Gas Transport and Erythrocyte Physiology Flashcards
What are the functions of blood
Deliver nutrients and oxygen
Removes waste products
Maintain Homeostasis
Circulation
what is the hematocrit of a women, men, newborn, and 2 mo old
what is the functions of the erythrocytes
40% women
45% men
55% newborn
35% 2 mo old
Carrying O2 from lungs to the body
Carrying CO2 from body to lung
Acid/base buffering
What is the process of Erythropoiesis
start as Hematopoietic Stem cells then will turn to a Proerythroblast
then will go to a Normoblast
Reticulocyte
finally a Erythrocyte
what is the principle regulator, where is it produced and what is the transcription factor to produce red blood cells
Erythropoietin (EPO) is the principle regulator
Produced by kidneys in response to anemia, low Hb, decreased renal blood flow (RBF), central hypoxia, low blood volume
Erythropoietin is regulated by the transcription factor Hypoxia inducible factor (HIF)
-impaired regulationn can lead to anemia, mutations in polycythemia, and also (too many RBC)
take me through the Erythrocyte life cycle, and the outcome of Heme
Red blood will rupture in the spleen and then will get ingested by monocyte-macrophage immediately
Fe3+ is removed from the Heme making it biliverdin, then converted to bilirubin
Bilirubin then circulates to the liver where it is sent to the small then large intestine where it is converted to Uroblinogen
some Uroblinogen will stay in large intestine and convert to stercoblin where it is pooped out
some Uroblinogen goes to the kidney where it is peed out as Uroblin
as far as the Fe3+ it is carried on transferrin to liver where it is converted to Ferritin
then taken to the bone marrow where it is converted back to Fe2+ and used by body
what are the two ways that oxygen is transported in the blood? which one is more significant
Dissolved into the blood
-only gets about 3ml O2/L Blood
or
Bound to the Hemoglobin (majority is done this way)
-since body can need up to 3000ml O2/L Blood
what are the types of hemoglobin chains and which ones are found in adults and fetal form? how much hemoglobin are in an adult?
Types of hemoglobin chains: alpha, Beta, delta, gamma
Adult form: 2 alpha and 2 beta chains called hemoglobin A
fetal: 2 alpha and 2 gamma chains
Hemoglobin F
these can carry 4 O2 molecules
Normal blood hemoglobin 14.0 g/dL in adult female and 15.5 g/dL in adult male will round avg to 15
what are the axis of the oxygen dissociation curve
x axis: PO2 mmHg of blood
y axis right: O2 concentration in blood
y axis left: Oxygen saturation or % Hb saturation
-% available binding sites in Hb that have oxygen bound
what is the normal Oxygen concentration in the blood?
15g Hb x 1.34 mL O2 = 20.1 mL of O2/dL blood
the 1.34 mL is a constant that Hb can bind too
what is the Oxygen saturation and PO2 for the venous and arterial blood
Arterial: PaO2 100 mmHg, O2 saturation about 97.5%
Venous: PvO2 40 mmHg, O2 satuuration is 75%
If the PaO2 is greater than 60 mmHg what is the % Hb saturation at or above on an oxygen dissociation curve
if the PaO2 is greater than 60 mmHg then the O2 saturation is at least 85 percent or higher
where does the location of shift normal occur on the oxygen dissociation curve
P50 = 50% Hb saturation
Normally 27 mmHg
can shift left or right depending on the situation
what is the advantage of how the Oxygen dissociation curve works
At normal or high levels of PO2 (60 or higher) the oxygen readily binds to Hb and Hb readily hangs on to oxygen really tight (top of the curve)
at tissue level PO2 levels when the oxygen levels are much lower, the oxygen readily jumps off Hb and Hb readily releases oxygen (good for giving oxygen to O2 hungry tissue)
how does the Hb concentration affect the oxygen dissociation curve?
if there is an Hb concentration decrease the oxygen carrying capacity will decrease regardless of O2 saturation
if there is an Hb concentration increase the oxygen carrying capacity will increase regardless of O2 saturation
what represents a left shift in the Oxygen dissociation curve?
