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BioChem Exam 3 > Blood > Flashcards

Blood Flashcards

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1
Q

3 basic components of blood?

A

Plasma/serum

Buffy coat

Erythrocytes

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2
Q

Main components of plasma?

A

Water 92%

Proteins 7%
Albumins mostly, 
Globulins
Fibrinogen
Regulatory proteins

Other solutes 1%
Electrolytes, Nutrients, Respiratory gases, Waste products

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3
Q

Components of buffy coat?

A

Platelets, WBCs

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4
Q

What is serum?

A

Liquid component of clotted blood

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5
Q

What is plasma?

A

Unclotted blood = all mixed together..RBCs, liquids, proteins, platelets

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6
Q

Most abundant non cellular protein in blood? Function?

A

Albumin

=> secreted by hepatocytes as carrier proteins
=> maintains oncotic pressure
=> helps keep fluid from leaking out

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7
Q

Hypoalbuminemia causes?

A

Through liver failure => fluid leaking => oncotic pressure falls

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8
Q

Second most common type of protein in blood?

A

Immunoglobulins

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9
Q

Where does heme synthesis take place?

A

Mitochondria and cytosol

=>liver

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10
Q

First and limiting step of heme synthesis in mitochondria?

A

Glycine + Succinyl-CoA –ALA synthase–> delta-ALA

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11
Q

Which enzyme is deficient in what disease causing the absence of Protoporphyrin IX?

A

Proto-porphyrinogen oxidase

=> variegate porphyria

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12
Q

Lack of Protoporphyrin IX causes?

A

Sideroblastic anemia

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13
Q

What are prophyrias?

A

Genetic diseases resulting in decreased activity of one+ enzymes involved in heme synthesis

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14
Q

How many O2 can Hgb bind?

A

Maximum of 4

But usually isn’t 4

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15
Q

Recognize structures on slide 8

A

K

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16
Q

What is anemia?

A

Quantity of RBCs = lower than normal => capacity of blood to carry adequate O2 is compromised

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17
Q

What causes anemia?

A

Failure to produce enough RBCs (iron deficiency=most common cause/aplastic anemia)

Loss of RBCs (hemorrhaging)

Increased destruction of RBCs that can not be compensated for by bone marrow (sickle cell anemia/autoimmune hemolytic anemia)

Sequestration of RBCs (spleen)

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18
Q

Why does CO have a 200x greater affinity for Hgb than O2?

A

CO is unstable => lone electron pair on positively associated carbon => gains stability by binding to Hgb

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19
Q

Diseases of inadequate Hgb synthesis?

A

Porphyrias

Hemoglobinopathies (thalessemias, sickle cell anemia)

Iron deficiency anemia

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20
Q

What is hemoglobinopathies? Whats the specific change leads to thalessemia?

A

Problem with hemoglobin synthesis => disorder of one of globin side chains of hemoglobin

Thalessemias => wrong amount of globin chains => 4 alpha-gene an 2 beta-globin genes

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21
Q

What kind of genetic mutation leads to thalessemia?

A

Frameshift or nonsense mutation

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22
Q

What is alpha-Thalessemia?

A

Underproduction of alpha-globin due to mutated alpha-globin genes

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23
Q

Sub-types of alpha-thalessemia?

A

Carrier: one alpha-globin gene mutated -> no clinical manifestations

Alpha-thalassemia trait: 2 alpha-globin genes mutated => mild microcytic anemia

Hemoglobin H disease: 3 alpha-globin genes mutated => bone marrow transplant/transfusions

Hemoglobin barts: 4 alpha-globin => intrauterine death

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24
Q

Sub-types of beta-Thalessemia?

A

Beta-Thalessemia train/minor

Beta-Thalessemia major and intermedia: 2 beta-globin genes mutated => major requires chronic blood transfusions

