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Heart
Chapter 14 Heart
Question | Answer |
---|---|
Base | Where the great vessels enter and leave the heart |
Apex | The point of maximum impulse, where the strongest beat can be heard. |
Coronary Arteries | Deliver oxygenated blood to the myocardium, while cardiac veins collect the deoxygenated blood. The two main. |
The two main coronary arteries are | Right and Left coronary artery-- arise from the ascending aorta and serve as the principle routes for supplying blood to the myocardium. |
Right coronary artery | Supplies blood to the right atrium, part of the left atrium, most of the right ventricle, and the inferior part of the left ventricle. |
Left coronary artery | Branches into the anterior descending and circumflex arteries, supply blood to the left atrium, most of the left ventricle, and most of the interventricular septum. |
Coronary Sinus | Most cardiac veins empty in -- , a large transverse vein on the hearts posterior, which returns the blood to the right atrium. (the exception is the anterior cardiac vein, which empty directly into the right atrium) |
Key structure of the heart | Pericardium, the heart wall, the chambers, and the valves |
The pericardum | Surrounding the heart is a double-walled sac called --. Anchored by ligaments and tissue to surrounding structures. |
Pericardium has 2 layers | The fibrous pericardium and Serous Pericardium |
The Fiberous Pericardium | a loose layer fitting sac of strong connective tissue-- is the outermost layer. |
The Serous Pericardium | Consists of two layers, covering the hearts surface. |
Parietal Layer | Lines the inside of the fibrous pericardium |
Visceral Layer | Covers the hearts surface |
Heart skeleton | A semi-rigid, fibrous, connective tissue called the skeleton of the heart, encircles each valve. Keeps the valves from stretching; it also acts as an insulating barrier between the atria and the ventricles, preventing electrical impulses from reaching the |
Heart wall consists of three layers | Endocardium, Myocardium, and Epicardium |
The endocardium | Lines the hearts chambers, covers the valves, and continues into the vessels. It consists of a thin layer of squamous epithelial cells. |
The Myocardium | Composted of cardiac muscle, forms the middle layer. It's the thickest of the three layers and performs the work of the heart. |
The Epicardium | Consists of a thin layer of squamous epithelial cells, covers the hearts surface. Also known as the visceral layer of the serous pericardium, the epicardium is closely integrated with the myocardium. |
The heart contains 4 hollow chambers | 2 upper chambers are called Atria. 2 Lower chambers are called Ventricles. |
Great Vessels | Attached to the heart are several large vessels that transport blood to and from the heart. They include the superior and inferior vena, pulmonary artery. |
Atria | Serve primarily as reservoirs, receiving blood from the body or lungs. The right and left -- are separated by a common wall of myocardium called the interatrial septum |
Ventricles | Serve as pumps, receiving blood from the atria and then pumping it either to the lungs (right ventricle) or the body (left ventricle). |
Interventricular septum | The right and left ventricles are separated by this. |
Cusps or Leaflets | Each valve is formed by two or 3 flaps of tissue called-- |
AV (atrioventricular) valve | Regulates flow between the atria and the ventricles |
Right AV valve | Also called the tricuspid vavle (because it has 3 leaflets) prevents the backflow from the right ventricle to the right atrium |
Left AV valve | lso called the bicuspid valve (because it has two leaflets) or, more commonly, the mitral valve-- prevents backflow from the left ventricle to the left atrium |
The semilunar valves | Regulate flow between the ventricles and the great arteries. |
Two semilunar valves | Pulmonary Valve and Aortic Valve |
Pulmonary Vavle | Prevents backflow from the pulmonary artery to the right ventricle |
Aortic Valve | Prevents backflow from the aorta to the left ventricle |
Valvular Disease | Heart valve that fails to prevent the backflow of blood during contraction is called imcompetent, and the condition is known as valvular insufficiency. |
Emotions and heart rate | Fear, grief, and anger all affect heart rate. This occurs because two almond- shaped areas of the brain, called amygdalae, are key players in the formation and storage of memories associated with emotion. |
Congestive heart failure | When either ventricle fails to pump effectively. This can occur because the ventricle is weakened from the myocardial infaraction. |
Arrhythmias | When part of the conduction pathway is injured or when part of the myocardium other than the SA node (called the ectopic focus) generates a beat. Common cardiac arrhthmias include atrial flutter, premature contractions, and ventricular fibrillation. |
Angina and Myocardial Infraction | Coronary artery disease is the leading cause of death in america today, causing almost one-half million deaths each year. The disease results when the coronary arteries become blocked or narrowed by a buildup of cholesterol and fatty deposits. |
Cardiac Conduction | Unique that it doesn't depend upon stimulation by extrinsic nerves to contract. It contains special pacemaker cells that allow it to contract spontaneously, an ability called automaticity. |
What is the SA node | The primary pacemaker. If the SA node failes to fire, pacemaker cells in the AV node or Purkinje fibers can initiate impulses, although at a slower rate. Pacemakers other than SA node are called Ectopic pacemakers. The hearts pacemakers and their firing r |
SA Node | Fires at 60 to 80 beats per minute |
AV node | Has a firing rate of 40 to 60 beats per minute |
Purkinje Fibers | Have a firing rate of 20 to 40 beats per minute |
Cardiac Cycle | The series of events that occur from the beginning of one heartbeat to the beginning of the next is called --- |
Cardiac cycle consists of two phases | Systole (contraction) Diastole (relaxation) |