- Apply the rules of medical language to build, analyze, spell, pronounce, abbreviate, and define terms as they relate to the cardiovascular system
- Identify meanings of key word components of the cardiovascular system
- Categorize diagnostic, therapeutic, procedural or anatomic terms related to the cardiovascular system
- Use terms related to the cardiovascular system
- Use terms related to the diseases and disorders of the cardiovascular system
Cardiovascular System – Heart Word Parts
Click on prefixes, combining forms, and suffixes to reveal a list of word parts to memorize for the cardiovascular system – Heart.
Introduction to the Heart
The heart is a fist-sized vital organ that has one job: to pump blood. If one assumes an average of 75 beats per minute, a human heart would beat approximately 108,000 times in one day, more than 39 million times in one year, and nearly 3 billion times during a 75-year lifespan. At rest, each of the major pumping chambers of the heart ejects approximately 70 mL blood per contraction in an adult. This would be equal to 5.25 liters of blood per minute and approximately 14,000 liters per day. Over one year, that would equal 10,000,000 liters of blood sent through roughly 100,000 km of blood vessels. In order to understand how that happens, it is necessary to understand the anatomy and physiology of the heart.
Watch this video:
Media 9.1. The Heart, Part 1 – Under Pressure: Crash Course A&P #25 [Online video]. Copyright 2015 by CrashCourse.
Cardiovascular System – Heart Medical Terms
Anatomy of the Heart
The human heart is located within the thoracic cavity, between the lungs in the space known as the mediastinum. Figure 9.1 shows the position of the heart within the thoracic cavity. Within the mediastinum, the heart is separated from the other mediastinal structures by a tough membrane known as the pericardium, or pericardial sac, and sits in its own space called the pericardial cavity. The , which carry blood to and from the heart, are attached to the superior surface of the heart, which is called the base. The base of the heart is located at the level of the third costal cartilage. The inferior tip of the heart, the apex, lies just to the left of the sternum between the junction of the fourth and fifth ribs.
- On the diagram below (Figure 9.1), locate the mediastinum, the pericardial cavity, the base of the heart and the apex of the heart.
- Locate the largest vein in the body superior vena cava.
Membranes and Layers of the Heart Walls
The heart and the are surrounded by a membrane known as the pericardium or pericardial sac. The pericardium consists of two distinct sub layers:
- The sturdy outer fibrous pericardium is made of tough, dense connective tissue that protects the heart and holds it in position.
- Separated by the pericardial cavity and containing pericardial fluid the inner pericardium consists of two layers:
- the outer parietal pericardium, which is fused to the fibrous pericardium.
- the inner visceral pericardium, or epicardium, which is fused to the heart and forms the outer layer of the heart wall.
The walls of the heart consist of three layers:
- The outer epicardium, which is another name for the visceral pericardium mentioned above.
- The thick, middle myocardium, which is made of muscle tissue and gives the heart its ability to contract.
- The inner endocardium, which lines the heart chambers and is the main component of the heart valves.
- Look at Figure 9.2 below, and name the layers of the heart wall and surrounding membranes, starting with the innermost layer.
- As shown on the diagram, suggest why is the myocardium layer is thicker than the endocardium layer?
Internal Structures of the Heart
The heart consists of four chambers:
- The upper chambers are the right and left atria (singular: atrium).
- The lower chambers are the right and left ventricles.
The interventricular septum is a muscular wall that separates the right and left ventricles. The interatrial septum separates the right and left atria.
The atrium and ventricle on each side of the heart are separated by an atrioventricular (AV) valve:
- The right AV valve, or tricuspid valve, separates the right atrium and right ventricle.
- The left AV valve, or bicuspid valve, separates the left ventricle and the left atrium. This valve is also called the mitral valve.
There are also two semilunar valves:
- The pulmonary valve separates the right ventricle from the pulmonary trunk.
- The aortic valve separates the left ventricle from the aorta.
Anatomy Labeling Activity
Physiology of the Heart
- Circulation through the heart: Blood is pumped by the heart in order to provide oxygen and nutrients to every cell in the body.
- The heart as an organ (coronary blood supply): The heart is an organ, made of cells and tissues which require their own blood supply.
- The heart’s electrical conduction system: The heart is able to independently generate and transmit instructions to the myocardium, in order to make it contract and pump the blood.
Circulation Through the Heart: The Heart as a Pump
The heart pumps blood to two distinct but linked circulatory systems called the pulmonary and systemic circuits. The pulmonary circuit transports blood to and from the lungs, where it picks up oxygen and drops off carbon dioxide. The systemic circuit transports freshly oxygenated blood to virtually all of the tissues of the body and returns relatively deoxygenated blood and carbon dioxide to the heart to be sent back to the pulmonary circulation.
