Respiration and Common Cold

There are three factors that control respiration. These factors are able to sense the body's increased or decreased need for oxygen. The levels of oxygen, carbon dioxide and hydrogen ion concentration is the blood will trigger the body's respiration. This occurs when the chemoreceptors in the body sense the concentration of oxygen, carbon and carbon dioxide. This information is then relayed to the central chemoreceptors that are located in the medulla .

The level of carbon dioxide in the body can trigger an increase or decrease in hydrogen ions. If there is an increase in carbon dioxide there will be an increase in hydrogen ions. The body send out a signal to increase ventilation. The amount of hydrogen ions in the body can be measured using the pH scale. A pH lower than 7.35 indicates acidity and a pH higher than 7.45 indicates alkalinity. An increase in ventilation can help to decrease carbon dioxide levels and increase pH levels. If carbon dioxide levels remain elevated, the stimulus to increase ventilation will discontinue and pH levels will continue to decrease creating a more acidic environment.

The carotid and aortic arteries all contain chemoreceptors that help to monitor any changes in oxygen pressure levels in the arteries. These specific receptors are called peripheral chemoreceptors and they are used to send messages to the respiratory center to increase or decrease ventilation. If oxygen pressure falls below 60 mmHg the peripheral chemoreceptors will trigger the medulla to increase ventilation.

There are several upper respiratory tract disorder that can occur and affect respiration. The common cold can cause upper respiratory problems due to the rhinovirus invading the nasopharyngeal tract. Usually inflammation occurs in the mucous membranes and there is an increase in nasal secretions.

On average, an adult will typically have anywhere from two to four colds per year. Children will usually have twice the number of colds, from 4 to 12 per year. Most rhinovirus infections occur in the winter, however, they do also occur in the summer and during other times of the year.

The rhinovirus is most contagiouis during the first four days before the patient notices any cold symptoms. During this incubation period, the virus can be transmitted by touching contaminated surfaces or by coming into contact with an infected patient.