Represents an increased affinity of Hb for O2
- associated with:
- Polycythemia
- Methemoglobinemia
what represents a right shift in oxygen dissociation curve
Represents a decreased affinity for Hb for O2
associated with:
-anemia
-advantageous for unloading oxygen
-excersise
(acidic, warm, high CO2 production (hypercarbic) all cause right shift)
(2,3-DPG/BPG, end point of RBC metabolism )
-more of it during chronic hypoxia
what are some general red blood cell disorders
Anemia of blood loss Anemia of chronic disease Hemolytic anemias Anemias of diminished erythropoiesis Polycythemia
what is required for erythropoiesis
Adequate nutrition
Vitamin B12 (cynocobalamin, cobalamin) and folate (B9) required for DNA synthesis
Iron availabillity- absorption, transport, and storage
what does a Folate or B12 deficiency result in?
what does Poor B12 absorption lead to
Folate or B12 deficiency results in Megalobastic macrocytic anemia
poor B12 absorption leads to Pernicious anemia
Microcytic anemia
Deficiency in Iron
- circulates in plasma as transferrin
- need absorption of approximately 1mg/d in men and 1.4 mg/d in women from diet to maintain homeostasis
Hypochromic anemia
Deficient transport of transferrin to developing erythrocytes
how does ATP contribute to Iron
ATP contributes to the membrane flexibility
Maintains iron if FE+2 (ferrous state) rather than Fe+3 (ferric state)
helps in Ion transport and will help prevent oxidative damage
Hemachromatosis and the 3 types of causes
Iron overload leading toliver cirrhosis, skin pigmentation, and diabetes mellitus
Primary/genetic
Secondary:
- multiple blood transfusions
- ineffective erythropoiesis
- increased iron intake
Neonatal:
- develops in utero
- unknown cause
How does anemia affect the oxygen dissociation curve
Anemia will decrease oxygen carrying capacity
this causes a right shift due to the less carrying capacity
the Hemoglobin concentration is proportional to blood oxygen content
-1/2 hemoglobin concentration means roughly 1/2 blood oxygen content
However, % Hb saturation does not change
what are the three different types of Polycythemia and their corresponding characteristics
Primary Polycythemia
- Genetic (low EPO)
- Extra RBCs
- increased total blood volume (2x)
- Increased Viscosity (10x water)
- Normalish cardiac outpuut
Secondary Polycythemia
- Hypoxia (high EPO)
- Extra RBCs
- Cardiac output may be abnormal
Physiologic Polycythemia
- High altitude adaptation
- extra RBCs
- Normal cardiac output
Methemoglobinemia
- Increased met-hemoglobin
- Iron is ferric form (Fe3+)
- Decreased oxygen availabillity to tissues
- Leftward shift of oxygen-hemoglobin disassociation curve
- Blood is chocolate colored
- Caucasian skin appears blue
what is the A-V O2 difference used for
difference between arterial blood O2 content versus venous blood O2 content
used to describe the oxygen consumption for the tissue
difference is how much O2 was used
what are the three ways that carbon dioxide is transported
Dissolved CO2
- not enogh to rely on dissolved transport alone
- 2.7ml CO2/dL Blood
- we produce 200 ml CO2
Carbamino compounds
- CO2 binds plasma proteins or Hb (amine group)
- Haldane shift: presence of O2 reduces affinity of amine chain for CO2
- 3ml CO2/dL Blood
as HCO3
-44 ml CO2/dL BLood
how is CO2 transported and converted to Bicarbonate
CO2 is produced and exits from the tissue and enters the RBC
Carbonic anhydrase in RBC hydrates CO2 to form H2CO3
H2CO3 dissociates H+ and HCO3-
H+ is buffered in RBCs by deoxyhemoglobin ad carried in venous blood here
HCO3- produced is exchanged for Cl- across RBCs and carried to lungs (chloride shift/hamburg shift)
what happens to the CO2 at the lungs
Dissolved CO2 moves down its concentration gradient into the alveoli
CO2 dissociates from proteins
HCO3- is converted back to CO2 at the lungs
Volume carried in blood, Major form transported, Volume dissolved, and other forms: O2 transport
Volume carried in blood: 20ml O2/dL blood
Major form transported: Bound to heme in Hb
Volume dissolved: O.3 ml O2/dL blood
Other forms: None
Volume carried in blood, Major form transported, Volume dissolved, and other forms: CO2 transport
Volume carried in blood: 50ml O2/dL blood
Major form transported: HCO3
Volume dissolved: 3 ml O2/dL blood
Other forms: Carbamino compounds
