5 - Gas Transport & Erythrocyte Physiology Flashcards
What are the functions of blood?
1) Deliver nutrients and oxygen
2) Removes waste products
3) Maintain homeostasis
4) Circulation
What are the percentages of hematocrit (amount of red blood cells in blood) for men, women, and babies?
Men = 45%
Women = 40%
2 month old = 35%
Newborn = 55%
What are the functions of erythrocytes?
1) Carrying O2 from lungs to body
2) Carrying CO2 from body to lungs
3) Acid/Base buffering
_________ mature into erythrocytes entering the circulation. Erythrocytes mature in the circulation based on oxygen demand.
Reticulocytes
This is the principle regulator in erythropoiesis. It is produced by the kidneys in response to anemia, low Hb, decreased RBF, and central hypoxia.
Erythropoietin (EPO)
This is what regulates EPO. It is a transcription factor, and its genetic deletion can result in anemia and mutations in polycythemia.
Hypoxia Inducible Factor (HIF)
Impaired regulation of EPO by HIF can lead to…
Erythrocytosis
Erythrocytes have a 120-day life cycle and rupture in the red pulp of the ________. The released hemoglobin is ingested by _________-_________ cells immediately.
Spleen
Monocyte-Macrophage
Oxygen transport is done in 2 ways in the blood, which are…
1 – Dissolved
2 – Bound to Hemoglobin
Which mode of transport of oxygen in the blood is considered inadequate?
Dissolved
The types of Hemoglobin chains determine iron binding affinity. The different chains are…
Alpha
Beta
Delta
Gamma
What is the normal blood Hemoglobin in an adult female and male?
Adult female = 14.0 g/dL
Adult male = 15.5 g/dL
How many O2 molecules can reversibly bind to 1 Hemoglobin?
4
Hemoglobin has ______ Heme sites and consists of ______ Alpha and ______ Beta chains.
4
2
2
The adult form of Hemoglobin is…
Hemoglobin A
The fetal form of Hemoglobin is…
Hemoglobin F
What is normal oxygen concentration in blood?
There is 15 g Hb/100 mL blood.
1 g Hb can combine with 1.34 mL O2.
15 x 1.34 = 20.1 mL O2/100 mL blood
***20.1 mL O2/dL blood
Oxygen saturation is the percent of available binding sites in Hb that have oxygen bound. What is the equation to calculate this percentage?
[ (O2 combined with Hb) / (O2 capacity) ] x 100
If the PaO2 > 60 mmHg, what is the O2 saturation?
At least 85%, and the concentration is 17 mL O2/dL blood.
***Just look at dissociation curve, you can find these numbers by looking at it.
T/F. At normal PO2 levels, oxygen readily binds to Hb and Hb readily hangs on to oxygen.
True
T/F. At tissue level PO2 levels, oxygen readily jumps off Hb and Hb readily releases oxygen.
True
If Hb concentration decreases, what happens to oxygen carrying capacity?
Oxygen carrying capacity will decrease regardless of O2 saturation
If Hb concentration increases, what happens to oxygen carrying capacity?
Oxygen carrying capacity will increase regardless of O2 saturation
What type of shift in the oxygen dissociation curve represents increased affinity of Hb for O2?
Left Shift
What is a left shit curve usually associated with?
- Polycythemia (elevated hematocrit)
- - Methemoglobinemia (blue hue to skin)
What type of shift in the oxygen dissociation curve represents decreased affinity of Hb for O2?
Right Shift
What is a right shift curve usually associated with?
Anemia
***Advantageous for unloading oxygen
During exercise, what kind of shift occurs in the oxygen dissociation curve?
Right Shift – due to acidic muscle (increased H+) and there is increased CO2
***Helpful mnemonic a girl left on GroupMe. CADET face RIGHT.
C - increased CO2 and H+ A - Anemia D - increased 2,3 BPG (DPG) E - increased exercise T - increased temp
What are RBC disorders?
Anemia of blood loss Anemia of chronic disease Hemolytic anemias Anemias of diminished erythropoiesis Polycythemia
What are the requirements for erythropoiesis?
