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85 Cards in this Set
- Front
- Back
- 3rd side (hint)
Blood is the body's only _____ tissue.
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fluid
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Blood includes liquid plasma and formed elements such as
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• Erythrocytes
• Leukocytes • Platelets • Plasma |
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Hemocrit
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% of RBCs out of total blood volume (normally ~45%)
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What are erythrocytes?
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red blood cells (RBCs)
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What are leukocytes?
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white blood cells (WBCs)
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What are platelets?
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membrane bound cell fragments (w/ enzymes); involved in blood clotting
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What is plasma?
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non-living fluid matrix (H₂O + electrocytes), proteins, glucose, etc
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What are the blood plasma components?
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1) water ~ 92% of plasma
2) > 100 dissolved solutes: a) plasma proteins b) non-protein solutes |
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What are plasma proteins?
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(~7% plasma), most produced in the liver
1) Albumin - most abundant (60% of plasma proteins) 2) Globulins - (35% plasma proteins) 3) Clotting proteins (4% plasma proteins) 4) Enzymes and Hormones (< 1% of plasma) |
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What are non-protein solutes?
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(~ 1% of plasma)
1) Nutrients/waste products 2) Electrolytes (ions) 3) Gases (O₂/CO₂) |
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All formed elements are from stem cells in _____
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bone marrow
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Only _____ are "complete" cells
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WBCs
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What formed element has no nuclei, few organelles; platelets are just cell fragments?
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RBCs
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Most formed elements survive in the bloodstream for a few/many days.
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few
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Most blood cells do not divide are renewed by cells in _____.
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bone marrow
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Describe the structure of an erythrocyte.
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• Biconcave discs
• Increased surface area for gas exchange (~30% more than a round cell) • enables RBCs to bend & flex - squeeze through capillaries • Anucleate - not a "true cell" and few organelles • filled with hemoglobin (Hb) - protein that functions in gas transport |
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What is hemoglobin?
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transports oxygen and carbon dioxide; makes RBCs red
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Describe the structure of RBCs
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Structure - complex, quaternary structure
• Globin (protein) + Heme (pigment complex) • Globin = 2 alpha chains and 2 beta chains of polypeptides • Each chain has 1 heme molecule with iron at the center • 1 heme unit "holds" iron in a way that iron can interact with 1 oxygen molecule |
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Oxygen loading of hemoglobin occurs in the _____.
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lungs
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O₂ diffuses from ______ to blood, then through RBC to bind with hemoglobin
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lung air sacs
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When O₂ binds to iron, Hb becomes _____.
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oxyhemoglobin changes to new 3-d shape → becomes ruby red
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When O₂ detaches to iron, Hb becomes _____.
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deoxyhemoglobin color changes to dark red
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Hb transports ______ of oxygen in the blood (bound to iron of heme group)
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~ 98.5%
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Hb transports _____ of carbon dioxide in the blood (bound to globin)
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~ 20%
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What is carbaminohemoglobin?
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when CO₂ bind to glob in's amino acids
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Carbon dioxide loading occurs at the _____.
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tissues
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What is hematopoiesis?
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blood cell formation in the red bone marrow
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What is hemocytoblasts?
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blood stem cells
• produce all formed elements (RBCs, WBCs, and platelets) |
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Regulation & Requirements for Erythropoiesis
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Circulating Erythrocytes - number remains constant and reflects balance between RBC production/destruction
• too few RBCs leads to tissue hypoxia • too many RBCs causes high blood viscosity |
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Erythropoiesis is _____ controlled
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hormonally
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Erythropoietin (EPO) released by the kidneys is triggered by:
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• Tissue hypoxia (due to decreased RBCs)
• Decreased O₂ availability • Increased tissue demand for O₂ |
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↑ erythropoiesis increases the:
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• RBC count in circulating blood
• O₂ carrying ability of the blood |
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Erythropoietin Mechanism
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Homeostasis: Normal blood oxygen levels
Stimulus: Hypoxia due to decreased RBC count, decreased amount of hemoglobin, or decreased availability of O₂ |
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What are two erythrocyte disorders?
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anemia and polycythemia
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What is anemia?
