Respiratory L1

Question 1

What are 6 basic functions of respiration?

Answer 1

1. Homeostasis of CO2, O2 and blood pH
2. Cleans and humidifies air
3. Generation of sounds
4. Nose-olfactory organ
5. Activation of some hormones
6. Inactivation of some hormones

Question 2

What are the 4 steps of external respiration?

Answer 2

1. Ventilation or gas exchange between atmosphere and air sacs (alveoli) in the lungs
2. Exchange of O2 and CO2 between air in the alveoli and the blood
3. Transport of O2 and CO2 between the lungs and the tissues
4. Exchange of O2 and CO2 between the blood and the tissues

Question 3

Where is the cartilage support present in respiratory?

Answer 3

Cartilage is present until the 5th generation branching

Question 4

What is the branching of respiratory?

Answer 4

• Up to airway generation 19:
  
  • Decreased of number of airways with decreasing diameter.
• Above airway generation 19:
  
  • Decreased of total cross section area

Question 5

What are the 2 types of alveolar cells?

Answer 5

1. Type I
2. Type II

Question 6

What is a type I alveolar cell?

Answer 6

forms alveoli walls

Question 7

What is a type II alveolar cell?

Answer 7

• oxygen in alveoli must dissolve = produce fluid = lines walls of cell
• Without fluid lining = no gas exchange

Question 8

What is Fick’s Law of Diffusion?

Answer 8

• The shorter the distance through which diffusion must take place, the greater the rate of diffusion
• The greater the surface area across which diffusion can take place, the greater the rate of diffusion

Question 9

At an air-water interface, the H2O molecules are attracted to each other. In a bubble like an alveolus, it results in _______ that causes a_____ pressure. Thus an alveolus resists being stretched, tends to _____ in size, and tends to______ after being stretched.

Answer 9

alveolar surface tension; inward; collapse/reduce; recoil

Question 10

Air/water interface —> water tension occurs –> want to get _____ (closer/further) —> ______ (inward/outward) pressure

Answer 10

closer; inward; increased

Question 11

In an air/water interface, type II cells produce ____ and ______ –> disperse between H20 –> ______ tension

Answer 11

lipids; proteins; decrease

Question 12

What is the Law of LaPlace?

Answer 12

Magnitude of inward-directed pressure (P) in a bubble (alveolus) = 2 x Surface tension (T) Radius (r) of bubble (alveolus)

Question 13

According to the Law of LaPlace, what would a small alveoli do?

Answer 13

Small alveoli would collapse and empty their air into neighbouring larger alveoli.

Question 14

What is pulmonary surfactant? Why is it important?

Answer 14

Intersperse between H2O molecules reducing the alveolar surface tension.

Helps maintaining lung stability by preventing small alveoli to collapse into larger ones.

1. It increases pulmonary compliance, reducing the work of inflating the lungs
2. it reduces the lungs’ tendency to recoil so that they do not collapse as readily

(complex mixture of lipids and proteins secreted by Type II alveolar cells)

Question 15

Surfactant reduces alveolar surface tension more in small or large alveoli? Why?

Answer 15

Small

The surfactant molecules are closer together in small alveoli.

Question 16

What are the 3 functions of pulmonary surfactant?

Answer 16

1. reduces the lung’s tendency to recoil
2. increases pulmonary compliance
3. helps maintaining lung stability by preventing small alveoli to collapse into larger ones

Question 17

What is alveolar interdependence? Why is it important?

Answer 17

If one alveoli starts to collapse then neighbouring alveoli will prevent collapsing