Laboratory Manual For Human Anatomy & Physiology
Laboratory Manual For Human Anatomy & Physiology
4th Edition
ISBN: 9781260159363
Author: Martin, Terry R., Prentice-craver, Cynthia
Publisher: McGraw-Hill Publishing Co.
bartleby

Videos

Textbook Question
Book Icon
Chapter 51, Problem 1PL

The size of the thoracic cavity is increased by contractions of all of the following muscles except the
a. diaphragm.
b. external intercostals.
c. pectoralis minor.
d. external oblique.

Expert Solution & Answer
Check Mark
Summary Introduction

Introduction:

Breathing is the movement of air from outside the body through the bronchial tree and into the alveoli and the reversal of this air movement allow gas exchange between air and blood. The cause for these movements is the change in the size of the thoracic cavity that result from skeletal muscle contractions.

Answer to Problem 1PL

Correct answer:

The correct answer is option (d) external oblique.

Explanation of Solution

Explanation for the correct answer:

Option (d)external oblique. The external oblique aids expiration by compressing abdominal contents which helps to raise the diaphragm. The external oblique originates at the anterior surface of ribs five to twelve. So, the correct answer is option (d).

Explanation for the incorrect answers:

Option (a) diaphragm. The diaphragm originates at the costal cartilages and ribs seven to twelve. Its insertion occurs at the central tendon of diaphragm.The diaphragm contraction flattens itself and thus, it expands the size of thoracic cavity. Therefore, option (a) in incorrect.

Option (b) external intercostals. External intercostal muscles originate at the inferior border of superior rib. These muscles tend to elevate ribs which expands the thoracic cavity during inspiration. Therefore, this option is incorrect.

Option (c) pectoralis minor. The pectoralis minor originates at the sternal ends of ribs three to five. This muscle elevates the 3rd and 5th ribs which aids in increasing the size of thoracic cavity. Therefore, this option is incorrect.

Conclusion

The correct answer is Option (d) external oblique because the external oblique aids expiration by compressing abdominal contents which helps to raise the diaphragm.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
Contraction of the external intercostal muscles causeswhich of the following to occur?a. The diaphragm moves downward.b. The rib cage is compressed.c. The thoracic cavity volume decreases.d. The ribs and sternum move upward.
The paranasal cavities open into the nasal cavity. They include which of the following? a. frontal sinuses b. maxillary sinuses c. ethmoid cells (sinuses) d. sphenoid sinus
Expansion of the chest cavity during normal relaxed breathing is accomplished by the diaphragm and______   A. external/internal abdominal oblique   B. intercostals   C. pectoralis major   D. trapezius
Knowledge Booster
Background pattern image
Biology
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.
Similar questions
Recommended textbooks for you
Text book image
Comprehensive Medical Assisting: Administrative a...
Nursing
ISBN:9781305964792
Author:Wilburta Q. Lindh, Carol D. Tamparo, Barbara M. Dahl, Julie Morris, Cindy Correa
Publisher:Cengage Learning
Text book image
Body Structures & Functions Updated
Biology
ISBN:9780357191606
Author:Scott
Publisher:Cengage
Text book image
Body Structures & Functions
Biology
ISBN:9781285695495
Author:Scott
Publisher:Cengage
Text book image
Basic Clinical Lab Competencies for Respiratory C...
Nursing
ISBN:9781285244662
Author:White
Publisher:Cengage
Text book image
Medical Terminology for Health Professions, Spira...
Health & Nutrition
ISBN:9781305634350
Author:Ann Ehrlich, Carol L. Schroeder, Laura Ehrlich, Katrina A. Schroeder
Publisher:Cengage Learning
Respiratory System; Author: Amoeba Sisters;https://www.youtube.com/watch?v=v_j-LD2YEqg;License: Standard youtube license