
177
what are more serious infections than dental caries caused by strep?
pneumonia (s pneumoniae)
rheumatic fever (s pyogenes)
heart valve infections (s viridans)
178
bacterial enzymes used clinically for removal of blood clots
staphylokinase
streptokinase
urokinase
179
what produces staphylokinase
staph aureus
180
what produces streptokinase
hemolytic streptococci
181
what do staphylokinase, streptokinase and urokinase do
they cleave plasminogen, producing plasmin, which causes liquefaction of fibrin
182
list bacteria that produce hyaluronidase
staph aureus
strep pyogenes
clostridium perfringens
183
name 2 types of bacteria that are acid fast
Mycobacterium spp
| Nocardia
184
M tuberculosis - gram + or -?
neither - it doesn't have the chemical characteristics of either
185
What kind of toxins do M tuberculosis produce?
neither exo nor endotoxins
186
are M tb motile?
no
187
what is the shape of M tb?
rods
188
what do M tb produce
niacin
189
where are most mycobacteria found?
dry and oily locales
190
what is the type of metabolism of M tb
obligate aerobe
191
in the classic case of TB where are M tb complexes found
in well aerated upper lobes of the lungs
192
what is the generation time of M tb
slow - 15 - 20 hours
193
is M tb parasitic
yes - facultative intracellular parasite of macrophages
194
what physiological characteristic of M tb contributes to its virulence
it slow generation time of 15-20 hours
195
name a method to diagnose active TB
acid fast staining
196
method of acid fast staining
1. smear on a slide is flooded with carbol fuchsin stain
2. decolorized with acid alcohol
3. counterstained with methylene blue
197
how do acid fast organisms react to acid fast staining
they resist decolorisation and appear red against blue background under microscope
198
what is the acid fast property attributable to
presence of lipids and waxes in cell wall of certain bacteria
199
what waxes do mycobacteria contain
mycolic acids
200
name the skin test used to test for TB
PPD skin test
201
how accurate is the ppd skin test in diagnosing TB
it indicates infection but not whether infection is active
202
PPD = ?
purified protein derivative
203
how is the PPD skin test done
a purified protein derivative extract from Mtb is injected subcutaneously and the area near injection is observed for evidence of delayed hypersensitivity reaction
204
what is an indicator of tb infection in ppd test
delayed hypersensitivity reaction
205
what does positive ppd test indicate?
hypersensitivity to tuberculo-proteins
206
Acid fast bacteria of medical importance
Mtb
Mycobacterium leprae
Mycobacterium avium complex (MAC)
207
What does mycobacterium avium complex consist of
2 species -
M avium
M intracellulare
208
what does the acid fast cell wall of mycobacterium consist of?
peptidoglycan
| glycolipids
209
name a specific type of glycolipids that make up approximately 60% of the acid fast cell wall of mycobacteria
mycolic acids
210
what is the cause of virulence of mycobacteria
a waxlike lipid coat
211
what is the mycobacterial coat made of
mycolic acid
cord factor
wax D
sulfolipids
212
what is mycolic acid
large a-branched b-hydroxy fatty acids
213
what is cord factor
glycolipid of trehalose and two mycolic acids
214
what is wax D
glycolipid of 15 to 20 mycolic acids and sugar
215
what is a characteristic of the lipid coat of mycobacteria
it is antiphagocytic
216
structure of mycobacteria
peptidoglycan layer intertwined with arabinogalactan polymer and surrounded by lipid coat
217
how is the peptidoglycan layer of mycobacteria attached to arabinogalactan polymer
covalently
218
what is the function of peptidoglycan in acid fast cell wall (mycobacteria)
prevents osmotic lysis
219
what is the function of mycolic acids and other glycolipids in mycobacterial cell wall
impede the entry of chemicals ---
- the organisms grow slowly
- are more resistant to chemical agents and lysosomal components of phagocytes
220
what is the function of surface proteins in acid fast cell wall
enzymes
| adhesins
221
what do adhesins do
they enable the bacterium to adhere intimately to host cells and other surfaces in order to
- colonise
- resist flushing
222
what is the role of periplasm in acid fast bacteria
Enzymes for nutrient breakdown
| periplasmic binding proteins to facilitate transfer of nutrients across cytoplasmic membrane
223
MoA of isoniazid
it inhibits mycolic acid biosynthesis
224
Ghon focus aka
tubercle
225
What is a tubercle
small, rounded nodule produced by infection by Mtb.
