BMS130 Lecture Notes - Lecture 3: Hyperventilation, Lung Volumes, Hypoventilation
RESPIRATORY SYSTEM
State the sources of resistance to pulmonary airflow and discuss their relevance
to respiration
1. Pulmonary compliance
- How easily the lungs expand
- Opposite of elasticity
- Lungs are a little more elastic than compliant
2. Bronchiole diameter
- Primary control over resistance to airflow
- Bronchoconstriction
- Triggered by airborne irritants, cold air,parasympathetic stimulation,
histamine
- Bronchodilation
- Sympathetic nerves, adrenaline
3. Alveolar Surface Tension
- Thin film of water needed for gas exchange
- Creates surface tension that acts to collapse alveoli and distal
bronchioles
- Pulmonary surfactant
- Produced by Type II alveolar cells
- Decreases surface tension using a similar action to detergent and
water
- Prevent alveolar collapse during expiration
- Premature infants that lack surfactant suffer from respiratory distress
syndrome
Document Summary
State the sources of resistance to pulmonary airflow and discuss their relevance to respiration: pulmonary compliance. Lungs are a little more elastic than compliant: bronchiole diameter. Triggered by airborne irritants, cold air,parasympathetic stimulation, histamine. Sympathetic nerves, adrenaline: alveolar surface tension. Thin film of water needed for gas exchange. Creates surface tension that acts to collapse alveoli and distal bronchioles. Decreases surface tension using a similar action to detergent and water. Premature infants that lack surfactant suffer from respiratory distress syndrome. Define terms for various deviations from the normal pattern of breathing. Hyperpnoea - increased rate and depth of breathing. Hypoventilation - reduced rate of breathing, not meeting metabolic demand. Kussmaul respiration - hyperpnoea in response to acidosis. Define clinical measurements of pulmonary volume and capacity: tidal volume (vt or tv ) - volume of air in one quiet breath, generally around. 500ml: residual volume (rv) - air remaining in lungs after maximum expiration, generally equal to 1300ml.
