Respiration lecture 6

Question 1

What does the chest wall include?

Answer 1

the rib cage, diaphragm and abdominal wall

Question 2

Explain how information travels from the brain to allow breathing

Answer 2

The brain sends a signal to the respiratory muscles, the muscles move the rib cage. The rib cage pulls the parietal pleura, which pulls the visceral pleura. Finally, the visceral pleura pulls on the lungs to make them expand.

Question 3

Are the lungs directly attached to the chest wall?

Answer 3

No

Question 4

How are the visceral and parietal pleura coupled together?

Answer 4

It’s a continuous membrane attached to the chest wall and the lungs to move together. In between, there is a small amount of liquid in the intrapleural space

Question 5

What is the function of the liquid inside the intrapleural space?

Answer 5

it allows the lungs to slide against the internal wall of the chest during breathing and to follow the change in thoracic configuration

Question 6

What is pleural pressure?

Answer 6

the pressure that can be measured in the liquid-filled space between lung and chest

Question 7

What happens if a hole is punctured through the chest wall?

Answer 7

Air is going to enter the pleural space. The ribs are going to expand to their resting volume and the lungs will collapse to their resting volume

Question 8

What do we measure to evaluate the elastic properties of the respiratory system?

Answer 8

changes in the recoil pressure of each separate structure for a given change in lung volume

Measures the tendency of the lungs to return to their original shape after inflation. (opposite of compliance)

Question 9

How are pressures measured for the respiratory system?

Answer 9

manometers or pressure transducers

Question 10

How are volumes measured for the respiratory system?

Answer 10

Spinometry

Question 11

What does “negative pressure” indicate?

Answer 11

pressure below the atmospheric pressure

Question 12

What does “positive pressure” indicate?

Answer 12

Pressure above the atmospheric pressure

Question 13

What is the recoil pressure defined as?

Answer 13

the pressure difference between the inside and outside of the structure, driving those structure to return to their resting positions

Question 14

What is the trans-chest-wall pressure?

Answer 14

the difference between the pleural pressure and the pressure at the body surface

Question 15

How can we measure pleural pressure?

Answer 15

using a flexible balloon introduced into the esophagus

Question 16

Why does esophageal pressure provide a close approximation of pleural pressure?

Answer 16

because the esophagus is located between the two pleural spaces

Question 17

What is the formula for trans-chest-wall pressure?

Answer 17

Pw = pleural pressure - body surface

Question 18

How is the transpulmonary pressure measured?

Answer 18

Pl = Palv - Ppl

Question 19

How is the transrespiratory system pressure measured?

Answer 19

Prs=Palv-Pbs

Question 20

How can we calculate Pbs?

Answer 20

That is the pressure around the body (=0 in lab)

Question 21

How can we calculate the Palv?

Answer 21

You ask the patient to hold their breath at maximum lung capacity and close their mouths. The pressure inside their mouth will be equal to their alveolar pressure

Question 22

What is the compliance of the lungs? (Definition)

Answer 22

the ease with which the structure can be distended

Question 23

What is the procedure for measuring the respiratory system compliance?

Answer 23

Determine the static pressure-volume relationship while the lung volume is decreased step by step from the TLC

Question 24

How is compliance expressed?

Answer 24

C=ΔV / ΔP

Question 25

When is compliance of the lungs altered?

Answer 25

in diseases such as emphysema and fibrosis

Question 26

The pressure required to maintain a given volume of gas inside the lungs ___ as the volume increases

Answer 26

increases

Question 27

What is the pressure difference between the alveoli and the pleural space?

Answer 27

it gives transpulmonary pressure

Question 28

What is the formula for compliance in the context of the lungs?

Answer 28

CL = ΔV/ (Δ Palv - Δ Ppl)

Question 29

How is the elastic recoil of the lungs produced?

Answer 29

The elastic recoil of the lungs is produced by the inherent elasticity of lung tissue and the surface tension within the alveoli. The lungs naturally retract inward after being stretched during inhalation.

Question 30

Where do a large part of the recoil forces arise from?

Answer 30

from the surface tension at the air-liquid interface within the alveoli and the elasticity of the lung tissue

Question 31

Why does the liquid film lining the inside of the lungs generate substantial force?

Answer 31

surface tension pulls the alveoli inward, contributing to the lungs' elastic recoil and creating a tendency for the alveoli to collapse (counteracted by surfactant to maintain alveolar stability.)

Question 32

What also has elastic properties that cause it to recoil either inward or outward, depending on its volume?

Answer 32

The chest wall also has elastic properties and they depend on the pressure

Question 33

What is the compliance of the chest wall defined as?

Answer 33

the change of the thoracic volume and a change in pressure across the chest wall

Question 34

What is the formula for the compliance of the chest wall?

Answer 34

Cw = ΔV/ΔPpl

Question 35

What is the sign of the pressure reported when measuring the compliance of the lungs?

Answer 35

The pressure in the lungs is always positive (wants to collapse) no matter the % of the vital capacity (volume of air in the lungs) see the curve on slide 14

Question 36

What is the sign of the pressure in the chest wall?

Answer 36

When exhaling, the pressure in the lungs is negative (it wants to expand) because the lungs are below their resting volume When inhaling, the pressure in the lungs is positive (it wants to collapse) because the lungs are above their resting volume see the curve on slide 19

Question 37

What is the Prs at FRC?

Answer 37

zero

Question 38

Why is the Prs zero at FRC?

Answer 38

There is no airflow because the lungs are at rest between breaths. With no airflow, the pressure at the airway opening (Pao) and the pressure in the alveoli (Palv) are equal.

Question 39

What causes the stable condition of the Prs at FRC?

Answer 39

Outward recoil of the chest wall: The chest wall naturally recoils outward due to its structural elasticity, creating a negative pressure in the pleural space. Inward recoil of the lungs: The elastic tissue of the lungs pulls inward, attempting to collapse the lungs, creating an equal but opposite pressrue to the chest wall.

Question 40

Why does air enter the pleural space during pneumothorax?

Answer 40

because the pleural pressure is less than the atmospheric pressure. The gradient is into the pleural space

Question 41

What happens to the lungs during pneumothorax?

Answer 41

they collapse

Question 42

What happens to the chest wall during pneumothorax?

Answer 42

it expands

Question 43

Why is pneumothorax a life-threatening emergency?

Answer 43

because you can't breath anymore... that's not very compatible with life