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blood has normally low oxygen-carrying capacity
**It is a symptom rather than a disease itself • Blood oxygen levels cannot support normal metabolism • Signs/Symptoms include fatigue, paleness, shortness of breath, and chills |
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What is polycythemia?
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excess RBCs that increase blood viscosity
Three main polycythemias are: 1) polycythemia vera (up to 80% hematocrit), bone marrow cancer 2) secondary polycythemia (decrease oxygen availability/excess EPO) 3) blood doping |
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Blood plasma can't transport enough O₂ or CO₂ to meet physiological needs
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• O₂ & CO₂ have limited solubilities in blood plasma
• Tissues need more O₂ & generate more CO₂ than can be absorbed or transported |
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Blood plasma can't transport enough O₂ or CO₂ to meet physiological needs and the problem is solved by:
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Red Blood Cells (RBC)
• Transport O₂ to, and CO₂ from peripheral tissues • Remove O₂ and CO₂ from plasma, allowing more gases to diffuse into blood |
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O₂ Transport
Molecular O₂ is carried in the _____: |
blood
• bound to hemoglobin (in RBC) • dissolved in plasma |
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O₂ Transport
O₂ binds to iron in hemoglobin (Hb) molecules: |
in a rapid & reversible reaction
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O₂ Transport
Each RBC has about _____ million Hb molecules: |
280 million
• each binds 4 oxygen molecules |
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O₂ Transport
• Hb-O₂ combination is |
oxyhemoglobin (HbO₂)
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O₂ Transport
• Hb that has released O₂ is |
deoxyhemoglobin (HHb)
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O₂ Transport
Each RBC has about _____ million Hb molecules: |
280 million
• each binds 4 oxygen molecules |
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What is hemoglobin saturation?
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percentage of heme units (collectively) in a hemoglobin molecule with bound O₂
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O₂ Transport
• Hb-O₂ combination is |
oxyhemoglobin (HbO₂)
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All 4 heme units bound with O₂ is _____ saturation
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100%
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O₂ Transport
• Hb that has released O₂ is |
deoxyhemoglobin (HHb)
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Each Hb (on average) carries 2 O₂ molecules is _____ saturation
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50%
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What is hemoglobin saturation?
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percentage of heme units (collectively) in a hemoglobin molecule with bound O₂
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What are the environmental factors affecting the rate of Hb binding/releasing of O₂?
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1) PO₂ of blood
2) Blood pH 3) Temperature 4) Metabolic activity within RBCs |
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All 4 heme units bound with O₂ is _____ saturation
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100%
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How does hemoglobin and PO₂ affect the rate of Hb binding?
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• Hb is almost completely saturated at a PO₂ of 70 mm Hg
• further increase in PO₂ = small increases in O₂ binding |
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Each Hb (on average) carries 2 O₂ molecules is _____ saturation
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50%
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What is oxygen-hemoglobin saturation curve?
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a graph relating the saturation of hemoglobin to PO₂
• rightward shift means more O₂ will be unloading from Hb at a given PO₂ • in active tissues, ↑ temperature, ↓ pH and ↑ PCO₂ promote unloading of O₂ |
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What are the environmental factors affecting the rate of Hb binding/releasing of O₂?
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1) PO₂ of blood
2) Blood pH 3) Temperature 4) Metabolic activity within RBCs |
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Hemoglobin and PO₂ is a curve rather than a straight line because
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• Hb changes its shape each time O₂ molecule binds
• allows Hb to bind O₂ when O₂ levels are low |
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How does hemoglobin and PO₂ affect the rate of Hb binding?
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• Hb is almost completely saturated at a PO₂ of 70 mm Hg
• further increase in PO₂ = small increases in O₂ binding |
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What is oxygen-hemoglobin saturation curve?
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a graph relating the saturation of hemoglobin to PO₂
• rightward shift means more O₂ will be unloading from Hb at a given PO₂ • in active tissues, ↑ temperature, ↓ pH and ↑ PCO₂ promote unloading of O₂ |
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Hemoglobin and PO₂ is a curve rather than a straight line because
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• Hb changes its shape each time O₂ molecule binds
• allows Hb to bind O₂ when O₂ levels are low |
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Hemoglobin and PO₂
Carbon monoxide (CO) from burning fuels: |
• binds strongly to hemoglobin and takes place of O₂
• can result in carbon monoxide poisoning |
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How does hemoglobin and pH affect the oxygen-hemoglobin saturation curve?
