Blood circulation Flashcards
1
Q
Systolic Pressure
A
LV at full contraction
Bp normal 120 (systolic) / 80 (diastolic)
2
Q
Major components of blood
A
Proteins Vitamins, Hormones Cells Lipids Electrolytes Glucose
3
Q
At what Partial Pressure of oxygen and to what does it freely bind to, partial pressure dissociation
A
@ 100 mm Hg
O2 binds freely to Fe2+
As p(O2) decreases, O2 dissociates and is replaced by CO2
4
Q
What does cyanide target and what does its effect on haemoglobin?
A
Forms cyanohaemoglobin (pink)
Targets Fe2+ containing cytochrome C oxidase (mitochondria), essential for respiration
Stops heart mucsles
5
Q
What is the pH of blood and what is it buffered by?
A
7.4
Albumin, bicarbonate (HCO3-), creatinine, phosphate
ABCP
6
Q
What is Hematocrit?
A
RBC : Total blood volume
7
Q
Layers of blood by centrifugation, and its %
A
Plasma (50%) - viscous/thick, uncoagulated blood, serum normally yellow after fatty meal due to lipids
Buffy Coat (10%) - WBC’s, platelets
RBC’s (40%)
8
Q
Why is fibrinogen absent in serum?
A
As it has formed an insoluble fibrin clot
9
Q
Erythrocytes quantity, function and structure
A
RBC’s
5/6 million per mL
Carries oxygen, biconcave, no nucleus
10
Q
Leukocytes quantity, function and structure
A
WBC’s
10,000 per mL
Immune defence
11
Q
Platelets quantity, function and structure and where it is derived
A
400,000 per mL
Coagulation and tissue repair
Bi-concave, no nucleus
Derived from megakaryocytes
12
Q
What are the 5 major proteins in blood separated by electrophoresis?
A
Albumin a1 a2 B Y (gamma)
13
Q
Plasma
A
Viscous/thick liquid fraction without cells
Contains fibrinogen removed before electrophoresis by coagulation
14
Q
Serum
A
Less viscous yellow liquid AFTER removal of clot (fibrinogen)
15
Q
What are the 2 groups separated by serum electrophoresis?
A
Albumin (50%)
Globulin (40%) - a1, a2, B, Y
16
Q
What is and how is Multiple Myeloma diagnosed?
A
Form of leukaemia, malignant mature B-lymphocyte produces antibody (monoclonal Ig) in v high amounts.
By serum electrophoresis, as it shows large peak of Ig
17
Q
What is the most abundant protein in blood and what is its function?
A
Albumin- 50% of total blood protein
Maintains/provides osmotic pressure
“SPONGE”- absorbs fluid- balance
Binds and transports small molecules, proteins, hormones
18
Q
What is fibrinogen cleaved by and how is it activated
A
Cleaved by Thrombin- forming cross-link fibrin
By coagulation cascade
19
Q
Function of Immunoglobins (Ig) / Antibody, where are the produced
A
10% of total blood
Immunity- elevated in disease
Produced by plasma B-lymphocytes
20
Q
Complement (C’) proteins function, most abundant component
A
9 major components ‘coat’ bacteria for phagocytosis- opsinization- signal neutrophils
Zymogens (inactive till cleaved)- most abundant is C3
Innate immunity
21
Q
Coagulation proteins, what ion is required for blood clotting
A
13 proteins contribute
Enzyme Thrombin cleaves fibrinogen
Ca2+ required for clotting
22
Q
What is haemophilia and its most common form?
A
X-linked recessive
Factor VIII deficiency
23
Q
Electrolytes Functions
A
Ca2+ and K+ - help with blood clotting
Isotonicity (two solutions of same conc. of solutes)
24
Q
Origin of blood and original cell
A
Bone marrow
Pluripotent (can give rise to several different cell types)
Haemotopoeitic stem cell (CD34+)
25
CD34+ gives rise to, and is most abundant in
Myeloid (partly form innate immunity) and lymphoid (adaptive immunity)
Umbilical cord blood
26
What cell gives rise to all innate immunity cells
Myeloblast
27
What are the three factors that drive haemotopoiesis
GM-CSF
G-CSF
EPO
28
Where is GM-CSF produced? What does GM-CSF stimulate production of
produced by TEF:
T-lymphocytes
Endocrine cells
Fibroblasts
```
stimulates production of: INNATE Immunity (BENM)
Basophils
Eosinophils
Neutrophils
Monocytes
```
29
Where is EPO produced? What does EPO stimulate production of
Produced in Kidney and Liver
Stimulates production of RBC's
30
What does G-CSF stimulate production of, what does it mature?
