Chapter 6 Flashcards
How many Heme Sites Does Hemoglobin Have?
4
How many chains does Globin have that can undergo Mutations?
- Two a Chains
- Two b Chains
What is Ferrous Iron? What happens when it is Oxidized?
Ferrous Iron
- Found on Adult hemoglobin A
Oxidized
- Becomes Ferric Iron
- Release of Oxygen to tissue is impaired
What does Fetal Hemoglobin F have? What does it help with?
Has
- High Oxygen Affinity
Use
- Helps Fetus tolerate hypoxic environment in Utero
What does Dissolved Oxygen Obey?
Henry’s Law
What is Henry’s Law?
- The amount of gas dissolved is proportional to the partial pressure
What is the ratio of O2 dissolved in 100ml of blood to PO2?
For each mmHg of PO2, 0.003ml O2 dissolved per 100ml of blood.
What is the normal arterial O2 Content?
0.3ml O2/100ml
What is the amount of dissolved O2 in Normal Arterial Blood with a Q= 50L/min?
0.3ml O2/100ml (normal Arterial Blood)
3ml/1L x 50L/min = 150ml/min O2
What is O2 Capacity?
- The maximum amount of O2 that can be combined with Hb.
How much O2 can 1g of Hb combine with?
1.39ml O2
How much Hb does normal blood have?
- 15g of Hb/ 100ml
What is the O2 Capacity of Blood?
- 20.8ml O2/ 100ml blood
What is the equation for O2 Saturation of Hb?
O2 Saturation of Hb = ((O2-Hb) / O2 Capacity) x 100
What is the normal SaO2 of Arterial Blood?
- 97.5%
What is the normal SaO2 of Venous Blood?
- 75%
What is the Equation to find the O2 Concentration of Blood (ml O2 / 100ml Blood)?
(1.39 x Hb x Sat/100) + 0.003Po2
What are the 5 steps that the Oxygen Transport System Cycles Between?
- Pulmonary Ventilation
- Hemoglobin Concentration
- Blood Volume and Cardiac Output
- Peripheral Blood Flow
- Aerobic Metabolism
What is the Equation for identifying VO2? (Oxygen Usage)
VO2 = Q x a-vO2 difference
What are the Useful Anchor Points of the Oxygen Dissociation Curve?
- PO2 40 has a SO2 of 75%
- PO2 100 has a SO2 of 97%
- P50 has a PO2 of 27 and SO2 of 50%
What causes the Oxygen Dissociation Curve to shift to the Right?
- Increase in Temperature
- Increase in PCO2
- Increase in H+
- Increase in 2,3 DPG
What does a Right Shift in the Oxygen Dissociation Curve mean?
- Lower Oxygen Affinity
- Allows for more Oxygen to be delivered to the Tissue
What does small additions of CO to blood do to the Oxygen Dissociation Curve?
- Shifts it left (impairs offloading of oxygen)
What are the three ways CO2 is transported in the Blood?
- Bicarbonate
- Carbamino
- Dissolved
What are the percentages of CO2 carried in Arterial Blood?
- 90% in Bicarbonate (HCO3-)
- 5% in Carbamino
- 5% in Dissolved
What are the percentages of CO2 carried in Mixed-Venous Blood?
- 60% in Bicarbonate (HCO3-)
- 30% in Carbamino
- 10% is Dissolved
What does the Bicarbonate Reaction depend on?
- Carbonic Anhydrase in the Red Cell (an enzyme)
What enhances the CO2 carriage in the form of Carbaminohemoglobin?
- Deoxygenation of the blood
How is the CO2 curve shaped in relation to the O2 Curve?
- Steeper and more linear
What shifts the CO2 dissociation curve to the right?
- An increase in SO2 (Haldane Effect)
What is the Haldane Effect?
Haldane Effect
- Deoxygenated Hemoglobin can carry more CO2
How much more soluble is CO2 than O2?
