Some consider it to be synonymous with circulatory system but this is not entirely accurate. The reason is the latter also includes the lymph vessels and lymph nodes which are not part of the cardiovascular system.
Knowledge of the structure of the cardiovascular system and medical terms pertaining to the different tests and procedures for evaluating it complement each other. In addition, acquaintance with the basic anatomy of blood vessels supplements the understanding of the system as a whole as well as some of the different diseases that affect it.
Cardiovascular Anatomy Medical Terminology
Arterial – Of or pertaining to an artery or arteries.
Arterial bed – Is the network of blood vessels on a whole within an organ or other structure of the body that carries blood to the tissues that comprise it. It forms from the branching of one or more larger arteries distal to entry into the structure. The branches include the arterioles.
Arteries – Are blood vessels which carry blood from the heart to the tissues. The aorta is the largest artery in the body. It arises from the left ventricle and branches into smaller arteries to provide blood flow to all regions of the body except the lungs. The two carotid arteries, right and left, and there branches carry blood to the brain. Coronary arteries provide blood flow to the heart muscle.
The pulmonary trunk is the large artery that arises from the right ventricle. It branches into the right and left pulmonary arteries which transport oxygen depleted blood from the right ventricle to the lungs. The smaller divisions (pulmonary capillaries) absorb oxygen from the lungs and release carbon dioxide into the lungs. They then form pulmonary venules which transport the blood back to the left atrium as they feed into pulmonary veins.
Capillaries (sing. Capillary) – Are the extremely small network of blood vessels which receive oxygen-rich blood from arterioles. They deliver oxygen to and remove carbon dioxide from tissue cells. They then convey blood to venules.
Cardiac apex – Is the left lower corner of the heart formed by the anterior, inferior and left lateral walls of the left ventricle. With a normal heart it is the point where the heartbeat can be best felt with a hand placed on the chest wall.
Conduction system of the heart – Is an array of heart muscle cells and specialized conducting fibers through which electrical impulses travel as they cause the heart to beat. The impulses (heartbeat signals) originate in the SA node then pass through the other parts of the system in the order as listed below. From a practical standpoint, the main other parts of the system are the AV node, the bundle of His, the left and right bundles, the fascicles, and the Purkinje fibers.
Chambers of the heart – Are the four compartments of the heart in which blood flows in and out. The left atrium is the small chamber which receives oxygenated blood returning from the lungs and pumps it into a larger chamber, the left ventricle. The left ventricle pumps blood into the tissues through the aorta and its branches. The right atrium is a small chamber which receives blood returning from the body through the superior and inferior vena cava and pumps it into the right ventricle, again a larger chamber. The right ventricle pumps blood into the lungs. In its passage through the lungs the blood takes up oxygen and gets rid of carbon dioxide. Between the right and left ventricles is the interventricular septum which serves as a partition.
Endocardium – The connective tissue and overlying membrane which form the lining of the cavities of the heart muscle. It also covers the heart valves. The cells of the membranous portion of it are similar to the cells of the endothelium, but there is some debate as to whether not they originate from the same precursor cell and whether or not endocardial and vascular endothelial cells are one in the same.
Pacemaker – Is the generator of electrical impulses which establishes heartbeats and heart rhythm. It can be natural or man-made. The natural pacemaker in humans is the sinoatrial node (SA node). An artificial pacemaker is a device that sends electrical signals to the heart thru leads. Leads are wires connecting the pacemaker to the location in the heart where which it sends the signals. It serves as a substitute for a malfunctioning SA node or a means of circumventing a faulty conduction system of the heart.
Valves of the heart – Are gate-like folds of tissue at the exit of each chamber of the heart which allow the one-way passage of blood from their respective chambers. The mitral valve is at the exit of the left atrium. The aortic valve is at the exit of the left ventricle. The tricuspid valve is at the exit of the right atrium. The pulmonic valve is at the exit of the right ventricle.
Veins – Are vessels which return blood from tissues to the heart. The superior vena cava is the largest vein which returns blood into the right atrium from the upper portion of the body. The inferior vena cava is the largest vein which returns blood into the right atrium from the lower parts of the body. Pulmonary veins, two on the right and two on the left, transport oxygenated blood from the lungs into the left atrium.
Venule (pl. venules) – Is a very tiny vein which connects with capillaries at one in and with a larger vein at the other in. When blood leaves capillaries it flows into venules. It then flows from venules into larger veins.
Venous bed – Is the network of blood vessels on a whole within an organ or other structure of the body that carries blood away from tissues that comprise it. It merges with one or more larger veins distal to the structure. The network includes the venules.
Blood Vessel Anatomy
The endothelium is the innermost lining of the first layer. It consists of tightly linked flat plate-shaped epithelial cells. Together with a supporting sublayer of collagen and elastic tissue, it forms the tunica intima.
The tunica adventitia is the outermost layer of tissue that forms the wall of a blood vessel. Another name for it is the tunica externa. It is primarily connective tissue, comprised mainly of collagen with some surrounding elastic fibers.
It is important to note that capillaries do not have the three different tissue layers like veins and arteries. They are entirely the endothelial in their structure. They have no other components of their walls than the endothelium.