Stimulates production of:
Granulocytes (eosinophils, basophils), stem cells
And it matures neutrophil
31
Stem cells
When it divides, new cell can either remain a stem cell or become another type of cell with a more specialized function
E.g. bone marrow, repair damaged/worn out tissue
32
Myeloid progenitor
| Phagocytosis and Innate Immunity
```
Gives rise to: EMMM
Erythrocytes
Myeloblasts (--> BENM)
Megakaryocyte (--> thrombocytes)
Mast cells
```
EMMM (every man makes money)
33
Lymphoid Progenitor
B (plasma cell) and T (Immature T's give CD4, CD8) lymphocytes
34
Three pathways of activating Complement
Classical
Alternative
Lectin
35
Classical Activation
Antibodies (IgM or IgG) bind to microbe surface
C1,2,3,4 condense on antibody --> (C2aC4b) = C3 convertase on surface
36
Alternative Activation
C3 activated by being close to surface of microbe
This activated another type of C3 convertase
C3 protein cleaved by C3 convertase --> C3b + C3 --> C5 convertase
37
Lectin Activation
Doesn't recognise an antibody bound to its target
Lectins are carbohydrate binding proteins in blood that bind to unusual carbohydrates found only on microbes
Complement condenses on these bound lectins
38
End stage complement
Surface bound convertases activate complement 5-9 forming lytic pore (MAC) causing bacteria to lyse
39
Anaphylotoxins
C3a,C4a,C5a (chemoattractants) recruit and activate phagocytes to site of infection
40
Virulence factors
Proteins produced by microbes that inhibit complement cascade
41
Phagocytic cells
Neutrophils and macrophages have complement receptor that bind complement and initiate phagocytosis
42
2 Coagulation pathway's and result
```
Intrinsic pathway (contact)
Extrinsic pathway (tissue damage)
```
Results in binding and activation of platelets that bind to vessel cell wall
43
Intrinsic pathway
Factors 8, 9, 11, 12
| Leads to cleavage of Factor X- converts prothrombin -> thrombin
44
Extrinsic
Factors 5, 7
| Activate Factor X
45
Thrombin use
Cleaves fibrinogen -> fibrin
46
Fibrin
Forms cross-links forming clot
47
Anti-coagulants
Produced by Hirudin, Heparin, Warafin, Mosquitoes
| Block thrombin, preventing clotting
48
What dissolves clot in blood
Plasminogen-> Plasmin
Plasminogen - activated by Tissue Plasminogen Activator (TPA) or streptokinase
Plasmin cleaves fibrin clot
49
Thromolysis
Plasmin cleaving fibrin clot
50
What does TPA and streptokinase prevent
```
Myocardial infarct (heart attack)
Pulmonary embolism (clot in lungs)
DVT (clot usually in leg)
```
51
Innate immunity features
Doesn't change/strengthen over time
No memory (1st and 30th response the same)
Immediate/rapid response
Recognises broad range of pathogens using small set of receptors
Distinguish self from non-self
52
Cellular Response and examples
Myeloid, Lymphoid cells
Phagocytosis, cytotoxic T-cells
Release of cytokines
Examples:
BENM + dendritic cells, natural killer cells
53
Humoral Response and examples
Soluble factors that can directly kill bacteria
```
Examples
Antimicrobial peptides
Antibodies produced by B-cells
C-reactive protein
Complement
LPS binding protein
Mannose binding lectin
```
54
3 types of innate immunity processes
Complement
Phagocytosis
Pattern recognition receptors (PRR)
55
Innate immunity complement process
Opsonisation of microbes by blood proteins and production of anaphylotoxins (chemoattractant) that attract & activate phagocytes
56
Innate immunity phagocytosis process
Engulfing by neutrophils or macrophages destroying organism
57
Innate immunity Pattern recognition receptors (PRR)
Recognise complex microbial molecular patterns
| Found on many myeloid cells
58
Viruses function, examples
Intracellular pathogen, use host machinery for replication
Examples
Influenza, smallpox, HIV, Polio, varicella (chicken pox)
59
How is bacteria distinguished, destroyed and give examples of bacteria
Mostly extracellular, engulfed by phagocytic cells
Most distinguishable by gram stain
