Anatomy and Physiology

With approximately 13% of the CBET exam coming from anatomy and physiology, the untrained eye may believe this will be the easiest portion of the certification exam. My take on this portion of the exam is that this may be one of the hardest sections. The difficulty lies in the portion of time you spend studying anatomy and physiology. With only 20 questions to assess your knowledge of this subject area, it becomes apparent your knowledge base must be very broad.

In preparing to take the CBET exam, all organ systems must be reviewed. The organ systems of the body are: integumentary, skeletal, muscular, nervous, endocrine, respiratory, circulatory, lymphatic, digestive, urinary, and reproductive. An exam question could come from any or all of these organ systems. The depth of a question in one of these areas could prove very difficult, as many working BMETs do not go as deeply into these areas when maintaining the equipment as some certification questions may.

So, what is the best way to study this area for the test? I would suggest you think about what systems correlate to the equipment most general biomed techs deal with on a day-to-day basis. With this in mind, several systems should be obvious where study time should be allocated. Probably the most obvious areas will be cardiovascular or circulatory and respiratory. Problems with this study method are apparent as the duties of a BMET can vary widely from facility to facility. Also, in larger facilities many biomeds begin their careers specializing in different areas such as the OR, respiratory therapy, or other areas in the hospital. This fact makes it all the more difficult to know where to target your study time. In some respect, the general biomed tech at a smaller facility may be better prepared as these techs are exposed to all areas of the hospital on a more regular basis.

Whether you work in a large facility or a smaller one, if you specialize in certain departments or work in all departments of the hospital you will definitely see questions on the test about the circulatory/cardiovascular system. This one area could take all 20 questions and still not fully assess your knowledge of the subject area; however, the questions will not cover just this area.

Heart Facts

Before taking your certification exam, you should be very comfortable with several areas of the cardiovascular system. First, you must know blood flow through the body. This begins with blood entering the heart from the superior and inferior vena cava, which delivers deoxygenated blood into the right atrium of the heart. Blood flows from the right atrium through the atrioventricular valve—or tricuspid valve—to the right ventricle. The right ventricle pumps blood to the lungs for oxygenation through the pulmonary or semilunar valve and the pulmonary arteries. Blood returns to the heart from the lungs via the pulmonary veins to the left atrium. The left atrium pumps blood into the left ventricle through the bicuspid or mitral valve. Blood is then pumped from the left ventricle through the aortic semilunar valve to the aorta, which distributes blood into the artery system for delivery throughout the body. Coronary arteries that carry oxygenated blood to the heart muscle or myocardium are attached just beyond the aortic valve.

Blood flow in the body begins with flow through the aorta to the arteries, to arterioles, to capillaries, to venules, to veins, and back to the heart via the inferior and superior vena cava with deoxygenated blood. As stated, veins carry deoxygenated blood back to the heart, so it stands to reason that arteries carry oxygenated blood from the heart to the tissue and cells of the body. This holds true except for the pulmonary artery and pulmonary vein. It is usually stated that arteries carry oxygenated blood and veins carry deoxygenated blood, but actually veins carry blood to the heart and arteries carry blood away from the heart.

When your study turns to the respiratory system, please do not forget this is a section of anatomy and physiology. I say this because so many test takers think of the lungs as the respiratory system. You must remember anatomy and physiology is defined as the structure and function of the body. With this in mind, the structure of respiratory organs begins with the nasal cavity, pharynx, glottis, larynx, trachea, bronchi, bronchioles, and alveoli, in that order. The function of these organs is to carry air to the alveoli for gas exchange deep within the lungs, except for the larynx, which has the function of producing sound.

The Mechanics of Breathing

During your study, do not overlook the mechanics of breathing. You should be knowledgeable about the procedure—the diaphragm creating a negative pressure in the thoracic cavity, which allows atmospheric pressure to push air into the lungs. The relaxation of the diaphragm will force the air out of the lungs. The rate at which this occurs is controlled by the respiratory center, which is located in a part of the brain called the medulla oblongata. This is a prime example of what I feel is such a difficult portion to prepare for in your certification studies. Everything is so interdependent and tied to one another that it is extremely difficult to know where test questions may come from.

Questions about the respiratory system have classically come from the pulmonary function analyzer. You need to study information about lung capacities before you take the CBET exam. Tidal volume, or TV, is about 500 mL and is the volume of air that is breathed in and out during normal breathing. Other volumes include IRV (3,100 mL), which is inspiratory reserve volume, ERV (1,400 mL), which is expiratory reserve volume, and RV (1,000 mL), which is residual volume. Many questions such as these have been noted on past CBET exams.

No discussion on the respiratory system would be complete without a little chemistry. The respiratory system’s function is to take oxygen to cells and remove carbon dioxide. Hemoglobin in the red blood cells contains iron, which has a mild attraction to oxygen and combines easily. When hemoglobin combines in the lungs with oxygen, it becomes oxyhemoglobin, and this is how oxygen is transported to the cells of the body. Oxyhemoglobin readily gives up its oxygen when exposed to a warmer, more acidic environment found in areas of tissue that are releasing carbon dioxide. Hemoglobin then picks up the carbon dioxide, which is referred to as carb-aminohemoglobin, for expulsion to the atmosphere during exhalation. This entire function is called internal respiration and external respiration. Internal respiration is the gas exchange between the blood and the cells, and external respiration is the gas exchange that occurs in the lungs.

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John Noblitt, BS, CBET, is the BMET program director at Caldwell Community College and Technical Institute, Hudson, NC. For more information, contact .