Fundamental Physiology of the Respiratory System
Diaphram – Muscular sheath
Phrenic Nerve – Important for regulation
Alveolar Organistaion
Elastic fibre – help expand and contract
Alveoli and capillary fused together – reduce distance
Macrophage – filter the air
Fine membranes are not only at the lungs but also down at respiring tissues
Oxygen moves from high concentration to a low concentration
Three steps of respiration:
1. Pulmonary ventilation
2. External respiration
3. Internal respiration
Divisions of the respiratory tract:
 Anatomical
Upper and lower part
 Functional
Conducting portion
Respiratory Portion
Damage to pherenic nerve can be very dangerous
Three main factors affecting compliance:
1. Levels of surfactant production
2. Connective tissue structure
3. Mobility of thoracic cage
The two MODES of quiet breathing:
1. Diaphragmatic (deep) breathing
2. Costal (shallow) breathing
Gases are transported in the blood as:
 Oxyhaemoglobin
 CO2 dissolved in plasma
 Carbamonohaemoglobin
 Bicarbonate ions
Major factors regulating O2 – Hb saturation are:
 Co2
 pH
 Temperature
Two main centres that control breathing:
1. Rhythmicity area
2. Pneumotactic area
Three important clinical tests:
1. Forced expiratory flow
2. Forced aspiratory flow
3. Peak expiratory flow