Respiratory Physiology

Question 1

What are the functions of the respiratory system

Answer 1

Gas exchanged
Acid base balance
Protect from infection
Communication

Question 2

What happens in systemic circulation

Answer 2

02 rich blood from L side of heart to tissue

CO2 rich blood from tissue taken to R side

Question 3

What happens in pulmonary circulation

Answer 3

C02 rich blood from R rich goes to lungs for gas exchange

Returns O2 rich blood to L side

Question 4

What is the pulmonary circulation compared to systemic

Answer 4

High flow but low pressure as 5l takes same time as it does to go through systemic

Question 5

How does actual lung tissue get its blood supply

Answer 5

From systemic

Part of bronchial circulation

Question 6

What is the conducting zone of the respiratory system

Answer 6

Trachea
Primary bronchi
Bronchioles
Resistance decreases as go down as less molecules and more anatomical dead space

Question 7

What is the respiratory zone / exchange

Answer 7

Alveoli surrounded by pulmonary capillaries

Question 8

What makes alveoli good for gas exchange

Answer 8

Single layer of epithelium

Elastic fibres that stretch when you breath in creating a recoil

Question 9

What are type 1 alveoli for

Answer 9

Gas exchange

Simple sqaumous

Question 10

What are type 2 alveoli for

Answer 10

Producing surfactant - decreased tension, prevent collapse and increase compliance

Question 11

What are the lungs enveloped in

Answer 11

Visceral (outer surface of lungs) and parietal (inner surface of ribs) pleura

Question 12

What is the space between lungs and thoracic wall called

Answer 12

Pleural space

Filled with pleural fluid (30ml) which creates a seal holding lungs to thoracic wall to move with breathing

Question 13

What content state are the lungs in

Answer 13

Wanting to recoil due to inspiration
Elastic recoil pushes chest out when inspire
Creates a negative pressure in the pleural cavity

Question 14

What are muscles of inspiration

Answer 14

Diaphragm = most important
External intercostal

Accessory
Scalene
SCM

Question 15

What are muscles of expiration

Answer 15

Passive at rest
Internal intercostal
Abdominal

Question 16

What is Boyle’s law

Answer 16

Pressure is inversely proportional to volume

As pressure increases volume decreases

Question 17

What happens in inspiration

Answer 17

Diaphragm contracts pushes abdominal cavity down
External intercostal and scalene pull ribs out
Leads to increase in volume of thoracic cavity
Intrapleural pressure decreases
Alveolar pressure becomes < than atmosphere and air drawn in

Question 18

What happens in passive expiration

Answer 18

Muscles relax
Elastic recoil of stretched lungs allow them to recoil back to original volume
Decreased volume so increased P and air drawn out

Question 19

What happens in forced expiration

Answer 19

Contraction of abdominal muscles push thoracic cavity up
Internal intercostal pull ribs in
Alveolar pressure increases pushing air out
Reduces duration of breathing cycle

Question 20

What happens in forced inspiration

Answer 20

Similar to normal
Requires accessory muscles
SCM, scalene, pec majro and minor, lattismus dorsi, serratura anterior

Question 21

What is the alveolar pressure

Answer 21

Pressure inside thoracic cavity

Equal to atmosphere

Question 22

What is intrapleural pressure

Answer 22

Pressur inside pleural cavity

Always -ve due to state of wanting to recoil

Question 23

What is transpulmonary pressure

Answer 23

Difference between alveolar and intrapleural
Always +ve
Opposes elastic recoil
Dpeendent on volume of lung
Larger lung = larger pressure

Question 24

What happens between breaths at the end of an unforced expiration

Answer 24

No air I flowing
Lungs stretched and attempting to recoil
Chest wall attempting to move out
Creates sub atmospheric intrapleural pressure
Transpulmonary pressure opposes this recoil