2. Anatomy of Chest Wall and Mechanics of Breathing

Question 1

What are the 4 main Gas Laws?

Answer 1

• Boyle’s
• Dalton’s
• Charles’
• Henry’s

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Question 2

What does Boyle’s Law state?

Answer 2

That the pressure exerted by a gas is inversely proportional to its volume (P a 1/V) (Note that gases - singly or in mixture - move from areas of high pressure to low pressure)

Question 3

What does Dalton’s Law state?

Answer 3

The total pressure of gas mixture is the sum of the pressures of the individual gases

Question 4

What does Charles Law state?

Answer 4

The volume occupied by a gas is directly related to the absolute temperature (V a T)

Question 5

What does Henry’s Law state?

Answer 5

That the amount of gas dissolved in a liquid is determined by the pressure of the gas and its solubility in the liquid

Question 6

Which of these Laws is the most important?

Answer 6

Boyle’s Law

Question 7

Which lung is divided into 3 lobes and which is divided into 2?

Answer 7

• Right - 3 lobes
• Left - 2 lobes

Question 8

Name these lobes

Answer 8

• Right - Superior, Middle, Inferior
• Left - Superior, Inferior

Question 9

What is the top and bottom of the lungs called?

Answer 9

Apex and Base

Question 10

What is each lung enclosed within?

Answer 10

Pleural membranes (Parietal and Visceral) and cavity filled with intrapleural fluid

Question 11

Which pleural membrane covers the outside of the lungs and which covers the inside of the ribs?

Answer 11

• Visceral - Lungs
• Parietal - Ribs

Question 12

What is pleurisy?

Answer 12

Inflammation of the pleura

Question 13

Expiration is passive at rest but what is used in the process?

Answer 13

Intercostal and abdominal muscles during severe respiratory load

Question 14

Based on Boyle’s Law are increase of volume equals?

Answer 14

A decrease in pressure and vice versa

Question 15

What does Inspiration use?

Answer 15

Intercostal muscles and the diaphragm

Question 16

Which muscles are used for ventilation?

Answer 16

• Inspiration
  
  • Sternocleidomastoids
  • Scalenes
  • External intercostals
  • Diaphragm
    
    • SSED
• Expiration
  
  • Abdominal muscles
  • Internal intercostal muscles
    
    • AI

Question 17

Which motion increases anterior-posterior dimension of ribcage?

Answer 17

Pump handle

Question 18

Which motion increases lateral dimension if the ribcage?

Answer 18

Bucket handle

Question 19

During respiration what happens to the diaphragm and thoracic volume?

Answer 19

• Inspiration - Thoracic volume increases - Diaphragm contracts
• Expiration is the opposite

Question 20

What is the pathophysiology of Asthma?

Answer 20

Over-reactive constriction of bronchial smooth muscle which increases resistance and makes expiration difficult

Question 21

Explain Pnemothorax

Answer 21

Question 22

What are the 3 Relevant pressures?

Answer 22

• Intra-thoracic (Alveolar) pressure
• Intra-pleural pressure
• Transpulmonary pressure

Question 23

What is Intra-thoracic pressure?

Answer 23

The pressure inside the thoracic cavity, may be -ve or +ve in compared to atmospheric pressure

Question 24

What is Intra-pleural pressure?

Answer 24

Pressure inside the pleural cavity, ALWAYS -VE

Question 25

What is Transpulmonary pressure?

Answer 25

The difference between alveolar pressure and intra-pleural pressure, this is ALWAYS +VE

Question 26

What equation can be assumed for Transpulmonary pressure?

Answer 26

P(T) = P(alv) - P(ip)