Grade 12 Biology: Heart Rate

Grade 12 Biology: Heart Rate

Read each question carefully and provide detailed answers. Use diagrams where appropriate to support your explanations.

1. Which part of the brain is primarily responsible for regulating heart rate?

2. Which hormone is released during stress and increases heart rate?

1. The pacemaker of the heart is the   node.

2. Parasympathetic stimulation of the heart is mediated by the   nerve, which releases  .

3. A normal resting heart rate for adults typically ranges from   to   beats per minute.

1. Briefly explain the difference between tachycardia and bradycardia.

2. Describe one method used to measure heart rate, and explain its principle.

Examine the diagram of the human heart below, then answer the following questions.

1. Identify two major blood vessels that carry deoxygenated blood to the heart.

2. Explain how the structure of the heart chambers and valves contributes to unidirectional blood flow.

1. An increase in body temperature generally leads to a decrease in heart rate.

2. Athletes often have a lower resting heart rate due to a more efficient cardiovascular system.

Discuss the primary intrinsic and extrinsic factors that regulate heart rate. Include a detailed explanation of the role of the autonomic nervous system and hormones.