A paramedic places sticky sensors on the chest of a patient who reports an irregular heartbeat. The monitor produces an electrocardiogram, which records ele...
Question 1 Report
A paramedic places sticky sensors on the chest of a patient who reports an irregular heartbeat. The monitor produces an electrocardiogram, which records electrical signals controlling heart muscle contraction. The patient has a normal number of red blood cells and normal blood pressure, but the ventricles sometimes beat too slowly. The cardiologist considers fitting a pacemaker. A pacemaker sends small electrical impulses that help the heart maintain a regular rhythm and therefore a regular supply of blood to organs.
(a) Identify the chambers that pump blood out of the heart. [1]
(b) Explain why an irregular ventricular rhythm can reduce blood supply to body cells. [2]
(c) Use the information to explain how a pacemaker can help this patient. [2]
(d) Give one organ that could be harmed if its blood supply stops for several minutes. [1]
Answer Details
(a) Ventricles. [1]
(b) Each ventricular contraction pumps blood. [1] An irregular or slow rhythm can reduce cardiac output, so less oxygen reaches body cells. [1]
(c) It sends electrical impulses to control contractions. [1] This restores a regular rhythm / maintains blood flow. [1]
(d) Brain / heart / kidneys. [1]
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