Lecture 14 - Gas Transport

Question 1

Methemoglobin has an iron moiety that is in the +___ state as opposed to the +___ state of normal Hb.

Answer 1

+3 (ferric)

+2 (ferrous)

Question 2

1 gram of Hb can combine with about ____mL of O2. Keep in mind the Hb content of blood is about ___g/100mL.

Answer 2

1.39mL

15g/100mL

Question 3

Decreasing the body’s pH, making it more acidic, will cause a ____ shift in the Oxyhemoglobin dissociation curve. Increasing pH will shift it to the _____.

Answer 3

Right (decreased Hb-O2 binding affinity)

Left (increased binding affinity)

Question 4

The Bohr effect describes how higher _____ concentration in the blood will decrease the pH –> ____ shift of the oxyhemoglobin dissociation curve.

Answer 4

Higher CO2 concentration

Right shift (decreased Hb-O2 binding affinity)

Question 5

2,3 BPG causes a ______ shift in the O2Hb dissociation curve.

Answer 5

Right shift (decreased binding affinity)

Remember that stored blood typically has a higher concentration of 2,3 BPG

Question 6

Equation for O2 content in blood (CaO2) = ____________

Keep in mind normal value for CaO2 = _____.

Answer 6

CaO2 = (1.39 x Hb x O2sat/100) + 0.003 PaO2

20.63

Question 7

Equation for O2 delivery: ________

Answer 7

O2 Delivery = CO [(1.39 x Hb x O2sat/100) + 0.003 PaO2]

Question 8

Which has a greater effect on CaO2, a change in Hb content or change in PaO2?

Answer 8

Change in Hb content will have a greater effect.

Question 9

Hb bound to CO is called ________. Bc CO binds Hb with 240x the affinity that O2 binds with, CO poisoning essentially has the same effect as _____ (there’s effectively less Hb available for O2 binding.)

Answer 9

Carboxyhemoglobin

Anemia

Question 10

The main compensatory mechanism for low PO2 at high altitude is ______ –> This lowers PCO2, which effectively increases PAO2.

Answer 10

Hyperventialtion

Question 11

_______ is an adaptation that people who live at high altitudes may exhibit. It raises their Hb content, and thus increases their CaO2.

Increasing _______, causing a rightward shift in the oxyhemoglobin dissociation curve can help at high altitudes as well –> more O2 is offloaded from Hb at Higher PaO2 (decreased Hb-O2 binding affinity).

Answer 11

Polycythemia

2,3 BPG

Question 12

At extreme altitudes, people may experience ______ _______ (secondary to hyperventilaton)–> the increase in pH causes a ____ shift in the oxyhemoglobin dissociation curve –> increased binding of O2 at the alveolar capillaries.

Answer 12

Respiratory Alkylosis

Left shift

Question 13

80-90% of CO2 is transported in the blood as _____.

Answer 13

HCO3-