Ventilation and compliance 2

Question 1

What is the purpose of surfactant in type 2 cells

Answer 1

reduces surface tension on alveoli wall

Question 2

How is surface tension created on the alveoli

Answer 2

the air water interface, causing a water interaction to apply pressure on to the alveoli

BASICALLY
the net movement of water means the water surrounding the alveoli will push into the middle

Question 3

How is surfactant more effective in smaller alveoli

Answer 3

is more concentrated

Question 4

How does the surfactant overcome the surface tension

Answer 4

contains the surface area and decreases the pressure

Question 5

What would happen if surfactant wasn’t present in alveoli

Answer 5

As the pressure is higher in the smaller alveoli they would push out all the air and collapse, which would then move into the larger alveoli increasing its surface area SUPER ALVEOLI - decreasing overall surface area though

Question 6

What are the benefits of surfactant

Answer 6

reduces lungs tendency to recoil
prevents collapsing of alveoli
increase lungs compliance
makes it easier to breathe

Question 7

What respiratory disease is associated with premature babies

Answer 7

Respiratory distress syndrome

making it harder for them to breathe as haven’t produced surfactant

Question 8

When does surfactant production start and end

Answer 8

start - 24 weeks gestation

complete - 36 weeks gestation

Question 9

What does babies breath in the utero and why is this easier than air?

Answer 9

They breathe in saline which requires less pressure than breathing in air due to not needing to overcome the surface tension created by an air water interface

Question 10

What is compliance?

Answer 10

The stretchability of the lungs

Question 11

Define high compliance

Answer 11

Large increase in lung volume for small decrease in pressure

Question 12

Define low compliance

Answer 12

Small increase in lung volume for large decrease in pressure

Question 13

What two factors alter compliance

Answer 13

age

disease

Question 14

What respiraratory disorder has a high compliance but struggles with expiration

Answer 14

EMPHYSEMA

Question 15

How does emphysema occur

Answer 15

expiration is passive, recovered by elastic coil, if you loose the elasticity, the expiration needs to be actively push the air out.

Question 16

What else can cause emphysema

Answer 16

destruction of alveoli

Question 17

What causes Fibrosis

Answer 17

Excess Fibrous connective tissue causes the compliance to decrease, resulting in a more difficult inspiration

Question 18

What are the two different classifications of lung diseases

Answer 18

Obstructive - increased airway resistance

Restrictive - loss of lung compliance

Question 19

What does obstructive lung diseases affect mostly

Answer 19

expiration

Question 20

What are examples of obstructive lung diseases

Answer 20

asthma
emphysema
chronic bronchitis

Question 21

what causes chronic bronchitis

Answer 21

inflammation of the bronchi

Question 22

In restrictive lung disease what does loss of compliance cause

Answer 22

lung stiffness

incomplete lung expansion

Question 23

Name four restrictive lung diseases

Answer 23

oedema
fibrosis
infant respiratory syndrome
pneumothorax

Question 24

What is the name of the test to measure lung function

Answer 24

spirometry

Question 25

What are the two spirometry test

Answer 25

static - volume exhaled

dynamic - time taken to exhale a certain value

Question 26

What type of respiratory volumes can spirometry measure

Answer 26

Measure anything that doesn’t include the residual volume

Question 27

What is the ratio FEV1/FVC a measure of

Answer 27

The measure of the percentage of air expired in a second compared to how much can be expired over all

Question 28

What is a normal FEV1/FVC value

Answer 28

80%

Question 29

Whys is spirometry not a good indicator on the health of your ventilation

Answer 29

In restrictive disorders the total volume expired but the lung is reduced but the ratio remains constant therefore the test allure that you are healthy

Question 30

In an obstructive disorder what affect does this have on the FEV1/FVC ratio

Answer 30

Rate at which air is exhaled is much slower so the FEV is reduced altering the FEV/FVC ratio

Question 31

What is the Forced expiratory flow

Answer 31

average expired flow in the middle of an FVC

Question 32

Why does the Alveolar ventiation declines with height from base to apex

Answer 32

greater volume change at the bottom of the lungs as the alveoil go from not inflated to fully flatted compared to the apex which is already partially flatted