226
what is the primary lung lesion of pulmonary TB
Ghon focus (tubercle)
227
Ranke complex
the result of ghon focus that has healed, fibrosed and is sometimes calcified
228
what is a major factor in the cariogenicity of S mutans
its ability to adhere to tooth surface
229
how is S mutans able to adhere to tooth surface?
presence of an extracellular glycocalyx
230
extracellular glycocalyx aka
capsule
231
what is the major function of the capsule in certain bacteria
to protect them against phagocytosis by eukaryotic cells
232
other important functions of the capsule
- mediate adherence of cells to surfaces
| - identification purposes
233
how are capsules used to identify bacteria
polysaccharide capsules when treated with antiserum swell, allowing them to be identified
234
what kind of capsule surrounds the cells of strains of streptococcus pneumoniae
polysaccharide capsules - they are antiphagocytic
235
the virulence of which bacteria is enhanced by capsule production?
- Haemophilus influenzae
- Klebsiella pneumoniae
- Cryptococcus neoformans
236
What % of plasma membrane is protein?
70% mass
237
Major functions of plasma membrane
- selective permeability
- electron transport
- excretion of hydrolytic exoenzymes
- bearing useful enzymes
- bearing receptors
238
Main role of cell wall
- rigidity for cell
- strength
- protection against mechanical stress
- essential role in cell division
- primer for its own biosynthesis
239
which one is thick, gram + or - cell wall
Gram +
240
how much of the cell wall does murein make up in gram + bacteria?
90%
241
thickness of gram + cell wall
15 - 80 nm
242
thickness of gram - cell wall
10 nm
243
which one is more complex - gram + or - cell wall?
Gram - cell wall
244
which one - gram + or gram -ve have lipoprotein as integral elements of cell wall?
Gram -ve
245
What apart from murein makes up gram +ve cell wall?
Teichoic acids
246
What is the role of teichoic acids in gram +ve cell wall?
attachment sites for bacteriophages
247
What apart from murein make up a part of gram -ve cell wall?
Lipoproteins
Lipopolysaccharide layers (endotoxin)
Phospholipids
Proteins
248
What does the gram -ve cell wall have that gram +ve doesn't?
Proteins, lipopolysaccharide layers and phospholipids, that form the cell envelope - it protects the cell from antibiotics and enzymes
249
Function of cell envelope in gram -ve bacteria
Protection from antibiotics like penicillin and enzymes like lysozyme
250
Definitive component of murein is
N-acetylmuramic acid which is contained in all bacterial peptidoglycans
251
What is the factor that distinguishes the archaebacteria from other bacteria?
the cell walls of archaea may be composed of protein, polysaccharides or peptidoglycan-like molecules, but never murein
252
What do most species of lactic acid bacteria ferment glucose to?
Lactic acid (duh)
253
Most common application of lactobacillus
Industrial - for dairy production
254
What part of the body do lactobacilli generally naturally occur in
vagina
255
why are lactobacilli abundant in the vaginal area
as they create an acidic environment derived from glucose, they inhibit growth of many bacterial species that can lead to urogenital infections
256
what is the most probable cause of the frequent association of lactobacilli with dental caries?
secondary microbial invaders
257
what is the most commonly associated lactobacillus with dental caries
Lactobacillus casei
258
what lactobacillus is added to milk to assist lactose intolerant individuals?
Lactobacillus acidophilus - it helps them digest lactose sugars
259
How does lactobacillus acidophilus help with lactose intolerant individuals?
It converts milk sugars to products that do not cause GI problems
260
Lactic acid bacteria include
Lactobacillus
| Streptococcus
261
Why are lactobacillus and streptococcus both lactic acid bacteria?
They use the lactic acid fermentation pathway
262
What happens in the lactic acid fermentation pathway
Pyruvate is reduced to lactic acid
263
Aciduric bacteria
another name for the lactic acid bacteria, as they can tolerate an acid environment
264
Lactic acid bacteria aka
```
Aciduric
Acidogenic (acid forming)
```
265
Main culprit in dental caries
Strep mutans
266
What kind of caries is Strep mutans especially implicated in?
