Respiratory physiology



Respiratory physiology is the branch of human physiology focusing upon respiration.

Topics include:

Volumes

 * lung volumes
 * vital capacity
 * functional residual capacity
 * dead space
 * spirometry
 * body plethysmography
 * peak flow meter

Mechanics


Breathing in, or inhaling, is usually an active movement. The contraction of the diaphragm muscles cause a pressure variation, which is equal to the pressures caused by elastic, resistive and inertial components of the respiratory system.

$$ \begin{align} P &= P_{el} + P_{re} + P_{in} \\ P &= EV + R\dot{V} + I\ddot{V} \end{align} $$

Where Pel equals the product of elastance E (inverse of compliance) and volume of the system V, Pre equals the product of flow resistance R and time derivate of volume V (which is equivalent to the flow), Pin equals the product of inertance I and second time derivate of V. R and I are sometimes referred to as Rohrer's constants.


 * Anatomy: pleural cavity, thoracic diaphragm, Intercostales externi muscles, Intercostales interni muscles
 * inhalation and exhalation
 * lung, pulmonary alveolus
 * With insufficient pulmonary surfactant, the pulmonary alveoli collapse, causing atelectasis (in infants, infant respiratory distress syndrome)
 * the law of Laplace,
 * compliance (physiology) - decreased with fibrosis, increased with emphysema
 * Poiseuille's law
 * asthma and COPD
 * hysteresivity

Circulation, ventilation, and perfusion

 * pulmonary circulation
 * positive pressure ventilation
 * hypoxic vasoconstriction
 * ventilation (physiology), perfusion, ventilation/perfusion ratio (V/Q), and ventilation/perfusion scan
 * shunts: right-to-left (tetralogy of fallot), left-to-right (patent ductus arteriosus)
 * respiratory rate and respirometer

Gas exchange/transport (primarily oxygen and carbon dioxide)

 * gas exchange
 * Dalton's law
 * hemoglobin
 * oxygen-haemoglobin dissociation curve, Bohr effect, Haldane effect
 * carbonic anhydrase
 * oxyhemoglobin
 * respiratory quotient
 * arterial blood gas

Control and response

 * control of respiration
 * reticular formation
 * pons (apneuistic and pneumotaxic)
 * chemoreceptors (medulla, carotid body, aortic body)
 * Hering-Breuer reflex
 * involuntary control of respiration
 * exercise
 * hyperoxia
 * hypoxemia (hypoxic hypoxia)

Disorders

 * altitude sickness
 * asthma
 * carbon monoxide poisoning
 * COPD
 * emphysema
 * infant respiratory distress syndrome
 * pulmonary edema