Principles Flashcards
1
Q
Which part of an antibody do immune cells bind to?
A
Fc region
2
Q
What is the most commonly produced immunoglobulin in the body?
A
IgA, however IgG is in the highest blood concentration.
3
Q
What is the role of IgD?
A
Activation of B cells
4
Q
What is the role of IgE?
A
Prevention against parasites and type 1 hypersensitity (allergies)
5
Q
What is the role of IgG
A
Immune complex mediated rections - enhances phagocytosis
6
Q
What is the role of IgM?
A
Produced in acute stages of infection and in cell bound type 2 hypersensitivity reactions.
7
Q
What is the main source of IL-1?
A
Macrophages and monocytes
8
Q
What type of medications may be used in an anaphylactic reaction?
A
Adrenaline, hydrocortisone, and chlorphenamine
9
Q
What type of immune cells produce large abounds of specific antibodies?
A
Plasma cells
10
Q
What is responsible for activating macrophages?
A
Interferon gamma
11
Q
What triggers the mannose binding lectin pathway?
A
Mannose binding lectin binds to carbohydrates in the surface of pathogens.
12
Q
What type of T cells mediate allergic asthma?
A
Th2 Cells
13
Q
What type of immune cells is responsible for defence against protozoa and helminths?
A
Eosinophils
14
Q
What is genetic nondisjuction?
A
Failure of the sister chromosomes to separate during mitosis. This can result in aneuploidy.
15
Q
What gene is defective in Li-fraumeni syndrome?
A
p53
16
Q
What is heteroplasmy?
A
The presence of more than one type of organellar genome - mitochondrial DNA or plastid DNA - within a cell or indicidual
17
Q
What is genetic linkage?
A
Two genes that are located close to each other on a chromosome are often inherited together.
18
Q
What is somatic hypermutation?
A
Where point mutation accumulate in the antibody V-regions of both heavy and light chains
19
Q
What does a low Km value represent?
A
High affinity of an enzyme for its substrate
20
Q
What is metaplasia?
A
Change from one mature cell type to another
21
Q
What is neoplasia?
A
Abnormal cell proliferation
22
Q
What is hyperplasia?
A
Physiological increase in cell numbers
23
Q
What is hypoplasia?
A
Physiological decrease in cell numbers
24
Q
What is morphogenesis?
A
The formation of a body plan during development
25
How long can ATP supply energy?
4 seconds
26
How long can phosphocreatinine supply energy?
15 seconds
27
How long can free circulating glucose supply energy?
4 minutes
28
How long can glycogen stores supply energy?
77 minutes
29
How long can fat stores supply energy?
4+ days
30
What component of MRSA causes a necrolytic skin infection?
Panton Valentine Leukocidin
31
What is Down's syndrome?
Trisomy 21, patients have three copies of chromosome 21
32
What form of inheritance is Sickle Cell anaemia?
This is a form of co-dominant inheritance
33
What is Klienfelter syndrome?
47XXY, they have 3 sex chromosomes and therefore have 49 in total
34
How many transmembrane proteins make up G proteins?
7
35
What is an adenoma?
A benign tumour derived from glandular epithelium
36
What is a papilloma?
A benign tumour derived from mucous membrane
37
What does the suffix -carcinoma represent?
Malignant
38
What does the suffix -sarcoma represent?
Partially malignant, partially beinign
39
What does the suffix -oma represent?
Benign
40
How is CO2 transported in the body?
Dissolved in the blood
As carboxyhaemoglobin
As HCO3
As carbamino compounds
41
What is the most common method of CO2 transportation?
As HCO3
42
Describe Pseudomonas aeruginosa...
A gram negative coccabicallus. Resistant to most oral antibiotics
43
What is immunophenotyping?
Investigation of the pattern of antigen expression on or in cells through a panel of antibodies
44
What is light microscopy?
An techniques used for the morphological assessment of cells
45
What is alpha haemolysis?
Partial haemolysis - green colour
46
What is gamma haemolysis?
No haemolysis
47
What is beta haemolysis?
Complete haemolysis - yellow colour
48
Describe neisseria meningitidis...
Aerobic gram negative coccus
49
Where dies fertilisation normally occur?
Ampulla of the uterine tube
50
What is atrophy?
Degeneration of cells
51
What is the efficacy of a drug?
The ability of an agonist to evoke a cellular response
52
Why is there a decreased blood volume in patients with sepsis?
Endotoxins cause vasodilation and intravascular fluid to leak into adjacent tissue
53
How can we classify streptococci?
They are classified according to their haemolysis on blood agar
54
What are the four medical principles defined by Beauchamp and Childress?
