Physiology: Surfactant, Compliance and Lung function tests Flashcards Preview

System 1: Respiratory AM > Physiology: Surfactant, Compliance and Lung function tests > Flashcards

Flashcards in Physiology: Surfactant, Compliance and Lung function tests Deck (28)
Loading flashcards...
1
Q

What is surfactant?

A

detergent like fluid which reduces surface tension

2
Q

What is surface tension?

A

attraction of water molecules which is seen in a air - water interface

3
Q

What cells produce surfactant

A

Type II alveolar cells

4
Q

What does surfactant do in the lungs? (5)

A

Reduces tendency for alveoli to collapse
Increases lung compliance
Reduces lungs tendency to recoil
Makes breathing work easier
More effective in smaller alveoli as the surfactant molecules are close together

5
Q

When does surfactant production start and finish in embryos?

A

~25 week it starts and finishes ~36 week mark

6
Q

What is the production of surfactant stimulated by in embryos?

A

Thyroid hormones and cortisol

7
Q

What respiratory problem do some premature babies suffer from?

A

Infant Respiratory Distress Syndrome (IRDS)

8
Q

What fills the alveoli in utero?

A

Saline

9
Q

What is the definition of compliance?

A

how much of a volume change for any give change in pressure

Ie how stretchable the lungs are

10
Q

What does a high compliance in the lungs mean?

A

large increase in lung volume for a small decrease in ip pressure

11
Q

What does low compliance mean?

A

Small increase in lung volume for a large decrease in ip pressure

12
Q

What is emphysema and what respiratory effort is required?

A

Loss of elastic tissue

Expiration requires a lot of effort

13
Q

What is Fibrosis and what respiratory effort is required?

A

Inert fibrous tissue

Inspiration requires an increase in effort

14
Q

What is the difference in pressure volume relationship at different areas of the lungs?

A

at the base the volume change is greater for any given change in pressure when compared to the apex of the lung

15
Q

Where is alveolar ventilation greatest when compared in the lungs?

A

Greatest at the base when compared to the apex

16
Q

Where is compliance higher in the lung?

A

Compliance is higher at the base when compared to the apex of the lung

17
Q

Which alveoli are smaller in the lung and why?

A

Alveoli are smaller at the base of the lung due to the weight of the compressing on the alveoli

18
Q

What is an obstructive lung disease?

A

Obstruction of air flow in the lungs

19
Q

What is a restrictive lung disease?

A

Restriction in lung expansion

20
Q

What are examples of Obstructive Lung Diseases?

A

Asthma

COPD

21
Q

What are examples of Restrictive Lung Diseases?

A

Fibrosis
Infant Respiratory Distress Syndrome
Pulmonary Oedema
Pneumothorax

22
Q

What is a test to measure lung function?

A

Spirometry

23
Q

What can be the measurements be classified in in spirometry?

A

Static - only volume exhaled is considered

Dynamic - time taken to exhale a certain volume

24
Q

What is FEV1/FVC?

A

FEV1 - forced expiratory volume in 1sec

FVC - Forced vital capacity

25
Q

What should a normal FEV1/ FVC measure?

A

80%

26
Q

What should someone with a obstuctive lung disease FEV1/ FVC measure and why?

A

Rate of air exhaled is slower
FEV1 is greatly decreased
FVC is slighlty decreased
The ratio is majorly decrease ie 40%

27
Q

What should someone with a Restrictive lung disease FEV1/ FVC measure and why?

A

Airflow rate is reduced greatly
Total volume is reduced greatly
Ratio either stays the same of increases

28
Q

What is the FEF25-75?

A

average of the expired flow in the middle of FVC

Normal range is greater the FEV1/FVC