```
Examples
Staph aureus - (boils, skin peeling)
Strep pyogenes - (swollen throat, lymph nodes)
Mycobacterium Tb - (cough, fever)
Vibrio Cholera
Yersinia pestis (plague)
```
60
How are Protozoa and parasites destroyed? What are Protozoa and parasites
Complex, mostly multicellular organisms
Direct killing by cytotoxic chemicals released by myeloid cells
CANT BE ENGULFED so BEM secrete chemical mediators (histamine)
Examples
Malaria
Helminths 'worms'
61
Gram positive and examples that show +ve
Thick peptidoglycan cell wall as defence
Phagocytosis needed, not directly killed by complement
Examples
Staph aureus
Strep pyogene
62
Gram negative and examples that show -ve
THIN peptidoglycan layer
Killed by complement MAC lysis, directly killed
antibiotics (e.g. penecillin) block peptidoglycan synthesis, bacteria can't divide
Examples
E-coli
H. Influenza
63
1st step in recruiting a neutrophil (extravasation)
Activation
Chemokines from site of infection activate endothelial cells to express adhesion molecules
Neutrophils express adhesion counter receptors
64
2nd step in recruiting a neutrophil (extravasation)
Tethering
Neutrophils slow down and tether (roll) along endothelial cells inside capillary
Slalyl Lweis X (carb) on neutrophil forms bonds in selectins on endothelial cells
65
3rd step in recruiting a neutrophil (extravasation)
Adhesion
Strong binding between neutrophil integrins and ICAM-1 on endothelial cells stops neutrophil from rolling
Neutrophil changes shape, flattens out
66
4th step in recruiting a neutrophil
Diapadesis
Neutrophil squeezes between endothelial cells into interstitial space (capillary --> tissue)
67
5th step in recruiting a neutrophil
Chemotaxis
Neutrophil travels to site of infection guided and travelling down chemokine gradient
68
Phagocytosis of opsinised cells
Bacteria treated with serum to opsonise them
Neutrophils detect c5a (chemoattractant) by their receptors on leading edge
Neutrophils migrate up chemoattractant gradient
- Polymerising actin @ leading edge
- De-polymerising actin @ trailing edge
Phagocytes mainly bind to C3b via receptors on microbe surface
69
Which complement receptor is the most important? what does this receptor bind to
C1 (MOST IMPORTANT) binds to C3b
70
Fc Receptor mediated phagocytosis
Ingestion- bacterium engulfed by Fc receptors on neutrophils binding to Fc on antibody
Fusion- Phagosome + lysosome -> phagolysosomes
Acidification- Phagolysosome acidifies with H+ pumped in
Digestion- Proteases activated from acidification, stimulating production of superoxides (H2O2 and HOCl)
Exocytosis- removal of digested microbe
71
Pattern Recognition receptors (PRR)
PRR recognise pathogen associated molecular patterns (PAMPS) - unique to microbes
Best known PRR's are Toll-like Receptors (TLR)- Leucine rich repeat (LRR)
Activation of TLR activates strong inflammatory response
72
Pattern associated molecular patterns (PAMPS) and example
LPS- lipopolysaccharides
Evolutionarily stable
'power switch' for adaptive response
73
LPS- lipopolysaccharides
Tiny amounts induce powerful response
Gram negative bacteria
Pyrogen
- causes fever, rigors (shivering), hypotension (low BP)
- this condition known as SEPTIC SHOCK- due to uncontrolled gram negative infection in blood
74
Which bacteria are gram +ve, -ve or neither
```
Staph aureus (+ve)
Strep. pyogenes (+ve)
```
Mycobacterium tuberculosis
(NEITHER- due to think LIPID cell wall)
```
Yersinia Pestis (-ve)
Vibrio Chlorae (-ve)
```
75
Adaptive Immunity
Memory (each successive response is stronger, more effective)
Affinity of B-cells towards antigen increases with time and perspective of antigen
Born with large repertoire of B&T lymphocytes
76
How is the large repertoire of B&T lymphocytes produced
Randomly produced by gene rearrangement that codes for antigen receptors
77
Where are B&T lymphocytes produced
Bone marrow, thymus, spleen
78
What is the specificity of each lymphocyte?