Ankle brachial reflex (ABI) – It is a test for diagnosing peripheral arterial disease in the doctor’s office. The first step is the measurement of the systolic blood pressure in the right and left brachial arteries of the arms using a Doppler. The Doppler detects and transmits sounds associated with the flow of blood through arteries. It also picks up the sounds of an artery opening and closing during blood pressure measurement. The next step is the measurement of the systolic blood pressure in the posterior tibial and dorsalis pedis pulses of an ankle and foot respectively. ABI is the higher of the 2 lower extremity readings on a given side divided by the higher arm reading. The ABI should be determined for both lower extremities separately, using the same higher arm reading. Interpretation of the ABI is as follows:
|1 – 1.4||Normal|
|9 – 1.0||Borderline|
|0.8 – 0.9||Some arterial disease|
|0.5 – 0.8||Moderate arterial disease|
|<0.5||Severe arterial disease|
Arteriogram (Angiogram) – Is a special x-ray study of an artery using a special dye (contrast medium) to determine if there is blockage to blood flow. It will also show other structural abnormalities such as an aneurysm.
Aortogram – An arteriogram of the aorta.
Cardiac catheterization – Is the placement of a catheter into the left or right chambers of the heart by means of an artery or vein respectively. It consists of placing the catheter into a vessel through a skin incision (usually in the groin) and slowly sliding it in until the tip of it enters the heart. Its purpose is to measure pressures and to inject contrast media (a special dye). The dye allows the taking of x-rays of the inside of the heart.
Left heart catheterization involves advancing a catheter through a path of arteries depending on its insertion point through the skin. When the tip of the catheter passes through the aortic valve it enters the left side of the heart where it allows the measuring of pressures. It also permits ventriculography – the injection of dye and the taking of x-rays of the inside of the heart including the valves. It helps to determine how well the heart muscle contracts when it pumps blood. A study of the left side of the heart usually includes coronary angiography – an x-ray study of the coronary arteries to find out if there is free flow of blood or blockage. It consists of injecting special dye directly into the coronary arteries by means of the catheter, followed by x-rays. A cardiologist usually performs a study of the left side of the heart or the left and right combined.
Right heart catheterization involves placement of a catheter only in the right side of the heart and in a pulmonary artery where pressures are measured. Cardiologists, pulmonologists, and intensive care unit specialists perform this procedure.
Cardiologist – A physician who specializes in medical problems of the heart. The diagnosis and treatment of heart diseases with medications is his or her primary skill set. One’s expertise might also include invasive heart procedures such as PCI or stent placement, depending on the doctor. But it does not include open heart surgery.
Echocardiogram (echo) – Is a sound wave study (ultrasound) of the heart which shows the inside of the heart including the valves. It can show if the heart is enlarged, thickened or weak in its pumping action. It can also show if there is a pericardial effusion.
Ejection fraction (EF) – Is the percentage of blood the heart pumps out during each heartbeat. A normal ejection fraction ranges from 55% to 70%. An echocardiogram or special x-rays of the heart during cardiac catheterization are the ways to measure it.
Exercise stress test – A modified EKG performed while the patient is walking, jogging, or running on a treadmill. A positive test for coronary artery disease is one in which signs of ischemia appear on the EKG monitor or the patient develops chest pain compatible with angina during the test. A significant drop in blood pressure might also be a positive test.
An event recorder – Is a portable heart monitor which a patient wears. It is a Holter monitor of sorts. But it differs in that it is a loop recorder. That means it does not permanently store all of the EKG data that it records. Rather, it overwrites (erases) much of the data because of its loop memory.
It does store a permanent recording of the heart rhythm though, when the patient activates it by pushing a button upon experiencing a symptom(s) suggestive of a heart rhythm problem, such as palpitations or lightheadedness. The record is for a programmed period of time before and after the pushing of the button. If fainting occurs and the person also pushes the button upon waking up the record will also include a period of time after the awakening.
The device also transmits a copy of the data via telephone to a doctor’s office or receiving center such as an emergency room or central laboratory. Instructions to the patient will depend upon the findings of the physician who reviews the EKG tracing. In the case of life-threatening findings the doctor would advise the patient to report to the emergency room.
Some devices are automatic. That means they don’t require manual activation to record and store heart rhythm data. They do it automatically upon detection of an arrhythmia, whether or not the patient has symptoms with it.
There are external and implantable devices. External loop recorders sense the electrical activity of the heart via electrodes in contact with the skin. Patients usually wear them for up to four to six weeks. Implantable loop recorders are small devices the size of a USB flash drive implanted under the skin. They have the same functional features as the external devices, but are usable for up to three years.
Left ventricular diastolic dysfunction – Is a state of decreased compliance or stiffness of the muscle of the left ventricle which results in abnormal filling of the chamber with blood. Depending on the degree of dysfunction, it can result in the backup of fluid and pressure into the lung vessels and right side of the heart. Certain forms of cardiomyopathy can cause it.
Percutaneous coronary intervention (PCI) – The general term for opening a narrowed artery with a procedure performed through the skin. It consists of puncturing the skin and placing a catheter with a balloon on the end into an underlying artery, then advancing both to the site of the blockage. The blocked artery is then opened by expanding the balloon. Stents are oftentimes also placed during PCI.
Stent – A small wire mesh tube placed in a previously blocked heart artery after unblocking during angioplasty. Stents are designed to decrease the chance of re-blockage. Stents coated with medication are referred to as drug-eluting stents. Those without medication are bare-metal stents.
Venogram – A special x-ray study of a limb (usually one of the lower extremities), in which dye or contrast medium is injected into a vein. Its purpose is to determine if there is evidence of blockage from a blood clot.
Venous Doppler – Is a sound wave test (ultrasound) of the veins, usually of a lower extremity. It is a noninvasive way of testing for a blood clot (deep venous thrombosis).