- Blood that is carrying carbon dioxide and waste products from the body tissues is returned to the right atrium via the and the .
- From the right atrium, the deoxygenated blood moves through the tricuspid valve into the right ventricle.
- The right ventricle pumps deoxygenated blood through the pulmonary valve into the , which splits into the right and left pulmonary arteries, leading toward the lungs. These arteries branch many times before reaching the pulmonary capillaries, where gas exchange occurs: carbon dioxide exits the blood and oxygen enters. The pulmonary arteries are the only arteries in the postnatal body that carry deoxygenated blood. Did you notice that they are often colored blue on diagrams of the heart?
- Freshly oxygenated blood returns from the lungs to the left atrium via the pulmonary veins. These veins are the only veins in the body that carry highly oxygenated blood, and are often colored red on heart images.
- From the left atrium, the blood moves through the mitral valve into the left ventricle.
- The left ventricle pumps blood through the aortic valve, into the aorta, delivering blood to all parts of the body.
Heart Terms not Easily Broken into Word Parts
Many terms and phrases related to the cardiovascular system- heart are abbreviated.
Learn these common abbreviations by expanding the list below.
Diseases and Disorders
The heart of a well-trained athlete can be considerably larger than the average person’s heart. This is because exercise results in an increase in muscle cells called . Hearts of athletes can pump blood more effectively at lower rates than those of non-athletes. However, when an enlarged heart is not the result of exercise, it may be due to hypertrophic cardiomyopathy. The cause of an abnormally enlarged heart muscle is unknown, but the condition is often undiagnosed and can cause sudden death in apparently otherwise healthy young people (Betts, et al., 2021).
Other types of cardiomyopathy include:
- Dilated cardiomyopathy, which also has an unknown cause and is seen in people of any age. In this disorder, one of the ventricles of the heart is larger than normal.
- Arrhythmogenic cardiomyopathy, an inherited condition which results in irregular heart rhythms.
- Restrictive cardiomyopathy, which is a complication of other conditions which cause the myocardium to scar or stiffen (Centers for Disease Control and Prevention, 2019).
Cardiomyopathy may also be caused by myocardial infarctions, myocardial infections, pregnancy, alcohol or cocaine abuse, autoimmune and endocrine diseases. Because the myocardium is responsible for contracting and pumping blood, patients with cardiomyopathy experience impaired heart function which may lead to heart failure. (Centers for Disease Control and Prevention, 2019). To learn more about cardiomyopathy visit the CDC’s cardiomyopathy web page.
Heart failure is defined as the inability of the heart to pump enough blood to meet the needs of the body. It is also called congestive heart failure (CHF). This condition causes swelling in the lower extremities and shortness of breath, due to a buildup of fluid in the lungs. It may be caused by cardiomyopathy and it may lead to and heart valve disorders (Heart & Stroke, n.d.). To learn more, visit the Heart & Stroke’s congestive heart failure web page.
Valvular Heart Disease
The four heart valves open and close at specific times during the cardiac cycle, in order to ensure that blood flows in only one direction through the heart. This requires that these valves open and close completely. Infections such as rheumatic disease or bacterial endocarditis can affect the heart valves and result in scar tissue formation which interferes with valve function. Other causes of heart valve disease include: congenitally malformed valves, autoimmune diseases, and other cardiovascular diseases such as aortic aneurysms and atherosclerosis (Centers for Disease Control and Prevention, 2019a).
Heart valve disease may be asymptomatic, or cause , , fatigue and other symptoms. It is often detected when a is heard through a stethoscope (Centers for Disease Control and Prevention, 2019a).
- Mitral Valve Prolaspse
- The mitral (bicuspid) valve is diseased or malformed and is not able to close completely, allowing the regurgitation of blood back into the left atrium during systole. Because some of the blood goes back into the atrium, insufficient blood is pumped out of the ventricle into the systemic circulation. This inability to close properly and the resulting regurgitation may also be found in other heart valves (Centers for Disease Control and Prevention, 2019a).
- Aortic Stenosis
- The aortic valve is narrowed and hardened, preventing it from opening fully and allowing sufficient blood to travel to the systemic circulation. Any heart valve can be stenosed, but this disorder most often affects the aortic valve (Centers for Disease Control and Prevention, 2019a).
Visit the CDC’s page on valvular heart disease to learn more.