Beneficence
Non-maleficence
Autonomy
Justice
55
What is an agonist?
This binds to the enzymes active site to enhance its effect
56
What is an antagonist?
This bind to the active site to block the binding of other molecules
57
What is FiFoATPase?
This is a proton pore which utilises the energy yielded from the return of protons along their electrochemical gradient in a condensation reaction with ADP and Pi to yield ATP
58
What activates C3 in the complement pathway?
The classical, alternative and lectin pathways
59
How do gram positive bacteria stain?
Purple due to thick peptidoglycan layer
60
How do gram negative bacteria stain?
Pink due to thin peptidoglycan layer
61
What is a granuloma?
A collection of macrophages that is a manifestation of an inflammatory process.
62
What is the role of ogliodendrocytes?
Produce myelin in the CNS
63
What receptor is responsible for glucose transport into the gut?
GLUT 5 - passive facilitated diffusion
64
Which G protein does M1 bind to?
Gq - stimulation of phospholipse C
65
What is the definition of Km?
The concentration of substrate which permits the enzyme to achieve half Vmax
66
What is muscle spasticity?
A muscle with increased tone, intact and functioning motor nerve but descending controls from the brain are not working
67
What is muscle paralysis?
Muscle with reduce tone, unable to contract and no functioning motor nerve supply
68
What is the rate limiting enzyme for the TCA cycle?
Isocitrate Dehydrogenase
69
What cells are the main producer of cytokines?
T helper cells
70
What is a type 1 hypersensitivity reaction?
Allergic Reaction
71
What is a type 2 hypersensitivity reaction?
Cytotoxic reaction
72
What is a type 3 hypersensitivity reaction?
Immunocomplex reaction
73
What is a type 4 hypersensitivity reaction?
Cell-mediated reaction
74
What causes the immune reaction in type 1 hypersensitivity?
IgE
75
What immune system components react to bacteria?
Antibodies and B lymphocytes
| Phagocytes
76
What immune system components react to viruses?
T lymphocytes
| Antibodies and B lymphocytes
77
What immune system components react to fungi?
T lymphocytes
Phagocytes
Complement proteins
78
What immune system components react to protozoa?
T lymphocytes
| Eosinophils
79
What immune system components react to worms?
Eosinophils
| Mast cells
80
What is inoculum size?
Median infecting dose required to cause disease in 50% of patients
81
What are the primary lymphoid tissues?
Thymus and Bone
| Where the immune cells originate
82
What are the secondary lymphoid tissues?
Lymph Nodes, Adenoids, Tonsils, Spleen, Peyer's Patches, Thoracic Duct
Where the immunity is propagated and refined
83
What are cytokines?
Small polypeptides released by a cell in order to change the function of the same or another cell
84
What is opsonisation?
The coating of pathogens by soluble factors (opsonins) to enhance phagocytosis
85
What are examples of opsonins?
C3b
CRP
IgG
IgM
86
What is the action of macrophages?
PAMPs bing to PRRs on the Mast Cell. This causes degranulation of inflammatory substances. There is then production of new pro-inflammatory mediators.
87
What are examples of pro-inflammatory mediators?
```
Leukotrienes
Prostaglandins
Nitric Oxide
Histamines
Pro-Inflammatory Cytokines (TNF alpha)
```
88
What are Leukotrienes?
Inflammatory chemicals the body releases after coming in contact with an allergen or allergy trigger.
89
What are Prostaglandins?
A group of lipids made at sites of tissue damage or infection that are involved in dealing with injury and illness. They control processes such as inflammation, blood flow, the formation of blood clots and the induction of labour.
90
What is the role of neutrophils?
They phagocytose and kill micro-organisms by releasing antimicrobial compounds
91
What do proinflammatory mediators promote?
Vascular changes
| Recruitment and activation of neutrophils
92
What is diapedesis?
The passage of blood cells (e.g.neutrophils) through the walls of intact blood vessels
93
What is chemotaxis?
The movement of a compound in response to a stimulus
94
What are the three neutrophil killing mechanisms?
Phagocytosis
Degranulation
Neutrophil Extracellular Traps (NETs)
95
What are neutrophil extracellular traps?
The neutrophils expel the contents of their nuclei and granule contents. This releases digestive enzymes that can trap and kill pathogens
96
What is TNF alpha?
Tumour Necrosis Factor alpha is an inflammatory cytokine produced by macrophages/monocytes during acute inflammation and is responsible for a diverse range of signalling events within cells, leading to necrosis or apoptosis.
97
What is the difference between macrophages and monocytes?
Macrophages are monocytes that have migrated to the tissues.
98
What is the role of dendritic cells?
