Respiration and Ventilation

Respiration

Process that provides every cell with oxygen for atp production and removes waste products - carbon dioxide

First process of respiration

Pulmonary ventilation in respiratory system, movement of air in and out of lungs, requires volume changes in the lungs to create a pressure gradient

Second process of respiration

External respiration - pulmonary gas exchange in respiratory system, gas exchange between alveoli and blood

Third process of respiration

Gas transport in cardiovascular system, transport of oxygen and carbon dioxide in blood

Fourth process of respiration

Internal respiration - tissue gas exchange in cardiovascular system, gas exchange between blood and tissue cells

Fifth process of respiration

Cellular respiration, process of oxidising food molecules to atp, carbon dioxide and water

Ventilation (breathing)

Continuous movement of fresh air high in oxygen into lungs and stale air high in carbon dioxide out of lungs

Respiratory cycle

One single breath = one complete inspiration and expiration

Resting respiratory rate

12 breaths per minute

Air flow driven by

Pressure gradient, flows from high pressure to low pressure

Intra-alveolar pressure at rest

Equal to atmosphere pressure = 760 mmHg, need pressure gradient between atmospheric and intra-alveolar pressures to inhale and exhale

To inhale

Requires decrease in intra-alveolar pressure in lungs to below atmospheric pressure for air to move in

To exhale

Requires increase in intra-alveolar pressure to force air out

Boyle’s law

Inverse relationship between pressure and volume, p1v1 = p2v2, p = k/v, pv = k

Pressure gradient during pulmonary ventilation - inhalation

When intra-alveolar volume increases = pressure decreases, if intra-alveolar pressure is less than atmospheric pressure = inhalation

Pressure gradient during pulmonary ventilation - exhalation

When intra-alveolar volume decreases = pressure increases, if intra-alveolar pressure is more than atmospheric pressure = exhalation

Lung wall

No skeletal muscles in lung wall to contract/relax, skeletal muscles of thoracic wall may help but do not directly attach to lungs

Pleurae and pleural cavity

Cavity filled with pleural fluid to decrease friction during breathing, creates subatomic pressure to keep lungs adhered to thoracic cage