An aneurysm is a defect in the wall of an artery in which the wall becomes thin and weak and starts to balloon out as blood pulses against the vessel wall. This can happen to any artery and even to the myocardial walls. Aneurysms sometimes occur in the portion of the aorta that is in the thorax (see Figure 9.4). If these aneurysms start to leak between layers of the vessel wall, the condition is known as aortic dissection. If an aortic or cardiac aneurysm bursts, there is sudden, massive internal bleeding (Centers for Disease Control and Prevention, 2019b).
People who smoke, have , , and/or have an increased risk of developing aneurysms. Having a family history of aneurysms or certain genetic diseases may also increase a person’s risk of developing an aneurysm.
Aneurysms are often asymptomatic and may be detected incidentally during diagnostic tests that are being done for other reasons. They are sometimes repaired surgically and sometimes treated with medications such as (Centers for Disease Control and Prevention, 2019b; Tittley, n.d.). Visit the Society for Vascular Surgery’s page on thoracic aortic aneurysms to learn more.
Fetal circulation is different from circulation. There are 2 extra openings in the fetal heart, the and the , which allow blood circulation that bypasses the immature fetal lungs. The fetal blood is reoxygenated by the mother’s lungs and transported between mother and fetus via the placenta. These two openings usually close around the time of birth (Betts, et al., 2021).
Septal defects are commonly first detected through . Unusual heart sounds may be detected because blood is not flowing and valves are not closing correctly. Medical imaging is ordered to confirm or rule out a diagnosis. In many cases, treatment may not be needed.
- Patent ductus arteriosus is a congenital condition in which the ductus arteriosus fails to close. If untreated, the condition can result in congestive heart failure.
- Patent foramen ovale is one type of atrial septal defect (ASD), due to a failure of the hole in the to close at birth.
- As much as 20 – 25 percent of the general population may have a patent foramen ovale, most have the benign, asymptomatic version but in extreme cases a surgical repair is required to close the opening permanently.
- Tetralogy of Fallot is a congenital condition that may also occur from exposure to unknown environmental factors; it occurs when there is an opening in the caused by blockage of the pulmonary trunk, normally at the pulmonary semilunar valve. This allows blood that is relatively low in oxygen from the right ventricle to flow into the left ventricle and mix with the blood that is relatively high in oxygen.
- Symptoms include a distinct heart murmur, low blood oxygen percent saturation, , , , and in children, difficulty in feeding or failure to grow and develop.
- It is the most common cause of following birth. Other heart defects may also accompany this condition, which is typically confirmed by imaging.
- In the case of severe septal defects, including both tetralogy of fallot and patent foramen ovale, failure of the heart to develop properly can lead to a condition commonly known as a blue baby. Regardless of normal skin pigmentation, individuals with this condition have an insufficient supply of oxygenated blood, which leads to , especially when active (Betts, et al., 2021).
Diseases of the Coronary Circulation
Coronary Artery Disease (CAD)
Coronary artery disease occurs when the buildup of in the coronary arteries obstructs the flow of blood and decreases of the vessels. This condition is called . As the disease progresses and coronary blood vessels become more and more narrow, cells of the myocardium become , which causes symptoms of , in some patients. If untreated, coronary artery disease can lead to MI.
The image below shows the blockage of coronary arteries on an (Betts, et al., 2021).
CAD is progressive and chronic. Risk factors include smoking, family history, , obesity, diabetes, high alcohol consumption, lack of exercise, stress, and . Treatments may include medication, changes to diet and exercise, angioplasty with a balloon catheter, insertion of a stent, or coronary artery bypass graft (CABG) (Betts, et al., 2021).
- Angioplasty is a procedure in which the is mechanically widened with a balloon. A specialized catheter with an expandable tip is inserted into a blood vessel in the arm or leg, and then directed to the site of the occlusion. At this point, the balloon is inflated to compress the plaque material and to open the vessel to increase blood flow. Once the balloon is deflated and retracted, a stent consisting of a specialized mesh is typically inserted at the site of occlusion to reinforce the weakened and damaged walls and prevent re-occlusion.
- Coronary bypass surgery (Coronary artery bypass graft CABG) is a surgical procedure which grafts a replacement vessel obtained from another part of the body to bypass the occluded area. (Betts, et al., 2021).
Myocardial infarction (MI) is the medical term for a heart attack.
An MI normally results from a lack of blood flow to a region of the heart, resulting in death of the cardiac muscle cells. An MI often occurs when a coronary artery is blocked by the buildup of atherosclerotic plaque. It can also occur when a piece of an atherosclerotic plaque breaks off and travels through the coronary arterial system until it lodges in one of the smaller vessels. MIs may be triggered by excessive exercise, in which the partially occluded artery is no longer able to pump sufficient quantities of blood, or severe stress, which may induce spasm of the smooth muscle in the walls of the vessel (Betts, et al., 2021).
