Why Do We Breathe in Oxygen and Breathe Out Carbon Dioxide?

Why Do We Breathe in Oxygen and Breathe Out Carbon Dioxide?

Why Do We Breathe in Oxygen and Breathe Out Carbon Dioxide?

Oxygen is necessary for many bodily processes, including digestion of food, muscle movement, and even simple thought. As a byproduct of these reactions, a gas known as carbon dioxide is created. Your lungs’ functions include supplying your body with oxygen and eliminating the waste gas, carbon dioxide.

The air we breathe fills a large portion of our alveoli with each inhalation. Oxygen moves from the alveoli to our blood through the capillaries in our alveolar walls. It gets picked up by the hemoglobin in red blood cells. This oxygen-rich blood flows back to our heart, which pumps it to the oxygen-hungry tissues of our body. Afterward, we breathe out carbon dioxide.

Air sacs

The air sacs, or alveoli, give our lungs their spongy texture. The alveoli are 0.2 millimeters in diameter, cup-shaped, and surrounded by blood vessels known as capillaries. The blood then moves through these tubes to take oxygen and expel carbon dioxide. The air sacs are the workhorses of the respiratory system, handling hundreds of liters of air each minute and making it possible for our bodies to breathe.

The air sacs transport oxygen and carbon dioxide to different body parts. As we breathe, oxygen travels through the lungs and enters the bloodstream, reaching all the cells in our body. As we exhale, carbon dioxide leaves the bloodstream, becoming a waste product of our bodies metabolism. Unlike oxygen, carbon dioxide moves in the opposite direction of oxygen. As we breathe, it leaves our body, entering the lungs and exiting the air sacs.

The air sacs surround a network of tiny blood vessels that link to the lungs. The capillaries pick up oxygen and send it to the rest of the body, while carbon dioxide travels back to the heart. These blood vessels are connected to veins and arteries. So when we breathe, the air is pumped to the rest of the body, where it is metabolized.


Our lungs contain about 300 million alveoli that absorb oxygen. When we breathe, this air travels across the walls of the air sacs and enters the bloodstream. Oxygen moves from the air sacs into the bloodstream and gets picked up by the hemoglobin in red blood cells. The blood then travels back to the heart and lungs, picking up carbon dioxide.

When we breathe, air moves through the trachea, lined with cilia, tiny hairs that move air through the lungs. Air passes through the cilia but can become blocked by substances such as cigarette smoke. As a result, healthy lungs are pinkish gray, whereas polluted lungs have black patches on the surface. The lungs are elastic, but emphysema disease makes them lose elasticity. If they lose their elasticity, they can no longer transfer oxygen to the blood and can no longer breathe.

The lungs transport fresh oxygen into the body and remove waste gases. The air we breathe passes through the trachea and travels through the bronchi. These bronchi split into thousands of smaller tubes called bronchioles. The air passes through these passages to the rest of the body and then out again. In the process, the air passes through the mouth and nose, exchanging oxygen and carbon dioxide.


The answer to the question, “Why do we breathe in oxygen and breathe out carbon oxide?” lies in the human body’s lungs. Our lungs contain approximately 300 million alveoli, which contain tiny blood vessels. During breathing, oxygen moves from the air sacs to the blood and is picked up by the hemoglobin in our red blood cells. The oxygen-rich blood then passes back to the heart, pumped to the rest of our body.

The trachea is divided into the left and right bronchi. The bronchi further branch into smaller tubes called bronchioles, and these connect to the lungs. The smaller bronchioles branch off to all body parts and finally end in alveoli, which are tiny sacs where oxygen and carbon dioxide exchange occurs. The lungs contain elastic tissues, which are covered in a thin lining, and the lungs and the air we breathe in are connected.

When you’re at rest, the lungs move around 5 to eight liters of air into and out of them. The oxygen in the air moves through the alveoli faster than carbon dioxide, so our respiratory rate increases when we breathe in more oxygen. In addition, the brain sends messages to the heart, which pumps oxygenated blood to our cells faster. The same happens when we exercise, requiring the human body to expend more than 100 liters of air per minute.