Different specificity on each antigen
ONE B cell = ONE antigen specificity
79
Transposon
"jumping gene"
DNA sequence that can move to new positions within genome
It is inserted into receptor gene
80
Transposase
Enzyme bound to end of transposon allowing it to move to other parts of the genome,
'in trans'- Rearrange other genes without affecting its own receptors
81
What is tranposase now called?
RAG 1 & 2 (recombination activation gene)
82
What are Recognition sequences (RS) and how are they shifted out
base pair sequences found @ ends of any gene segments that rearrange
Shifted out by RAG 1&2, to be recombined with other sequences
83
Immunoglobin fold, approx. how many amino acids
two anti-parallel B-sheets
| 30 degree twist to each other, forms soluble "B-barrel structure" (approx. 110 a.a's)
84
What makes up immunoglobulin domains?
7 (constant) or 9 (variable) B-strands
85
How are the B-sheets stabilised?
Single disulphide bond between sheets
86
How are B-strands connected? and what do the "connections" do?
Loops
| Loops are not constrained, extreme amino acid diversity
87
Ig Antibody structure
4 protein chains, 2 heavy chains, 2 light chains
| 4 loops on Heavy chain, 2 on light chain
88
What are the two parts of a H and L chain
Variable and Constant region
Variable region is where loops of a.a. diversity occurs
89
How many loops per variable region on each chain
3 per variable region per chain, 6 in total per antigen binding site region
90
Effector region
Bound by Fc receptors on myeloid and complement`
91
IgM properties, 2 different forms
Default Ig, made by ALL B-cells (naive)
Low affinity
Membrane form- B-cell antigen receptor (BCR)
Soluble form- Pentameric structure (10 antigen binding sites)
LOW affinity as its naive- doesn't know what antigen it is going to bind to
HIGH avidity "stickiness"- good at fixing complement
Good @ binding to microbe surfaces
92
Affinity, example
"how good @ finding each other"
Sum of attractive forces @ two surfaces exceeds repulsive forces- so bind together
Antibodies v. high affinity, less antigen required for immune response to be initiated
93
Avidity, example
"Velcro"
Multiple affinity contact points
Individually weak, LOTS together= strong
IgM (e.g. 10 contact points, stronger than 1)
94
IgG
MOST abundant
Activates complement
Placental transfer
95
IgA
Secreted @ mucosal surfaces
| In breast milk gives strong gut immunity for baby
96
IgD
Membrane-form
| 2nd LEAST abundant
97
IgE
LEAST abundant
Causes atopic allergy
High affinity receptor on mast cells, activated when IgE binds to e.g. pollen and allergens
98
Why can a.a's form complementarity to most things?
A.a diversity @ antigen binding site is huge
99
Where is the a.a. variation found? and what do they do?
3 regions of Complementary Determining Regions (CDR)
These are the 3 loops that connect the strands in the 1st domains of the H and L chains
6 in total- connect B-strands in the Ig variable domain ( first N terminal domain in H chains and L chains
100
How many loops in an antigen binding sites? Area of surface
3 loops from VH and 3 from VL juxtapose in the folded protein
Roughly rectangular surface of ~800-1000 Å^2
Two ABS per antibody
101
Recombination
1 D segment combines with 1 J segment
everything in between is lost, (e.g. introns)
RAG 1 & 2 bring these two segments from long distances together
double strand unwinds, editing; adding and deleting bp's occur before strand is rewound
102
2 step of recombination
1 V segment joins with 1 D segment, producing VDJ segment
Huge variation in VDJ segments
VDJ codes for CDR3, center
103
Somatic hypermutation
One Naive B-cells has the IgM receptor for the antigen for the antigen
Then replicates to form progeny which undergo random mutation of gene adding to the VDJ gene
104
Where does clonal selection occur in body
In B-cell follicles in your lymph nodes
105
How does a cell achieve a higher affinity receptor?
