Anatomy of Chest Wall and Mechanics of Breathing

Question 1

Gas Laws

Answer 1

Boyle’s
Dalton’s
Charles’s
Henry’s

Question 2

Boyle’s Law

Answer 2

States that the pressure exerted by a gas is inversely proportional to its volume

Question 3

Dalton’s Law

Answer 3

States that the total pressure of a gas mixture is the sum of the pressures of the individual gases

Question 4

Charles’s Law

Answer 4

Sates that the volume occupied by a gas is directly related to the absolute temperature (v a T)

Question 5

Henry’s Law

Answer 5

States 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

Importance of relationship between pleural membranes (2)

Answer 6

1. Elastic recoil of lungs creates an inward pull

2. If pleural cavity is opened, air flows in and lung collapses to unstretched size

Question 7

Parietal Sac

Answer 7

coats inner surface of the ribcage (can sense pain)

Question 8

Visceral Sac

Answer 8

outer surface of lungs

Question 9

What does the relationship between the parietal and visceral do

Answer 9

Lungs are effectively stuck to rib cage through this relationship

Question 10

Pleurisy

Answer 10

Inflammation of the pleura

Question 11

Increase in volume

Answer 11

Decrease in pressure

Question 12

Decrease in volume

Answer 12

Increase in pressure

Question 13

Gases move from

Answer 13

High pressure to low pressure

Question 14

What muscles do inspiration use

Answer 14

External intercostal muscles
Diaphragm
Scalene
Sternocleiomastoids

Question 15

What muscles do expiration use

Answer 15

Internal intercostal muscles

Abdominal muscles

Question 16

Intra-thoracic (Alveolar) Pressure (PA)

Answer 16

Pressure inside the thoracic cavity (essentially pressure inside the lungs). May be negative or positive compared to atmospheric pressure

Question 17

Intra-pleural Pressure (Pip)

Answer 17

Pressure inside the pleural cavity always negative

Question 18

Describe the pump handle movement of Ribs

Answer 18

Anterior parts of the ribs move anteriorly

This action moves the sternum up and down

Question 19

Describe the bucket handle movement of the ribs

Answer 19

This motion increases the lateral dimension of the rib cage and increases the transverse diameter of the thorax

Question 20

Explain why intrapleural pressure is always less than alveolar pressure (intra-thoracic)

Answer 20

Pressure within the pleural cavity is negative
Pressure within the lungs is normally positive
The negative pressure creates a suction force and helps keep the lungs inflated

Question 21

What is a Pneumothorax

Answer 21

Pressure within the pleural cavity becomes 0 as it is exposed to the atmosphere when the chest wall is punctures and lungs collapse

Question 22

What is Asthma

Answer 22

Over-reactive constriction of bronchial smooth muscle. Expiration is difficult because airways are compressed by physical force as well as bronchial constriction