Term | Definition |
Cardiac Cycle | One total heart beat, i.e., one complete contraction and relaxation of the heart. In man this normally occupies 0.85 seconds. |
Cardiac Output | The amount of blood pumped by the heart per minute. |
Cardiovascular | Pertaining to the heart and blood vessels |
Describe the Carotid Sinus | A slight dilation at the point where the internal carotid artery branches from the common carotid artery. The carotid arteries are those which supply blood to the head and neck. |
What does the Carotid Sinus do? | The carotid sinus contains special nerve end organs which respond to changes in blood pressure by causing a change in heart rate. External pressure on the carotid sinus stimulates the nerves in the sinus causing a drop in blood pressure and faintness. |
Chordae Tendinae | Fibrous cords serving as guy ropes to hold valves between the upper and lower chambers of the heart secure when forced closed by pressure of blood in lower chambers. They stretch from the cusps of the valves to the papillary muscles in the lower chambers |
Commissurotomy | Operation to widen the opening in a heart valve which has become narrowed by scar tissue. The individual flaps of the valve are cut or spread apart along the natural line of their closure. This operation often performed in cases of rheumatic heart disease |
Congestive heart failure (also called myocardial insufficiency) | When the heart cannot adequately pump out blood returning to it there's a back up of blood in the veins leading to the it. Congestion or accumulation of fluid in parts of the body may result from the hearts failure to maintain satisfactory circulation. |
Coronary arteries | Two arteries arising from the aorta, arching down over the top of the heart, and conducting blood to the heart muscle. |
Coronary occlusion (sometimes called a coronary heart attack or simply a heart attack) | An obstruction (generally a blood clot) in a branch of one of the coronary arteries which hinders the flow of blood to some part of the heart muscle. This part of the heart muscle then dies because of lack of blood supply. |
Coronary Thrombosis | Formation of a clot in a branch of one of the arteries which conduct blood to the heart muscle. A form of coronary occlusion. |
Cor Pulmonale | Heart disease resulting from disease of the lungs of the blood vessels in the lungs. This is due to resistance to the passage of blood through the lungs. |
Cyanosis | Blueness of the skin caused by insufficient oxygen in the blood. Oxygen is carried in the blood by hemoglobin, which is bright red when saturated with oxygen. When hemoglobin is not carrying oxygen it is purple and is called reduced hemoglobin. |
At what point does Cyanosis cause blueness in the skin? | When the amount of reduced hemoglobin exceeds 5 grams per 100 cc of blood. |
Decompensation | Inability of the heart to maintain adequate circulation, usually resulting in a waterlogging of tissues. A person whose heart is failing to maintain normal circulation is said to be "decompensated". |
Defibrillator | Any agent or measure such as an electric shock which stops an incoordinate contraction of the heart muscle and restores a normal heart beat. |
Dextrocardia | 2 different types of congenital phenomena are often described as dextrocardia. 1st is a condition where the heart is slightly rotated and lies almost entirely in the right (instead of the left) side of the chest. |
Dextrocardia (cont.) | The second is a condition in which there is a complete transposition, the left chamber of the heart being on the right side and the right chambers on the left side, so that the heart presents a mirror image of a normal heart. |
Diastole | In each heart beat, the period of relaxation of the heart. Auricular diastole is the period of relaxation of the atria. Ventricular diastole is the period of relaxation of the ventricles. |
Digitalis | A drug prepared from the leaves of the foxglove plant which strengthens the contraction of the heart muscle, slows the rate of contraction of the heart, and by improving the efficiency of the heart, may eliminate the buildup of fluids in the body tissues. |
Dilation | A stretching or enlargement of the heart or blood vessels beyond the norm. |
Dyspnea | Difficult or labored breathing. |