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PATHOBIOLOGY BMS106 > path terms > Flashcards

path terms Flashcards

1
Q

pathogenesis

A

the pathological mechanism that results in clinically evident disease e.g. the way in which the interaction between M. tuberculosis and the host immune system produces the caveating granulomatous lesion of TB

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2
Q

non sense mutation

A

a single nucleotide change in which theDNA base pair change leads to a stop codon being present and a premature chain termination occurs during translation

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3
Q

missense mututtion

A

point mutation where a single nucleotide change results in a codon that codes for a different amino acid e.g. in sickle cell anaemia the mutation change A to T and thus glutamic acid to valine (in a beta chain polypeptide)

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4
Q

null mutation

A

completely inactivates the function of the gene and the encoded product

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5
Q

frameshift mutation

A

may be a single nucleotide addition or deletion- altering the frame read by the ribosome to translate mRNA sequence downstream of mutation so ribosomes can still synthesise a poylpeptide chain (with a triplet code) i.e. a protein is still made
BUT
the protein will have an altered or abnormal function
due to the part encoded by the gene beyond the mutation having the wrong sequence of amino acids

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6
Q

examples of Mendelian inheritance

A

huntingdon’s chorea (disease)
Haemophilia
Brachydactyly (shortening of fingers and toes)
Alkaptonuria (black urine/bone disease)- can’t process phenalylaline and tyrosine

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7
Q

cancer is caused by

A

dominant, gain of function mutations in proto- oncogenes

or recessive loss of function mutation in tumour suppressor genes

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8
Q

proto gene function

A

to regulate cell proliferation

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9
Q

Duchenne Muscular dystrophy gene

A

the DMD gene is encoded on the x chromosome.
so females are either unaffected (not carrying any mutant allele) or a carrier (possessing a mutant allele but not affected)
Males, if they inherit a mutant allele in their X chromosome they will be affected due to their NOT possessing a normal coy of the gene

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10
Q

single gene disorders

A

are due to abnormal structure and are inherited in mendelian fashion

whereas abnormalities of chromosome number are not inherited normally

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11
Q

imprinting

A

silences genes and occurs to some genes during gametogenesis so that either only the father’s or other’s allele will be expressed

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12
Q

common disorders of imprinting

A

pradar-willi syndrome
angelman’s syndrome
beckwith-wiedemann syndrome

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13
Q

pyknosis

A

clumping of the nuclear chromatin (due to decrease in PH in cell from anaerobic metabolism)

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14
Q

characteristics of HIV

A

HIV are retrovirurses that are characterised by being enveloped and containing 2 copies of a single-stranded RNA genome. The mature virus also contains enzymes such as reverse transcriptase, integrase and a protease. The virus also posses in it’s envelope proteins (gp120 and gp41) that enable the virus to bind to CD4 and its co-receptor CCR5 and effect entry into T-helper cells.

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15
Q

Hypertrophy

A

increase in cell size

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16
Q

Hyperplasia

A

Increase in cell number (in tissues that can divide or have abundant Stem cells.

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17
Q

Metaplasia

A

Change in cell differentiation (replacement of one mature cell type with another mature cell type).

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18
Q

Dysplasia:

A

Change in cell differentiation (replacement of one mature cell type with another LESS mature cell type) – tends to be disordered.
presence of abnormal cell type in a tissue - precancerous

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19
Q

examples of tumour suppressor genes

A 
Rb
p53
WT-1
ptc
BRCA-1
Apc
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20
Q

neutrophils

A

most abundant WBC
pus made of these
self destruct

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21
Q

macrophages

A

derived from monocyte WBC

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22
Q

Natural killer cells

A

can kill own cells if become infected with virus or become cancerous

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23
Q

MHC

A

major histocompatibility complex I
normal healthy cells have this protein on it’s surface
infected cells can’t produce these

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24
Q

MHC

A

major histocompatibility complex I
normal healthy cells have this protein on it’s surface
infected cells can’t produce these