20x
What are the steps in CO2 being changed to Bicarbonate?
CO2 + H20 –(CA)– H2CO3 — H+ + HCO3-
1. Slow, in Plasma. Fast in Red Blood Cell because of Carbonic Anhydrase (CA) enzyme.
2. Dissociation of Carbonic Acid, Fast without enzyme
What happens when Ions Rise within the RBC?
- HCO3- diffuses out, but H+ cannot.
How does the RBC maintain electrical Neutrality after CO2 converts to Bicarbonate?
– Cl- ions move into the cell from plasma to offset the H+ buildup
– Called the Chloride Shift
How does the product of H+ from the CO2 to Bicarbonate reaction help with CO2 offloading?
- H+ ions bind to hemoglobin and reduce it
- Reduced hemoglobin contributes to the Haldane Effect, which helps with offloading of CO2
What is the Reaction that causes CO2 to become part of a Carbamino Compound?
Hb.NH2 + CO2 — Hb.NH.COOH
- CO2 combines with a Terminal Amine Group of Blood PRotein
Describe the Reaction of CO2 and a Terminal Amine Group of Blood Protein.
- Product is a Carbamino Compound
- Occurs rapidly without an enzyme
- Reduced Hb can bind with more CO2 as Carbamino-hemoglobin than with HbO2
- Unloading of O2 in peripheral capillaries facilitates the loading of CO2, whereas oxygenation has the opposite effect
What are the 4 Causes of Primary Acid-Base Abnormalities?
- Respiratory Acidosis
- Respiratory Alkalosis
- Metabolic Acidosis
- Metabolic Alkalosis
What are the Causes of Respiratory Acidosis?
- Opiate Overdose
- Severe Chronic Obstructive Pulmonary Disease
- Neuromuscular Disease
- Obesity Hypoventilation Syndrome
What are the Causes of Respiratory Alkalosis?
- Anxiety Attack
- High Altitude
- Hypoxemic Lung Disease
Metabolic Acidosis
- Lactic Acidosis
- Diabetic, Starvation, or Alcoholic Ketoacidosis
- Uremia
- Renal Tubular Acidosis
- Severe Diarrhea
What are the Causes of Metabolic Alkalosis?
- Vomiting
- Loop Diuretics
- Excess Alkali Ingestion
- Hyperaldosteronism
What is the Henderson-Hasselbatch Equation?
CO2 + H2O –(CA)– H2CO3 – H+ + HCO3-
- Ka = [H+][A-] / [HA]
- HA = molar concentration of weak acid
- A- = molar concentration of the acid’s conjugate base
- HA = H2CO3
- A-= HCO3-
- pH = pKa + log([HCO3-]/0.03PCO2)
What are the physiological changes that cause Respiratory Acidosis?
- Increase in PCO2, which reduces the HCO3-/PCO2 ratio
- Depresses pH
- Body Conserves HCO3- to help stabilize ratio
What are the Physiological changes that cause Respiratory Alkalosis?
- Decrease in PCO2
- Increases HCO3-/PCO2 ratio
- Elevates pH
- Body Excretes HCO3- to stabilize ratio (pH)
What are the physiological changes that result in Metabolic Acidosis?
- Ratio of HCO3- to PCO2 falls
- Depresses pH
- Body increases VE to lower PCO2 and stabilize pH
How does the body regulate Acid-Base ratio?
- Chemical Buffers
- Pulmonary Ventilation
- Renal Function
What are some Chemical Buffers used to regulate body pH?
H+ + Buffer — H-Buffer
- Bicarbonate Buffer
- Phosphate Buffer
- Protein Buffer
How does the body regulate pH using Ventilation?
Ventilatory Buffer
- increase in ventilation reduces PACO2, which causes CO2 to be blown off, which will accelerate H+ + HCO3-
How does the body use kidneys to regulate pH?
- Excretion of H+ by kidneys