Lecture 15 - Resp Physiology pt2 Flashcards
Ventilation —> Pressure gradient —-> Air flow
Need
- Something for rhythm/variation
- Something that shouldn’t be paralysed or fatigued
- Lungs that are not too stiff
- Air ways that are not too narrow
Muscles need to do enough to:
1. Expand chest/lungs = overcome what? (two things)
2. Move air = overcome what? (something i.e. something)
What does this equal?
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Compliance is a measure of what? What about work if low compliance?
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On the compliance graph - what’s on the x and what’s on the y axis?
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Surface tension
- What exerts surface tension which causes alveoli to contract/resist expansion
- Need to overcome this ____ to expand lungs
- What reduces surface tension
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Surfactant
- What is it and what produces it?
- Lowers what?
- Reduces a____ forces between fluid molecules lining alveoli
- What has increased since surface tension has been lowered? - What happens if lack of surfactant?
- What are examples of lack of surfactant?
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Consequences of lack of pulmonary surfactant
- Not produced in fatal lung until what month?
- Premature born infants lack what? So they have great difficulty doing what? What collapse may this lead to?
- Lack of surfactant can result in two things - what are they?
- What can this cause in babies?
- What is ARDS?
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The main area of airway resistance = ?
Most is in the upper airway and the first ___ generation of the _____ airway
Why do the small airways contribute so little?
There are many smaller airways but because they get SHORTER with each branching generation, their contribution to airways is more trivial. Furthermore, there are so many of them in PARALLEL compared to the larger airways that they have a low combined resistance.
Measurement of lung function - what are the two ways and what 2 things does the first one measure?
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Spirometer
- how does it work?
- what does it measure?
- common and what test?
- tests response to what?
-Breathe into/out of a hollow bell inverted over water
In your head, tell me where all the values go and draw the graph in your head
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Four volumes:
- Tidal volume
- How much?
- Volume of air moved in and out during ____ _____ breath - Inspiratory reserve volume
- How much?
- _____ volume that can be inspired with _____ inhalation - what muscle? - Expiratory reserve volume?
- How much?
- _____ volume that can be exhales with _____ effort - what two muscles? - Residual volume
- How much
- Volume ____ in lungs after what?
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How many litres in total lung capacity?
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What does the line between Inspiratory capacity and forced residual capacity mean?
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IRV + VT = ?
ERV + RV = ?
IRV + VT + ERV = ?
VC + RV = ?
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Lung capacities (don’t measure these - derive them by ______)
- Vital capacity
- How much?
- ____ breath in to ____ breath out - volume of air you can ____ in/out of lungs? - Total lung capacity
- How much?
- ____ volume in lungs when ____ full = VC + ? - Inspiratory capacity
- How much (by calculation?)
- VT + ? - Functional residual capacity
- How much?
- Volume at end of ____ ___ out
- ____ point for thorax/lungs
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Residual volume
- Air ____ in lung at end of ____ ____
- How much does it average between?
- Can you measure it directly with spirometry?
- Use what method to measure?
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Spirometry: How fast?
- Forced measurements give info about?
- Forced Vital Capacity (FVC) - ___ breath in to ____ breath out (VC) - ____ as hard as possible
- Forced Expiratory Volume in One second (FEV) - reduced with ____ causing _____ to airflow (airways obstructed e.g. asthma) or ___ lungs
FEV1/FVC ratio - how does volume out in 1s compare with ____ ____. What’s the normal ratio? Below what ratio indicates airways obstructed?
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FEV1 = the _____ of air expelled during ____ ____ of ____ manoeuvre
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What are the three variables that determine the normal/predicted values?
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Spirometry can identify:
- I____ airway r_____
- E.g. a____
- Obstructive or restrictive lung disease? - D_____ total lung c_____ from s___/f_____ problems
- E.g. f_____
- Obstructive or restrictive lung disease?
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Obstructive
- Increased what to airflow?
- Three examples
Restrictive
- Decreased what?
- Reduced lung c____ (e.g. fibrosis)
- Chest wall ____
- Respiratory ____ disease
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What does PEFR stand for?
What does it give info about?
Is it portable?
What does it give (i.e. NOT v____)
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PEFR:
- Determine “normal” value from n_____
- But absolute value ____ that ____ since wide range of _____ (but still should be ____)
- Changes in PERF from a person’s ___ value are ____
- Decrease in PEFR suggests what? E.g. what - Can use to ____/_____ therapy
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