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25
Treatment of thalessemia?
Complete bone marrow transplantation
26
Iron deficiency anemia is? Two causes he thinks matter?
Inadequate iron supply to sustain erythropoiesis Causes: lack of iron in diet, inability to absorb iron
27
Difference between Myoglobin and Hemoglobin?
Mgb: Single polypeptide chain containing 8 alpha helices, coiled => binds 1 O2 (released by Hgb) Hgb: is tetrameric/made of 2 subunit types: 2 alpha and 2 beta chains = 2 alpha beta protomers 4 Heme groups (4 protoporphyrin rings)=> binds up to 4 O2
28
Chemical orientations of heme due to O2 binding?
Unstable: Deoxygenated Hgb - tense state (angled) => low affinity for O2 => more likely to transfer O2 to tissues Stable: Oxygenated Hgb - relaxed state (planar) => high affinity for O2 => recruit O2 in lungs (15 degrees rotational change) Difference by 100 fold
29
Binding/coordination sites of Fe(2+) in heme?
Total of 6 binding sites: 1-4 => protoporphyrin ring along its plane 5 => proximal histidine 6 => O2 binding site
30
Oxygen - Hgb dissociation curve type?
Sigmoidal O2 dissociation curve
31
Which conditions cause the sigmoidal curve to shift to the left?
Stabilization of R state => favor O2 binding
32
Which changes lead the sigmoidal curve to shift to the right?
Stabilization of T state will favor O2 loss
33
Why is O2 a positive allosteric effector?
Bc the ligand affinity of Hgb is increased by successive O2 binding
34
Type of relationship between O2 and Hgb?
Positive cooperativity
35
Function of negative allosteric regulators? Name them
=> drive the release of O2 in tissues => shift curve to right => help Hgb unload O2 => reduced O2 binding/affinity of O2 => T state > R state Increased Temp/CO2 Decreased pH 2,3-BPG (Citric Acid Cycle)
36
What is the Bohr Effect?
Contribution of H+/CO2 and therefore Hgb in acid-base regulation Acidic = low pH => right shift => decrease in O2 affinity => response to low blood pH => resulting from increased CO2 concentration in blood
37
Which enzyme catalyzes the buffer reaction between H2O + CO2 H2CO3 H + HCO3
Carbonic anhydrase (between CO2 and H2CO3)
38
How is the T state stabilized?
3 factors: H+ => pH CO2/HCO3- Increased temp
39
What is altitude sickness?
Leads to hypoxia => headache/nausea/ life threatening pulmonary/cerebral edema => death Treat: enzyme inhibitor causing alkaline blood
40
Difference between fetal and normal Hbg?
Fetus has to extract O2 from mothers RBC Uses different set of globin genes as part of Hgb Adult uses HgbA, fetus uses 2 alpha+2 gamma chains = HgbF
41
What is the immediate response to Hypoxia?
Cells must turn to anaerobic respiration => lactic acid => lower pH (=>shifts O2 curve to right/favors T state/releases more O2)
42
What is the 24h response to hypoxia?
RBCs increase 2,3BPG => lowers O2 affinity of Hgb (right shift/increased O2 delivery to tissues)
43
What is the days-4weeks response of hypoxia?
Goal: create more RBCs by secreting erythropoietin (Epo): Kidney cells = high O2 demand = sensors of O2 delivery Low O2 to kidney cells => hypoxia-inducible factor (transcription factor) not degraded => turns on multiple genes => incl. gene to secrete Epo Epo migrates to bone marrow => binds to Epo receptor => activates JAK and STAT (signal transducer and activator of transcription) => blocks RBC apoptosis => increase hematocrit => increase O2 carrying capacity
44
Type of gene mutation of sickle cell disease?
Recessive point mutation in beta-globin gene => mutation results in substitution of neg charged glutamic acid with hydrophobic valine at AA in pos #6 => early mortality => hydrophobic = sticky patch
45
Treatment of SCA and hydroxyurea?
Use of hydroxyurea => increase expression of gamma-globin => can replace beta-globin in Hgb
46
Functions of iron?
Oxygen carrier: 2/3 of 4g in Hgb Immediate oxygen storage: myoglobin in muscle Energy production: cofactor (cytochromes of oxidative phosphorylation) Detoxification => cytochrome p450 enzymes Immune protection
47
Fe3+ ?
Ferric
48
During iron transport in the GI, what reaction happens in the intestinal lumen?
Fe(3+) --ferric reductase--> Fe(2+)
49
What happens with iron in the enterocyte cell?
Fe(2+) uses DMTI (divalent metal transporter to enter cell) --> blood through ferroportin --> Fe(2+) => converted back to Fe(3+) => bound to transferrin => carried
50
After iron is taken up by the intestines (1-2mg/day), transferrin transports iron to?
75% bone marrow for red blood cell production 10-20% storage via ferritin in liver/heart 5-15% other
51
What is the most abundant protein for iron storage (cytosolic protein)? Stored in what type of cells?
Ferritin in reticuloendothelial cells => 24 unit multimer of heavy/light chains => hollow shell => plasma ferritin = indirect marker for amount of iron stored
52
Excess iron leads to? Treatment?
