High Yield Exam Cram Flashcards
(125 cards)
Which muscles are used during inspiration?
External intercostals and diaphragm
Is expiration active or passive at rest?
Passive
Which muscles are used in forced expiration?
Internal intercostal and abdominal muscles
What is meant by ‘lung compliance’?
The lung’s ability to stretch and expand
What is an average tidal volume?
500ml
What is the average volume of ‘dead space’?
150ml
What is ‘dead space’?
Places in the respiratory system where gas exchange cannot happen (e.g. trachea, bronchi, bronchioles)
What does residual volume prevent?
Alveolar collapse
Does breathing air in cause an increase or a decrease in pressure inside the chest?
decrease
how is pulmonary ventilation calculated?
respiration rate x tidal volume
What is the definition of pulmonary ventilation?
total air movement into/out of the lungs
What is the definition of alveolar ventilation?
the volume of fresh air getting to alveoli and therefore available for gas exchange
How is alveolar ventilation calculated?
{Tidal volume-dead space volume] x respiratory rate
Where in the lung is alveolar ventilation rate at it’s greatest and worst- why?
is greatest at the base of the lung and worst at the apex bc compliance is lowest at apex and highest at base
What is compliance?
The lung’s ability to stretch out when you breathe in?
What is elasticity?
The lung’s ability to recoil when you breathe out
Name the two different alveolar cells and their role
Type 1 - Gas exchange
Type 2 - Surfactant production
What is the function of surfactant?
reduces surface tension and makes alveoli less likely to collapse
At what stage in gestation does surfactant production begin and by what stage of gestation is production of surfactant adequate?
Production begins - 25 weeks
Surfactant levels adequate - 36 weeks
What is the ideal V/Q ratio in the lungs and what does that number mean?
V/Q= 1
this means that ventilation and perfusion match
Where in the lung would you find a V/Q <1?
in the lung base
Where in the lung would you find a V/Q >1?
In the lung apex
What is meant by the term ‘shunt’?
Shunt = alveoli are perfused but under ventilated
What is meant by the term ‘alveolar dead space’?
Alveolar dead space = alveoli that are well ventilated but under perfused