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Erik Helms

Program Director

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Respiratory and Circulatory System

Respiratory System

Each cell of the body requires a regular supply of oxygen in order to stay alive. Because the body cannot store oxygen as it does food and water, we must continually breathe oxygen into the lungs. Respiration is the process of taking in oxygen and giving off carbon dioxide. The respiratory system is a collection of involved in this organs process. Basically, the system is made up of the lungs (A), bronchial tubes (B), nose (C), mouth (D), windpipe (E), and diaphragm (F). When you take a breath, the diaphragm moves down and the chest moves out drawing air into the lungs. This is called inhalation. The air we inhale contains approximately 21% oxygen. In the lungs, Oxygen is absorbed into the bloodstream and circulated throughout the body. When the diaphragm moves up, air exits the lungs (exhalation). Carbon dioxide is released in the exhaled air. Not all of the oxygen is used by the body in the breathing process. Exhaled air contains about 16 - 17% oxygen. When this air is delivered during rescue breathing, there is still enough oxygen to support life.

Circulatory System

The function of the circulatory system is to use the blood stream to deliver oxygen and nutrients to the body tissues and remove waste products from them. The driving force of the system is the heart (A). Special tissue runs throughout the heart that is capable of creating and conducting electric current. This electric current triggers the rhythmic mechanical contractions that create the flow of blood through the body's blood vessels and heart (circulation). Large vessels called arteries Carry oxygenated blood from the heart to body tissues.


Capillaries are where oxygen, nutrients and waste products are exchanged and where arteries connect to veins to return used blood back to the heart. From there, the used blood is sent to the lungs where carbon dioxide is released and fresh oxygen picked up. The fresh blood is returned to the heart and the cycle repeats. The body cannot survive when circulation stops. Brain tissue is especially sensitive to a lack of oxygen. External chest compressions combined with rescue breathing (CPR) is essential for providing blood flow to vital organs during cardiac arrest. Immediate CPR can double or triple a victim's chance of survival.

Unfortunately, the majority of cardiac arrest survivors remain in a coma for varying lengths of time and full brain recovery is rare.