1. 1 December 2009 Respiratory Physiology
Lab this week: A case study and measuring lung volumes and capacities with Powerlab.
Bring calculator and textbook to lab.
About the Final Exam…..
Choice of Tuesday, Wednesday or Friday

2. Pulmonary arterial blood = low in O2
Cartilage prevents collapse of airways during expiration.

3. Figure 22.10

4. Type I pneumocytes are simple squamous epithelia that comprise the majority of the surface area.
Type II pneumocytes secrete surfactant.
Gas exchange by diffusion based on gradients.

5. Figure 13.17 Who cares? Respiratory Distress Syndrome of the Newborn
Law of LaPlace
Surfactant reduces surface tension which reduces the mechanical effort of ventilation and prevents the collapse of smaller alveoli.

7. Figure 13.19
Tidal inspiration
At end of normal tidal expiration

8. V = VT x f
VA = (VT – VDS) x f
Anatomic dead space = air remaining in conducting zone (typically 150 ml.)
What is VA if Tidal Volume is 150 ml?

9. CO2 production
O2 uptake

10. CO2 production
= Respiratory Quotient
O2 uptake
= 0.8 for proteins
= 0.7 for fat
= 1.0 for carbohydrates
=0.8 for mixed diet 200 mlCO2/min ml O2/min

11. Alveolar to arterial gradient is due to ventilation/perfusion inequality.
Ventilation by Bulk Flow
Pulmonary Venous blood is equivalent to Systemic Arterial blood.
Gas exchange
Gas exchange
Gradient for CO2 is only 6 mmHg;
CO2 is more soluble and permeable than O2

12. Landmark numbers to memorize.

13. Matching blood flow (Q, also called “perfusion” ) to ventilation (V) by pulmonary arterioles that constrict in response to low O2 and dilate in response to hi O2
(Note this response to O2 is opposite that of systemic arterioles!)
Thus, poorly ventilated regions of the lung will receive less blood flow.
So…. Q is “matched” to V, but not perfectly.
And low perfusion in a region leads to bronchoconstriction.

14. Figure 13.27
CO2 and O2 bound to Hb do not contribute to partial pressure (no longer a dissolved gas!)

15. Table 13.08

16. Figure 13.31 Hb can bind O2, CO2, and H+
Increases in CO2 and H+ decrease the affinity of Hb for O2

17. Steep
Flat

18. Shifting the Oxyhemoglobin dissociation curve
At 40 Torr, more DPG, higher temperature, and greater acidity (all indicative of increased metabolism) shift dissociation curve down (Hb has a lower affinity for O2) and thus more O2 is unloaded into the tissues.
Notice the main affect is on the steep portion of the curve which means that there is little influence on the loading of O2 onto Hb in the lungs

19. Table 13.09

20. Carbon dioxide transport
carbaminohemoglobin
Chloride
Shift
CA = carbonic anhydrase
Hb is a Buffer
Carbon dioxide transport