Mechanism of ventilation pt.1 Flashcards
What are the 2 zones of respiratory passage
Conducting zone and respiratory zone
Which generation is each zone
conducting zone: 1-16
Respiratory zone: 17-23
What are the innervations for smooth muscle cells
Parasympathetic N.S (muscarinic receptors): bronchodilatation
Sympathetic N.S (beta 2 adrenergic receptors): bronchoconstriction
What are the 2 layers covering the lungs
Visceral pleura
parietal pleura
what are the functions of the pleural fluid
Prevent lung and chest from being pulled apart
Allows them to easily slide over each other
What happens during excess accumulation of pleural fluid
Pleural effusion
What is the normal respiratory rate for adults and children
Adults: 12-18
children: 30-40
what are the 3 changes in dimensions of the thoracic cage
Longitudinal
transverse
vertical
What is normal breathing called
Eupnea
Why is inhalation active during eupnea
It involves contraction of diaphragm and external intercostal muscles
Why is expiration passive during eupnea and how is it achived
No muscle contraction
Achieved by elastic recoil of lungs
What is the origin, insertion and innervation of the diaphragm
Origin: Lower ribs
Insertion: Central tendon
Innervation: Phrenic nerve (C4, 5)
What is the origin, insertion and innervation of the external intercoastal muscles
Origin and insertion: runs down and forwards from rib to rib
Innervation: intercoastal nerves
which dimensions does contraction of external intercoastal muscles increase
Transverse and anteroposterior
What changes during forced breathing
Both inspiration and expiration is active
What changes during forced breathing in terms of inspiration
stronger diaphragm contraction
contraction of accessory muscles
what are the 3 accessory muscles
Sternomastoid
Serratus anterior
Scalene muscles
What changes during forced breathing in terms of expiration
Contraction of internal intercoastal muscles
contraction of abdominal wall muscles
How are lung volumes measured
spirometer
What and how much is tidal volume (TV)
The air inhaled or exhaled each breath
~500ml
What and how much is Inspiratory reserve volume
Air forcibly inhaled above tidal volume
~3000ml
What and how much is Expiratory reserve volume (ERV)
Air forcibly exhaled above tidal volume
~3000 ml
What and how much is Residual volume (RV)
The air that remains in lungs after maximum/forced expiration (cannot be measured by spirometer
~1200ml
What is lung capacity
2 or more lung volumes added together
What and how much is Inspiration capacity (IC)
Maximum volume of air inspired after normal expiration
TV+ IRV
~3500ml
What and how much is Functional residual capacity (FRC)
It is the remaining volume of air after normal expiration when all respiratory muscles are relaxed
ERV + RV
~2300ml
What and how much is Vital capacity (VC)
Maximum volume inhaled and exhaled
IRV + ERV + TV
~4600ml
What and how much is Total lung capacity
Total volume of air after maximum inspiration/ total lug volumes
~5800ml
why is RV is >30%
Obstructive lung disease -> difficulty exhaling which causes more air to be remained in the lungs
How to measure RV
Helium dilution method
