Textbook Question
The detergent-like substance that keeps the alveoli from collapsing between breaths because it reduces the surface tension of the water film in the alveoli is called:
a. Lecithin
b. Bile
c. Surfactant
d. Reluctant
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Ch. 22 The Respiratory System
Marieb, Hoehn7th EditionHuman Anatomy & PhysiologyISBN: 9780805359091
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Table of contents
- Ch. 1 The Human Body: An Orientation24
- Ch. 2 Chemistry Comes Alive25
- Ch. 3 Cells: The Living Units24
- Ch. 4 Tissue: The Living Fabric19
- Ch. 5 The Integumentary System10
- Ch. 6 Bones and Skeletal Tissues19
- Ch. 7 The Skeleton11
- Ch. 8 Joints7
- Ch. 9 Muscles and Muscle Tissue26
- Ch. 10 The Muscular System26
- Ch. 11 Fundamentals of the Nervous System and Nervous Tissue23
- Ch. 12 The Central Nervous System26
- Ch. 13 The Peripheral Nervous System and Reflex Activity28
- Ch. 14 The Autonomic Nervous System18
- Ch. 16 The Endocrine System26
- Ch. 17 Blood27
- Ch. 18 The Cardiovascular System: The Heart22
- Ch. 19 The Cardiovascular System: Blood Vessels27
- Ch. 20 The Lymphatic System and Lymphoid Organs and Tissues16
- Ch. 21 The Immune System: Innate and Adaptive Body Defenses29
- Ch. 22 The Respiratory System20
- Ch. 23 The Digestive System30
- Ch. 24 Nutrition, Metabolism, and Energy Balance26
- Ch. 25 The Urinary System25
- Ch. 26 Fluid, Electrolyte, and Acid-Base Balance24
- Ch. 27 The Reproductive System23
Marieb, Hoehn7th EditionHuman Anatomy & PhysiologyISBN: 9780805359091Not the one you use?Change textbook
Chapter 21, Problem 6
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 guidance1
Understand the role of inspiratory muscles, primarily the diaphragm and external intercostal muscles, in the process of inspiration (inhalation).
Recall that when the diaphragm contracts, it moves downward, increasing the vertical length of the thoracic cavity.
Recognize that contraction of the external intercostal muscles elevates the ribs, which increases the diameter of the thoracic cavity.
Combine these effects to see that both the length and diameter of the thoracic cavity increase during inspiration.
Conclude that an increase in both length and diameter leads to an increase in the overall volume of the thoracic cavity, facilitating lung expansion.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Thoracic Cavity Anatomy
The thoracic cavity is the chamber within the chest that houses the lungs and heart. Its size can change in different dimensions—length and diameter—due to the movement of the rib cage and diaphragm during breathing.
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Organization of the Thoracic Cavity
Role of Inspiratory Muscles
Inspiratory muscles, primarily the diaphragm and external intercostal muscles, contract to expand the thoracic cavity. This expansion increases the cavity's volume, facilitating air intake into the lungs.
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5:41Muscle Actions
Mechanics of Breathing and Volume Changes
When inspiratory muscles contract, the thoracic cavity enlarges in both length (due to diaphragm contraction) and diameter (due to rib cage elevation), increasing its volume. This volume increase lowers pressure inside the lungs, causing air to flow in.
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6:28Lung Volumes
Related Practice
Textbook Question
Oxygen and carbon dioxide are exchanged in the lungs and through all cell membranes by:
a. Active transport
b. Diffusion
c. Filtration
d. Osmosis
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Textbook Question
Under ordinary circumstances, the inflation reflex is initiated by:
a. Noxious chemicals
b. The ventral respiratory group
c. Overinflation of the alveoli and bronchioles
d. The pontine respiratory centers
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Textbook Question
The nutrient blood supply of the lungs is provided by:
a. The pulmonary arteries
b. The aorta
c. The pulmonary veins
d. The bronchial arteries
Textbook Question
Which of the following determines the direction of gas movement?
a. Solubility in water
b. Partial pressure gradient
c. Temperature
d. Molecular weight and size of the gas molecule
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Textbook Question
Most oxygen carried in the blood is:
a. In solution in the plasma
b. Combined with plasma proteins
c. Chemically combined with the heme in red blood cells
d. In solution in the red blood cells