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25
HIV
enveloped virus 2 copies of single stranded RNA genome binds to chemokine receptors present on macrophages and T cells
26
forms of genetic medallion inheritance
autosomal recessive autosomal dominant X linked
27
examples of autosomal recessive diseases
cystic fibrosis, alkaponuria, sickle cell anaemia
28
examples of autosomal dominant diseases
hunting tons disease, brachydactyly, aniridia
29
examples of x linked diseases
duchenne muscular dystrophy, haemophilia, x lnked mental retardation
30
sickle cell anaemia
missense mutuation glu-val | single point mutation in the codon for aa 6 in the B global subunit
31
aniridia
loss of iris | deletion of single point mutation in one cope of PAx6 gene
32
indentification
genes can be identified purely on the basis of their choromosomal position without prior knowledge of the functions of their proteins
33
obligate pathogens
can only survive on host (usually specific to host species)
34
facultative pathogens
present in environment (reservoirs) waiting for host
35
opportunisitic pathogens
normally benign but cause disease in compromised host
36
cancers can be linked to inflammation
1) directly- due to organisms that modify and mutate DNA 2) indirectly- through mechanisms that provoke the release of reactive oxygen species by inflammatory cells, causing DNA damage
37
HIV
infects and destroys the CD4+ cells that are at the heart of the immune system CD4+ help T lymphocytes recognise microbial antigens presetned to them by antigen presenting cells they also stimulate effector cells: the CD8+ and T-cytotoxic lymphocytes and B cells to produce antibodies. both CD8+ and T cytotoxic lymphocytes and the antibodies are specifically targeted to attack the same antigen recognised by the CD4+ cell. Also the generation of memory cytotoxic T cells and B cells is also stimulated by the CD4+ cell.
38
CD4+
vulnerable to infection by HIV CD4 is a glycoprotein receptor found on the Th cells (T helper), dendritic cells, macrophages and monocytes of the central nervous system) however the virus must bind to co-receptor e.g. CCR5 to gain entry to the cell
39
origin of HIV
from a mutated simian virus (SIV) found in certain monkeys and chimps present in humans in 1950s or even earlier
40
earliest confirmed HIV
1959- from patient blood in congos
41
slim disease
attributed to HIV lymphadenopathy
42
HIV link
lin between herpes simplex virus (type II) and an increased infection with the virus later shown to be HIV HSV induced-ulceration deprives the mucosa of its protective epithelia barrier increasing the risk of transmission of HIV also HSV stimulates the proliferation of CD4+ which increased HIV viral synthesis by the infected CD4+ cells
43
link between homosexuality and HIV
reflects the reduced barrier to infection offered by the glandular surface epithelium in the rectum, which is only one cell think, compared to the stratified squamous epithelium lining of the vagina and ectocervix
44
transmission of HIV
``` sexually, infected blood (from shared needles) breast milk NOT saliva swear or tears HIV does not normally cross the placenta ```
45
when is the risk of transmission of HIV through placenta increased
increased risk in patients whose recently acquitted hiv or have high blood viral levels or if there is a intrauterine infection or mother is malnourished or if mother has: malaria, STD, UTI or respiratory e.g. TB
46
how non developed viruses get into cells
taken up by receptor mediated endocytosis | or injected into the host cell by phages
47
HIV getting into cells
hiv's gp120 surface antigen binds to CD4 recpor on the T helper cells and some macrophages, and also needs to bind to co-receptor cell CCR5 (attached to a G protein within the cell) the purpose of CCR5 it to recognise chemokine and is central to several inflammatory responses after binding it meld and fuses its envelope with the hosts phospholipid bilayer and uncoats its viral RNA which enters the cytosol the viral protein and genome are released and activate the transcription of new viral particles HIV (retrovirus) can 'reverse transcribe' its RNA into DNA which enters the host cell nucleus and is then replicated forming new viral particles which bud out of the cell
48
after initial infection of HIV
it might be silent or produce flu like symptoms for 2 weeks, may be ineffective for several years during which time lymph node enlargement may occur at sites
49
action of HIV
gradually causes death of T cells (by T cell's own PRR) which assemble into an inflammasome, activating capsizes and causing death of cell host T cell may take many 8 years before the count of circulating cD4 T cells in blood falls below critical level of 500/uL
50
without CD4+ cells (t helper)
