The Respiratory System PSE4U Mr. MacMillan

What Makes Up the Respiratory System? The Conductive Zone Nose, pharynx, trachea, bronchi, bronchioles The Respiratory Zone Respiratory bronchioles, alveolar ducts, alveoli sacs.

Main Functions Supply Oxygen to the blood Remove CO2 from the blood Regulate blood pH

Internal Respiration Is the exchange of gases at the tissue level where Oxygen is delivered and Carbon Dioxide is removed

External Respiration The processes that occur within the lung involving the exchange of Oxygen and Carbon Dioxide

Mechanisms of Breathing Diaphragm Contracts and moves downward towards the abdominal cavity when stimulated by the brain Ventilation The combination of inspiration (breathing in) and expiration (breathing out) Tidal Volume Volume of air in each breath Respiratory Frequency The number of breaths taken per minute

Controlling Ventilation Respiratory Control Centre Found within brain stem Medulla oblongata and pons

Lung Volumes Static Lung Volume Dynamic Lung Volume Determined by actual structure of lung Dynamic Lung Volume Dependent, not only on volume, but on the movement or flow of air Three important Static Lung volumes Total lung capacity, vital capacity, residual volume TLC = VC + RV

Gas Exchange Diffusion The movement of gas, liquid or solid from a region of high concentration to low concentration.

Oxygen Transport 2% of Oxygen found within plasma of blood Hemoglobin Specialized protein found in erythrocytes that binds to Oxygen

Carbon Dioxide Transport Small amount is dissolved in the plasma (5 – 10%) 90 – 95% of CO2 diffuses into erythrocytes, passed to alveoli and is exhaled

Ventilation and pH Blood pH is a measure of how acidic and basic blood is Blood pH is close to 7.4 – neutral is 7 More acidic during exercise – lactic acid (decreased pH) Ventilation increase pH back to normal