Resp Physiology 1

Question 1

What are the two main functions of the lungs?

Answer 1

Gas exchange

Acid-base balance

Question 2

Which lung is larger?

Answer 2

Right lung

Question 3

How many lobes does each lung have?

Answer 3

Right: 3 (upper, middle, lower)

Left: 2 (upper, lower)

Question 4

What is the lingula?

Answer 4

Left lung equivalent of the right middle lobe

Question 5

What supplies blood to the lungs for gas exchange?

Answer 5

Pulmonary artery

Question 6

What supplies blood to the lung stroma (supporting tissue)?

Answer 6

Bronchial arteries

Question 7

How many bronchial arteries are there?

Answer 7

Right: 1

Left: 2

Question 8

Where do bronchial arteries originate from?

Answer 8

Left: Descending aorta

Right: Intercostal artery

Question 9

What is the function of the trachea?

Answer 9

Conducts air to bronchi

Question 10

What is the carina?

Answer 10

Bifurcation of the trachea into bronchi

Question 11

What are the two groups of extrinsic muscles of the larynx?

Answer 11

Suprahyoid

Infrahyoid

Question 12

What is the main nerve supply of the pharynx?

Answer 12

Pharyngeal plexus (CN IX, X, XI)

Question 13

Which nerve is affected in Cricothyroid paralysis?

Answer 13

Superior laryngeal nerve (SLN)

Question 14

Which nerve is affected in vocal cord paralysis?

Answer 14

Recurrent laryngeal nerve (RLN)

Question 15

What happens in bilateral RLN (Recurrent laryngeal nerve) injury?

Answer 15

Stridor

Question 16

What happens in unilateral RLN (Recurrent laryngeal nerve) injury?

Answer 16

Hoarseness

Question 17

What are the two phases of breathing?

Answer 17

Inspiration (active)

Expiration (passive)

Question 18

What law governs airflow resistance?

Answer 18

Hagen-Poiseuille law

F= ΔP⋅r4 / 8ηl

Where:
F = Flow
ΔP = Pressure difference
r = Radius of the tube
η = Viscosity of the gas
l = Length of the tube

This shows flow is most dependent on radius – small changes in airway diameter make a huge difference!

Question 19

What law describes flow in the airways?

Answer 19

Darcy’s law: Flow = (P1 - P2) / R

F= P1-P2 / R
​
Where:

P 1 = Proximal (airway opening) pressure

P 2 = Distal (alveolar) pressure

R = Resistance

Question 20

What happens in forced expiration?

Answer 20

Increased intra-thoracic pressure → airway compression

Question 21

What muscles are used in quiet breathing?

Answer 21

Diaphragm

External intercostals

Question 22

What muscles are used in forced inspiration?

Answer 22

Sternocleidomastoid

Scalene

Question 23

What muscles are used in forced expiration?

Answer 23

Abdominals

Internal intercostals

Question 24

What is tidal volume (VT)?

Answer 24

Normal breath (~500ml)

Question 25

What is inspiratory reserve volume (IRV)?

Answer 25

Extra air inhaled after tidal volume

Question 26

What is expiratory reserve volume (ERV)?

Answer 26

Extra air exhaled after tidal volume

Question 27

What is residual volume (RV)?

Answer 27

Air remaining in lungs after maximal expiration

Question 28

What is vital capacity (VC)?

Answer 28

VT + IRV + ERV

Question 29

What is total lung capacity (TLC)?

Answer 29

VC + RV

Question 30

What is anatomical dead space?

Answer 30

Conducting airways (~150ml)

Question 31

What is alveolar dead space?

Answer 31

Alveoli not participating in gas exchange

Question 32

What is physiological dead space?

Answer 32

Anatomical + alveolar dead space

Question 33

How is compliance calculated?

Answer 33

C = ΔV / ΔP Where: C = Compliance ΔV = Tidal volume (VT) ΔP = Pressure difference 🔹 Static Compliance: 𝐶 =𝑉𝑇/𝑃Plat−PEEP 𝑃Plat = Plateau pressure PEEP = Positive end-expiratory pressure 🔹 Dynamic Compliance: 𝐶=𝑉𝑇/𝑃Peak−PEEP P Peak = Peak inspiratory pressure Key Difference? Dynamic compliance includes airway resistance, static compliance does not.

Question 34

What is static compliance?

Answer 34

Compliance measured without airflow

Question 35

What is dynamic compliance?

Answer 35

Compliance measured with airflow

Question 36

What are the two main types of lung disease?

Answer 36

Obstructive Restrictive

Question 37

What happens to FEV1/FVC in obstructive disease?

Answer 37

Decreased

Question 38

What happens to FEV1/FVC in restrictive disease?

Answer 38

Normal or increased

Question 39

What is an example of an obstructive lung disease?

Answer 39

COPD (Chronic Obstructive Pulmonary Disease) Asthma

Question 40

What is an example of a restrictive lung disease?

Answer 40

Pulmonary fibrosis

Question 41

What happens to lung compliance in restrictive disease?

Answer 41

Decreased

Question 42

What happens to lung compliance in obstructive disease?

Answer 42

Increased

Question 43

What are causes of pulmonary oedema?

Answer 43

Heart failure ARDS (Acute Respiratory Distress Syndrome) Fluid overload

Question 44

What is ARDS?

Answer 44

Acute Respiratory Distress Syndrome

Question 45

What are the criteria for ARDS?

Answer 45

Acute onset Bilateral infiltrates No heart failure PaO2/FiO2 <300 ** FiO 2/PaO 2 <40 kPa Severity Breakdown (Berlin Criteria): Mild: 26.7–40 kPa Moderate: 13.3–26.6 kPa Severe: <13.3 kPa **

Question 46

What are causes of atelectasis?

Answer 46

Mucus plugging Compression Loss of surfactant

Question 47

What are signs of PE (pulmonary embolism)?

Answer 47

Sudden dyspnoea Pleuritic chest pain Tachycardia

Question 48

What is the most common ECG finding in PE?

Answer 48

Sinus tachycardia (44%) Complete or incomplete RBBB (18%) Right ventricular strain pattern – T wave inversions in the right precordial leads (V1-4) ± the inferior leads (II, III, aVF). This pattern is associated with high pulmonary artery pressures (34%) SI QIII TIII pattern – deep S wave in lead I, Q wave in III, inverted T wave in III (20%). This “classic” finding is neither sensitive nor specific for PE

Question 49

Causes of Hypoxia: "H-H-V-D-D"

Answer 49

Hypoventilation High altitude V/Q mismatch Diffusion defect Dead space

Question 50

ARDS Criteria: "ABCD"

Answer 50

Acute onset Bilateral infiltrates CXR (no heart failure) Decreased PaO2/FiO2