In the case of acute MI (AMI), there is often sudden pain beneath the sternum (retrosternal pain) called angina pectoris, often radiating down the left arm in males but not in female patients. Other common symptoms include , , nausea and vomiting, , anxiety, and . Many of the symptoms are shared with other medical conditions, including anxiety attacks and simple indigestion, so differential diagnosis is critical (Betts, et al., 2021).
An MI can be confirmed by examining the patient’s .
Other diagnostic tests include:
- Common blood tests indicating an MI include elevated levels of and , both of which are released by damaged cardiac muscle cells (Betts, et al., 2021).
MIs may induce dangerous heart rhythms and even cardiac arrest. Important risk factors for MI include coronary artery disease, age, smoking, high blood levels of , low levels of , , , obesity, lack of physical exercise, chronic kidney disease, excessive alcohol consumption, and use of illegal drugs (Betts, et al., 2021).
Diseases of the (Electrical) Conduction System
The heart’s natural pacemaker, the sinoatrial (SA) node initiates an electrical impulse 60-90 times per minute in a resting adult. This impulse travels through the heart’s conduction system in order to ensure a smooth, coordinated pumping action. This electrical activity can be detected and recorded through the skin using an . may occur when the SA node fails to initiate an impulse, or when the conduction system fails to transmit that impulse through the heart.
In the event that the electrical activity of the heart is severely disrupted, cessation of electrical activity or fibrillation may occur. In fibrillation, the heart beats in a wild, uncontrolled manner, which prevents it from being able to pump effectively.
- Atrial fibrillation is a serious condition, but as long as the ventricles continue to pump blood, the patient’s life may not be in immediate danger.
- Ventrical fibrillation is a medical emergency that requires life support, because the ventricles are not effectively pumping blood, left untreated ventricular fibrillation may lead to brain death.
The most common treatment is defibrillation which uses special paddles to apply a charge to the heart from an external electrical source in an attempt to establish a normal sinus rhythm. A defibrillator effectively stops the heart so that the SA node can trigger a normal conduction cycle. External automated defibrillators (EADs) are being placed in areas frequented by large numbers of people, such as schools, restaurants, and airports. These devices contain simple and direct verbal instructions that can be followed by non-medical personnel in an attempt to save a life (Betts, et al., 2021).
Abnormal Heart Rates
Bradycardia is the condition in which resting adult heart rate drops below 60 bpm. a client exhibiting symptoms such as weakness, fatigue, dizziness, , chest discomfort, palpitations or respiratory distress may indicate that the heart is not providing sufficient oxygenated blood to the tissues. If the patient is not exhibiting symptoms then bradycardia is not considered clinically significant. The term relative bradycardia may be used with a patient who has a HR in the normal range but is still suffering from these symptoms. Most patients remain asymptomatic as long as the HR remains above 50 bpm.
Tachycardia is the condition in which the resting rate is above 100 bpm. Tachycardia is not normal in a resting patient and may be detected in pregnant women or individuals experiencing extreme stress. Some individuals may remain , but when present, symptoms may include dizziness, shortness of breath, rapid pulse, heart palpitations, chest pain, or syncope. Treatment depends upon the underlying cause but may include medications, , , or surgery (Betts, et al., 2021).
A heart block refers to an interruption in the normal conduction pathway. Heart blocks are generally named after the part of the conduction system that is causing the problem. For example, bundle branch blocks occur within either the left or right atrioventricular bundle branches.
Medical Terms in Context
Medical Specialties and Procedures Related to the Heart
Cardiologists and Cardiovascular Surgeons
Cardiologists are medical doctors that specialize in diagnosing and treating heart disease non-invasively. Cardiovascular/thoracic surgeons provide surgical treatments for the heart and other thoracic organs (American Medical Association, 2020). To learn more about these specialists please visit the AMA’s Specialty Profiles web page.
Cardiology Technologists complete a college training program and perform diagnostic tests such as , stress testing, Holter monitor testing, ambulatory blood pressure testing, as well as monitoring and programming (American College of Cardiology). Please visit the American College of Cardiology webpage for more information.
Cardiovascular perfusionists complete a college training program and are responsible for operation of the heart-lung bypass machine during open heart surgery. They also monitor the patient’s vitals, administering IV fluids, and other drugs (Mayo Clinic). Please visit the Mayo Clinic: Cardiovascular Perfusion page for more information.