Smooth surface caries
267
What kind of problems does lactobacillus cause in humans?
It's generally harmless
268
What is the relationship of lactobacillus to antibiotics?
It is resistant to vancomycin
Treated with high doses of penicillin in combination with gentamycin
269
Name a causative agent of root caries
Actinomyces
270
Two organisms most commonly associated with the etiology of localized aggressive periodontitis
Capnocytophaga ochraceus
Actinobacillus actinomycetemcomitans
271
forms of aggressive periodontitis
Generalized
| Localized
272
Predominant microbes in generalized aggressive periodontitis
Prevotella intermedia
Elkenella corrodens
(gram negative anaerobes)
273
At what ages does generalised aggressive periodontitis occur
12-25 years of age
274
What are the characteristic features of generalised aggressive periodontitis
Rapid, severe periodontal destruction around most teeth
Episodic, rapid, and severe attachment loss
275
In what kind of patient does localised aggressive periodontitis occur
otherwise healthy adolescents - 12-19 years of age
276
Characteristic features of localised aggressive periodontitis
- rapid and severe attachment loss confined to the incisors and first molars
- relative absence of local factors to explain the severe periodontal destruction
277
at what pH does S mutans grow optimally?
well below 7 - acidophilic
278
what points determine the range of pH over which an organism can grow?
minimum pH
maximum pH
optimum pH
279
What are bacteria that grow best at neutral pH (7.0) called?
neutrophils
280
What are most bacteria - acidophils, neutrophils or basophils?
neutrophils
281
name some neutrophilic bacteria
- Pseudomonas aeruginosa
- Clostridium sporogenes
- Proteus spp
282
Name some acidophilic bacteria
- Thiobacillus thiooxidans
- Sulfolobus acidocaldarius
- Bacillus acidocaldarius
283
What are obligate acidophiles?
Bacteria that actually require low pH for growth as their membranes dissolve and the cells lyse at neutrality
284
examples of alkaliphiles
Nitrobacter spp
| Streptococcus pneumoniae
285
Aciduric vs Acidogenic
Aciduric bacteria are capable of or can tolerate living under acid conditions, while acidogenic bacteria produce high concentrations of acid
286
What are the primary acidogenic microorganisms of the oral cavity?
Streptococci
287
What is the main cause of enamel decalcification?
Lactic acid
288
Most well-known enteric bacteria
E coli
Shigella
Salmonella
289
Infections that E coli is responsible for in humans
UTIs
Neonatal meningitis
intestinal diseases
290
what are capnophilic bacteria
bacteria that require carbon dioxide for growth
291
example of capnophilic bacteria
Capnocytophaga ochraceus
292
are streptococci gram + or gram -ve?
Gram +ve
293
what kind of metabolism do streptococci have
facultative anaerobes or capnophilic
294
which ones are catalase negative - strep or staph?
strep
295
What is one of the most frequent pathogens of humans?
Strep pyogenes (group A streptococcus)
296
Order of phases of phagocytoses
```
chemotaxis
adherence
ingestion
phagosome
phagolysosome
digestion
residual body
discharge
```
297
Types of phagocytes
Fixed
| Free
298
types of fixed phagocytes
(do not circulate)
fixed macrophages
cells of reticuloendothelial system
299
Types of free phagocytes
(circulate in bloodstream) leukocytes
| free macrophages
300
What kind of hb has gamma chains?
Fetal globin - 2 alpha and 2 gamma chains
301
describe structure of heme
nitrogen containing organic pigment molecule that has a single atom of ferrous iron
302
where does hb combine with co2?
protein portion
303
how much higher is carbon monoxide affinity for hb than oxygen
240x
304
how is pH related to hb affinity for o2?
directly proportional
305
can methemoglobin function as an oxygen carrier
no because it has iron in ferric state
306
additional function of hb in blood
H+ buffer - deo2 hb is less acidic than oxyhb therefore ideally suited to buffer h+ ions coming from tissue CO2
307
Most common form of Hb in adults
Hb A
308
Hb H is composed of what kind of chains?
4 beta chains
309
What causes formation of Hb H?
Defect in 3 of the 4 alpha chain genes
310
What is Hb H an indicator of?
Alpha thalassemia
311
What Hb has valine instead of glutamic acid in the beta chain?
Hb S
312
What does the presence of Hb S cause?
