Question

Brain Teasers!
Inspiration of air takes place with the help of external inter coastal muscles and diaphragm while forceful expiration takes place with the help of Internal inter coastal muscles. EICM are under involuntary control of medulla (respiratory centres) then how are we able to breathe voluntary?

Answer 1

The thing I wanted to ask is that what muscles help in achieving voluntary control of breathing?

Answer 2

As you breathe in there is a sheet of muscles at the base of your chest. This is known as your diaphragm. When slack and relaxed, it forms a dome shape, and your lungs are small. To breathe in, it contracts and flattens. The muscles between your ribs also contract to pull the ribs up and out. These actions make your chest bigger and stretch the lungs inside. Air is sucked in through your mouth and down your windpipe.

Answer 3

When you breathe in, air contains nearly 21 percent oxygen. On the way out, this is broken down to 16 percent; the extra 4 or 5 percent is made up of carbon dioxide. Your breathing is controlled by your brain. When your muscles work harder they need more oxygen, which they take from your blood, and so the oxygen level of blood falls. The carbon dioxide levels however rise.

Answer 4

@MedicalDoctor , radial muscles of diaphragm are under control of respiratory center situated in medula and hence are under involuntary control. They don't help in voluntary control of breathing.

Answer 5

Even muscles between intercostal space (External intercostal muscles) are under involuntary control

Answer 6

Understood the breathing muscles are controlled automatically from the brainstem during normal breathing but can also be controlled voluntarily from the motor cortex.

Answer 7

@Abhisar

Answer 8

Voluntary control is influenced indirectly by the cerebral cortex and affects the output of the respiratory centres in the medulla oblongata.

Answer 9

Yes but the muscles which help in forceful breathing are different. Question is what are those muscles?

Answer 10

@Abhisar are you referring to the Expiratory muscles?

Answer 11

In that case postural muscles, which are used when coughing, speaking, singing, and playing wind instruments.

Answer 12

@Abhisar

Answer 13

The diaphragm is both voluntary and involuntary for instance when you take a deep breath you contract your diaphragm way down.

Answer 14

Hey @Rushwr I believe that he was referring to the diaphragm because it can be both voluntary and involuntary it is the same just controlled by both systems.

Answer 15

When you take a deep breath on will you are not controlling diaphragm muscles instead you are controlling abdominal muscles. They force the visceral organs to move towards posterior and hence the thoracic volume increase which induces inspiration.

Answer 16

You can not feel or control your diaphragm muscles what you feel (sense of control) is your internal intercoastal muscles and other accessory muscles like abdominal muscles involved in breathing.

Answer 17

So muscles involved in VOLUNTARY or FORCEFUL respiration are Internal intercoastal muscles and abdominal muscles for expiration and Mostly abdominal muscles for inspiration

One more thing which I'll like to add about muscles of diaphragm, as we know these are skeletal muscles and they themselves have nothing to do with voluntary or involuntary control. It just depends on the part of brain from where they are receiving signals. Now radial muscles of diaphragm has mostly nerves coming from medulla but they do have few nerves coming from cerebral cortex so they do have some voluntary control over them.

Answer 18

Except external intercoastal muscles each of them are under voluntary control.

Answer 19

One more thing which i would like to point out that though I may have used the terms deep breathing and forced breathing interchangeably they are not the same.

Deep breathing means when breathing (inspiration or expiration) occurs for longer period while forced breathing means when inspiration or expiration is done with certain amount of additional force like when we sneeze.

We have sound ability to expire forcefully which is attained by contraction of abdominal muscles but we have very little ability to inspire forcefully!

Now you may try to inspire forcefully and it may appear that you are inspiring forcefully but what you are doing is simply inspiring for longer duration (deep inspiration). Of course we do have little ability to inspire forcefully due to muscles like Pectoralis Majos but not as much we have the ability of forced expiration.

Answer 20

Oh ok I see I didn't realize you were looking for a group of muscles rather than a certain one.

Answer 21

i have no clue what this is ;~;

Answer 22

Very interesting, saving this post as a favorite! :D I have great interest in bio, just learned something today!

Answer 23

love cardio... This post is very informative!