Problem 50
Question
A typical human contains \(5.0 \mathrm{~L}\) of blood, and it takes \(1.0 \mathrm{~min}\) for all of it to pass through the heart when the person is resting with a pulse rate of 75 heartbeats per minute. On the average, what volume of blood, in liters and cubic centimeters, does the heart pump during each beat?
Step-by-Step Solution
Verified Answer
The heart pumps approximately 0.0667 liters (66.7 cc) per beat.
1Step 1: Determine Total Volume of Blood
We know the total volume of blood in a human is 5.0 liters.
2Step 2: Calculate Volume of Blood Pumped Per Minute
Since all 5.0 liters of blood pass through the heart in 1 minute, the volume of blood pumped per minute is 5.0 liters.
3Step 3: Calculate the Volume Per Beat in Liters
The pulse rate is 75 beats per minute, so to find the volume per beat, divide the total volume per minute by the number of beats:\[ \text{Volume per beat} = \frac{5.0\, \text{liters}}{75\, \text{beats per minute}} \approx 0.0667\, \text{liters per beat} \]
4Step 4: Convert the Volume per Beat to Cubic Centimeters
Since 1 liter is equivalent to 1000 cubic centimeters (cc), convert the volume from liters to cubic centimeters:\[ 0.0667\, \text{liters per beat} \times 1000 \approx 66.7\, \text{cc per beat} \]
Key Concepts
Human Circulatory SystemCardiac OutputUnit ConversionBlood Volume
Human Circulatory System
The human circulatory system is like the highway of the body, delivering essential nutrients and oxygen to cells and carrying away waste products. It comprises the heart, blood vessels, and blood itself. Think of the heart as the engine, pumping blood throughout the network of arteries and veins.
The main function of this system is to maintain homeostasis by distributing oxygen and nutrients to tissues and organs and removing carbon dioxide and other wastes. Understanding how this system works gives you a foundation for comprehending more complex biophysical concepts. When you grasp the roles of the heart, blood, and vessels, you can better appreciate how life-sustaining substances reach every part of your body.
The main function of this system is to maintain homeostasis by distributing oxygen and nutrients to tissues and organs and removing carbon dioxide and other wastes. Understanding how this system works gives you a foundation for comprehending more complex biophysical concepts. When you grasp the roles of the heart, blood, and vessels, you can better appreciate how life-sustaining substances reach every part of your body.
Cardiac Output
Cardiac output is a critical measure of heart function. It represents the total volume of blood the heart pumps per minute. This is significant because it reflects how well your heart is supplying the rest of your body with blood.
To calculate cardiac output, you multiply the heart rate (the number of beats per minute) by the stroke volume (the volume of blood pumped from the heart with each beat). For our problem, we figured out the stroke volume by dividing the total liters per minute ( 5.0 ext{ liters}) by the heart rate ( 75 ext{ beats per minute}).
To calculate cardiac output, you multiply the heart rate (the number of beats per minute) by the stroke volume (the volume of blood pumped from the heart with each beat). For our problem, we figured out the stroke volume by dividing the total liters per minute ( 5.0 ext{ liters}) by the heart rate ( 75 ext{ beats per minute}).
- Cardiac Output = Heart Rate × Stroke Volume
- Determining cardiac output helps in diagnosing and understanding various heart conditions.
Unit Conversion
Unit conversion is a fundamental skill in science, important for making measurements understandable and comparable. In biophysics, it is essential when dealing with volumes, masses, and temperatures across different systems. For instance, converting between liters and cubic centimeters is a simple yet frequently necessary task due to the varying scales used in scientific measurements.
For example, remember that 1 liter equals 1000 cubic centimeters. So, converting 0.0667 liters to cubic centimeters involves multiplying by 1000, yielding approximately 66.7 cc. This conversion consolidates understanding and ensures consistency, especially for medical professionals and researchers who rely on precise data.
Practicing these conversions helps build confidence and aids in tackling more complex problems, where maintaining accuracy is key to successful analysis and experimentation.
For example, remember that 1 liter equals 1000 cubic centimeters. So, converting 0.0667 liters to cubic centimeters involves multiplying by 1000, yielding approximately 66.7 cc. This conversion consolidates understanding and ensures consistency, especially for medical professionals and researchers who rely on precise data.
Practicing these conversions helps build confidence and aids in tackling more complex problems, where maintaining accuracy is key to successful analysis and experimentation.
Blood Volume
Blood volume refers to the total amount of blood circulating within the body at a given time. For an average adult, this is around 5 liters. Blood volume plays a key role in homeostasis and is vital for efficient function of the circulatory system.
When you know the blood volume, you can understand how pressure and flow impact the cardiovascular system's performance. Detecting changes in blood volume can indicate various medical conditions. For instance:
When you know the blood volume, you can understand how pressure and flow impact the cardiovascular system's performance. Detecting changes in blood volume can indicate various medical conditions. For instance:
- Decreased blood volume (hypovolemia) can result from dehydration or blood loss.
- Increased blood volume can be due to fluid retention from conditions like heart failure.
Other exercises in this chapter
Problem 48
Baseball mass. Baseball rules specify that a regulation ball shall weigh no less than 5.00 ounces and no more than \(5 \frac{1}{4}\) ounces. What are the accept
View solution Problem 49
Velocity vector \(A\) has components \(A_{x}=3 \mathrm{~m} / \mathrm{s}\) and \(A_{y}=4 \mathrm{~m} / \mathrm{s}\) A second velocity vector \(\vec{B}\) has a ma
View solution Problem 52
A woman starts from her house and begins jogging down her street. In order to keep a record of her workout, she carries a stopwatch and records the time it take
View solution Problem 53
While surveying a cave, a spelunker follows a passage \(180 \mathrm{~m}\) straight west, then \(210 \mathrm{~m}\) in a direction \(45^{\circ}\) east of south, a
View solution