Pulmonary Ventilation

Question 1

Define pulmonary ventilation

Answer 1

Work of breathing

Question 2

Factors that determine energy of breathing

Answer 2

1. Compliance of lungs and thorax
2. Resistance of airways

Question 3

Inhalation vs. exhalation

Answer 3

• Inhalation: negative pressure in lungs by increasing the volume by diaphragm contracting and pulling down
• *- Inspiration pressure: 758 mmHg**
• Exhalation: positive pressure in the lungs by decreasing the volume by diaphragm relaxing and coming back up
• *- Expiration pressure: 763 mmHg**

Question 4

Boyle’s Law

Answer 4

At a constant temperature, pressure and volume are inversely proportional

Question 5

Muscles used for forced inspiration and forced expiration breathing

Answer 5

Inspiration: scalenes, sternocleidomastoid, pectoralis

Expiration: latissimus dorsi, quadratus lumborum, abs

Question 6

Static Lung Volumes (Vt, IRV, ERV, FVC, RLV)

Answer 6

• Tidal volume: Air moved during inspiration and expiration (0.4-1.0 L/breath)
• Inspiratory Reserve Volume: Additional 2.5-3.5 L above tidal volume reserve for inhalation
• Expiratory reserve volume: after normal exhalation, the additional volume that can be exhaled 1-1.5L
• Forced vital capacity: total air volume moved in 1 breath from full inspiration to max expiration (based on body size and position)
• Residual lung volume: Following max exhalation - volume of air that remaind that cant be exhaled (1.0-1.2 for women; 1.2-1.6 for men)

Question 7

Dynamic lung volumes (FEV₁/FVC and Minute Ventilation)

Answer 7

FEV₁/FVC = expiratory power and overall resistance to air movement; averages 85%

Minute Ventilation (V_E): Breathing rate x Tidal volume

Question 8

Atmospheric pressure

Answer 8

760 mmHg

Question 9

Intrapulmonic pressure

Answer 9

760 mmHg

Question 10

Bohr Effect

Answer 10

Decrease O₂ affinity of hemoglobin in response to decreased blood pH (high acidity) results from increased CO₂ concentration

Question 11

Haldane effect

Answer 11

- Deoxygenation of blood increases ability to carry carbon dioxide

- Oxygenated blood has reduced capacity for CO2

Question 12

Altitude

Answer 12

- Decreases performance because less oxygen in the air, decreased air pressure

- Lowers partial pressure of oxygen so not as much is taken in

Question 13

How is O2 and CO2 carries in the blood?

Answer 13

• O2 transport in blood: 98% of O2 is bount to hemoglobin in RBCs
• 2% dissolved in plasma
• CO2 transport in blood: dissolved in solution, carbonic acid
• 75% in RBC
• 25% in plasma

Question 14

Oxyhemoglobin Dissociation Curve

Answer 14

• Shows oxygen’s affinity for hemoglobin depending on PO2
• High PO2 (in lungs) loading portion of O2 - high affinity
• Low PO2 (body tissues) unloading of O2 - low affinity
• Right shift indicates: acidic; increased temp; exercise; oxygen has a lower affinity for hemoglobin so it will unload more readily
• Left shift indicates: basic; decreased temp; oxygen has higher affinity - more loading

Question 15

Ventilatory Threshold

Answer 15

• Point at which pulmonary ventilation increases disproportionately with oxygen uptake during graded exercise
• Relates to Co2 increase from buffering of lactate that begins to accumulate from anaerobic metabolism

Question 16

Regulation of pulmonary ventilation

Answer 16

1. Neural regulation
   - Respiratory cycle - inherent automatic activity of inspiratory neurons
2. Chemoreceptor regulation
   - Stimulated by increase in CO2 in cerebrospinal fluid - increases rate and depth to remove CO2
3. Mechanoreceptor regulation
   - Excessive stretch decreases depth of breathing
   - Located in plerua, bronchioles and alveoli