Human Physiology: Breathing and Lung Volumes
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Questions and Answers

Which muscle contraction assists in exhalation during heavy breathing?

  • External intercostal muscles
  • Internal intercostal muscles (correct)
  • Diaphragm
  • Scalenes

What primarily causes the increase in alveolar pressure that leads to exhalation?

  • Increased atmospheric pressure
  • Contraction of inspiratory muscles
  • Decreased thoracic cavity volume
  • Elastic recoil of the lungs (correct)

What happens to the alveolar pressure during elastic recoil?

  • It decreases to below atmospheric pressure
  • It remains constant
  • It increases above atmospheric pressure (correct)
  • It fluctuates randomly

How does the body compensate for rapid breathing during exercise?

<p>By aiding exhalation through muscle contractions (B)</p> Signup and view all the answers

In premature infants, the lack of which substance can lead to respiratory distress due to increased surface tension in the alveoli?

<p>Surfactant (D)</p> Signup and view all the answers

What is a likely consequence of inadequate elastic recoil in the lungs?

<p>Inability to exhale effectively (D)</p> Signup and view all the answers

What role do abdominal muscles play during heavy breathing?

<p>They force organs upward into the diaphragm (B)</p> Signup and view all the answers

Newborn respiratory distress syndrome is primarily associated with the deficiency of what?

<p>Surfactant production (C)</p> Signup and view all the answers

What role does surfactant play in the alveoli?

<p>It decreases surface tension (C)</p> Signup and view all the answers

How does alveolar pressure change during inhalation?

<p>It decreases below atmospheric pressure (B)</p> Signup and view all the answers

What is a characteristic of premature infant respiration related to alveolar function?

<p>Alveolar collapse occurs due to high surface tension (D)</p> Signup and view all the answers

Which condition is characterized by newborn respiratory distress syndrome?

<p>Inadequate alveolar expansion during breathing (B)</p> Signup and view all the answers

Energy expenditure in breathing is typically affected by which factor?

<p>The efficiency of gas exchange (C)</p> Signup and view all the answers

What effect does high altitude have on atmospheric pressure?

<p>Decreases it compared to sea level (D)</p> Signup and view all the answers

When exhaling, what must occur with alveolar pressure?

<p>It must be higher than atmospheric pressure (A)</p> Signup and view all the answers

What function is primarily disrupted in infants with respiratory distress due to insufficient surfactant?

<p>Gas diffusion across the alveolar membrane (A)</p> Signup and view all the answers

What is the primary function of the work of breathing?

<p>To facilitate gas exchange in the alveoli. (B)</p> Signup and view all the answers

How much of total body energy consumption is typically used for breathing in a healthy adult?

<p>3-5% (C)</p> Signup and view all the answers

What increases the energy expenditure in breathing during restrictive airway conditions?

<p>Greater muscle contraction requirements. (C)</p> Signup and view all the answers

What is the Functional Residual Capacity (FRC) in an average young adult male?

<p>2.3 liters. (A)</p> Signup and view all the answers

What are the two components of Functional Residual Capacity (FRC)?

<p>Expiratory Reserve Volume and Residual Volume. (B)</p> Signup and view all the answers

What role does exercise play in energy expenditure for breathing?

<p>It can lead up to 50% energy expenditure in breathing. (A)</p> Signup and view all the answers

What happens to breathing efficiency in individuals with asthma?

<p>It decreases as the airways become restricted. (C)</p> Signup and view all the answers

Which of the following best describes the Residual Volume (RV)?

<p>The air left in the lungs after maximum exhalation. (C)</p> Signup and view all the answers

Study Notes

Breathing and Energy

  • Breathing requires energy, accounting for 3-5% of total body energy consumption in a healthy adult.
  • This energy is used for contracting skeletal muscles involved in air movement.
  • Individuals with restricted airways, such as asthma, require more energy for breathing due to increased muscle effort.
  • During heavy exercise, the energy expenditure for breathing can reach 50% of total body energy consumption.

Pulmonary Volumes

  • Pulmonary volumes are measures of air in the lungs at different times.
  • Functional Residual Capacity (FRC) is the volume of air left in the lungs after a normal exhale, approximately 2.3 liters in a young adult male.
  • FRC consists of Expiratory Reserve Volume (ERV) and Residual Volume (RV).
  • ERV is the amount of air that can be exhaled after a normal breath, while RV is the air remaining in the lungs after maximum exhalation.

Mechanics of Exhalation

  • Relaxation of inspiratory muscles, like the diaphragm, causes the lungs to pull inward due to their elasticity.
  • This inward pull decreases the volume of alveoli, increasing the pressure of the gas inside.
  • Air flows from the higher pressure in the alveoli to the lower pressure in the atmosphere, resulting in exhalation.

Active Exhalation

  • During heavy breathing, like exercise, exhalation requires additional effort to ensure rapid air expulsion.
  • This is achieved by contracting the internal intercostal muscles, abdominal recti muscles, and abdominal muscles.
  • Contraction of these muscles actively decreases thoracic cavity volume, increasing alveolar pressure and resulting in faster air expulsion.

Respiratory System Functions

  • The respiratory system's primary roles are to supply the body with oxygen and remove carbon dioxide.
  • This process involves:
    • Pulmonary ventilation: bringing air into and out of the lungs
    • Gas diffusion: exchange of gases between alveoli and blood
    • Transport of oxygen and carbon dioxide in the blood
    • Regulation of breathing
    • Special topics related to respiration

Pulmonary Mechanics

  • Air moves from higher pressure to lower pressure.
  • Atmospheric pressure (Patm) is the weight of air molecules pressing down due to gravity.
  • Alveolar pressure (Palv) is the pressure of air inside the alveoli.
  • Inhalation occurs when Patm is greater than Palv, causing air to move into the lungs.
  • Exhalation occurs when Palv is greater than Patm, driving air from the lungs.
  • Atmospheric pressure decreases with altitude.

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Description

This quiz covers key concepts related to breathing energy requirements, pulmonary volumes, and the mechanics of exhalation. It delves into how breathing consumes energy during different states, such as rest and exercise, and explains the various lung volume measurements. Test your understanding of respiratory physiology and its implications on health.

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