Respiration II Flashcards
What is ventilation
volume of air moved out of the lungs per unit time
What volume of air stays in the anatomical dead space
150mls
What is alveolar ventilation
volume of fresh air reaching the respiratory zone
What are the two zones of the respiratory system
conducting and respiratory
What does ventllation rate determine
partial pressure of carbon dioxide in the alveoli and arterial gas
Where is the alveolar level of CO2 lowest
end of the capillary
What is the effect of hyperventilation on the body
respiratory alkalosis
What is excreted by alveolar ventilation
CO2
What contributes to pH levels
CO2
What increases when there is a high rate of gas turnover
oxygen concentration reaching the alveoli
Where is the rate of ventilation highest
base of the lung
What impacts starting volume of alveoli
posture, gravity
Where is compliance highest
at the base
Where is the alveoli starting volume largest
apex
Where is the intrapleural space value most positive
base of the lung
Where do alveoli have a higher density of surfactant
base of the lung
What is the effect of alveolar expansion on surfactant
surfactant becomes diluted and moves against expansion
Name a low pressure system
pulmonary circulation
What is the function of the pulmonary system
bring blood back to the lungs
What does resistance depend on
lung volume, respiratory cycle
When is overall pressure at a minimum
at functional residual capacity
What are the vessels in the pulmonary system
alveolar and extra alveolar
what is the effect of alveoli expansion on capillaries
lumen of capillaries narrow, resistance increases
what is the effect of inspiration of alveolar vessels resistance
increases
What is the effect of inspiration on extra alveolar resistance
decreases
How do blood vessels accommodate extra blood flow
recruitment of capillaries in lungs and round alveoli
Example of when redundant capillaries are recruited
increased exercise or blood flow
why do we need redundant capillaries
prevent pulmonary resistance rising too high
What is transmural pressure
difference between the pressure in the blood and in the alveoli
What is alveolar pressure relative to
barometric pressure
How many zones of the lung are there
4
Which lung zone rarely occurs
zone 1
When does zone 1 occur
when partial pressure is high or during haemorrhage
where is blood flow low
apex of the lung
Why is blood flow low at apex of the lung
negative transmural pressure
What is the effect of negative transmural pressure
capillaries are crushed down and blood flow through the capillaries is LOW
Describe the capillaries in zone 2 of the lung
partly open, partly reduced
Where does the effect of compression occur on the capillaries in zone 2
end of the capillary
What zone is level with the heart
zone 3
Describe the capillaries in zone 3
expand as they go through the alveolar bed
What is the benefit of capillary expansion
higher rate of perfusion
which zones vessels are under the highest influence from the intrapleural pressure
zone 4
What is the effect of intrapleural pressure on capillaries in zone 4
compression
what is the effect of increased CO2 on blood vessels
constriction
What happens to the ventilation perfusion ratio if alveoli aren’t being ventilated
ventilation perfusion ratio drops to 0
Where is the ventilation perfusion ratio highest
apex
How would the body compensate if a group of alveoli are not receiving blood
would receive reduced blood flow and ventilation
What is a shunt
something blocking an airway
How would the body compensate for a ventilation perfusion ratio of 0
bronchiole dilation and vasoconstriction
What happens if there is ventilation but no perfusion
the ventilation perfusion ratio becomes infinity
