Respiratory Physiology II

Question 1

Exceptions to elastic recoil during exhalation

Answer 1

Exercise
Disease
Horses
Neonates (compliance)
Small mammals (compliance)

Question 2

Compliance

Answer 2

The pressure-volume relationship of the lung (describes the distensibility of the chest wall and lung)

Question 3

Muscles of inhalation

Answer 3

Diaphragm
External intercostal muscles
Upper airway abductor muscle

Question 4

Muscles of exhalation

Answer 4

Elastic recoil - lungs and muscles
Internal intercostal muscles
abdominal muscles - rectus abdominus, external obliques

Question 5

Equation for pulmonary pressure

Answer 5

P = Q x R
where P = pressure difference
Q = airflow
R = resistance

Question 6

Factors that influence airway resistance

Answer 6

Viscosity of air
Length of the airway
Radius of the airway

Question 7

What does Poiseuille’s state?

Answer 7

When the radius of an airway decreases by one-half, the resistance of airflow through that airway increases by 16-fold

Question 8

Smooth muscle relaxation and bronchodilation can be achieved by what?

Answer 8

Sympathetic activation and beta-adrenergic receptor agonists

Question 9

Smooth muscle contraction and bronchoconstriction can be caused by what?

Answer 9

“Heaves” in horses

“Asthma” in cats

Question 10

Describe reason for lung sounds during auscultation

Answer 10

The high velocity of airflow in the trachea and bronchi causes turbulent flow. Normal noises are exaggerated with airway inflammation

Question 11

Law of LaPlace

Answer 11

P = 2T/r

The pressure of a sphere equals 2 x tension divided by the radius of the sphere

Question 12

Surfactant

Answer 12

A mixture of phospholipids that line the alveoli and reduce their surface tension, which reduces the collapsing pressure for a given radius