Electrocardiogram
Beep!âĂ¬Ā¦Beep!âĂ¬Ā¦Beep! is the audible rhythmic sound made as the strength of the heart muscle is measured. The signal cadence has a characteristic record that varies in every individual. This record is called an electrocardiogram, or ECG.
In the body, an array of systemic neural responses constantly occur, emitting electric currents. The electric currents can be detected on the surface of the body, and if a person is hooked to an amplifier, these impulses are recorded by an electrocardiograph.
Most of the information obtained is about the heart because the heart sends out electric currents in waves. This âĂ¬Å“wave of excitationâĂ¬Ā¯ spreads through the heart wall and is accompanied by electric changes. The wave takes place in three distinct steps.
Initially, the âĂ¬Å“wave of excitationâĂ¬Ā¯ accompanied by an electric change lasts for approximately 1 to 2 seconds after the contraction of the cardiac muscle. The electric impulses are discharged rhythmically from the sinoatrial (SA) node, the pacemaker of the heart. This spread of excitation over the muscle of the atrium indicates that the atrium has contracted.
Next, the peak of the ECG reading is due to the atrioventricular (AV) node, causing the ventricle to become excited.
Finally, the ventricles relax, and any changes in the wave indicate to trained medical staff any abnormalities within the heart
In the body, an array of systemic neural responses constantly occur, emitting electric currents. The electric currents can be detected on the surface of the body, and if a person is hooked to an amplifier, these impulses are recorded by an electrocardiograph. What is the meaning of the word emitting as it is used in the second paragraph?
Correct Answer: B
Rationale: The correct answer is B, 'Releasing.' In this context, 'emitting' refers to the action of releasing electric currents. The passage describes how electric currents are constantly emitted by systemic neural responses in the body. These emitted currents can be detected on the body's surface and recorded by an electrocardiograph. Therefore, the term 'emitting' in this context means 'releasing' electric currents.
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