Gas Exchange

Gas Exchange in Alveoli (Gas Laws) 2

Dalton’s and Ficks

 Dalton’s law of partial pressures

• Total pressure of the mixture is sum of pressures of individual gases

• Each gas exerts the same pressure as it would exert alone

Fick’s law of diffusion

• Amount of a gas that diffuses across membrane determines by

  • Partial pressure difference

  • Total surface area

Respiratory pigments: Oxygen transport Function

Combine reversibly with oxygen and Increase amount of oxygen transported in fluid

Types of respiratory pigments

-Hemoglobin [contains iron]: In vertebrates and some invertebrates and ~99% of O2 in human blood transported by hemoglobin

-Hemocyanin [contains copper]: In hemolymph of many species of mollusks and arthropods

-Myoglobin: In muscle fibers (form of hemoglobin): extracts oxygen from hemoglobing and delivers to muscle tissue

O₂ carrying capacity

Maximum amount of O2 that can be transported by hemoglobin

O₂ content

Actual amount of O2 bound to hemoglobin

Percent O₂ saturation

 how much could you carry vs how much you are carrying

Normal curve

Bohr Effect (pH

Acidic (7.2): shift curve to right

: Under acidic conditions, what does hemoglobin want to do?

Donate Hydrogen (Vice Versa)

Why is curve shifting right under high amount of CO2

higher partial pressure to get saturated

As CO2 levels rise in blood, which way will it shift?

Right, Acidic

Equation for Bohr Effect with Carbonic Anyhrase

CO2 + H2O <-> H2CO3 <-> H+ +HCO3-

Haldane Effect

For Haldane Effect what happens to curve when there is high vs low CO2

High=acidic= shift right

Low=Basic=Left

Temperature Effect

Why is right shift combined relates to?

Excersise (temp, CO2, O2, pH)

Cooperative binding:

if one binds, two binds easier than one, three binds even easier

Carbonic anhydrase reaction

        Rev. rxn      Carbonic Acid                      Bicarbonate Ion

• CO₂ + H₂O    <->   H₂CO₃     <->   H⁺ + HCO₃⁻ 

Carbon dioxide transport at tissue level

into rbc > carbinic anhydrase reaction runs> Bicarbonate ion produced and moves into blood-> Cl- taken out of blood (one in one out) -> Hydrogen provides acidic environment for hemoglobin

Carbon dioxide transport at lung level

Lungs:CO2 from lung into alveoli
- Bicarbonate into cell >Cl out -> carbonic anhydrase opposite direction to produce CO2 and H2O -> increases PP on blood side -> diffuse over to alveoli
- O2 high into alveolus diffusing in-> displaces H2 and CO2 from hemoglobin