Pulmonary artery

When we breathe, air from the lungs flows through the pulmonary artery, a blood vessel in the upper chest. The air carries oxygen and carbon dioxide. As the oxygen travels through the artery, it gets carried to the alveoli, where it is carried by the tiny blood vessels called capillaries. Finally, the oxygen-rich blood flows back to the heart, which is pumped to the various organs and tissues.

The pulmonary artery is the primary source of blood flow to the lungs. It brings in blood with a high carbon dioxide concentration and no oxygen. That blood returns to the heart while the oxygen-rich blood is pumped to the rest of the body. During the breathing process, the diaphragm, a muscle that separates the abdominal cavity from the chest cavity, contracts to inflate the lungs. Intercostal muscles also help expand the chest cavity, giving room for breathing.

A condition known as pulmonary artery stenosis affects the pulmonary artery, which narrows in diameter. This makes it difficult for blood to pass through the valve, which can be congenital or acquired. In some cases, the pulmonary artery can also be caused by a heart defect or a muscle disease. Both conditions increase pressure in the pulmonary artery, making it harder for the heart to pump blood through the valve.

Respiratory muscles

The respiratory muscles of the human body are responsible for breathing in and exhaling carbon dioxide and oxygen. It is a complex process involving several muscle groups. A child’s breathing rate varies from thirty to sixty breaths per minute (bpm). As the child ages, it gradually decreases to twelve and eighteen bpm. The respiratory system is regulated by neural networks in the brain stem, which controls different muscles in the thorax and abdomen. These signals also determine the length and force of respiratory muscle contractions.

The diaphragm and the accessory breathing muscles are located in the chest and overlie the thorax. They act as semi-rigid bellows that move air in and out of the thoracic cavity. The diaphragm is the primary muscle for breathing in oxygen, and the outer intercostal muscles are located between the ribs. The accessory muscles of respiration are the abdominal muscles, including the rectus abdominis, transversus abdominis, and internal oblique.

Besides the diaphragm, other muscle groups contribute to breathing. The diaphragm is the primary muscle responsible for breathing in oxygen and breathing out carbon dioxide. The other muscle groups that support this action include the intercostal muscles and the sternocleidomastoid muscles. The larynx and nasal pharynx are also crucial in breathing.

Gas exchange

Our respiratory system transports oxygen and carbon dioxide to our cells. The process takes place in millions of alveoli in our lungs. Oxygen moves into the alveoli and is taken up by the hemoglobin in red blood cells. As a result, our blood is oxygenated, and our carbon dioxide-rich blood returns to the heart and is pumped to the rest of our body. After the oxygen-rich blood reaches the tissues, we breathe it out.

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The lungs are responsible for supplying oxygen to our body, and the rate at which we do so is an excellent way to measure our energy use. For example, while resting, our lungs bring five to eight liters of air into our bodies. During exercise, we move more than 100 liters of air per minute, and three liters of oxygen can be drawn out of 26 gallons of air.

Our lungs are the primary organs responsible for delivering fresh oxygen to our cells, and they remove carbon dioxide and other waste gases. Air enters the lungs through the pharynx, larynx, and voice box and travels through the trachea, divided into two air passages called bronchi. Finally, the air in these passages passes through the trachea, a tube lined with tiny blood vessels.

Effects of breathing rate

During intense, short-duration physical training, the breathing rate will be elevated during the warm-up, peak during the set, and remain elevated post-workout. During aerobic fitness training, respiratory rates will also increase to a “steady state,” where oxygen supply and carbon dioxide expulsion match exercise demands. As these changes increase, the respiratory rate will continue to increase throughout the workout.

Breathing rate is measured in breaths per minute. To determine respiratory rate, you must observe a person’s chest rise and fall. A single breath consists of inhalation and exhalation, and you can measure it by counting breaths. This method helps you to understand how breathing works, as it relies on signals from the brain to respiratory muscles. In other words, breathing rate is an essential factor in exercise efficiency.

Patients with respiratory failure should be monitored for a significant range of respiratory rate variations. The absence of spontaneous ventilation should prompt controlled ventilation (CPV), also known as rescue breathing. The usual range of breathing rates is shown in table 4.8. The normal range is less than 8 breaths per minute for children and adults. Consequently, checking the respiratory rate in critically ill patients with poor regularity is essential.