Why do we breathe in oxygen and breathe out carbon dioxide

Breathing is central to life, as it allows the human body to obtain the energy it needs to sustain itself and its activities. But how does it work?

Table of Contents Show

Do humans breathe in oxygen and breathe out carbon dioxide?
Why do we not breathe in carbon dioxide?
Why do we release carbon dioxide?
Why do we inhale oxygen only?

Abstract
Breathing uses chemical and mechanical processes to bring oxygen to every cell of the body and to get rid of carbon dioxide. Our body needs oxygen to obtain energy to fuel all our living processes. Carbon dioxide is a waste product of that process. The respiratory system, with its conduction and respiratory zones, brings air from the environment to the lungs and facilitates gas exchange both in the lungs and within the cells. Nurses need a solid understanding of how breathing works, and of vital signs of breathing and breathing patterns, to be able to care for patients with respiratory problems and potentially save lives in acute situations.

Citation: Cedar SH (2018) Every breath you take: the process of breathing explained. Nursing Times [online]; 114: 1, 47-50.

Author: SH Cedar is associate professor and reader in human biology at the School of Health and Social Care, London South Bank University, and author of Biology for Health: Applying the Activities of Daily Living.
This article has been double-blind peer reviewed
Scroll down to read the article or download a print-friendly PDF here

The role of the respiratory system is to breathe in oxygen and breathe out carbon dioxide. This is known as respiration. The cells of the body use oxygen to perform functions that keep us alive. The waste product created by the cells once they have performed these functions is carbon dioxide. The respiratory system helps provide a voice. It also assists with the sense of smell and taste.

The Respiratory System

The respiratory system is made up of the nose, mouth, throat, trachea (windpipe) and lungs. The diaphragm is the main breathing muscle of the body. The accessory breathing muscles assist the diaphragm and are made up of:

muscles surrounding the ribs
abdominal muscles
muscles in the neck and shoulders

How the Breathing Muscles Work

When the diaphragm and accessory muscles contract, your chest expands and pulls air into the lungs; this is inhaling. As your muscles relax, the space inside your chest gets smaller and under more pressure and the air is pushed out of the lungs; this is exhaling – similar to letting air out of a balloon.

How the Body Uses Oxygen

The cells of the body use oxygen to produce energy. Oxygen is carried by the hemoglobin on the red blood cells. The blood vessels in the lungs bring oxygenated blood to the heart. The heart then pumped it out to the cells of the body. The waste product of this process is carbon dioxide. The hemoglobin then returns the carbon dioxide back to the lungs where it is exhaled.

How High Altitude Effects Oxygen

Oxygen makes up 21% of the gas in air. The air is less dense at higher altitudes because there is less atmospheric pressure. This means the oxygen molecules are spread further apart. Less oxygen will enter the lungs with each breath. Atmospheric pressure also helps to push oxygen across the membrane of the cells in the lungs. In Denver, the altitude is 5,280 ft. and we breathe in 17% less oxygen than someone does at sea level. We breathe in 50 percent less oxygen at 18,000 feet.

Our bodies adjust to higher altitude by creating more red blood cells. It takes 21 to 28 days for this process to occur. The amount of oxygen needed by the body varies. It will depend on a person’s level of activity, age, weight, and overall health. Individuals who are ill or injured may require more oxygen to help their bodies function and heal.

How Spinal Cord Injury and Traumatic Brain Injury Can Affect the Lungs

Respiratory Failure: Spinal cord injuries at the C3 level or higher effect the phrenic nerve. The phrenic nerve controls the diaphragm. Individuals with these injuries will not be able to breathe on-their-own and will need assistance from a ventilator.

Respiratory Insufficiency: Spinal cord injuries at the level of T6 and higher will affect the accessory breathing muscles. These individuals will have trouble taking a deep breath. This is known as respiratory insufficiency. Respiratory insufficiency happens when the body is too weak to fully expand the lungs. These individuals may not be able to bring in enough oxygen or get rid of enough carbon dioxide.

Brian Injury: Brain injuries can also affect the parts of the brain that control or regulate breathing.

Swallow: Spinal cord or brain injuries that affect the parts of the body that control swallow can leave patients without the ability to protect their airway.

Chemistry of the Lungs

The respiratory system can sometimes go a little haywire if the nerves that control breathing are damaged. The lungs might overreact or underreact. They may make too many secretions or the airways and blood vessels may constrict when they need to dilate.

Mucus and Cough

We all produce mucus. But mucus can be a problem if you are unable to cough or have a weak cough. If someone is unable to clear the mucus form their lungs it can become infected and cause the tissues in the lungs to stick together. This puts people at risk for pneumonia.

Lung Health After Injury

It is extremely important to keep the lungs healthy. Respiratory infection is the number one reason patients with cervical spinal cord injuries return to the hospital after being discharged from rehab. It is also the leading cause of death after these people are released back to home.

Ways to Stay Healthy

Wash your hands #1
Get out of bed
Turn frequently
Deep Breathing
Exercise if you are able
Weight shifts in the wheelchair
Stay clear of sick friends and family until they are healthy
Clean equipment
Take breathing treatments as they are scheduled
See your doctor if you feel sick or there is a change in your mucus
Positive attitude

Download PDF Version

Revised: 1/2016

References:

http://gotlungs.ca/index.php/health-facts/kids-how...

http://www.innerbody.com/anatomy/respiratory

BioMed Research InternationalVolume 2013 (2013), Article ID 168757

http://www.medterms.com/script/main/art.asp?articl...

Critical Care Research and Practice Volume 2012 (2012), Article ID 207247, 8 pages http://dx.doi.org/10.1155/2012/207247

http://anthro.palomar.edu/adapt/adapt_3.htm

Do humans breathe in oxygen and breathe out carbon dioxide?

When you inhale (breathe in), air enters your lungs, and oxygen from that air moves to your blood. At the same time, carbon dioxide, a waste gas, moves from your blood to the lungs and is exhaled (breathed out).

Why do we not breathe in carbon dioxide?

Carbon dioxide acts as a simple asphyxiant; in other words, as CO2 levels in a closed room rise, carbon dioxide replaces the oxygen your body needs. When your body can't get oxygen, it slows down and does not function properly. Because carbon dioxide is an asphyxiant, it mostly affects your brain.

Why do we release carbon dioxide?

Human activities that lead to carbon dioxide emissions come primarily from energy production, including burning coal, oil, or natural gas.

Why do we inhale oxygen only?

All cells in our body need oxygen to create energy efficiently. When the cells create energy, however, they make carbon dioxide. We get oxygen by breathing in fresh air, and we remove carbon dioxide from the body by breathing out stale air.