What are methods for monitoring the activity of the heart?
▶️ Answer/Explanation
Ans: D
The image likely depicts an electrocardiogram (ECG), a standard method for monitoring heart activity by measuring electrical impulses. Other methods include pulse monitoring (checking heart rate manually) and stethoscope auscultation (listening to heart sounds). Option D is correct as it aligns with these diagnostic techniques, while the distractors (A–C) may refer to irrelevant or incorrect procedures.
Scientists used an ECG trace to monitor the heart of a student at rest and during exercise. What is the explanation for the difference in the ECG traces?
A) During exercise the heart rate increases to transport more oxygen to muscles.
B) During exercise the heart rate increases to breathe in more oxygen.
C) During exercise the breathing rate increases to supply more oxygen to muscles.
D) During exercise the breathing rate increases to breathe in more oxygen.
▶️ Answer/Explanation
Ans: A
The ECG trace shows a faster heart rate during exercise because:
- Muscles need more oxygen for aerobic respiration to produce energy.
- The heart beats faster to pump more oxygen-rich blood to the muscles.
- This is reflected in the ECG as more peaks (heartbeats) in the same time period.
Option A correctly links the increased heart rate to oxygen transport, while other options confuse heart function with breathing or are irrelevant to ECG changes.