Respiratory physiology

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Gaseous exchange in the lung.

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

Topics include:

1 Volumes
2 Mechanics
3 Circulation, ventilation, and perfusion
4 Gas exchange/transport (primarily oxygen and carbon dioxide)
5 Control and response
6 Disorders
7 See also
8 Additional images
9 References
10 External links

[edit] Volumes

[edit] Mechanics

Front view of thorax.

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 P_el equals the product of elastance E (inverse of compliance) and volume of the system V, P_re equals the product of flow resistance R and time derivate of volume V (which is equivalent to the flow), P_in 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^[1]
Poiseuille's law
asthma and COPD
hysteresivity

[edit] Circulation, ventilation, and perfusion

Pulmonary circulation

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

[edit] Gas exchange/transport (primarily oxygen and carbon dioxide)

Oxygen-hemoglobin dissociation curve

[edit] Control and response

Pons

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)

[edit] Disorders

[edit] See also

[edit] Additional images

[edit] References

^ Compliance

[edit] External links

v • d • e Respiratory system, physiology: respiratory physiology

Volumes	lung volumes - vital capacity - functional residual capacity - respiratory minute volume - closing capacity - dead space - spirometry - body plethysmography - peak flow meter - thoracic independent volume - bronchial challenge test

Airways	ventilation (V) (positive pressure) - breath (inhalation, exhalation) -respiratory rate - respirometer - pulmonary surfactant - compliance - hysteresivity - airway resistance

Blood	pulmonary circulation - perfusion (Q) - hypoxic pulmonary vasoconstriction - pulmonary shunt

Interactions	ventilation/perfusion ratio (V/Q) and scan - zones of the lung - gas exchange - pulmonary gas pressures - alveolar gas equation - hemoglobin - oxygen-haemoglobin dissociation curve (2,3-DPG, Bohr effect, Haldane effect) - carbonic anhydrase (chloride shift) - oxyhemoglobin - respiratory quotient - arterial blood gas - diffusion capacity - Dlco

Control of respiration	pons (pneumotaxic center, apneustic center) - medulla (dorsal respiratory group, ventral respiratory group) - chemoreceptors (central, peripheral) - pulmonary stretch receptors (Hering-Breuer reflex)

Insufficiency	high altitude - oxygen toxicity - hypoxia

Categories: Respiratory therapy | Respiration