Mechanism of ventilation, gas exchange

Mechanism of ventilation, gas exchange

Sáringer Szabolcs

Medical Physiology

Joint seminar

Silbernagl, Stefan, and Agamemnon Despopoulos. Color Atlas of Physiology

• Surface tension • Thorax+pleura• Interdependency of

the alveoli

Az orvosi élettan tankönyve - Attila, Fonyó

Thorax

• Surface tension • Thorax+pleura• Interdependency of

the alveoli• Surfactant


Thorax

Pleura space

Parietal pleura

Visceral pleura

Lungs

Athmospheric pressure

Intrapulmonary pressure

Intrapleural pressure

Transpulmonary pressure


Thorax

Pleura space

Parietal pleura

Visceral pleura

Lungs

Athmospheric pressure

Intrapulmonary pressure

Intrapleural pressure

Transpulmonary pressure

Az orvosi élettan tankönyve - Attila, FonyóGuyton and Hall Textbook of Medical Physiology

Thorax

Pleura space

Parietal pleura

Thorax

Pleura space

Parietal pleura


Lung volume (liter)

Thorax Lungs Thorax + lungs

Transpulmonary pressure(H2O cm)

Compliance


Saline

AirLu

ngv

olu

me

(%

TLC

)

Transpulmonary pressure(H2O cm)

𝑅 =𝑣𝜌𝑑

𝜇

Resistance

• Elastic recoil: resistance from lung tissue • Viscose resitance: resistance from the air

Silbernagl, Stefan, and Agamemnon Despopoulos. Color Atlas of PhysiologyAz orvosi élettan tankönyve - Attila, Fonyó

Respiratory volume(liter)

IntrapleuralPressure(H2Ocm)

Speed of flow(liter/s)

Intrapulmonary pressure(H2Ocm)

Start of insp. End of insp. End of exp.

~3500 ml

~500 ml

~1200 ml

~1200 ml

~2400 ml

~4800 ml

~6000 ml

Guyton and Hall Textbook of Medical Physiology


Vo

lum

e (m

l)

Time (s)

Dead space

• anatomical • alveolar

Silbernagl, Stefan, and Agamemnon Despopoulos. Color Atlas of PhysiologyGuyton and Hall Textbook of Medical Physiology

https://en.wikipedia.org/wiki/High-frequency_ventilationhttps://www.youtube.com/watch?v=guodauleCC0

High frequency ventilation – Taylor dispersion

V= 𝑘 𝑥 𝐴 𝑥 ഥ𝐷Δ𝑃

0,75s


98 Hgmm

40 Hgmm

40 Hgmm

46 Hgmm

V/Q mismatch

Perfusion (Q) Ventilation (V)


https://rk.md/2018/hypoxic-pulmonary-vasoconstriction-hpv/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5310129/

• Hem + globin • 2 alpha & 2 beta chains• Binding 4 molecules of O2

HbO2

CO2 CO2

CO2+H2O

H2CO3

H+ HCO3-

Hamburger shift

HHb

O2O2

Cl-HCO3-

Cl-HCO3-

Periphery

O2

O2+HHbHaldane effect

Cl-HCO3-

Cl-HCO3-

H2CO3H2O+CO2

CO2

Lungs

• Dorsal respiratory center

• Ventral respiratory center(Pre-Bötzinger complex)

• Bötzinger complex

• Pneumotaxic center

• Apneustic center

• Pons: parabrachial nucleus, Kölliger –Fuse nucleus


• Dorsal resp. center ->resting inspiration, rythm generator

• Ventral respiratory center (Pre-Bötzinger complex) -> forced in & expiration

• Bötzinger complex -> inhibitory, startin postinhibitory phase

• Pons: parabrachial nucleus, Kölliger –Fuse nucleus

• Pneumotaxic center

• Apneustic center

inhibition


• Slow adapting receptors

• Inhibiting inspiratory reflex

• Hering Breuer reflex

• Fast adapting receptros

• In the wall of the airways

• Histamin, PG, dust

• Coughing, hyperpnoe, mucus secretion

• Juctacapillary receptors

• Chemical stimuli in blood

• Apnoe, bronchoconstriction, mucus secration


• Central chemoreceptors

• Ventral part of medulla

• CO2 diffuses through BBB

• H+ + HCO3- in CSF

• Emelkedett H+ ingerli a receptorokoat-> ventilation stimulus

• Peripherial receptors

• Glomus caroticum, glomus aorticum

• Sensitive: hypoxia, hypercapnia, acidosis


Mechanism of ventilation, gas exchange

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