Gas transport and electrolyte physio Flashcards by Natalie Powell

what is the composition of blood?

plasma (55%): water (mostly), proteins, other

ethryocytes (44%)

buffy coat (1%): wbc’s and platelets

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what are functions of erthrocytes?

carrying O2 from lungs to body
carrying CO2 from body to lungs
acid/base buffering

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what is the process of erthyropoiesis? what is it regulated by?

reticulocytes mature into erthrocytes and enter circulation based on O2 demand (hypoxia, anemia, decreased Hb, etc)

erthropoietin (EPO) is principle regulator and is controlled by HIF (transcription factor and when impaired can lead to erythrocytosis)

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when and where does erthyrocytes life cycle end?

after 120 days when they rupture in red pulp of spleen

Hb that is released is digested by macrophages

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what two ways is O2 transported?

dissolved: inadequate due to its low solubility (0.3 mL/ 100 mL) not keeping up with tissue demands
bound to hemoglobin

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what is the structure of Hb? what is its normal value?

4 heme sites so that 4 O2 can reversibly bind to it

globin has 2 alpha, 2 beta chains

adult form is hemoglobin A

fetal form is hemoglobin F

14.0 g/dL in female; 15.5 g/dL in male

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what is the correlation of % Hb saturation with PO2 and O2 concentration?

as PO2 increases, % Hb saturation (amount of binding sites being taken up by O2) increases, and O2 concentration increases

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how do you calculate normal oxygen concentration?

or just look at oxygen dissociation curve

(Hb * amount of O2 it can bind) = __ O2 /100mL blood

ex: (15 g Hb/100mL blood * 1.34 mL O2) = 20.1 O2 /100mL blood

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how do you calculate oxygen saturation?

what is the normal value in arteries?

what is the normal value in veins?

or just look at oxygen dissociation curve

O2 combined with Hb/ O2 capacity * 100

PaO2 is usually 100 mm Hg, therefore O2 saturation will be 97.5% in arteries

PvO2 is usually 40 mm Hg so O2 saturation will be 75% in veins

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what is p50?

what is normal value?

50% Hb saturation

normally 27 mm Hg

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at normal O2 levels (21 O2/dL) whats Hb doin?

what about PO2 at tissues?

O2 readily binds to Hb cause Hb wants it

O2 readibly jumps off and releases oxygen

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what happens when Hb conc dereases?

O2 carrying capacity decreases regardless of O2 saturaiton

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what happens when Hb conc increases?

O2 carrying capactiy increases regardless of O2 saturtion

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what does a left shift represent?

what disease associated with it?

increased affinity of Hb for O2

polycythemia and methemoglobinemia

*keeps O2

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what does right shift represent?

what disease associated with it?

decreased affinity of Hb for O2

associated with anemia

*helps release O2

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what kind of shift does excersice give?

what factors cause this?

right

muscle is acidic (inc in H+)
muscles is warm (Bohr effect)
hypercarbic (CO2)
2,3-DPG (from metabolism of RBCs)- more during chronic hypoxia

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what is oxygen capacity?

normal value?

max oxygen that can be carried by Hb in blood

20.1 O2/ dL

what is oxygen content?

normal value?

how much O2 is actually being carried by blood

19.5 mL o2/dL

what is O2 saturation?

sites that are occupied by O2 on Hb out of total binding sites- given as %

what are some red blood cell disorders? name 5

anemia of blood loss
anemia of chronic disease
hemolytic anemias
anemias of diminished erythropoiesis
polycythemias

what are the requirements for erythropoiesis?

adequate nutrition
vitamin B12- dna synthesis
folate- dna synthesis
iron availability- absorption, transport (ciculates as transferrin), storage—> needed for Hb to function and receive O2
* need about 1 mg/d in men and 1.4mg/ day in women

what does deficency in B12 or folate result in?

megaloblastic macrocytic anemia

what does poor absorption of B12 result in?

pernicious anemia

what does deficiencey in iron result in?

microcytic anemia (most common)

what does defiency in the transport of transferrin to developing erthyroblasts result in?

hypochromic anemia

what functions do ATP and iron contribute to in a RBC?

ATP- membrane flexibitly, gives energy (because no mitochondria), ion transport (ATPase) iron- maintains FE2 (ferrous state) rather than FE3 (ferric state), prevents oxidative damage

what is hemachromatosis? what can it lead to? what are the three types and what are each caused by?

iron overload liver cirrohosis, skin pigmentation, diabetes mellitus 1. primary 2. secondary \*\* both caused by blood transfusions, ineffective erythropoiesus, increased iron intake 3. neonatal- develps in utero with unknown cause

how do Hb conc, PO2, %Hb saturaton change in anemia?

half the Hb content--\> half blood oxygen content (they are proportional) BUT % Hb saturation does not change

for primary polycythemia, what is its: cause? effect on # of RBC's total blood volume viscosity cardiac output

genetic--\> low EPO extra RBCs increase in total BV (2x) increase in viscosity normal (kinda) CO

for secondary polycythemia, what is its: ## Footnote cause? effect on # of RBC's cardiac output

hypoxia--\> high EPOs extra RBCs CO may be abnormal

for physiologic polycythemia, what is its: ## Footnote cause? effect on # of RBC's cardiac output

high altitude adaption extra RBCs normal CO

what are characteristics of methemoglobinemia? shift is ODC?

increase met-hemoglobin iron is in ferric form decreased O2 to tissues blood is brown skin is blue _leftward shift is ODC_

how do you describe oxygen consumption in a tissue? how do you figure it out?

a-v O2 content difference (how much O2 tissues consumed) 20mL (going into tissue)- 15 mL(out of the tissue)= 5 mL O2 (that tissues consumed)

how does exercise effect a-v O2 difference?

tissues consume more O2 (due to increase of CO2 being produced by them)--\> less venous O2 (only now about 5 mL vs 15)--\> bigger a-v difference

how do you use the a-v difference to calculate RQ? what is the normal values?

volume CO2 produced/ volume O2 consumed---\> VdotCO2/VdotO2 200 mL CO2 produced/ 250 mL O2 consumed = 0.8

how is RQ determined (real world wise, not equation)?

the type of fuel being used by body carbs- 1:1 ratio fat- 7:10 ratio protein- 9:10 ratio (\_\_ CO2 produced for every __ O2 consumed)

how is RQ affected by exercise?

increases with # of calories burned

what are the three ways CO2 is transported?

1. dissolved CO2- not enough on its own * travels down its conc gradient into alveoli 2. carbamino compounds- bound to plasma proteins or Hb (not heme, but amine group) * once in lungs, dissociates from the proteins 3. as HCO3 **(most)**- a lot more on that in another card

what is the Haldane shift?

presence of O2 reduces affinity of amine chain (on Hb) for CO2

how is CO2 converted to HCO3? how is it exported from cell? what kind of shift does HCO3 cause?

converted by carbonic anhydrase exported by chloride causes "chloride shift" or "hamburger shift"

what are the 5 steps of how CO2 is carried to lungs in the blood as HCO3?

1. Co2 produced and exits tissue 2. CO2 hydrates into H2CO3 by carbonic anhydrase in RBCs 3. H2CO3 dissociates into H+ and HCO3- 4. H+ is buffered by deoxyhemoglobin in RBC's and carried to venous blood 5. HCO3- is exchnaged for Cl- across RBCs and carried to lungs once HCO3 is in lungs---\> converted back to CO2