Test 3 Blood Flashcards
(108 cards)
1
Q
What are the components of blood?
A
Plasma
Erythrocytes
Buffy Coat (Platelets and WBC)
2
Q
What is the plasma made up of?
A
Water 92%
Proteins 7%
Other Solutes 1%
3
Q
Within the Erythrocytes how many are found per cubic mm?
A
4.2-6.2 million per cubic mm
4
Q
How much blood is found within the human adults?
A
5L
5
Q
The entire volume of blood circulates through the body within what time frame?
A
1-2 minutes
6
Q
What are the cellular components of blood?
A
RBC (most abundant)
WBC
Platelets
7
Q
The generation of new RBCs (Erythrocytes) from bone marrow is called?
A
Erythropoiesis
8
Q
Erythropoiesis relies on what kidney-secreted hormone?
A
Erythropoietin (Epo)
9
Q
What is the 1st enzyme in the process of Synthesis of Heme?
A
AminoLevulinicAcid (ALA) Synthase (1st enzyme and rate-limiting step)
10
Q
What provides feedback inhibition (Negatively regulates) the Synthesis of Heme?
A
Increased Levels of Heme negatively regulate AminoLevulinicAcid Synthase
11
Q
What catalyzes final the step of the synthesis of Heme by adding Fe2+?
A
Ferrochelatase
12
Q
What does Heme consists of?
A
Protoporphyrin Ring w/central coordinated Fe2+
13
Q
How much greater of an affinity to Hemoglobin does Carbon Monoxide have when compared to Oxygen?
A
200 times greater
14
Q
This is defined by: Rare diseases characterized by the inability to efficiently synthesize the protoporphyrin ring?
A
Porphyrias
15
Q
This is defined by: ‘Pathies’ of hemoglobin synthesis- disorders of one of the globin side chains of hemoglobin (e.g. Sickle Cell Anemia, Hemolytic Anemia, Thalassemias)?
A
Hemoglobinopathies
16
Q
What is defined by: Defect in amount of globin chains synthesized (of the 4 Alpha-globin genes and 2 Beta-Globin genes)?
A
Thalassemias
17
Q
This condition is the underproduced beta-globin subunit because of mutations in the beta-globin genes (Frameshift or nonsense mutation)
A
Beta-Thalassemia
18
Q
Define: Iron Deficiency Anemia.
A
Inadequate iron supply to sustain erythropoiesis
1Billion affect, usually: too much cow’s milk
19
Q
What are some of the common causes of Iron Deficiency Anemia?
A
Parasitosis Blood Loss Lack of iron in diet Inability to absorb Iron Pregnancy
20
Q
What are the characteristics of the relaxed state of the heme molecule?
A
Oxygenated (O2 Binding) and heme molecule assumes a planar conformation
21
Q
What are the characteristics of the tense state of the heme molecule?
A
Deoxygenated (#6 coordination site is empty) and heme assumes a domed formation (strained)
22
Q
What are the two seemingly opposing functions hemoglobin must be able to carryout?
A
(1) Become fully saturated with O2 in Lungs
(2) Able to efficiently unload O2 in the tissues
23
Q
O2 Binding does not Guarantee what?
A
O2 Delivery
24
Q
What affect does increasing temperature have on Hemoglobin binding of Oxygen?
A
Reduces affinity (binding) Hgb of O2 (T State > R State)
25
At higher temperature Hgb will more readily do what?
More readily release O2
26
What are the functions of Iron?
- Oxygen Carrier
- Immediate Oxygen Storage
- Energy Production
- Detoxification
- Immune Protection
27
Within the Intestinal Lumen (Ingested Iron) Fe3+ (Ferric) is converted to Fe2+ (Ferrous) Iron by what?
Ferric Reductase
28
Fe2+ is transported into enterocyte via what?
Divalent metal Transporter (DMT1)
29
What is the most important protein for iron storage and found in most tissues as a cytosolic protein?
Ferritin
30
What is the most common porphyria?
Coproporyphyria
31
What is Pyridoxal Phosphate derived from?
Vitamin B6
32
What are some Anemias in which destruction of RBCs cannot be compensated for by bone marrow?
Sick Cell Anemia
| Autoimmune Hemolytic Anemia
33
Deficiency at the Protoporphyrin IX step of Heme Synthesis produces what kind of anemia?
Sideroblastic Anemia
34
This Hemoglobinopathy is caused by under produced alpha-globin subunit because of mutated alpha genes (frameshift or nonsense mutation)
Alpha-Thalassemia
35
What is the difference between the carrier state and Trait exhibiting of Alpha-Thalassemia?
