Final answer:
The sound monitored with a stethoscope is the vibration of the heart and blood as pumping occurs. This technique called auscultation is used to detect the normal lub dub sounds as well as murmurs. The echocardiogram may be used for further evaluation if murmurs are detected.
Step-by-step explanation:
When a doctor uses a stethoscope, the sound being monitored is b) The sound made by the vibration of the heart and blood as pumping occurs. This technique known as auscultation has been a cornerstone in medical diagnostics since ancient times. The characteristic lub dub sounds are those of the heart valves opening and closing, and the movement of blood through the chambers of the heart. Should a physician hear any additional sounds, such as murmurs indicative of turbulent blood flow, further investigation with an echocardiogram or other diagnostic tests might be warranted.
Additionally, the stethoscope may be used during the measurement of blood pressure using a sphygmomanometer, which involves inflating a cuff to restrict blood flow in the brachial artery. When the cuff's pressure equals systolic pressure, the blood begins to spurt into the artery creating a sound detectable by the stethoscope. Listening continues until this sound ceases, indicating the diastolic pressure. Both values give a complete blood pressure reading, essential for assessing cardiovascular health.