Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

22. The Respiratory System

Pressure in the Lungs and Pleural Cavity

Anatomy & Physiology

22. The Respiratory System

Pressure in the Lungs and Pleural Cavity

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2:09 minutes

Problem 6

Textbook Question

When the inspiratory muscles contract:
a. The size of the thoracic cavity increases in diameter
b. The size of the thoracic cavity increases in length
c. The volume of the thoracic cavity decreases
d. The size of the thoracic cavity increases in both length and diameter

Verified step by step guidance

Understand the role of inspiratory muscles: Inspiratory muscles, such as the diaphragm and external intercostal muscles, are responsible for increasing the volume of the thoracic cavity during inhalation.

Analyze the diaphragm's action: When the diaphragm contracts, it moves downward, increasing the vertical length of the thoracic cavity.

Examine the external intercostal muscles' action: When these muscles contract, they lift the ribs outward and upward, increasing the diameter of the thoracic cavity.

Combine the effects: The contraction of both the diaphragm and external intercostal muscles results in an increase in both the length and diameter of the thoracic cavity, which leads to an overall increase in thoracic volume.

Eliminate incorrect options: Based on the physiological actions described, eliminate options that do not align with the increase in both length and diameter of the thoracic cavity during inspiration.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Inspiratory Muscles

Inspiratory muscles, primarily the diaphragm and intercostal muscles, are responsible for expanding the thoracic cavity during inhalation. When these muscles contract, they create a negative pressure within the thoracic cavity, allowing air to flow into the lungs. Understanding their function is crucial for analyzing how changes in muscle contraction affect lung volume and airflow.

Thoracic Cavity Dynamics

The thoracic cavity is the chamber within the rib cage that houses the lungs and heart. Its size can change in both diameter and length due to the contraction of inspiratory muscles. Recognizing how these changes impact the volume of the thoracic cavity is essential for understanding respiratory mechanics and the process of breathing.

Pressure-Volume Relationship

The pressure-volume relationship in the thoracic cavity is governed by Boyle's Law, which states that at constant temperature, the pressure of a gas is inversely proportional to its volume. When the thoracic cavity expands due to muscle contraction, the pressure inside decreases, allowing air to enter the lungs. This principle is fundamental for grasping how changes in thoracic cavity size influence respiratory function.

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Related Practice

Textbook Question

More than one choice may apply.

During inspiration, intrapulmonary pressure is

a. Greater than atmospheric pressure

b. Less than atmospheric pressure

c. Greater than intrapleural pressure

d. Less than intrapleural pressure

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Textbook Question

More than one choice may apply.

Which of the following changes will accompany the loss of lung elasticity associated with aging?

a. Increase in tidal volume

b. Increase in inspiratory reserve volume

c. Increase in residual volume

d. Increase in vital capacity

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Textbook Question

A member of the 'Blues' gang was rushed into an emergency room after receiving a knife wound in the left side of his thorax. The diagnosis was pneumothorax and a collapsed lung. Explain exactly

Why the lung collapsed?

Why only one lung (not both) collapsed?

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Textbook Question

Describe the functional relationships between volume changes and gas flow into and out of the lungs.

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Multiple Choice

Which of the following pressures must remain negative to prevent lung collapse?

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