Activation if naieve T lymphocytes to initiate that adaptive immune response
99
What are natural killer cells?
Recognise and destroy virally-infected host cells and cancer cells
100
What are B cell receptors?
These are membrane bound antigens
101
What are T cell receptors?
These are membrane bound protein heterodimers. The have alpha and beta chains with unique binding sites.
102
What molecules are required to present peptide antigens to T cell receptors?
```
Major HistoCompatibility molecules
MHC molecules (human leucocyte antigens)
```
103
Describe class I MHC molecules?
These are expressed on ALL nucleatred cells and present peptide antigens to CD8+T cells
104
Describe class II MHC molecules?
These are only expressed on antigen presenting cells e.g. dendritic cells, macrophages, and B cells
The preent Peptide antigens to CD4+T cells
105
What are end-stage B lymphocytes?
Plasma cells - they secret large quantities of soluble immunoglobulins
106
What is the variable part of immunoglobulins responsible for?
Form the diverse portion of the antigen to which pathogens can bind
107
What is the constant part of the heavy chain of the antibody responsible for?
This dictates the function of the antibody
108
What two signals does a B cells need to receive for it to be activated?
Antigen - BCR + Antigen
Helping signals - PRR + PAMP (non protein antigens)
Help from TH cells (protein antigens)
109
What is the first soluble antibody to be produced?
IgM
110
Which soluble antibodies mediate agglutination?
IgM and IgG
111
What is agglutination?
When an antibody cross-links multiple antigens producing clumps of antigens
112
Which soluble antibodies activate the classical pathway of the compliment system?
IgM and IgG
113
Which soluble antibody is responsible for foetal immune protection?
IgG
114
Which soluble antibody is responsible for neutralising bacterial and viral toxins?
IgG and secretory IgA
115
Which soluble antibody is an excellent opsinin?
IgG
116
Which soluble antibody is involved in natural killer activation?
Antigen bound IgG
117
What is the function of membrane bound IgD?
Mediates B cell activation
118
What are two signals needed for T cell activation?
Binding by MHC molecule
| Co-stimulatory molecules
119
What is the role of Tfh cells?
To stimulate B cells to become plasma cells or memory B cells
120
Which interleukin is required to proliferate CD8+ T cells?
IL-2
121
What is the role of Th1 cells?
Increased macrophage killing
122
What type of ribosome do eukaryotes have?
80s ribosome
123
What type of ribosome do prokaryotes have?
70s ribosomes
124
What is peptidoglycan?
A polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of most bacteria, forming the cell wall
125
What type of bacteria has lipopolysaccharides?
Gram -ve
126
What type of bacteria has fimbriae?
Gram +ve
127
What type of bacteria has pilus?
Gram -ve
128
What are mesophiles?
Organisms that grow best at moderate/body temperature
129
What are psycrophiles?
Organisms that grow best at a low temperature
130
What are thermophiles?
Organisms that grow best at a high temperature
131
What are the common shapes of bacteria?
Coccus
Bacillus
Spiral-shaped
132
How do cocci divide?
Divide in one plane to pro
133
What is the purpose of a mannitol salt agar?
It allows for the preferantial isolation of staphylococci
134
What is the purpose of MacConkay Agar?
Facilitate identification of enterobacteriaceae
135
What is the purpose of eosin and methylene blue?
Allows the identification of lactose fermenters e.g. E.Coli
136
What is virulence?
The capacity of a microbe to cause damage to the host
137
What are coliforms?
A species of gram -ve bacilli that look like E. coli on gram film and when cultured on blood agar
138
Name some key gram -ve pathogens?
E. Coli
Nesseria Meningitidis
Nesseria Gonorrhoeae
139
Name some key gram +ve pathogens?
Streptococcus spp.
Staphylococcus spp.
C. dificile
140
What is a virus?
A small obligate intracellular parasite
141
What is the name of a viral particle?
Virion
142
What is the growth cycle of a pathogen?
Attachment, Entry, Uncoating, Synthesis of Viral Components, Assembly and Release
143
What is a syncytia?
A mass of cytoplasm that has many nuclei and an enclosing membrane but no individual cells.
144
What are antibiotics?
A drug used to treat or prevent infection caused by microorganisms.
145
Name some antibiotic targets?
```
Cell wall - peptidoglycan synthesis
Ribosomes - protein synthesis
DNA replication - nucleic acid synthesis
DNA gyrases
Metabolic pathways
Cell membrane function
```
146
What are examples of antibiotics that target eh cell membranes?
Polymixins
147
What are examples of antibiotics that inhibit cell wall synthesis?
