Pulmonary Ventilation

A set of flashcards covering key concepts in pulmonary ventilation and respiratory physiology.

What is the major function of the respiratory system?

To supply the body with oxygen and to dispose of carbon dioxide.

What are the four processes involved in respiratory physiology?

Pulmonary ventilation, external respiration, respiratory gas transport, internal respiration.

What is pulmonary ventilation?

A mechanical process that depends on volume changes occurring in the thoracic cavity.

Explain Boyle's Law in relation to breathing.

When the volume of gas increases, pressure decreases, and when the volume decreases, pressure increases.

What are the two phases of breathing?

Inspiration and expiration.

What are the layers of pleura surrounding the lungs?

The outer layer is called the parietal pleura and the inner layer is called the visceral pleura.

What is the function of pleural fluid?

It lubricates the pleural surfaces, allowing the lungs to move easily during breathing.

What happens during inspiration?

The diaphragm and external intercostals contract, increasing the size of the thoracic cavity and decreasing intrapulmonary pressure.

Is expiration an active or passive process?

Expiration is a passive process that depends on the elastic recoil of the lungs.

What muscles are involved in forced expiration?

Internal intercostal muscles and abdominal muscles.

What is tidal volume?

The amount of air moved in and out of the lungs during normal quiet breathing, about 500 ml.

What is inspiratory reserve volume?

The amount of air that can be forcibly inhaled after a tidal inspiration.

What is expiratory reserve volume?

The amount of air that can be forcibly exhaled after a tidal expiration.

What is residual volume?

The air that remains in the lungs after a forceful exhalation.

Define vital capacity.

The maximum amount of air that can be exhaled after taking the deepest breath possible.

What is alveolar ventilation?

The rate at which new air reaches the gas exchange areas of the lungs.

What is dead space in respiratory physiology?

Air that occupies the respiratory passages but does not participate in gas exchange.

What is the normal dead space volume in a young adult man?

About 150 ml.

Describe the mechanics of unforced expiration.

Unforced expiration is passive, involving the relaxation of inspiratory muscles and elastic recoil of the lungs.

What occurs when atmospheric pressure is equal to intrapulmonary pressure?

No air movement occurs; pressure outside and inside are equal.

What is the significance of the pressure gradient in the pleural cavity?

It assists in lung inflation due to lower pressure in the pleural cavity compared to atmospheric pressure.

Define sighing as a respiratory movement.

A long-drawn and deep inhalation followed by a shorter but forceful exhalation.

What triggers a cough reflex?

A long-drawn inhalation followed by a closure of the rima glottidis, leading to a strong exhalation.

What is the primary purpose of the Valsalva maneuver?

Forced exhalation against a closed rima glottidis, often used during straining.

How does breathing affect thoracic cavity volume during inhalation?

Inhalation increases thoracic cavity volume.

What happens to intrapulmonary pressure during breathing?

It decreases during inhalation and increases during exhalation.

What is modified respiratory movement?

Non-respiratory actions such as laughing, crying, or sneezing that involve respiratory muscles.

What role do scalenes and sternocleidomastoid muscles play in respiration?

They are involved in forced inspiration.

What is the purpose of the pleural cavity?

It is a potential space that allows for lung expansion and contraction due to pleural fluid.

What happens when the diaphragm contracts during breathing?

The lungs are stretched, increasing intrapulmonary volume and causing a decrease in pressure that draws air in.