there is no generation of memory T and Bcells so no memory of past infection, so body relies on innate immune system
51
which cells have CD4+
T helper cells, monocytes, dendritic cells, macrophages
52
after the infection of HIV happens
a person has AIDS characterised by either: CD4 count under 200/uL or development of AIDS defining illnesses e.g. oppotunitic infections, which take advantage of deficient immune response e.g pneumonia (p. jirovecii or cytomegalovirus (CMV), oesophageal candidiasis, small bowel cryptosporidiosis or atypical mycobacteriosis (Mycobactierm avid-intracellulare), or cryptococcal meningitis (cryptococcus neoformans).
53
AIDs defining malignancies
intracerebral lymphoma and Kaposi;s sarcoma (both secondary to infection with HHV8)
54
natural immunity to HIV/AIDs
those with delta (triangle)32 mutations in their CCR5 receptor genes seen in around 16% of people in northern europe this mutation prevents the HIV p120 protein antigen from binding to mutated CCR5 receptor on the host cell surface
55
HIV can be useful
a modififed and non pathogenic form of HIV can be used for gene therapy of X linked Wiskott- Aldrich syndrome (WAS gene) bone marrow stem cells can be transfected with working genes using modified HIV
56
symptoms of AIDS
``` lip warts shingles PCP thrush Kaposi's sarcoma ```
57
3 classes of anti-retroviral drugs preventing formation of HIV DNA
integrase inhibitors prevent HIV DNA integrating into host DNA Nucleoside reverse transcriptase inhibitors (NRTIs) Protease inhibitors prevent new viruses being formed on-nucleoside reverse transcriptase inhibitors (NNRTIs)
58
CD$ receptors are essential for immune response
macrophages engulfs pathogen presents antigens on surface Class II MHC molecule helps CD4 bind to Th cell (activated by interleukin 1) interleukin 2 and other cytokines activate Th cells, B cells and Tc (cytotoxic) Tc : cell mediated immunity (attack on infected cells) B cell: humoral immunity (secretion of antibodies by plasma cells)
59
where is there greatest frequency of CCR5 delta 32 mutated allele
european populations
60
active immunity
protecting produced by a person's own immune system takes days/weeks to develop is usually permananet can be natural or acquired
61
passive immunity
protection transferred from one human or animal to another, by the transfer of an antibody (igG) immediate but short term protection (Weeks or months) can be natural (transplacental) or acquired
62
active immunisation
(the more similar the vaccine is to the natural disease the better the immune response to the vaccine) 1) live pathogens -attenuated (i.e. weakened virulence) 2) killed micro-organisms 3) microbial extracts 4) vaccine conjugates( A conjugate vaccine is created by covalently attaching a poor antigen to a strong antigen thereby eliciting a stronger immunological response to the poor antigen. Most commonly, the poor antigen is a polysaccharide that is attached to strong protein antigen). 5) toxoids (chemically modified (with formaldehyde) toxin from pathogen but is no longer toxic but still antigenic)
63
why was eradicating small pos successful
no animal reservoir subclinical cases rare infectivity does not precede overt symptoms one Variola serotype (the virus comes in one variety) effective vaccine lifelong immunity major commitment by governments
64
problems with developing vaccines
different viruses may cause similar disease alternation to virus e.g. antigenic drift (accumulation of mutations) or antigenic shift (recombination) immune system cannot detect viral antigens HIV and inflenza virus are particularly difficult due to their rapidly changing properties
65
primary and secondary immune response and Booster effect
primary response: first encounter with an antigen relatively slow for B cells to produce antibodies (initially IgM) subsequent response is more rapid because of memory B cells
66
live attenuated vaccines
``` polio (oral: sabin) measles mumps rubella TB ```
67
inactivated vaccines
``` polio (subctaneous: salk) pertussis typhoid hep A influenza ```
68
toxoid vaccines
tetanus | diphtheria
69
components of organisms (fragment) vaccines
``` haemophilus influenzae type b (hib) heb B (surface protein recombinant) pneumococci ```
70
important pathogens which don't have vaccines
``` rhinoviruses (colds) HIV/AIDs * cytomegalovirus epstein barr virus hep C gonorrhoea syphilis leprosy tachoma malraia * all parasitic and protozoal infections ```
71
calor
heat
72
rubor
redness
73
tumor
swelling
74
dolor
pain
75
cyanosis
blue coloured deoxyhaemoglobin
76
atherosclerosis
plaques form in arteries
77
vascular occlusion
blocking of arteries depends on: type of tissue involved how quickly the occlusion develops whether there is collateral circulation