Penicillins
Cephlasporins
Carbapenems
Glycopeptides (non beta lactam)
148
Why doesn't beta lactams affect human cells?
We dont have peptidoglycans in our cells
149
What is the target of beta lactams?
Penicillin Binding Proteins
150
What are examples of antibiotics that inhibit DNA synthesis?
Quinolones
Nalidixic Acids
Nitrosimadazoles
151
What are examples of antibiotics that inhibit RNA synthesis?
Rifamycin
152
What are examples of antibiotics that inhibit protein synthesis?
Aminoglycosides
Tetracyclines
Macrolides
Lincosamides
153
Name some penicillins?
Penicillin
Flucloxacillin
Amoxicillin
Co-amoxiclav
154
Name some cephalosporins?
Ceftriaxone
155
Name some glycopeptides?
Vancomycin
| Teicoplanin
156
What penicillin is used on gram +ve organisms?
Flucloxacillin
157
What penicillin is used on gram -ve organisms?
Temocillin
158
What penicillin is used on gram +ve and gram -ve organsims?
Amoxicillin/Co-amoxiclav
159
Name some aminoglycosides?
Gentamicin
160
Name some tetracyclines?
Deoxycycline
| Minocycline
161
Name some Macrolides?
Erythromycin
Clarythromycin
Azithromycin
162
Name some Lincosamides?
Clindamycin
163
What antibiotics inhibit folic acid synthesis?
Trimethoprim
164
What are the 4 "C" antibiotics?
Clindamycin
Co-Amoxiclav
Cephalosporins
Ciprofloxacin
165
What is the mechanism of macrolides?
Inhibit protein synthesis by acting on the 50s subunit of ribosomes
166
What is the mechanism of tetracyclines and aminoglycosides?
Bind to the 30s ribosomal subunit
167
What are the microbial factors that can lead to inflammation?
Virulence Factors
| Pathogen Associated Molecular Patterns (PAMPs)
168
What do integrins bind to?
ICAM
169
Where are selectins expressed?
On endothelial and white cells
170
What is the action of tumour necreosis factor and IL-1?
Increase endothelial expression of VCAM and ICAM
171
What is the action of histamine and thrombin?
Increase selectin expression
172
How do phagocytes kill and degrade pathogens?
Reactive Oxygen Species
| Reactive Nitrogen Species
173
Which enzyme causes NADPH to become oxidated?
NADPH Oxidase - allows oxygen to gain and electron and become superoxide
174
Which enzyme combines NO with superoxide?
Nitrogen Oxide Synthase - produces ONOO
175
Name some inflammatory mediators?
NO
Prostaglandins
Inflammatory Cytokines - IL-1, TNFa, IL-6, IL-15
176
What are the three types of necrosis?
Caseous
Liquefactive
Coagulative
177
What are the two options for cell death?
Necrosis or Apoptosis
178
What is coagulative Necrosis?
Caused by hypoxia which leads to structural proteins bending out of shape and dysfunctional lysosomal proteins.
The cell retains some structure.
179
What is liquefactive necrosis?
Where hydrolytic enzymes digest dead cells into a creamy substance full of dead immune cells
180
What is caseous necrosis?
This is a mix between liquefactive and coagulative necrosis. Associated with TB. The tissues are disintegrated but not fully digested.
181
What is gangrenous necrosis?
Caused by hypoxia, it causes the tissue to dry up like a mummy
182
What is fat necrosis?
Caused by trauma to fatty organs which leads to release of fatty acids and dystrophic calcification of the tissue
183
What is the mitochondrial intrinsic pathway of apoptosis?
Bax and Bak bind to the mitochondrial membrane which increases its permeability and causes release of proteins to stimulate the caspase cascade
184
What is the main protein that stimulates the caspase cascade?
Cytochrome C
185
What do macrophages release to initiate the extrinsic apoptitic pathway?
TNFa
186
What do cytotoxic t cells express to initiate the extrinsic apoptitic pathway?
Fas Ligand
187
In competitive inhibition..
Vmax is the same
| Km varies
188
In non-competitive inhibition...
Vmax varies
| Km stays the same
189
What is the only immunoglobulin that can cross the placenta?
IgG
190
What is redundancy in relation to codons?
Where different codons can encode the same amino acids
191
What is the use of array CGH?
It is used to identify small imbalances e.g. extra or missing chromosomes. It doesn't detect balanced variation e.g. no extra or missing material
192
What is the karyotype of turners syndrome?
45 XO
193
What is Pleiotropy?
Pleiotropy is a condition where a single mutation causes more than one observable phenotypic effect.
194
What is the difference between an oncogene and a tumour suppressor gene?
