Mechanics of Resp part 2 - Quiz 2

Question 1

What conditions might cause a reduced lung compliance?

Answer 1

Higher or Lower lung volumes
Higher expansion pressure, 
venous congestion, 
alveolar edema, 
atelectasis & fibrosis

Question 2

What conditions might cause an increased lung compliance?

Answer 2

Advanced Age

emphysema (due to alteration of elastic fibers)

Question 3

How much of the elastic forces of the lung is created by the Surface Air-Fluid Interface?

Answer 3

2/3 of totla elastic force

Question 4

Why is surfactant important?

Answer 4

elastic force (keeps alveoli open)
Breaks surface tension of H2O (makes water wetter)

Question 5

What is surfactant and what is it made by?

Answer 5

It is a synthesized fatty-acid product of Type II Pneumocytes
Has hydrophobic and hydrophyllic heads

Question 6

What is Surface Tension Elastic Forces in relation to the lung? What stops it from happening?

Answer 6

The net effect on the lung to sumultaneously attempt to collapse alveoli by water tension.
-Surfactant stops process

Question 7

Name 3 functions of Surfactant.

Answer 7

1. Lowers surface tension of alveoli & lung
2. Promotes stability of alveoli
3. Prevents transudation of fluid into alveoli

Question 8

What are the equations for Minute Ventilation (MV) and alveolar ventilation (VA)?

Answer 8

• MV = Vt x resp

- VA = MV x 70%

Question 9

What is Anatomic Dead Space?

Answer 9

Areas of the airway that are ventilated but not perfused

Question 10

How do you calculate Dead Space?

Answer 10

2ml/kg of Ideal Body Weight or weight in pounds

Vt = VA + Vd

Question 11

What is Wasted Ventiliation and what could cause it?

Answer 11

areas of the lung that are ventilated and are normally perfused but has a blockage of blood flow causing a V/Q mismatch.
Could be caused by Pulmonary Embolism

Question 12

Describe Poiseuille Law

Answer 12

Describes resistance to flow through a tube.
Pressure increases proportional to flow rate and gas viscosity.
Smaller airway radius and longer distances increase flow resistance.
**reducing radius by 16% double the Resistance
** reducing radius by 50% increases resistance 16-fold

Question 13

Ohm’ s Law equation

Answer 13

P = F x R where P=pressure, F=flow, R=resistance

Question 14

What can cause turbulent flow?

Answer 14

• higher flow rates or air velocity
• Local eddies form at sides of airway and stream lines of flow become disorganized
• pressure no longer proportional to flow
• Increases in density, velocity, and airway resistance make turbulence more probable.

Question 15

What is the chief site of airway resistance?

Answer 15

Medium-sized bronchi

Question 16

Where does most pressure in the airways decrease?

Answer 16

Most pressure drops occur at SEVENTH division

Question 17

What is the work of breathing equation?

Answer 17

W = P x V
W = work of breathing
P = Pressure
V = Volume