Carrier: One Alpha-Globin gene mutated (no S&S)
Trait: Two Alpha-Globin genes mutated (mild microcytic anemia)
36
What are the Sub-types of Alpha-Thalassemia?
- Hemoglobin H Disease: Three Alpha-globin genes mutated (Requires RBC transfusion or bone Marrow)
- Hemoglobin Barts: Four Alpha-Globin genes mutated (Intrauterine Death)
37
What are the Beta-Thalassemia Sub-Types and Characteristics?
- Beta-Thalassemia Trait/minor: one Beta-globin gene mutated (Mild microcytic anemia)
- Beta-Thalassemia Major and Intermedia: Two Beta-globin genes mutated (Chronic blood transfusions)
38
What are the Signs and Symptoms of Beta-Thalassemia?
Birth the baby seems normal and anemia begins within the first months and progresses to severe symptoms
39
What is the curative treatment of Alpha and Beta Thalassemia?
- Curative treatment complete marrow transplantation
| - Recipient endogenous bone marrow ablated
40
What are the names of the O2 binding proteins?
Myoglobin (Mgb)
| Hemoglobin (Hgb)
41
What are the characteristics of Myoglobin (Mgb)?
Single polypeptide chain w/ 1 O2 binding site
Composed of 8 Alpha-helices bound by coil structures
Binds O2 that is released by Hgb
42
What are the characteristics of Hemoglobin (Hgb)?
Tetrameric
Subunit Types: 2 Alpha-chains and 2 Beta-chains
Each subunit contains one protoporphyrin ring,
allowing for 4 O2 molecules to bind to one Hgb
43
What are the 6 coordination sites Ferrous iron (Fe^2+) has regarding heme and O2 binding?
Sites 1-4 w/ Protoporpphyrin ring along its plane
Site 5 w/ Proximal histidine
Site 6 for O2 Binding
44
What causes the Tense State/Strained state of heme in which it assumes a domed formation?
Iron projects outward from center of protoporphyrin ring when #6 coordination site is empty
45
What state and formation does heme assume when O2 binding occurs at #6 coordination site?
Relaxed State
| Planar Conformation
46
Describe the affinity for O2 of Deoxy Hgb in Tense State.
Low affinity for O2
| More likely to Transfer O2 to tissues
47
Describe the affinity for O2 of Oxy Hgb in Relaxed State.
High affinity for O2
| More likely to Recruit O2 in lungs
48
Approximately how much greater is the affinity for O2 is Oxy Hgb Relaxed state than Deoxy Hgb Tense state?
100 fold
49
What determines the overall Sigmoidal O2 dissociation curve?
Equilibrium between relaxed and tense states
50
What shift is seen in O2 dissociation curve when the Relaxed State is greater than the Tense State?
Left Shift due to greater affinity for O2
51
What shift is seen in O2 dissociation curve when the Tense State is greater than the Relaxed State?
Right Shift due to decreased affinity for O2
52
What is an Oxygen-Hgb Dissociation Curve depicting?
Saturation of Hgb w/ O2 as a function of the partial pressure of O2 (pO2)
53
pO2 is directly related to what?
O2 in the tissues
54
What is the pO2 of metabolically active tissues?
approx. 40mmHg
55
What is significant about pO2 = 40mmHg
affinity steeply declines and Hgb surrenders O2 to tissue
56
Ligand affinity of Hgb is increased by successive binding of O2, so O2 is considered what type of effector?
Positive Allosteric Effector
57
The sigmoidal (S shape) curve of O2-Hgb dissociation curve depicts what type of relationship between the percent saturation or the Hgb molecule and PO2?
Positive Cooperativity
58
What accounts for tissues with high metabolic demand receiving more O2 delivered? In which the opposite is true of tissue with low metabolic demand
High Metabolic Demand = LOW pO2 (more O2 delivered)
| Low Metabolic Demand = High pO2 (less O2 delivered)
59
Hgb must be able to become fully saturated with O2 in the lungs and efficiently unload O2 in tissues and this unloading is driven by what?
Negative Allosteric Regulators
60
What are the bodies Negative Allosteric Regulators that drive the release of O2 into the tissues thus shifting the curve to the right and decreasing O2 affinity?
Increased Temperature
Increased CO2
Decreased pH
2,3-bisphophoglycerate (2,3-BPG)*****
61
What is the side product of glycolysis from 1,2-BPG and also known as 2,3-diphophoglycerate, present in the same concentration as Hgb in RBC and is the key molecule in assuring that Hgb does not bind O2 too tightly?
