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The Heart
Chapter 14 Q & A
Question | Answer |
---|---|
What are the 3 layers of the heart wall? | The endocardium, the myocardium, and the epicardium |
What is the function of the endocardium? | Consisting of a thin layer of squamous epithelial cells, it lines the heart's chambers, covers the valves, and continues into the vessels |
What is the function of the myocardium? | Composed of cardiac muscle, it forms the middle layer of the heart wall. It is the thickest layer and performs the work of the heart |
What is the function of the epicardium? | Consisting of a thin layer of squamous epithelial cells, it covers the heart's surface |
What is the location of the heart chambers? | On the left and right are 2 upper chambers called atria and 2 lower chambers called ventricles |
What is the function of the atria? | Serving as reservoirs, the right atria receives blood from the body and the left atria receives blood from the lungs |
What is the function of the ventricles? | Serving as pumps, the right ventricle pumps blood to the lungs and the left ventricle pumps blood to the body |
What are the great vessels? | The inferior and superior vena cava, pulmonary artery, 4 pulmonary veins, and the aorta |
What is the primary function of the great vessels? | They transport blood to and from the heart |
What is the function of the superior and inferior vena cavae? | Transport deoxygenated blood to the right atrium |
What is the function of the pulmonary artery? | Transports blood from the right ventricle to the lungs |
What is the function of the pulmonary veins? | Transport oxygenated blood from the lungs to the left atrium |
What is the function of the aorta? | Transports blood from the left ventricle to every organ in the body |
How many valves are in the heart? | 4; 2 atrioventricular (AV) valves and 2 semilunar valves |
What are the atrioventricular valves? | The tricuspid valve and the mitral (bicuspid) valve |
What are the semilunar valves? | The pulmonary valve and the aortic valve |
What is the function of the tricuspid valve? | It prevents backflow from the right ventricle to the right atria |
What is the function of the mitral valve? | It prevents backflow from the left ventricle to the left atria |
What is the function of the pulmonary valve? | It prevents backflow from the pulmonary artery to the right ventricle |
What is the function of the aortic valve? | It prevents backflow from the aorta to the left ventricle |
What is the location of deoxygenated blood? | The right atrium, through the right ventricle, then into the lungs |
What is the location of oxygenated blood? | The left atrium, through the left ventricle, throughout the body |
What is the first step of blood flow through the heart? | The right atrium receives deoxygenated blood returning from the body through the superior and inferior vena cavae |
What is the 2nd step of blood flow through the heart? | Once the right atrium is full, it contracts. The tricuspid valve opens and blood flows to the right ventricle. When the right ventricle is full, the tricuspid valve closes |
What is the 3rd step of blood flow through the heart? | The right ventricle contracts. The pulmonary valve opens. Blood travels thru the pulmonary arteries to the lungs. The pulmonary valve closes |
What is the 4th step of blood flow through the heart? | After replenishing its supply of oxygen in the lungs, the blood enters the pulmonary veins and into the left atrium |
What is the 5th step of blood flow through the heart? | When the left atrium is full, it contracts. The mitral valve opens and blood enters the left ventricle |
What is the final step of blood flow through the heart? | When the left ventricle is full, the mitral valve closes. The ventricle contracts. The aortic valve opens. Blood flows through the aorta to every organ in the body |
How does coronary circulation supply blood to the heart muscle? | Coronary arteries deliveer oxygenated blood to the myocardium, while cardiac veins collect the deoxygenated blood |
What does the right coronary artery supply? | It supplies blood to the right atrium, part of the left atrium, most of the right ventricle, and the inferior part of the left ventricle |
What does the left coronary artery supply? | It branches into the anterior descending and circumflex arteries, supplying blood to the left atrium, most of the left ventricle, and most of the interventricular septum |
What is the function of the coronary sinus? | Most cardiac veins empty deoxygenated blood in to the coronary sinus, which returns blood to the right atrium |
What is the first step of the cardiac conduction cycle? | Normal cardiac impulses arise in the SA node in the right atrium |
What is the 2nd step in the cardiac conduction cycle? | An internodal bundle of conducting fibers rapidly conducts the impulses to the left atrium, and both atria begin to contract |
What is the 3rd step in the cardiac conduction cycle? | The impulse travels along 3 internodal bundles to the AV node. The impulse slows as the ventricles fill |
What is the 4th step in the cardiac conduction cycle? | After passing through the AV node, the impulse picks up speed, then travels down the bundle of His (AV bundle) |
What is the 5th step in the cardiac conduction cycle? | The AV bundle soon branches into right and left bundle branches |
What is the final step in the cardiac conduction cycle? | Purkinje fibers conduct the impulses throughout the muscle of both ventricles, causing them to contract almost simultaneously |
What is a P wave? | On an ECG, it represents atrial depolarization and occurs right before the atria contract |
What is a PR interval? | On an ECG, it represents the time it takes for the cardiac impulse to travel from the atria to the ventricles |
What is the QRS complex? | On an ECG, it represents ventricular depolarization |
What is the ST segment? | On an ECG, it represents the end of ventricular depolarization and the beginning of ventricular repolarization |
What is the T wave? | On an ECG, it represents ventricular repolarization |
What is valvular insufficiency? | A condition of an incompetent heart valve - one that fails to prevent the backflow of blood during contraction |
What is a stenotic valve? | One that has become narrowed, such as from scar tissue |
What is a heart murmur? | An abnormal heart sound that can be heard through a stethoscope |
What is artherosclerosis? | Results when the coronary arteries become blocked or narrowed by a buildup of cholesterol and fatty deposits |
What is ischemia? | Any interruption in blood supply to the myocardium that deprives the heart of oxygen |
What is angina pectoris? | Temporary ischemia; when the demand for oxygen exceeds the supply and ischemia and chest pain result |
When does an arrhythmia occur? | When part of the conduction pathway is injured or when a part of the myocardium other than the SA node generates a beat |
What is an atrial flutter? | An arrhythmia that occurs when an ectopic focus in the atria fires rapidly, causing the atria to contract between 200 & 400 times per minute; not usually life-threatening |
What are PVCs? | Premature ventricular contractions which may occur as a single beat or in bursts of several beats; results from the firing of an ectopic focus in the ventricles |
What are possible causes of PVCs? | May indicate a serious underlying condition or may be caused by a lack of sleep, caffeine, or emotional stress |
What is ventricular fibrillation? | Causes the heart to quiver rather than contract; cardiac output plummets and cardiac arrest may quickly follow; life-threatening |
How does emotion affect heart rate? | Stimulation of the amygdalae causes it to send impulses to the ANS. Anxiety, fear, and anger cause the heart to beat faster; grief slows the heart rate |
What is CHF? | Congestive heart failure; results when either ventricle fails to pump blood effectively; usually due to a weakened ventricle |
What happens if CHF has caused left ventricle failure? | The ventricle falls behind in ejecting all of the blood it receives from the lungs. Blood backs up in the lungs. This causes shortness of breath, pulmonary edema, and coughing |
What happens if CHF has caused right ventricle failure? | The ventricle falls behind in ejecting all of the blood it receives from systemic circulation. Blood backs up into the vena cava and the peripheral vascular system. |
What are the results of right ventricle failure? | Systemic edema, enlargement of the liver and spleen, ascites, distension of the jugular veins, and swelling of the ankles, feet, and fingers |