1) Adequate nutrition
2) Vitamin B12 (cyanocobalamin, cobalamin) and Folate (B9) – required for DNA synthesis
3) Iron availability – absorption, transport, storage
Folate or B12 deficiency results in…
Megaloblastic Macrocytic Anemia
Poor B12 absorption leads to…
Pernicious Anemia
Iron is needed for Hb to function and receive oxygen. A deficiency results in ________ ________ (most common cause worldwide). It circulates in plasma as ________.
Microcytic Anemia
Transferrin
***Transferrin is iron-binding plasma protein.
Deficient transport of transferrin to developing erythroblasts can result in…
Hypochromic Anemia
How much iron absorption is needed from the diet to maintain homeostasis?
Men = 1 mg/d Women = 1.4 mg/d
______ contributes to membrane flexibility for iron. It maintains iron in Fe2+ (Ferrous state) rather than Fe3+ (Ferric state). Prevents oxidative damage.
ATP
_______ overloading can lead to liver cirrhosis, skin pigmentation, and diabetes mellitus.
Iron
Primary iron overloading is due to…
Genetics
Secondary iron overloading is due to…
- Multiple blood transfusions
- Ineffective erythropoiesis
- Increased iron intake
_________ iron overloading develops in utero. The cause is unknown.
Neonatal
Anemia decreases oxygen carrying capacity. Hb concentration is proportional to blood oxygen content but _________ doesn’t change.
% saturation
What type of polycythemia is being described?
- Genetic (low EPO)
- Extra RBCs
- Increased total blood volume (2x)
- Increased viscosity (10x water)
- Normal (sort of) Cardiac Output
Primary polycythemia (vera)
What type of polycythemia is being described?
- Hypoxia (high EPO)
- Extra RBCs
- Cardiac Output may be abnormal
Secondary polycythemia
What type of polycythemia is being described?
- High altitude adaptation
- Extra RBCs
- Normal Cardiac Output
Physiologic polycythemia
This is caused by increased met-hemoglobin. Iron is in Ferric form (Fe3+) and there is decreased oxygen availability to tissues.
Methemoglobinemia
***Blood is chocolate-colored, causes a blue hue to skin.
The difference between arterial blood O2 content versus venous blood O2 content is used to describe…
Oxygen Consumption
***PaO2 = 20 mL and PvO2 = 15 mL
20 - 15 = 5 mL O2/100 mL blood
What is the RQ value for glucose/sugar?
1.0
What is the RQ value for fatty acid?
0.7
What is the RQ value for protein?
0.9
What are the forms of CO2 transport?
1) Dissolved CO2
2) Carbamino Compounds
3) As HCO3
This is CO2 bound to plasma proteins or Hb. It does not bind to heme groups, but binds to amine groups.
Carbamino Compounds
A _________ shift is when the presence of O2 reduces affinity of the amine chain for CO2. Involved with Carbamino Compounds.
Haldane
In RBC, CO2 is converted to HCO3 by…
Carbonic Anhydrase
HCO3 is exported from the cell by ________. The exchange is called a ________ ________ or ________ ________.
Chloride
Chloride Shift
Hamburger Shift
Put the following steps involving CO2 and Bicarbonate in order:
A. H+ is buffered in RBCs by deoxyhemoglobin and carried in venous blood here.
B. CO2 is produced and exits tissue.
C. HCO3- produced is exchanged for Cl- across RBCs and carried to lungs.
D. H2CO3 dissociates into H+ and HCO3-.
E. Carbonic Anhydrase (high levels in RBCs) hydrates CO2 to form H2CO3.
1) B.
2) E.
3) D.
4) A.
5) C.
Dissolved CO2 moves down its concentration gradient into the ________. CO2 dissociates from proteins. HCO3 is converted back to CO2.
Alveoli
What is the O2 and CO2 volumes carried in the blood?
O2 = 20 mL O2/100 mL blood CO2 = 50 mL CO2/100 mL blood
What is the major form transported of O2 and CO2?
O2 = Bound to heme in Hb CO2 = HCO3
What is the volume dissolved of O2 and CO2?
O2 = 0.3 mL O2/100 mL blood CO2 = 3 mL CO2/100 mL blood
