Respiratory Physiology, Waters and Leffler

Question 1

Total Lung Capacity Equals…

Answer 1

Vital Capacity + Residual Volume

-Normal: 6-7 L

Question 2

Vital Capacity Equals…

Answer 2

Tidal volume + Inspiratory Reserve Volume + Expiratory Reserve Volume
-Normal: 3-5 L

Question 3

Functional Residual Capacity Equals…

Answer 3

Expiratory Reserve Volume + Reserve Volume

• Amount of air in lungs after a NORMAL expiration
• Normally 2.5 L

Question 4

Residual Volume Equals…

Answer 4

• Amount of air in lungs after a MAXIMAL expiration

- Normally 1000 L

Question 5

Effect of Obstructive Lung Disease on FEV1

Answer 5

-FEV1 is decreased

Question 6

Effect of Restrictive Lung Disease on FEV1

Answer 6

• FEV1/FVC ratio is normal

- FVC is decreased

Question 7

What determines air movement into and out of lungs?

Answer 7

Trans-respiratory system pressure

P(alveolar) - P(atmospheric)

Question 8

Transpulmonary Pressure

Answer 8

P(Alveolar) - P(intrapleural)

Question 9

Inspiratory Muscles

Answer 9

Diaphragm
Accessory Muscles (Scalene, Sternocleidomastoid)

Question 10

Expiratory Muscles

Answer 10

Abdominal Muscles (Rectus Abdominis, Obliques)
Internal Intercostal Muscles

Question 11

Compliance Equals…

Answer 11

(Change in Pressure)/(Change in Volume)

• SLOPE of a Pressure-volume curve
• Measure of DISTENSIBILITY of lungs
• Normal: 0.2 L/cmH2O

Question 12

Methemoglobin

Answer 12

• Oxidized form of Hb; Fe3+

- DOES NOT bind O2

Question 13

Fetal Hemoglobin (HbF)

Answer 13

• higher affinity for O2 than normal hemoglobin

- has alpha2gamma2 subunits instead

Question 14

Factors which cause the Hb Saturation Curve to shift to the RIGHT (DECREASE AFFINITY FOR O2, facilitate unloading)

Answer 14

• Increased PCO2
• Decreased pH (acidosis)
• Increased Temperature (Metabolism)
• Increased 2,3 DPG (RBC metabolism)

Question 15

Factors which cause the Hb Saturation Curve to shift to the LEFT (INCREASE AFFINITY FOR O2, facilitate loading)

Answer 15

• Decreased PCO2
• Increased pH (alkalosis)
• Decreased Temperature (Metabolism)
• Presence of Fetal Hemoglobin
• Decreased 2,3 DPG

Question 16

Bohr Effect

Answer 16

• As H+ binds to hemoglobin, O2 binds less strongly; this shifts the O2 saturation curve to the right, facilitating unloading of O2.
• Occurs in venous blood

Question 17

Haldane Effect

Answer 17

• Deoxygenation of the blood leads to an increased ability for the blood’s ability to carry CO2.
• Decreases in O2 facilitate H+ binding to hemoglobin; this results in a “left shift” in the position of the CO2 curve, this increasing the ability to remove CO2.

Question 18

Medullary Control of Breathing

Answer 18

Central Respiratory Center (DRG, VRG)

• Drives inspiration and expiration
• Establishes and Maintains Rhythmicity
• NORMALLY, not active
• DRIVEN BY pH!!!

Question 19

Pontine Respiratory Contorl Centers

Answer 19

• Apneustic Center

- Pneumotaxic Center

Question 20

Apneustic Center

Answer 20

• Stimulates inspiration

- produces a deep and prolonged inspiratory gasp

Question 21

Pneumotaxic Center

Answer 21

• Inhibits inspiration

- Regulates inspiratory volume and respiratory rate

Question 22

Peripheral Chemoreceptors

Answer 22

• Aortic Bodies (efferent via Vagus Nerve)
• Carotid Bodies (efferent via Glossopharyngeal N.)
• Respond to low PaO2, stimulating inspiration