Tumour suppressor genes - loss of function results in an increased risk of cancer
Oncogenes - gain of function results in an increased risk of cancer
195
What is the difference between expressivity and penetrance?
Expressivity describes the severity of the phenotype
| Penetrance describes the likelihood that a phenotype will develop
196
What is haploinsufficiency?
Haplo-insufficiency refers to the inability of a single allele to confer the usual phenotype to an individual
197
What is phase I drug metabolism?
The drug is changed via oxidation, reduction or hydrolysis to become more polar.
198
What is phase II drug metabolism?
The drug is combined with several polar molecules to bake a water soluble metabolite.
199
What is Frank Starlings Law of the Heart?
As the end-diastolic (preload) volume increases, the stroke volume also increases
200
What is the main site of systemic vascular resistance?
Arterioles because they are converting the pulsatile aortic blood to the non-pulsatile venous blood
201
What is the equation for MAP?
MAP = CO x SVR
202
What is the basal metabolic rate?
Minimum amount of energy required to sustain vital body functions
203
What is raditation?
Emission of heat energy in the form of electromagnetic waves from a surface
204
What is conduction?
Transfer of heat between objects in contace
205
What is convection?
Transfer of heat energy by are or water currents
206
What is the temperature control centre in the brain?
Hypothalamus
207
What part of the hypothalamus does cold activate?
Posterior hypothalamic centre
208
What part of the hypothalamus does warmth activate?
Anterior hypothalamic centre
209
What does increased sympathetic nervous activity do to the Frank-Starling Curve?
Shifts it left
210
What does heart failure do the the frank starling curve?
Shifts it right
211
What is the extracellular fluid composed volume of?
Plasma volume and interstitial fluid volume
212
What are the two main factors that affect extracellular fluid volume?
Water excess or deficit
| Na+ excess or deficit
213
Where is renin released from?
Juxtaglomerular Apparatus
214
What mechanisms increased renin release?
Renal artery hypotension
Stimulation of renal sympathetic nerves
Decreased sodium concentration in renal tubular fluid
215
What stimulates the release of Natriuretic peptides?
Cardiac distensionor neurohormonal stimuli
216
What is the action of natriuretic peptides?
Excretion of salt and water in the kidneys
Decrease renin release
Vasodilation
217
What stimulates the release of antidiuretic hormone?
Reduced extracellular fluid volume
| Increased extracellular fluid osmolality
218
What is the action of ADH?
Vasoconstriction
Increase water reabsorption
Increase extracellular and plasma volume
219
What are the four types of shock?
Hypovolaemic
Cardiogenic
Obstructive
Distributive
220
What is a nerve plexus made up of?
Intertwining of the nerve fibres of the anterior rami.
221
What level does the spinal cord end?
L1 / l2
222
When is it considered a blastocyst?
When a cavity forms in the middle of the cells.
223
When is the morula formed?
When there are 16-32 blastomeres
224
What are the two layers of the bilaminar embryo called?
Epiblast and hypoblast
225
What are the layer of the mesoderm?
Paraxial mesoderm, intermediate mesoderm, lateral plate mesoderm
226
What is haploinsufficiency?
One functioning allele is not sufficient for normal development.
227
What does a low Km indicate?
A high affinity
228
What enzyme transcripts genetic material?
RNA polymerase
229
Where is myoglobin mostly found?
Muscle
230
What is the humoral immune response?
The adaptive immune response
231
Are staphylococcus and streptococcus gram +ve or gram -ve?
B
232
Why is there a decrease in blood volume in patients with sepsis?
Endotoxins cause vasodilation and intravascular fluid to leak into adjacent tissues
233
What type of bacteria are classified by the haemolysis test?
Streptococci
234
What type of viruses may encode p53?
DNA viruses
235
What is Km?
Exactly half the mamximum velocity
236
What is the longest phase of the wound healing process?
Remodelling
237
What are myofibroblasts?
They are differentiated fibroblasts in which the cytoskeleton contains actin filaments
Found in wounds >1 month
238
What do helper T cells express?
CD4 + T cells
239
What do cytotoxic T cells express?
CD8+ T cells
240
What antibody provides local protections on the mucous membranes?
IgA
241
What type of cell is key in class switching of IgM?
Th2 cells
242
What interleukin is responsible for the proliferation of B cells?
IL-4
243
What is a nonsense mutation?
A mutation that results in a premature stop codon or termination of transcription
244
What is incidence?
New cases of a disease occurring in a population in a defined time period
245
What is the antibiotic for coliform infection?
Gentamicin
246
What stimulates protein kinase A?
cAMP
247
Where are ribosomes produced?
Nucleolus
