The respiratory or pulmonary system performs the important functions of supplying oxygen (O2) during inhalation, removing carbon dioxide (CO2) during exhalation, and adjusting the acid-base balance (pH) of the body by removing acid-forming CO2.
All humans and animals require oxygen to carry out cellular processes of energy transformation essential for life. During cellular metabolism, oxygen is consumed when nutrients such as protein, carbohydrate and fat are oxidized, and carbon dioxide is produced as a gaseous waste product. Collectively, the processes whereby oxygen is taken up from the atmosphere, delivered to body cells and consumed, and the processes of producing carbon dioxide and delivering it to the lungs for excretion into the atmosphere constitute respiration.
Processes of respiration fall into one of three categories: external respiration, gas transport, and internal respiration. External respiration refers to mechanisms by which a person obtains oxygen from the external environment and eliminates carbon dioxide into the external environment. Gas transport refers to mechanisms used to distribute oxygen to and remove carbon dioxide from cells. Internal respiration refers to the chemical reactions of cellular metabolism in which oxygen is consumed and carbon dioxide is produced.
Gas exchange between the air in the lung and the blood is a process of simple diffusion. A gas diffuses from a region of higher concentration to a region of lower concentration, or, from an area of higher partial pressure to an area of lower partial pressure. Partial pressure is simply a way of expressing the concentration of gas molecules.
Blood transports gases to and from the body’s cells. The respiratory system supplies oxygen to the blood and removes carbon dioxide from the blood. At the beginning of inspiration, the thoracic cavity is enlarged by contraction of the diaphragm and the external intercostal muscles. Expiration begins when the inspiratory muscles relax. The diaphragm returns to its resting dome shape, decreasing thoracic and intrapulmonic volume.
What are some common measurements extracted when we measure respiration and how are these measurements acquired and analyzed?
Pulmonary Airflow — The pulmonary airflow analysis uses a calibrated airflow signal from a pneumotach transducer, of which there are many types for various airflow applications.
Compliance and Resistance Analysis is measured on a breath-by-breath basis by diving tidal volume by change in pressure between the exhale start and inhale start locations of the breath.
Respiratory Gas Analysis uses the BIOPAC O2100C and CO2100C amplifier modules for measuring and analyzing oxygen and carbon dioxide content.
Anaerobic Threshold uses AcqKnowledge software to establish a ratio of inspired volume and VO2 consumption and to integrate the air flow signal to obtain total inspired volume in real time.
Respiratory Exchange Ratio is determined by dividing VCO2 produced by VO2 consumed. An automated script for computing RER is available via download from BIOPAC.
Respiration, Gas Analysis, Pulmonary Function, and Exercise Physiology for Research applications and Education curriculum are available.
Respiratory Cycle and Exercise Physiology are supported by the new BSL HOME Practical Lab Kit, enabling students to keep abreast of curriculum demands while safely distanced.
We invite you to sign up for BIOPAC’s upcoming free How to Record Great Respiration Data webinar on August 27, 2020. You may also watch archived webinar events on demand by visiting our Webinars page.
BIOPAC offers a wide array of wired and wireless equipment that can be used in your research. To find more information on solutions for recording and analyzing signals such as ECG, heart rate, respiration, and more using any platforms mentioned in this blog post, you can visit the individual application pages on the BIOPAC website.
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