Gas Exchange

The majority of carbon dioxide in the body is carried in bicarbonate ions in the red blood cells. Ions are particles in the body that are electrically charged, either positively or negatively. Bicarbonate ions are types of ions formed when carbon dioxide enters the blood during diffusion and combines with water.

Bicarbonate ions in the blood carry carbon dioxide back to the lungs. There, the carbon dioxide diffuses into the alveoli. Regardless of how carbon dioxide returns to the lungs, it always leaves the body during exhalation.

The carbon dioxide transport pathway is the route that carbon dioxide takes when it leaves the cells of the body as a waste product, diffuses into the blood, and then moves from the blood into the alveoli of the lungs.

Carbon dioxide moves through the body in three ways: binding with hemoglobin. dissolving into the plasma. binding with bicarbonate ions.

During gas exchange, air comes into the body through the mouth or nose. It then travels into the left and right bronchial tubes, part of the pathway that feeds air from the nose and mouth down to the lungs. The lungs are two spongy structures in the chest that are responsible for breathing.

Inside the lungs, the bronchial tubes branch into smaller tubes, called bronchioles. Bronchioles are the smallest tubes in the airway that lead to the alveoli. The alveoli are tiny clusters of air-filled sacs. The exchange of gases occurs in the alveoli. Oxygen and carbon dioxide move back and forth between the alveoli and the capillaries that surround them. Capillaries are the smallest blood vessels of the circulatory system.

Respiration is the act of breathing air in and out of the body. Respiration is vital to human life and many other internal processes The respiratory system is the system within the body that is responsible for taking in oxygen and removing carbon dioxide to meet the health and energy requirements of the body.

Oxygen is a life-sustaining odorless gas in the air. Carbon dioxide is a waste product of respiration. The body needs to rid itself of carbon dioxide to stay healthy. Oxygen transport is the process that moves oxygen through the body after it is taken in.

The body is constantly working to maintain an ideal level of oxygen so its cells remain healthy. Oxygen uptake is the rate at which oxygen is taken in by the alveoli and used by the body. Oxygen uptake increases as the body requires more oxygen and an increased removal of carbon dioxide.

Oxygen uptake can be faster or slower, depending on different factors. For instance, when a person is exercising, his or her breathing rate increases, bringing more air into the body. Oxygen uptake in the alveoli increases because of the body's increased oxygen requirement.

Oxygen can also be carried throughout the body by plasma. Plasma is the yellowish liquid portion of the blood. It is a combination of water, sugar, proteins, and fat. Blood cells are carried around the body in this liquid.

Plasma is responsible for transporting the blood cells to deliver oxygen and collect carbon dioxide. The plasma in the blood also carries nutrients, proteins, and hormones. Hormones are substances that affect body processes, such as growth and development.

When gas exchange occurs in the lungs, oxygen moves from the alveoli into the blood in the capillaries. It is there that the blood fills with oxygen, making the blood oxygen-rich. The technical term for blood that has a lot of oxygen in it is oxygenated blood.Blood without much oxygen in it is deoxygenated blood.

Red blood cells are cells in the blood that transport oxygen and carbon dioxide into and out of the cells of the body. The red blood cells in the blood move throughout the body within the circulatory system.

Another way that carbon dioxide moves through the body is by dissolving into the plasma and binding with its proteins. Carbon dioxide dissolves into the plasma as a result of a difference in concentration between the plasma and the body's cells. When there is a lower concentration of carbon dioxide in the plasma, carbon dioxide moves from the body's cells into the plasma, because there is more room for it there.

Roughly 10% of the carbon dioxide in the body is transported by binding with plasma.

Carbon dioxide is a waste product of respiration. The body needs to rid itself of carbon dioxide to stay healthy. Having too much carbon dioxide trapped in the body can harm the cells. The level of carbon dioxide in the blood helps regulate respiration. When carbon dioxide increases, nerves in the alveoli send signals to the brain to increase the breathing rate to remove the gas from the body. Nerves are bundles of fibers through which signals pass between the brain and other parts of the body. The brain is the part of the body responsible for controlling the nerves and other functions.

When the brain receives a signal that the body contains too much carbon dioxide, it causes the body to exhale and expel the carbon dioxide.

Oxygen can be carried throughout the body and diffused to the cells through two particular substances found in the blood: Hemoglobin Plasma

You will next learn about the hemoglobin and plasma oxygen-transportation processes.

Diffusion is the process of a concentrated substance moving into an area of lower concentration. Diffusion occurs as oxygen and carbon dioxide move into and out of cells in the lungs. After oxygen comes into the body and moves into the lungs and alveoli, it is diffused into the blood and then moves to other parts of the body. Diffusion is made possible by the alveolar-capillary membrane, which is the layer of cells through which gases are exchanged between the alveoli and the surrounding capillaries.

Diffusion occurs again when blood returns from the body and flows into the lungs through the tiny capillaries that surround the alveoli. Carbon dioxide diffuses through the thin cell layer of the air-filled sacs and is released during exhalation.

After oxygen leaves the hemoglobin to enter the cells of the body, the hemoglobin is free to bind with carbon dioxide. Once carbon dioxide binds with the hemoglobin, it travels through the blood vessels back to the lungs in blood whose oxygen level is low because it has just been circulated around the body.

Finally, the carbon dioxide that has traveled back the lungs in the blood is exhaled.

One of the ways that oxygen-rich blood from the lungs can travel through the body is via hemoglobin.

Hemoglobin is a protein in red blood cells that assists with the respiration process by binding with and carrying oxygen. A protein is one of the components that make up living cells. Proteins are involved in many body functions.

When people inhale, or "breathe in," they take in oxygen. The oxygen travels to the blood after it is inhaled. At the same time, carbon dioxide is removed from the blood and exhaled through the mouth or nose. Gas exchange is the process of exchanging oxygen and carbon dioxide between the respiratory system and the circulatory system. The circulatory system is the body system that transports blood, nutrients, and oxygen to all the cells in the body. Cells are the structural units of all living things.

The circulatory system consists of the heart, the blood, and blood vessels. Blood vessels are tubes that carry blood to all parts of the body, and back to the heart, in a continuous loop. Gas exchange is crucial for life, because the body needs oxygen and must get rid of carbon dioxide. Too much carbon dioxide in the body can damage cells.

Oxygen binds with, or attaches to, the hemoglobin as blood passes through the lungs. As the hemoglobin travels through the rest of the body, it releases oxygen to all the cells. The hemoglobin is then free to attach to carbon dioxide as it moves away from the cells.

The hemoglobin brings carbon dioxide back to the lungs, where it diffuses into the alveoli. The carbon dioxide is then exhaled out of the body.

The blood that flows into the lungs and past the alveoli is blood that has just circulated around the body. This blood is now low in oxygen, because the oxygen was diffused into the cells of the body during circulation. Now the concentration of oxygen is higher in the alveoli than in the bloodstream. As a result, new oxygen diffuses into the blood. After the blood is replenished with new oxygen, it travels throughout the body. Just as oxygen diffuses into the blood from the alveoli because of a difference in concentration, oxygen diffuses from the blood into the cells.

This process is important, because when the cells of the body are deprived of oxygen, they can be damaged or die. Oxygen must be carried properly in the blood to sustain the overall health and functioning of the body.