A&P 3 Midterm Study Guide

Covers Ch. 19-21 Format: 35 multiple choice @ 3 pts each, 4 multiple answer @ 5 pts, 11 fill in the blank @ 2 pts, 2 calculations @ 4 pts, 1 essay @ 20 pts = 175 pts total Ch. 20 ECG • Electrocardiogram o A recording of the electrical changes that accompany each cardiac cycle (heartbeat) • Helps to determine if the conduction pathway is abnormal, if the heart is enlarged, and if certain regions are damaged. • P wave: atrial depolarization • QRS Complex: ventricular depolarization • T wave: ventricular repolarization Cardiac cycle • Consists of the systole (contraction) and diastole (relaxation) of both atria, rapidly followed by the systole and diastole of both ventricles. • Pressure and volume changes during this. Atria and ventricles alternately contract and relax forcing blood from areas of high pressure to areas of lower pressure. Tachycardia • Rapid but regular heart beat – 100 BPM (supraventricular tachycardia – SVT) o Ventricular tachycardia (CT or V-tach): originates in the ventricles and causes contractions to occur too fast (120 beats/min). Bradycardia • Heart rates too slow. Common in older people. BPM of fewer than 60. Fibrillation • Atrial fibrillation (AF): atrial contraction is not synchronous. Irregular heartbeat. • Ventricular fibrillation (VF or V-fib): most deadly, occurs when contractions of the ventricles are not synchronous Location of the heart • Situated between the lungs in the mediastinum with about 2/3 of its mass to the left of the midline. Anatomy of the heart and valves • Heart: four chambers, two atria (upper chambers) and two ventricles (lower chambers) • Valves: where blood passes before leaving each chamber, prevents backward flow of blood. Have sphincter muscles, or two or three membranous flaps/folds. Tricuspid valve and mitral valve.