30 Questions
Which muscles are responsible for raising the rib cage during inspiration?
The external intercostals
What is the main muscle involved in normal quiet breathing?
The diaphragm
Which muscles are responsible for pulling the rib cage downward during heavy expiration?
The internal intercostals
What happens to the diaphragm during normal and quiet expiration?
It relaxes
What causes the necessary rapid expiration during heavy breathing?
Contraction of the abdominal muscles
What are the two ways in which the lungs can be expanded and contracted?
By downward and upward movement of the diaphragm
What is the function of the sternocleidomastoid muscles during inspiration?
Lift upward on the sternum
What is the function of the scaleni muscles during inspiration?
Lift the first two ribs
What is the function of the abdominal muscles during heavy breathing?
Push the abdominal contents upward
What are the two important pressures that cause inspiration and expiration?
Alveolar pressure and intrapleural pressure
According to Laplace's law, the pressure generated in an alveolus is inversely proportional to the radius of the alveolus. Which of the following statements is true?
In the absence of surfactant, smaller alveoli generate higher pressure than larger alveoli.
Which of the following is NOT a function of surfactant?
Increases lung compliance.
Which of the following is true about lung compliance?
Lung compliance is defined as the change in lung volume resulting from a 1–cm H2O change in the distending pressure of the lung.
What is the formula for lung compliance?
$Compliance = \frac{\Delta V}{\Delta P}$
What is the average radius of an alveolus with normal surfactant?
100 micrometers
What is the collapse pressure of an alveolus lined with pure water without any surfactant?
18 cmH2O
What is the role of surfactant in reducing surface tension?
Decreases surface tension
What is the main component of surfactant?
Phospholipid
What is the function of surfactant apoproteins?
Stabilize alveolar size
What is the share and role of surface tension compared to lung tissue in lung compliance?
Surface tension is twice as important as lung tissue in lung compliance.
Which pressure is responsible for the inflow of air during inspiration?
Alveolar pressure
What is the range of pleural pressure during inspiration?
-5 to -7.5 cm H2O
What is the range of alveolar pressure during expiration?
0 to +1 cm H2O
What is the difference between the alveolar pressure and the pleural pressure at each instant of inspiration or expiration called?
Transpulmonary pressure
What are the two main components of alveolar elastic recoil force?
Elastic force of the lung tissue and elastic force caused by surface tension
What happens to the alveolar pressure during inspiration as the alveolar volume increases?
Alveolar pressure falls below atmospheric pressure
What happens to the alveolar pressure during expiration as the alveolar volume decreases?
Alveolar pressure increases above atmospheric pressure
What is the role of the inspiratory muscles during normal and quiet inspiration?
Contract to increase chest volume
What is the role of the inspiratory muscles during normal and quiet expiration?
Relax to decrease chest volume
What is the function of the increased alveolar elastic recoil during expiration?
To return the alveoli to their preinspiratory volumes
Test your knowledge on the contraction and expansion of the lungs in this quiz. Learn about the different ways the lungs can be expanded and contracted, including the movement of the diaphragm and the elevation and depression of the ribs. Also, explore the muscles involved in respiration.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
