Respiratory Physiology (Law Of Laplace)

Question 1

What is surfactant?

Answer 1

Detergent like fluid produced by Type II Alveolar cells

Question 2

What is the role of surfactant?

Answer 2

Reduces surface tension on alveolar surface membrane
thus reducing tendency for alveoli to collapse

Question 3

What is surface tension?

Answer 3

surface tension occurs where ever there is an air- water interface and refers to the attraction between water molecules

Question 4

What is the alveolar sac covered in?

Answer 4

Water molecules

Question 5

Why does air need to be saturated in the lungs?

Answer 5

The body needs enough oxygen to keep the blood adequately saturated, so that cells and tissues get enough oxygen to function properly.

Keep lungs inflated

Question 6

Why is it important for alveolar type II cells to produce surfactant?

Answer 6

Increase lung compliance and less recoil to over come, making inspiration easier

Question 7

Are water molecules attracted to one another?

Answer 7

Yes

Question 8

Is surfactant more effective in small or large alveoli?

Answer 8

Small

Question 9

Why is surfactant more effective in small alveoli?

Answer 9

because surfactant molecules come closer together and are therefore more concentrated.

Question 10

Is surfactant more numerous in small or large alveoli?

Answer 10

Small

Want to maintain surface area for gas exchange

Question 11

Do small alveoli have greater surface tension compared to large alveoli?

Answer 11

Yes, hence why more surfactant is required to compensate for this

Question 12

Why is the pressure greater is smaller alveoli?

Answer 12

Same surface tension but smaller radius, creates a higher pressure in smaller alveoli

Question 13

When does surfactant production begin?

Answer 13

Around 25 weeks

Question 14

When is surfactant production completed during pregnancy?

Answer 14

Around 36 weeks

Question 15

What stimulated surfactant production?

Answer 15

Thyroid hormones and cortisol

Question 16

What can premature barbarise suffer from?

Answer 16

Premature babies suffer Infant Respiratory Distress Syndrome (IRDS).

Question 17

What is compliance?

Answer 17

change in volume relative to change in pressure

i.e. how much does volume change for any given change in pressure

Question 18

What does compliance represent?

Answer 18

It represents the stretchability of the lungs (not the elasticity!)

Question 19

What is healthy lungs with regards to compliance?

Answer 19

large increase in lung volume for small decrease in ip pressure

Question 20

What is low compliance?

Answer 20

small increase in lung volume for large decrease in ip pressure

Question 21

What is emphysema?

Answer 21

a lung disease that results from damage to the walls of the alveoli in your lungs. Not high elasticity, Ned to put in effort for expiration.

High lung compliance but low elasticity

Question 22

What disease is low compliance associated with?

Answer 22

COPD