1.
Your heart pumps 8,000 gallons of blood every day.
Correct Answer
A. True
Explanation
The heart is responsible for pumping blood throughout the body, delivering oxygen and nutrients to various organs and tissues. It is estimated that the average adult heart pumps about 2,000 gallons of blood per day. However, during periods of physical activity or exercise, the heart may need to pump more blood to meet the increased demand. Therefore, it is plausible that the heart could pump up to 8,000 gallons of blood in a day, making the statement true.
2.
A mature heart beats over 100,000 times in 24 hours.
Correct Answer
A. True
Explanation
The statement is true because a mature heart is constantly pumping blood throughout the body, and this requires it to beat regularly and frequently. On average, a healthy adult heart beats around 60-100 times per minute, which adds up to over 100,000 beats in a 24-hour period. This continuous pumping action ensures that oxygen and nutrients are delivered to all the organs and tissues in the body, supporting their proper functioning.
3.
When you listen to your heart through a stethoscope, the beats you hear are the valves slamming shut.
Correct Answer
A. True
Explanation
When you listen to your heart through a stethoscope, the sound you hear is the result of the valves in your heart closing. The valves in the heart prevent the backflow of blood and ensure that it flows in the correct direction. As the valves close, they create a distinct sound that can be heard with a stethoscope. Therefore, the statement "the beats you hear are the valves slamming shut" is true.
4.
The heart squirts about ½ cup of blood through its valves with every heartbeat.
Correct Answer
A. True
Explanation
The statement is true because with every heartbeat, the heart pumps blood through its valves. This blood is then circulated throughout the body, supplying oxygen and nutrients to the organs and tissues. The amount of blood pumped by the heart with each beat is approximately equal to half a cup, which is a significant amount considering the heart beats around 100,000 times a day.
5.
Between beats, your heart relaxes for about 5 seconds.
Correct Answer
B. False
Explanation
During the relaxation phase of the cardiac cycle, known as diastole, the heart actually relaxes for a longer period of time than 5 seconds. This allows the heart chambers to fill with blood before the next contraction. The relaxation phase typically lasts for about 0.4 to 0.5 seconds, which is shorter than the contraction phase (systole). Therefore, the statement that the heart relaxes for about 5 seconds between beats is false.
6.
Your veins collect blood from all over your body and return it to the heart. The entire trip from the heart to the muscles and back again takes less than one minute.
Correct Answer
A. True
Explanation
The statement is true because veins are responsible for collecting deoxygenated blood from all parts of the body and returning it to the heart. This process is essential for the circulation of blood throughout the body. The blood travels from the heart to the muscles and organs through arteries, and then it returns to the heart through veins. This entire cycle, known as systemic circulation, typically takes less than one minute to complete. Therefore, the statement is correct.
7.
During an average lifetime, a human heart will beat almost 3 billion times.
Correct Answer
A. True
Explanation
The human heart is responsible for pumping blood throughout the body, and it beats continuously from the moment of birth until death. The average heart rate is around 60-100 beats per minute, depending on factors such as age and physical activity. Considering an average lifespan of around 80 years, which is approximately 42 million minutes, the heart would beat nearly 3 billion times. Therefore, the statement is true.
8.
Your blood makes 1,000 complete trips around your body every day.
Correct Answer
A. True
Explanation
The human circulatory system consists of blood vessels that carry blood throughout the body. The heart pumps blood, and it takes approximately 60 seconds for blood to complete one cycle. This means that in a day, blood makes multiple trips around the body. Since the question states that blood makes 1,000 complete trips around the body every day, it is true.
9.
In a lifetime, your heart might pump up to 50 million gallons of blood.
Correct Answer
B. False
Explanation
The statement claims that in a lifetime, a person's heart might pump up to 50 million gallons of blood. However, this is false. On average, a person's heart pumps about 2,000 gallons of blood per day, which would amount to approximately 720,000 gallons of blood in a lifetime. Therefore, the given statement is incorrect.
10.
Your blood contains about 250 trillion red blood cells.
Correct Answer
A. True
Explanation
Red blood cells are the most abundant type of blood cells in the human body. On average, there are about 4-6 million red blood cells per microliter of blood. Considering that the average adult has about 5 liters of blood, this would amount to approximately 25 trillion red blood cells. However, since the question states "about 250 trillion," it is within the range of the estimated number of red blood cells in the body, making the answer "True."
11.
A person's resting pulse rate increases with age.
Correct Answer
B. False
Explanation
Resting pulse rate does not necessarily increase with age. In fact, it is more common for resting pulse rate to decrease with age. This is because as individuals age, their cardiovascular system becomes more efficient, resulting in a lower resting pulse rate. However, it is important to note that individual variations exist and certain factors such as fitness level, overall health, and medication use can also influence resting pulse rate.
12.
Generally, larger people have a slightly higher pulse rate.
Correct Answer
B. False
Explanation
The statement is false because pulse rate is not directly correlated to a person's size. Pulse rate is primarily determined by factors such as age, fitness level, and overall health, rather than body size. While it is true that certain medical conditions or medications may affect pulse rate, there is no general rule that larger people have a higher pulse rate.
13.
Canaries live longer than elephants.
Correct Answer
B. False
Explanation
This statement is false. Canaries have a much shorter lifespan compared to elephants. Canaries typically live for about 10-15 years, while elephants can live up to 70 years or more. Therefore, elephants live longer than canaries.
14.
Your heart is good for over 2 ½ billion beats in a lifetime of 70 years.
Correct Answer
A. True
Explanation
The human heart is capable of beating continuously for an average lifespan of around 70 years. During this time, it beats approximately 2 ½ billion times, pumping blood and oxygen throughout the body. This makes the statement "Your heart is good for over 2 ½ billion beats in a lifetime of 70 years" true.
15.
In 2001, the life expectancy of the average American was 80 for men and 74.4 for women.
Correct Answer
B. False
Explanation
The statement is false because it states that the life expectancy of the average American in 2001 was 80 for men and 74.4 for women. However, according to the data available, the life expectancy for men in 2001 was around 74.4 years, while for women it was around 79.8 years. Therefore, the given statement is incorrect.