Video Transcript
What is the name of the major
muscle of respiration located below the lungs? (A) Pleura, (B) intercostal muscle,
(C) diaphragm, (D) thorax.
This question asks us about a
muscle involved in respiration. Respiration is the process of
inhaling air containing oxygen and exhaling carbon dioxide. Let’s review some of the structures
involved in respiration in order to answer this question correctly.
Here’s a diagram of the respiratory
system that shows the lungs below and the ribs on the side. In between the ribs are special
muscles called the intercostal muscles. Located below the lungs is a muscle
called the diaphragm.
Both the diaphragm and the
intercostal muscles play an important role in respiration. During inhalation, the diaphragm
muscle contracts and moves downward. This action causes the chest cavity
to expand and increase the volume of the lungs, drawing in air during
inhalation.
The intercostal muscles that lie
between each rib support this process by helping to expand the chest cavity. These muscles pull the ribcage up
and outwards. When we exhale, the opposite
happens. Here, the diaphragm relaxes and
moves upwards. The intercostal muscles here help
to shrink the rib cage. This causes the volume of the chest
cavity to decrease, allowing for exhalation.
So to go back to our question, the
major muscle of respiration that is located below the lungs is given by answer
choice (C), diaphragm.