2,3-bisphosphoglycerate (2,3-BPG)
62
2,3-BPG is created in greater amounts in response to what?
High Oxygen Demand (Altitude, Airway Obstruction)
| Internal RBC control of O2 binding curve
63
How does Fetal Hgb differ regarding 2,3-BPG
Lower affinity for 2,3-BPG and a higher affinity for O2
64
As a Negative Allosteric Effector how does 2,3-BPG bind to Hgb?
Binds into a cleft present in T-State, Polyanionic 2,3-BPG stabilizes the T state through a series of ionic interactions w/ cationic residues in globin chain.
-Does not bind to Ligand-binding site
65
How is O2 affinity affected by increasing and decreasing 2,3-BPG and is represented on the dissociation curve in what way?
Increase 2,3-BPG = Decrease O2 affinity: Right Shift
| Decrease 2,3-BPG = Increase O2 affinity: Left Shift
66
What is the Bohr Effect?
Regulation of Hgb binding of O2 by acid-base status
| H+ and CO2 (both are considered acids)
67
H+ directly facilitates the formation of what?
Salt bridges that stabilize the T-state (low affinity state)
68
CO2 directly stabilizes the T-state by binding to what?
Amino terminal ends of the globin chains to generate a Carbamate moiety
69
How does CO2 indirectly stabilizes the T-State?
CO2 converted by Carbonic Anhydrase into Carbonic Acid which generates H+ which form salt bridges and stabilize the T-state
70
The decrease in Oxygen affinity of a respiratory pigment (Hgb) in response to decreased blood pH resulting from increased CO2 concentration in the blood is called what?
Bohr Effect
71
What are the Characteristics of Altitude Sickness?
Low to High Altitudes, resulting in inadequate O2 to peripheral tissues, especially the Brain (Hypoxia)
72
What are some Signs and Symptoms of Altitude Sickness?
Headache, Nausea resolve w/no intervention
| -Severe AS: Pulmonary and Cerebral Edema
73
What are the treatments for altitude Sickness?
Move to Lower Elevation
-Prophylactic Acetazolamide (Carbonic anhydrase inhibitor): Causes alkalinization of urine leading to acidification of blood (Right Shift, Lower affinity, Increased Peripheral O2)
74
How is Fetal Hgb different from Adult Hgb?
- Globin genes: 2 Alpha-globin chains and 2 Gamma-globin chains (HgbF)
- HgbF lower affinity for 2,3-BPG, increased affinity for O2 (Left Shift)
- Allows O2 from HgbA across placenta to HgbF for fetal tissues
75
What is the Immediate Physiological Response to Hypoxia?
- Cells turn to anaerobic respiration
- Produces Lactic Acid
- Lowers pH
- Right Shift, releases O2, favors deoxy T-State
76
What is the physiological Response to Hypoxia within 24 hours?
- Increase 2,3-BPG
- Lowers O2 affinity
- Right Shift
- increase O2 in tissues
77
What is the physiological response to hypoxia within days to 4 weeks?
- Secret Erythropoietin, Create RBC's
- Kidney cells sensor of O2
- Low O2 to Kidney: Hypoxia-inducible factor turns on genes to secret EPO
- EPO: migrates to bone marrow activates Janus Kinase (JAK) and Signal Transducer and Activator of Transcription (STAT)--> block RBC apoptosis--> increased RBC maturation--> increased hematocrit--> increased O2 carrying capacity of blood
78
Sickle Cell Disease/Anemia is caused by what?
-Genetic mutation in Beta-Globin gene results in substitution of negatively-charged glutamic acid w/ hydrophobic valine at position 6
79
What is significant of the hydrophobic valine at position 6 in Sickle Cell Disease?
- Tense state exposes valine at position 6 creating "hydrophobic (sticky) patch"
- Sticky patch interacts w/ second Hgb sticky patch creating stiff Hgb polymers, leading to sickle shape
- HgbSS when bound to O2 has normal biconcave shape
80
Sickle Cell Disease creates what problems with the RBCs?
1) RBCs loses pliability and form blockages (veno-occlusive crisis)
2) Dehydration increases HgbSS polymerization
3) Repeated shape change (polymerization) RBC loses elasticity and permanently stiffened and destroyed
4) Leads to persistent and severe anemia
81
What is sickle cell trait?
-Inheritance of mutation from one parent (heterozygous)
82
What is the lifespan of a sickle RBC vs normal RBC?