Successive rounds of affinity maturation, B-cell is mature
106
What can mature B-cell become?
Plasma cell- secretes high affinity soluble IgG
Memory cell- resides in lymph nodes long-term waiting for next encounter with that antgen
107
How does immune system produce antigen receptors to encounter all antigens in the future?
Stochastic gene rearrangement
Produces as many possible antigen receptor combinations as it can
108
Fundamentals behind vaccination
Weak naive B-cell undergoes rearrangement & hypermutation eventually secreting high affinity IgG
Next time you are exposed to antigen, high affinity IgG neutralises pathogen before it can grow/damage
109
What is the molecular weight of IgG?
150 kDA (kilodaltons)
110
Molecular weight of Heavy and Light chain?
```
HC = 50-75 kDa
LC = 25 kDa
```
111
Thymus
Where immature lymphocytes from bone marrow mature
Gland sits above heart, largest at birth, decreases with age
112
What surface antigens are expressed on T-lymphocytes
MHC class 2- CD4
80% of T-cells
secrete cytokines --> drive immune response
MHC class 1- CD8
20% of T-cells
Cytotoxic cells, kill other infected cells
Suppress autoimmune cells
113
Derivatives of CD4
T-reg (suppress immune system)
Th-1 (cellular immunity/response)
Th-2 (antibody immunity/ humoural response)
Th-17 (promotes inflammation)
114
How is T-cell signalling initiated by CD4 and CD8
CD4 and CD8 contain tyrosine kinases (transfer phosphate group from ATP to protein); causing phosphorylation
115
T-cell receptor (TcR)
Ig like molecule on ALL surfaces on T-lymphocytes
TcR gene locus undergoes rearrangement like in B-cells
Two gene loci- a-chain and B-chain
Only recognise ONE antigen (unlike antibodies)
116
Major Histocompatibility Complex (MHC)
"flags"
| present virus or bacteria to surface of cells to T-cells
117
T-cells see what two antigens @ the same time
Foreign peptide antigen (non-self) imbedded in MHC - encoded by virus
MHC molecules (self)
118
Cytotoxic T-lymphocytes (CTL)
Can only kill infected cells from own strain (congenic mouse experiment)
Restricted by MHC, as only difference between epithelial cell C and D was in the MHC cells (present antigens differently)
119
Polymorphic
More than one form, varies between individuals
Each polymorphic gene as 12 copies
120
MHC restriction, structure
TcR is membrane bound like Ig molecule on T-cells
6 loops, CDR 1,2,3 each have 2- variable region many combinations
antigen binding surface of TcR binds to top of MHC "peptide groove" (contains foreign peptide antigen)
MHC molecules expressed on most cells and present antigens to T-cells. HIGHLY POLYMORPHIC`
121
Two different classes of MHC, and HLA parts
HLA- human leukocyte antigens
Class 1 = HLA A, B, C
Class 2 = DP, DR, DQ
Each gene has 2 alleles, 12 in total
2 Parental alleles are CO-DOMINANT
122
MHC class 1
Picks up peptide antigens from inside the cell
| Presents them to CD8 cytotoxic T cells
123
MHC class 2
Picks up digested antigens from phagolysosome (extracellular pathogens) and present them to CD4 helper cell
124
CD4 helper T-cells
Phagocytic cell takes up bacteria, some captured by MHC class 2, expresses it on surface, where it is recognised by CD4 helper cell
MORE helper T-cells produced which produce cytokines that "help" other cells replicate
125
What destroys CD4+
HIV. Uses CD4 antigen as its receptor to enter and replicate in helper T-cells
126
AIDS
Resulting from long-term depletion in CD4 T-cells
Lose ability to respond to simple infections
127
Why is no vaccine available for AIDS
Have 100's of viral mutants that can't all be covered by vaccine
128
Problem with transplantation
T-cells of recipient recognise MHC donor antigens as foreign
129
What suppresses T-cell response in transplantation recipients
Immunosuppresive drug (cyclosporine)