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standarized for normal blood (pH 7.4, 37°C)
• When pH drops → more O₂ is released (curve shifts to right & downward) ∙ causes a decrease in oxygen's binding affinity • When pH rises → less O₂ is released (curve shifts to the left & upward) |
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How does hemoglobin and temperature affect the oxygen-hemoglobin saturation curve?
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standarized for normal blood (pH 7.4, 37°C)
• When temperature rises → more O₂ is released (curve shifts to the right & down) • When temperature drops → less O₂ is released (curve shifts to the left & up) |
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Hemoglobin and temperature
When pH drops or temperature rises: |
more oxygen is released (curve shifts to the right)
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Hemoglobin and temperature
When pH rises or temperature drops: |
less oxygen is released (curve shifts to the left)
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Hemoglobin and pH
active tissues generate ____ which lowers the pH of _____ |
acids; interstitial fluid
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Hemoglobin and pH
A decrease in pH changes the shape of _____ |
Hb
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Hemoglobin and pH
Shape change = release of ____ by Hb |
O₂ which causes the Hb saturation to decline
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Hemoglobin and temperature
An increase in temperature causes Hb to release more _____ |
O₂
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Hemoglobin and
A decrease in temperature causes Hb to bind to _____ more tightly |
O₂
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How does hemoglobin and BPG (RBC metabolic activity's effect on Hb) affect the binding and release of O₂?
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RBC (lack mitochondria) generate ATP by glycolysis which forms lactic acid and BPG (2,3-biphosphoglycerate)
BPG directly affects O₂ binding and release ↑ BPG → ↑ O₂ release |
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What are the key concepts of hemoglobin in RBC in O₂ Transport?
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• carries most blood oxygen
• Hb releases bound O₂ in response to low O₂ partial pressure in surrounding plasma |
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If PO₂ increases, hemoglobin _____ oxygen
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binds
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If PO₂ decreases, hemoglobin _____ oxygen
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releases
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At a given PO₂: hemoglobin will release additional oxygen if:
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• pH decreases or
• temperature increases or • BPG increases |
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What is the Bohr effect?
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effect of pH on hemoglobin saturation curve (caused by CO₂)
1. CO₂ rapidly diffuses into RBCs once in the blood 2. in RBC, carbonic anhydrase (enzyme) catalyzes a reaction with H₂O to produce carbonic acid (H₂CO₃) 3. Carbonic acid (H₂CO₃) dissociates into hydrogen ion (H+) and bicarbonate ion (HCO₃-) 4. Increase in H+ = decrease in pH |
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↑ CO₂ causes the reaction to proceed to the _____
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RIGHT
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↓ CO₂ causes the reaction to proceed to the _____
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LEFT
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According to the Bohr effect, how does an increase in CO₂ affect the binding affinity of O₂?
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add answer here
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CO₂ is generated as a byproduct of _____.
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aerobic metabolism (cellular respiration)
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CO₂ in the bloodstream may be:
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1. converted to carbonic acid
2. bound to protein portion of hemoglobin 3. dissolved in plasma |
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CO₂ in the bloodstream
___% transported as bicarbonate (HCO₃-) • carbonic acid (H₂CO₃) quickly dissociates into H+ * HCO₃- ___% bound to Hb molecule forming carbaminohemoglobin ___% transported as CO₂ dissolved in plasma |
70%, 23%, and 7%
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Bicarbonate ions move into plasma by an exchange mechanism called the ______ that takes in Cl- ions without using ATP
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chloride shift
counterbalances negative bicarbonate ions from RBCs |
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CO₂ travels in the bloodstream primarily as bicarbonate ions, which form through dissociation of carbonic acid produced by ______ in RBCs
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carbonic anhydrase
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Lesser amounts of CO₂ are bound to _____ or dissolve in the _____
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Hb; plasma
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