78
thrombosis
blocking of arteries caused by blood clot
79
embolism
fragments of clot break away and travel to elsewhere
80
burst blood vessels
haemorrhage
81
blood vessels bulging before bursting
aneursym
82
infarct
localised areas of schematic tissue necrosis generally caused by an impaired bloody supply
83
haemotoma
extravasuclar accumulation of clotted blood
84
petechaie purpura, ecchymoses
small haemorrhages
85
hyperaemia
an increased volume of intravascular blood in an affected tissue which may result from increased flow (active hyperaemia) or reduced drainage (passive hyperaemia =congestion)
86
infarction
'stuffed'
87
collaterals
venous system has more collaterals than arterial
88
where are arterial colaterals
gut, the circle of Willis and to some extent the heart
89
arterial thrombosis
middle aged and elderly circulatory problems due to atherosclerosis smokers, diabetes
90
venous thrombosis
at any age generally immobile e.g. after operation calf muscle pain swelling of foot and ankle
91
virchow's triad
alteration to the consituents of blood damage to the endothelial layer of blood vessels changes in the normal flow of blood
92
Alterations to blood constituents:
Blood becomes hypercoagulable Increased cells, platelets and plasma proteins Decreased fluid
93
damage to endothelial layer of vessels
Exposes the highly thrombogenic sub epithelial tissue Balance between release of thrombogenic and anti-thrombogenic stimuli is shifted Occurs due to physical, chemical or inflammatory disturbances
94
changes to flow
``` Turbulence: Alteration to the normal lamellar flow pattern Can damage endothelium More important for arterial thrombosis Stasis: Speed of flow is reduced Results in changes of thrombogenic and anti-thrombogenic stimuli More important in venous thrombosis ```
95
role of thrombosis 3 phases
1) adhesion of platelets to vessel wall 2) activation of platelets leading to change in shape and secretion of granules 3) aggregation of platelets and amplification of processes
96
adhesion
when endothelium is damages and collagen is exposed gpIa binds to collagen gpIb binds to von Wille brand's factor (vWF) gpIIb/ IIIa which binds to fibrinogen and vWF
97
thrombosis need for calcium
required for coagulation pathway
98
thrombosis need for ADP
induces platelet activation which change shape and synthesise thromboxane (TxA2) a prostaglandin prostacyclin produced by epithelial cells and thromboxane produced by platelets interact with endothelium and other platelets to influence clot formation in opposing ways
99
most common cause of defective platelet function
is aspirin therapy due to inhibition of cyclooxyrgenase resulting in impaired thromboxane synthesis after a single dose of aspirin the defect lasts 7-10 days (the life of a platelet) aspiriin also inhibits PGI2 prodution in endothelial cells and
100
pulmonary embolism
from venous emboli that pass through the right side of the heart into the pulmonary artery
101
systemic embolism
from arterial system to a variety of organs
102
arteriosclerosis
disease of the media leading to increased wall thickness decreased elasticity hypertension
103
atherosclerosis
``` disease of the intimate damage to endothelium narrowing of vessel obstruction thrombosis ```
104
fibrous cap content (of plaque)
smooth muscle cells, collagen, elastin and proteoglycans
105
cellular layer (of plaque)
macrophages, t lymphocytes and smooth muscle cells
106
necrotic core
lipid, cellular debris, cholesterol clefts, foam cells
107
difference between arterial and venous thrombosis
``` arterial: risk from atheroma due to turbulent blood flow damage to endothelium sudden onset infarction arterial embolism entire plaque embolisms (plaque forms against blood flow..) ``` ``` venous risk from immobility due to stasis and hyper coagulability slow onset pulmonary embolism fragments of plaque embolism (plaque forms towards blood flow...) ```
108
coronary heart disease
due to narrowing of coronary arteries angina is caused by pain from this narrowing complete blocakge= myocardial infarction (heart attack)
109
stability of plaque
activated macrophages secrete matrix metalloproteinases MMP which degrade collagen and decrease the structural stability of the plaque also secreted are cytokines and interferon which may initiate smooth muscle apoptosis and damage endothelial cells
110
unstable plaque characteristics
``` eccentric architectures lipid rich macrophage rich inflammation endothelial damage ```
111
desmoplasia
gives tumour hard texture due to proliferation of fibroblasts which produce collagenous connective tissue
112
carcinomas
epithelia
113
sarcomas
connective tissue
114
lymphomas
lymphoid tissue

PATHOBIOLOGY BMS106 (1 decks)

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