Respiratory movements 1

Question 1

Describe the structure of the lungs

Answer 1

Trachea in middle and splits into 2 lungs:
1. Primary Bronchi- splits into smaller bronchi
2. This further splits into bronchioles
2. End of bronchioles = alveoli

• each division increases surface area to maximise gas exchange

Question 2

Can posture affect your breathing?

Answer 2

Yes

Slouching doesn’t allow for air to fill the alveoli in the lower part of your lungs

Question 3

How does SA change as the trachea divides?

Answer 3

As the windpipe divides further the SA increases - this is why alveoli are effective for gaseous exchange

more divisions = bigger SA

Question 4

What are the 4 things that can affect the amount of oxygen that can enter the lungs?

Answer 4

• Volume
• Pressure (must be maintained)
• Temperature (this affects the pressure)
• Motion (affects final pressure of the lungs)

Question 5

What is the kinetic theory of gases?

Answer 5

Change volume, temp or pressure- speed of particles will change
- Pressure is generated by collisions of molecules
- The more freq & harder the collisions = higher pressure

Question 6

What is Boyle’s law?

Answer 6

Pressure is inversely proportional to volume at a constant temp
picture A- increased collisions due to reduced volume = increased pressure
picture B- pressure and volume equal
Picture C- more volume = less collisions = reduced pressure

Question 7

What is inspired air saturated with and what does this cause?

Answer 7

with water vapour in upper airways
- saturation = dilution of gases

Question 8

At 37 degrees, what is the partial pressure of saturated water vapour?

Answer 8

= 6.3kPa

Question 9

What is the relevance of inspired air being saturated with water vapour?

Answer 9

enables effective gas exchange

Question 10

What is the partial pressure of air?

Answer 10

101.3kPa = 100% = sum of partial pressure of individual gases that make up air

Question 11

What is the partial pressure of oxygen?

Answer 11

21kPa = 21% = fraction of inspired gas

Question 12

What is the partial pressure of oxygen after being inspired and why is this?

Answer 12

19.9kPa- diluted due to presence of water vapour in upper airway

Question 13

What is Daltons law of partial pressure?

Answer 13

Pressure exerted by each gas in a mixture of gases is independent of the other gases present

Total pressure of mixture of gases is equal to the sum of individual gas pressures

Question 14

What gases make up air and what are their partial pressures?

Answer 14

O2 = 21kPa
CO2 = 0.04kPa
Nitrogen = 79kPa
Argon
Water vapour

Question 15

What do you have to take into account when measuring partial pressure?

Answer 15

Altitude
Temperature

Question 16

How does the partial pressure of oxygen vary between dry air and moist air?

Answer 16

dry = 21.2kPa
moist = 19.9kPa- at sea level

Question 17

How does the partial pressure of oxygen vary at sea level and at higher altitudes?

Answer 17

sea level = 19.9kPa
higher altitudes = 5.8kPa

assuming temp remains at 37 degrees

Question 18

Describe alveolar gas exchange of oxygen

Answer 18

has single cell layer that gases need to travel into bloodstream down a partial pressure gradient
1. deoxygenated blood in veins comes in- O2 partial pressure = 5.3kPa
2. Oxygen is picked up = blood becomes oxygenated and goes to heart- O2 PP = 13.3kPa
3. O2 entering has partial pressure of 19.9kPa in upper airways, as it travels into alveoli- partial pressure of O2 reduces further = 13.3kPa

= creates pressure gradient

Question 19

Describe gas exchange of CO2

Answer 19

1. Venous deoxygenated blood CO2 PP = 6kPa
2. CO2 in alveoli = 5.3kPa
3. Oxygenated blood going to heart = 5.3kPa

= pressure gradient created

Question 20

Why is it important that the partial pressure gradient is maintained in the lungs?

Answer 20

PP of O2 entering via veins is lower than PP of O2 in arteries= so O2 moves down gradient into blood to oxygenate it

PP of CO2 is greater in veins than PP in arteries = so CO2 moves down gradient out of blood and into alveoli for excretion

Question 21

Name +define 2 basic mechanics of breathing?

Answer 21

Inspiration = breathing in
Expiration = breathing out

Question 22

Describe the process of inspiration

Answer 22

1. Rib cage expands
2. Lungs stretched
3. Diaphragm moves downward
4. Alveolar pressure reduced

= air drawn into lungs

Question 23

How do we measure the pulmonary ventilation rate?

Answer 23

Frequency x tidal volume

Question 24

What is the alveolar ventilation rate?

Answer 24

= the actual amount of air that reaches the alveolar- not all air reaches alveoli

Question 25

When calculating the alveolar ventilation rate what do you have to account?

Answer 25

allow for wasted ventilation of dead spaces

Question 26

Describe the perfusion in the lungs

Answer 26

Deoxygenated blood passes through the lungs and becomes reoxygenated

Question 27

What is the ventilation perfusion ratio?

Answer 27

ratio of alveolar ventilation to blood flow

Question 28

In a normal person, what should the ventilation perfusion ratio be?

Answer 28

1

Question 29

What happens if you have normal ventilation but no perfusion?

Answer 29

= no capacity to carry O2 away or bring CO2 to alveoli = no gas exchange alveoli and blood

Question 30

What happens if you have no ventilation but normal perfusion?

Answer 30

Shunt can be inserted so gas can escape
= No new O2 into system = pressure gradient disrupted with venous blood

Question 31

What happens if there is low O2 entering blood?

Answer 31

constricts pulmonary arterioles = hypoxia

Question 32

What happens if there is high O2 entering blood and where is this observed?

Answer 32

dilates pulmonary aterioles- observed in foetus

Question 33

What happens is there is high CO2 entering blood?

Answer 33

dilates bronchioles- lung disease e.g. COPD