American Medical Association. (2020). Specialty Profiles. https://freida.ama-assn.org/specialty/cardiovascular-disease-im
American College of Cardiology (2020). Home. https://www.acc.org/#sort=%40commonsortdate%20descending
Centers for Disease Control and Prevention. (2019). Cardiomyopathy. CDC. https://www.cdc.gov/heartdisease/cardiomyopathy.htm
Centers for Disease Control and Prevention. (2019a). Valvular heart disease. CDC. https://www.cdc.gov/heartdisease/valvular_disease.htm
Centers for Disease Control and Prevention. (2019b). Aortic aneurysm. CDC. https://www.cdc.gov/heartdisease/aortic_aneurysm.htm
[CrashCourse]. (2015, July 6). The heart, part 1 – under pressure: Crash course A&P #25 [Video]. YouTube. https://youtu.be/X9ZZ6tcxArI
Heart & Stroke. (n.d.). Heart failure. Heart and Stroke Foundation. https://www.heartandstroke.ca/heart/conditions/heart-failure
Mayo Clinic. (n.d.). Cardiovascular perfusion. Mayo Clinic. https://college.mayo.edu/academics/explore-health-care-careers/careers-a-z/cardiovascular-perfusionist/#:~:text=Cardiovascular%20perfusionists%20are%20responsible%20for,patient’s%20circulatory%20or%20respiratory%20function
Eagleton, M. J. (n.d.). Thoracic aortic aneurysms. Retrieved from Society for Vascular Surgery: https://vascular.org/
Unless otherwise indicated, this chapter contains material adapted from Anatomy and Physiology (on OpenStax), by Betts, et al. and is used under a a CC BY 4.0 international license. Download and access this book for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction.
The number of times the heart contracts in one minute.
The great vessels include the superior vena cava, inferior vena cava, aorta and pulmonary trunk.
The part of each great vessel (aorta, pulmonary trunk, inferior vena cava, superior vena cava) that connects to the base of the heart
You may recall that serous membranes throughout the body are folded back on themselves, which results in a double-layered membrane separated by serous fluid. The serous membrane surrounding the lungs is called pleura, The serous membrane surrounding the abdominopelvic organs is called peritoneum.
One of the two largest veins in the body. It carries deoxygenated blood from the head and upper extremities back to the heart
One of the two largest veins in the body. It carries deoxygenated blood from the torso and legs back to the heart.
very large artery referred to as a trunk, a term indicating that the vessel gives rise to several smaller arteries
excessive development; increase in the size of cells but not the number of cells
High blood pressure
absence of a regular heart rhythm
an abnormal heart sound
higher than normal levels of cholesterol in the blood
a hardening of the arteries that involves the accumulation of plaque
class of medications used to treat high blood pressure
Pertaining to after birth
opening between right and left atria, which is normal in the fetal heart
connection between pulmonary trunk and aorta in the fetal heart
listening to the heart using a stethoscope
the wall separating the right and left atria.
The wall of myocardium that separates the right and left ventricles
a disorder in which too many red blood cells are produced
broadening of the nails and exaggerated curvature of the nails
abnormal condition of blue (bluish colour, lips and nail beds) caused by deoxygenation.
process of using sound to record the heart
a fatty material including cholesterol, connective tissue, white blood cells, and some smooth muscle cells
the ability of the blood vessels to dilate and constrict as needed
ischemia is a condition in which cells receive insufficient amounts of blood and oxygen
an x-ray of the coronary blood vessels using a special catheter and an injection of dye
Excessive fat in the blood
A myocardial infarction without symptoms. The patient may not know that they are having an MI.
A feeling in the chest that may be caused by an irregular heart rhythm
ECG/EKG both these abbreviations mean electrocardiogram or a recording of the electrical impulses in the heart
Computerized tomography: a special 3-dimensional x-ray, also called CAT=Computerized Axial Tomography
Magnetic Resonance Imaging: Highly detailed images produced using a strong magnet and radio waves
an enzyme that catalyzes the conversion of creatine to phosphocreatine, consuming ATP
the regulatory protein for muscle contraction
low-density lipoprotein, often referred to as 'bad' cholesterol
high-density lipoprotein, often referred to as 'good' cholesterol
An endocrine system disorder in which the pancreas does not produce insulin or the cells of the body do not respond to insulin. This results in high levels of glucose in the blood.
a complete absence of electrical activity in the heart, which is represented by a flat line on ecg
instrument used to record electrical activity within the heart
pertaining to without symptoms
ICD, an electronic implant that provides an automatic shock to convert a dangerous heart rhythm to a normal heart rhythm
Using extreme heat or extreme cold to destroy cells in part of the heart which were causing abnormal rhythms.
process of recording electrical activity of the heart
An electronic implant that initiates a heart beat