Damaging O2 free radicals => toxic to heart/liver mostly Treat: iron chelator => deferoxamine/deferasirox => binds free iron in blood = iron-chelator complex
53
Function of hepcidin?
Body's way of regulating uptake/availability of iron High iron stores => hepcidin high for example as a result of inflammation (IL-6) => negative regulator of ferroportin = blocks ability of cells to secrete iron into blood: Enterocytes: decreased iron absorption Reticuloendothelial cells: decreased ability of iron to be mobilized
54
Diagnosis of iron deficiency anemia?
``` Diagnosis: Microcytic anemia (smaller/pale RBCs) => poor Hgb production ``` Low ferritin (ferritin increases in times of stress/illness) Low transferrin saturation (~10% iron compared to normal 30-40%)
55
Treatment of iron deficiency anemia?
Provide dietary iron => red meat, oral elemental iron+OJ/Vit C (helps reduce iron for DMTI) Can be due to excessive milk consumption =>inflammation=>poor absorption => give elemental iron+decrease milk consumption Intravenously Supplemental iron
56
Two phases of clotting?
Platelet plug formation: Temporary repair until a proper clot can form Clot formation: Longer term, stronger, clot formation stops
57
Steps of platelet plug formation?
Damage of endothelial lining => expose collagen on basement membrane and von Willebrand Factor vWF Adhesion => aggregation (fibrin linking of glycoprotein Gp IIb/IIIa receptors)=> activation (adhesion=> degranulate =>ADP,TXA2)
58
Drug that inhibits platelet plug formation/aggregation?
Nonsteroidal anti-inflammatory drugs NSAIDs act by inactivating/inhibiting cyclooxygenase COX => inhibit resultant prostaglandins/prostacyclins/thrombaxans => Aspirin noncompetitively/irreversible inhibits COX enzyme (acetylation) => Ibu is reversible
59
Two pathways of clotting cascade and their relationship? Combine where?
Intrinsic pathway (Factor 8,9,11,12 activated by Ca, triggered by 12) Extrinsic pathway (triggered by Factor 7, tissue Factor 3) Both triggered by injury duuhh => independent Combined efforts lead to common pathway
60
Steps leading up to common pathway and committing step in the clotting cascade?
Factor X is cleaved into Xa Committing step: Factor Xa/Ca/V => convert prothrombin into thrombin Fibrinogen --thrombin--> fibrin
61
Factor X in the clotting cascade is activated how?
Intrinsic/extrinsic activated factors, Ca, PL
62
Fibrinogen's monomer is?
Fibrin | => mesh ensnare RBCs
63
Function of thrombin?
Activation of fibrin Thrombin cleaves FPA and FPB domains to convert fibrinogen to fibrin and fibrinopeptides => breaks Arg-Gly bond
64
Fibrin aggregation results in? Steps sorta?
Forms a soft clot Fibrinogen --thrombin-->Fibrin monomer (FPA/FPB) => fibrin dimer => fibrin polymer
65
What causes the soft clot to turn into a hard clot?
``` Factor XIII cross linking: Factor XIIIa (enzyme) stabilizes soft clot=>hard clot ```
66
Characteristics of hemophilia? Treatment?
Group of diseases characterized by frequent hemorrhages (spontaneous/traumatic) - Hemophilia A => 80% of patients => Factor VIII deficiency - Hemophilia B => 20% of patients => Factor IX deficiency => both intrinsic pathway factors => intravenous factors fix it
67
Characteristics of von Willebrand's disease vWD?
- mild, most common bleeding disorder due to vWF deficiency => vWF => platelet adhesion/Factor VIII survival
68
3 major regulators that serve to control clot formation?
Anti-Thrombin III (ATIII) Protein C Protein S => hypercoagulable state
69
function of protein C/S?
Protein C + Protein S => degrade/inactivate Factors Va and VIIIa Protein C (MEMBRANE BOUND COMPLEX)--thrombin etc-->activated protein C + Protein S
70
Protein C/S and Thrombomodulin/thrombin lead to?
Lyses of fibrin
71
What vitamin contributes to clotting and it's deficiency hinders clot formation and causes chronic bleeding?
Vit. K Can be deficient due to antibiotic damage to gut flora
72
How do plasminogen activators contribute to plasmin and clot dissolution?
They break plasminogen between arginine 560 and valine 561 (SS bond) => further cleavage produces angiostatin
73
Function of angiostatin?
Limits new growth of blood vessels
74
Which condition is attempted to diagnose by measuring the level of D-dimers?
Deep Vein Thrombosis DVT or pulmonary embolism | => confirm and grade extent of existing clot
75
3 enzymes/factors increasing plasminogen dissolution (clot dissolution)?
Tissue type plasminogen activator Streptokinase Urokinase-type plasminogen activator Plasminogen --> plasmin
76
Characteristics of Factor V Leiden Polymorphism?
=> changes Arg->Glutamine in Factor V clotting factor Thats where protein C acts => protein C less efficient in regulating Factor V => higher levels of Factor Va => excessive thrombin production, fibrinogen activations, clot formation => hypercoagulable state => causes DVT => pulmonary embolism etc

BioChem Exam 3 (5 decks)

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