Lecture 15 - Resp Physiology pt2

Question 1

Ventilation —> Pressure gradient —-> Air flow

Need

1. Something for rhythm/variation
2. Something that shouldn’t be paralysed or fatigued
3. Lungs that are not too stiff
4. 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?

Answer 1

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Question 2

Compliance is a measure of what? What about work if low compliance?

Answer 2

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Question 3

On the compliance graph - what’s on the x and what’s on the y axis?

Answer 3

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Question 4

Surface tension

1. What exerts surface tension which causes alveoli to contract/resist expansion
2. Need to overcome this ____ to expand lungs
3. What reduces surface tension

Answer 4

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Question 5

Surfactant

1. What is it and what produces it?
2. Lowers what?
   - Reduces a____ forces between fluid molecules lining alveoli
   - What has increased since surface tension has been lowered?
3. What happens if lack of surfactant?
4. What are examples of lack of surfactant?

Answer 5

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Question 6

Consequences of lack of pulmonary surfactant

1. Not produced in fatal lung until what month?
2. Premature born infants lack what? So they have great difficulty doing what? What collapse may this lead to?
3. Lack of surfactant can result in two things - what are they?
4. What can this cause in babies?
5. What is ARDS?

Answer 6

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Question 7

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?

Answer 7

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.

Question 8

Measurement of lung function - what are the two ways and what 2 things does the first one measure?

Answer 8

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Question 9

Spirometer

• how does it work?
• what does it measure?
• common and what test?
• tests response to what?

Answer 9

-Breathe into/out of a hollow bell inverted over water

Question 10

In your head, tell me where all the values go and draw the graph in your head

Answer 10

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Question 11

Four volumes:

1. Tidal volume
   - How much?
   - Volume of air moved in and out during ____ _____ breath
2. Inspiratory reserve volume
   - How much?
   - _____ volume that can be inspired with _____ inhalation - what muscle?
3. Expiratory reserve volume?
   - How much?
   - _____ volume that can be exhales with _____ effort - what two muscles?
4. Residual volume
   - How much
   - Volume ____ in lungs after what?

Answer 11

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Question 12

How many litres in total lung capacity?

Answer 12

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Question 13

What does the line between Inspiratory capacity and forced residual capacity mean?

Answer 13

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Question 14

IRV + VT = ?
ERV + RV = ?
IRV + VT + ERV = ?
VC + RV = ?

Answer 14

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Question 15

Lung capacities (don’t measure these - derive them by ______)

1. Vital capacity
   - How much?
   - ____ breath in to ____ breath out - volume of air you can ____ in/out of lungs?
2. Total lung capacity
   - How much?
   - ____ volume in lungs when ____ full = VC + ?
3. Inspiratory capacity
   - How much (by calculation?)
   - VT + ?
4. Functional residual capacity
   - How much?
   - Volume at end of ____ ___ out
   - ____ point for thorax/lungs

Answer 15

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Question 16

Residual volume

1. Air ____ in lung at end of ____ ____
2. How much does it average between?
3. Can you measure it directly with spirometry?
4. Use what method to measure?

Answer 16

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Question 17

Spirometry: How fast?

1. Forced measurements give info about?
2. Forced Vital Capacity (FVC) - ___ breath in to ____ breath out (VC) - ____ as hard as possible
3. 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?

Answer 17

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Question 18

FEV1 = the _____ of air expelled during ____ ____ of ____ manoeuvre

Answer 18

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Question 19

What are the three variables that determine the normal/predicted values?

Answer 19

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Question 20

Spirometry can identify:

1. I____ airway r_____
   - E.g. a____
   - Obstructive or restrictive lung disease?
2. D_____ total lung c_____ from s___/f_____ problems
   - E.g. f_____
   - Obstructive or restrictive lung disease?

Answer 20

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Question 21

Obstructive

• Increased what to airflow?
• Three examples

Restrictive

• Decreased what?
• Reduced lung c____ (e.g. fibrosis)
• Chest wall ____
• Respiratory ____ disease

Answer 21

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Question 22

What does PEFR stand for?

What does it give info about?

Is it portable?

What does it give (i.e. NOT v____)

Answer 22

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Question 23

PEFR:

1. Determine “normal” value from n_____
2. But absolute value ____ that ____ since wide range of _____ (but still should be ____)
3. Changes in PERF from a person’s ___ value are ____
   - Decrease in PEFR suggests what? E.g. what
4. Can use to ____/_____ therapy

Answer 23

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