Change in shape of RBC when exposed to decreased amounts of oxygen - sickle shape
313
When might an rbc be exposed to reduced amounts of oxygen
- exercise
| - peripheral circulation
314
In which people is HbS the predominant form of Hb?
People with sickle cell anemia
315
Where do you see decreased solubility of deoxy form of Hb
Sickle cell anemia
316
Hb M
Group of Hb in which a single amino acid substitution favors formation of methemoglobin
317
What kind of Hb is associated with methemoglobinemia
Hb M
318
What is the normal kind of Hb?
Hb A
319
In what kind of Hb has lysine replaced glutamic acid?
Hb C
320
What do you see in people with high Hb C?
Reduced plasticity of rbcs
321
List types of Hb
```
Hb A
C
M
H
S
```
322
90:10 erythropoietin production to which organs in normal adults?
kidneys, liver
323
what kind of molecule is erythropoietin
a glycoprotein
324
how is the production of erythropoietin regulated?
a negative feedback mechanism that is sensitive to the amount of oxygen delivered to the tissues
325
what does inadequate erythropoiesis lead to?
anemia
increased cardic output
hypoxia
326
What does anoxia lead to?
greater production of erythropoietin
327
what is the site of action of erythropoietin
hemocytoblast
328
what is the hemocytoblast
pluripotent stem cell
329
what is anoxia
low oxygen
330
what does excessive erythropoiesis lead to
- polycythemia
- increased blood viscosity
- sluggish blood flow
331
what is a hallmark of anemic people wrt oxygen in blood?
normal oxygen tension
| reduced oxygen content in systemic arterial blood
332
diameter of rbcs
7-8 microns
333
what do rbcs contain
Hb
| Carbonic anhydrase in large quantity
334
what does carbonic anhydrase do
converts carbon dioxide and water to bicarbonate and proteins
335
what is the lipid membrane of rbcs made of
lipoproteins
| specific blood group substances
336
what is a good indication of amount of erythrocyte destruction per day?
amount of bile pigments excreted by the liver per day
337
erythrocyte production in early embryo
yolk sac
338
erythrocyte production in mid-gestation
mostly liver
spleen
lymph nodes
339
At what stage of life are erythrocytes exclusively produced in bone marrow?
from final month of gestation to about 20 years old
340
After the age of 20, where are erythrocytes produced?
marrow of membranous bones such as vertebrae
sternum
ribs
ilia
341
what are the factors that cause the oxyhb dissociation curve to shift to the right?
increased co2 concentration
increased blood temperature
increased 2,3 - biphosphoglycerate
decreased pH
342
What are the characteristics of active tissues?
during active muscle contraction:
| lactic acid is produced, co2 is produced by the tissues and heat is produced
343
How does lower pH shift the curve to the right?
Acidic conditions decrease the affinity of Hb for o2 because the higher the H+ concentration, the less o2 is bound to Hb
344
how does increased arterial pco2 affect the oxyhb dissociation curve?
co2 molecules bind with Hb and alter Hb conformation from the R state to the T state (low oxygen affinity)
345
what is intrinsic factor essential for
absorption of vitamin b12 in the ileum
346
what cells secrete intrinsic factor?
parietal cells
347
what is the stomach lining made of
columnar epithelium folded into gastric pits
348
what is a gastric pit
the opening of a duct into which one or more gastric glands empty
349
how many distinct regions is the gastric mucosa divided into
three-
oxyntic or parietal
cardiac glandular region
pyloric gland region
350
where is the cardiac glandular region located
just below the lower esophageal sphincter
351
what kind of cells does the cardiac glandular region contain
mucus secreting gland cells
352
what kind of secretions does the oxyntic region have
acidic
353
where is the parietal gland region situated?
above the gastric notch (equivalent to the proximal part of the stomach)
354
where is the pyloric gland region situated
below the notch
355
what are the two important types of glands in the stomach mucosa
oxyntic
| pyloric
356
oxyntic glands aka
gastric glands
357
what do the oxyntic glands secrete
hydrochloric acid
pepsinogen
intrinsic factor
mucus
358
What do pyloric glands secrete
mainly mucus
| hormone - gastrin
359
what is the difference between pyloric and oxyntic glands
pyloric have no peptic cells and almost no parietal cells
