telemetry med surg exam 3 2023- solved

sinus node - ANSWER-The intrinsic pacemaker. Cell membrane "leakiness" causes spontaneous depolarization at a rate of 60-100 times a minute. AV node - ANSWER-Acts like a resistor to slow the impulse allowing time for the atria to completely contract before initiating ventricular contraction. Back up pacemaker if SA fails, pacing at a rate of 40-60 times a minute. Bundle of his - ANSWER-"Cable" that passes through the fibrous sheath separating atria from ventricles. Divides into the bundle branches. Bundle branches - ANSWER-"Wires" that run down the septum and into the ventricles. There are two left bundle branches and one right. Purkinje - ANSWER-Terminal fibers branches from the bundles, distributing the impulse throughout the ventricles. Intranodal pathways - ANSWER-"Wiring" that allows rapid impulse movement around the atria to coordinate simultaneous atria contraction Impulse vectors - ANSWER-SA node Atria AV node The depolarization wave in the ventricles also travel in specific directions forming vectors. Because the left ventricle has a bigger muscle mass, the wave of depolarization (starts in mid septum) is greater than the right and is represented as a bigger vector. which ventricle has bigger muscle mass - ANSWER-left ventricle degree of perpendicular - ANSWER-If the current is running at an angle to the field, the angulation is seen as so much positive and so much negative depending on how parallel and perpendicular the current vector is to the field. The degree of perpendicular can also be seen as a decrease in amplitude only. leads - ANSWER- PQRST - ANSWER- P wave - ANSWER-ATRIAL DEPOLARIZATION Normal: small, round, positive in lead II