Physiology of Respiratory System

Respiration

• Pulmonary ventilation– Breathing- air movement in and out of body

• External respiration– Oxygen loading and Carbon dioxide loading

• Respiratory gas transport– Gases transported via bloodstream

• Internal respiration – Exchange between capillaries and tissue cells

Breathing

• Inspiration– Diaphragm flattens creates a vacuum pulling air

into the lungs

• Expiration– Muscles relax and push air out of the lungs

Respiratory Volumes and Capacities

• Tidal Volume (TV)- volume of air moved into and out of the lungs each breath

• Inspiratory reserve volume (IRV)- amount of air you can forcibly be taken in

• Expiratory reserve volume (ERV)- amount of air that can be forcibly expelled

Respiratory Volumes and Capacities

• Residual Volume- air that cannot be expelled from the lungs

• Vital capacity (VC)- total amount of exchangeable air TV + IRV + ERV

• Dead Space volume- the amount of air that doesn’t make it to the lungs in a breath

External Respiration

• Gas exchange at the lungs

• Oxygen into blood and CO2 removed from blood

Gas Transport in the Blood

• Oxygen forms oxyhemoglobin with hemoglobin molecules

• CO2 in transported via

bicarbonate in plasma

Internal Respiration

• Exchange of gases between blood and tissue cells

• Oxygen unloaded and CO2 loaded

Hypoxia

• Inadequate supply of oxygen to the body tissues

• Causes skin to become cyanotic

Carbon Monoxide Poisoning

• CO binds to the binding site that oxygen binds to on hemoglobin preventing gas transport of oxygen

Respiratory Terms

• Eupnea- normal respiratory rate

• Hyperpnea- increased respiratory rate (exercising)

• Apnea- stopped breathing

• Dyspnea- difficult breathing

Hyperventilation

• Body’s reaction to increased levels of carbon dioxide or acids in blood

Smoker’s Lungs Versus Healthy Lungs