10 days: destroyed by macrophages in spleen and liver
| Normal: 120 days
83
Patients suffering from Sickle Cell Disease/anemia have increased risk of what?
1) Organ ischemia and damage due to sickle cell blockages
2) Bone marrow unable to compensate for increased RBC hemolysis
3) Persistent severe anemia and microvasculature blockages
4) Risk of infections by Streptococcus (causing sepsis) or Salmonella (causing osteomyelitis)
84
The treatment of SCD/SCA using hydroxyurea works in what way?
- Increase expression of gamma-globin to replace mutated beta-globin in Hgb molecule
- Gamma-globin does not have valine mutation at position 6
85
What are the functions of Iron in the human body?
1) Oxygen Carrier
2) Immediate Oxygen Storage (muscle myoglobin)
3) Energy Production
4) Detoxification
5) Immune Protection
86
How does iron provide its Oxygen Carrier function?
- Binds O2 in Hgb
| - 4g in body 2/3 in Hgb
87
How does iron provide its Energy production function?
Mediates oxidative-reductive reactions by serving as cofactor (cytochromes of oxidative phosphorylation)
88
How does iron provide its Detoxification function?
In Liver cytochrome p450 enzymes
89
How does iron provide its Immune protection function?
Iron is sequestered from microorganisms
90
How is Iron absorbed by Enterocyte cells (brush border) as part of GI Metabolism?
1) Ingested Fe3+ converted by Ferric Reductase to Fe2+
2) Transported into Enterocytes via: 1. Divalent Metal Transporter (DMT1) 2. Endosomes 3. Heme Transporter
3) Transported out of Enterocytes and into blood via Ferroportin
91
Once iron is in the blood how is it transported?
Fe2+ converted back to Fe3+ and bound to Transferrin
92
What has a high affinity for iron (10^-23 at pH 7.4), prevents free iron in the blood, and is a clinical marker for total iron binding capacity in the blood?
Transferrin
93
Transferrin transports iron to what places in the body and what is it used for in those places?
1) Bone Marrow: Erythropoiesis (75%)
2) Liver and Heart: Storage in ferritin (10-20%)
3) Body enzymatic reactions (5-15%)
94
What is the most important protein for iron storage and found in most tissues as a cytosolic protein?
Ferritin
95
Excess iron can cause Toxicity, how does the body rid itself of excess iron?
- No natural way to excrete
- Excess free iron generate O2 free radicals
- Infusion of Iron Chelator (Deferoxamine or Deferasirox) bind free iron in blood and iron-chelator complex is excreted (feces)
96
How does the human body regulate the uptake and availability of iron?
- Hepcidin: synthesized by the Liver
| - Negative Regulator of ferroportin
97
Hepcidin production is increased in response to what?
Inflammatory cytokine interleukin-6 )IL-6) as host defense mechanism to sequester iron away from infectious organisms
98
Persistent (chronic) inflammation can lead to what?
High amounts of hepcidin limits iron to cells and leads to anemia of inflammation or anemia of chronic disease
99
A blood clot consist of what?
Platelets
Fibrin (protein)
RBCs
100
What are the two phases of clot formation?
1) Platelet plug formation
| 2) Clot Formation
101
Damage to the endothelial lining of blood vessels eposes what, promoting Platelet plug formation?
- Collagen on Basement membrane
| - von Willebrand Factor (vWF) located between endothelium and basement membrane
102
What are the three steps to Platelet Plug Formation called?
1) Adhesion
2) Aggregation
3) Activation
103
Platelet Plug Formation Step 1: Adhesion of platelets to endothelium occurs why?
Collagen is highly thrombogenic and platelets adhere to it and vWF enhances adhesion by increasing links between platelets and collagen fibrils
104
Platelet Plug Formation Step 2: Aggregation of platelets to one another occurs why?
Fibrin linking the Glycoprotein IIb/IIIa of one platelet to the Gp IIb/IIa of another
105
Platelet plug formation Step 3: Activation refers to what?
Adhesion causes platelets to release stored granules (activation) which contain compound that act to enhance plug formation and limit bleeding
106
What drugs act by inactivating or inhibiting Cyclooxygenase (COX) activity and the resultant prostaglandins, prostacyclins, and thromboxanes?
NSAIDs
107
What NSAID noncompetitively and irreversibly inhibits the COX enzyme via acetylation?
Aspirin
108
Aspirin is the only NSAID that blocks production of what, limiting formation of what?
Blocks: Thromboxane A2 (TXA2)
| Limits formation: Platelet Plug
