Problem 80 - Objective Biology for NEET

Question

How many double circulation are normally completed by the human heart in one minute? (a) 8 (b) 16 (c) 36 (d) 72

Step-by-Step Solution

Answer

The human heart normally completes 72 double circulations in one minute. So, the correct answer is (d) 72.

Step 1: Understand the question

The question asks for the number of double circulations completed by the human heart in one minute.

Step 2: Conversion rates

The important thing to remember here is that one heart beat completes one cycle of double circulation. Under resting conditions the average heart beats per minute range from 60 to 100. However, for simplicity and it being a much commonly referred value, we can consider the heart beat as 72 times per minute.

Step 3: Compute

Thus, given that each heartbeat equals one double circulation, and given that we are considering an average heartbeat rate of 72 per minute, the human heart completes 72 double circulations in one minute under normal conditions.

Key Concepts

Heart Rate

Heart rate refers to the number of times your heart beats in one minute. It is a vital indicator reflecting the efficiency of your circulatory system. Generally, heart rate fluctuates based on activity levels, emotions, workout intensity, and overall health. A resting heart rate, which is measured when you are calm and relaxed, usually ranges from 60 to 100 beats per minute.

Both athletes and those in excellent physical shape might experience lower resting heart rates, sometimes around 40 beats per minute. On the other hand, factors such as stress, dehydration, and medical conditions like hyperthyroidism can cause an increase in heart rate.

To monitor your heart rate, you can check your pulse using your fingertips on your wrist or neck. Alternatively, wearable technology like fitness trackers can also provide continuous, real-time heart rate data. Keeping an eye on your heart rate is an excellent way to get insights into your cardiovascular health and make informed lifestyle choices.

Human Heart

The human heart is a muscular organ that functions as the center of our circulatory system. Its primary job is to pump blood throughout the body, ensuring that nutrients and oxygen reach every cell, while also removing waste products.

Your heart consists of four chambers:

• Two upper chambers called atria (right atrium and left atrium)
• Two lower chambers called ventricles (right ventricle and left ventricle)

Blood first enters the right atrium from the body and is then pumped into the right ventricle. Here, it is sent to the lungs to receive oxygen.

The oxygen-rich blood then returns to the left atrium, moves into the left ventricle, and is finally distributed throughout the body through the aorta. Heart's Role in Double Circulation
Double circulation refers to the cycle in which blood passes through the heart twice during one complete circuit of the body. This ensures efficient oxygenation of blood and effective removal of carbon dioxide from the system.

Circulatory System

The circulatory system is an intricate network responsible for transporting blood, nutrients, and gases throughout the body, maintaining a balance between oxygen supply and waste removal.

This vital system comprises the heart, blood vessels, and blood itself, working together to sustain life. The blood vessels are of three major types:

• Arteries - Carry oxygen-rich blood away from the heart
• Veins - Return deoxygenated blood back to the heart
• Capillaries - Tiny vessels where the exchange of gases and nutrients occurs

In double circulation, blood circulates twice through the heart in one complete body loop: once for oxygenation (in the lungs) and once to deliver oxygenated blood to the body's cells.

By separating these two processes, double circulation ensures high efficiency in oxygenating blood and transporting it throughout the body. It is essential for supporting higher metabolic rates and maintaining stable internal environments.