Measuring the Human Heart - Heartbeat, Blood Pressure, and Cardiac Output | Visible Body
Summary
TLDRThis video explores the mechanics of the human heart, focusing on heartbeat, blood pressure, and cardiac output. It explains the heart's size, weight, and the two phases of a heartbeat—systole and diastole. Viewers learn about how blood pressure is measured, the function of heart valves, and how cardiac output is calculated based on stroke volume and heart rate. The video emphasizes the importance of these metrics in understanding heart function and encourages using interactive 3D models to explore circulatory system anatomy.
Takeaways
- 💪 The human heart is a powerful organ, weighing around 300 grams, and is about the size of a fist.
- 🧔 Typically, an adult male's heart is larger than that of an adult female.
- 💓 The average resting heart rate is about 72 beats per minute.
- 🫀 The heartbeat results from the contraction and relaxation of the ventricles, the heart's lower chambers.
- 🔄 The heartbeat has two phases: systole (ventricles contract) and diastole (ventricles relax).
- 🔊 The sound of the heartbeat comes from the closing of the heart's valves during systole and diastole.
- 📊 Blood pressure is measured with two numbers: systolic pressure (when ventricles contract) and diastolic pressure (when ventricles relax).
- 🩸 The average systolic pressure is around 120 mmHg, while the average diastolic pressure is around 70 mmHg.
- 📏 Blood pressure is measured in millimeters of mercury (mmHg) using a sphygmomanometer.
- 🚴 Cardiac output, the volume of blood the heart pumps per minute, is calculated by multiplying stroke volume (average 70 mL) by heart rate (average 72 beats per minute), resulting in 5.4 liters per minute.
Q & A
What is the average weight of an adult human heart?
-The average adult human heart weighs around 300 grams, which is less than a pound.
How does the size of a male's heart compare to a female's heart?
-Typically, the heart of an adult male is slightly larger than the heart of an adult female.
How many times does the average human heart beat per minute at rest?
-The average human heart beats around 72 times per minute at rest.
What are the two phases of the heartbeat?
-The two phases of the heartbeat are systole, when the ventricles contract and pump blood out, and diastole, when the ventricles relax and fill with blood.
What causes the heartbeat sound?
-The heartbeat sound is caused by the closing of the heart's valves. During systole, the mitral and tricuspid valves close, while during diastole, the semilunar valves close.
How is blood pressure measured and what do the two numbers represent?
-Blood pressure is measured using two numbers. The systolic pressure represents the highest pressure when the ventricles contract, while the diastolic pressure represents the lowest pressure when the ventricles relax.
What is the average systolic and diastolic blood pressure?
-The average systolic pressure is around 120 millimeters of mercury, and the average diastolic pressure is around 70 millimeters of mercury.
What unit is used to measure blood pressure?
-Blood pressure is measured in millimeters of mercury (mmHg), which is a manometric unit used to measure force applied by a liquid.
How is cardiac output calculated?
-Cardiac output is calculated by multiplying the stroke volume (amount of blood pumped per beat) by the number of heartbeats per minute. For example, with a stroke volume of 70 milliliters and a heart rate of 72 beats per minute, the cardiac output would be 5040 milliliters, or 5.4 liters per minute.
How does cardiac output change with physical activity?
-Cardiac output increases with a higher heart rate, which is required during increased physical activity to supply more oxygenated blood to the body.
Outlines
🔍 Understanding the Heartbeat and Circulatory System
This introduction sets the stage for exploring the anatomy and function of the heart. It teases the learning journey ahead, involving the exploration of heartbeat, blood pressure, and cardiac output using 3D visuals and models. Before diving into details, it touches upon the heart's impressive power relative to its small size, comparing the weight of the average adult heart (around 300 grams) to the size of a fist, while noting the slight size difference between male and female hearts.
💓 What Makes Your Heartbeat?
This section focuses on the heart's rhythmic beating and how it circulates blood. It explains that the average human heart beats around 72 times per minute at rest. The heartbeat is powered by the contraction and relaxation of the ventricles, the heart’s lower chambers. These two phases of the heartbeat are introduced: systole (when the ventricles contract and pump blood) and diastole (when the ventricles relax).
🔊 The Sound of Your Heartbeat
The paragraph dives into the mechanics behind the sounds of a heartbeat. It describes how the closing of heart valves produces the characteristic sounds. During systole, the mitral and tricuspid valves close, while the semilunar valves open to allow blood out. During diastole, the semilunar valves close, and the mitral and tricuspid valves open to let blood flow into the ventricles from the atria.
📊 Blood Pressure: Understanding the Numbers
Blood pressure is explained here in terms of systolic and diastolic measurements. Systolic pressure is the maximum pressure on artery walls during the contraction of the heart's ventricles, with an average of 120 mmHg. Diastolic pressure measures the lowest pressure during ventricular relaxation, with an average of 70 mmHg. These numbers reflect the force exerted by blood against vessel walls.
🧪 What Are Millimeters of Mercury?
This part clarifies how blood pressure is measured. Blood pressure is recorded using a device called a sphygmomanometer and is measured in millimeters of mercury (mmHg). It explains that one millimeter of mercury represents the pressure exerted by a one-millimeter-high column of mercury, providing a standard for measuring the force of blood against arterial walls.
📈 Cardiac Output: Calculating Heart Efficiency
Cardiac output refers to the volume of blood the ventricles pump per minute. The calculation requires knowing the stroke volume (the amount of blood pumped with each heartbeat) and the heart rate (beats per minute). The average stroke volume is 70 milliliters, and multiplying this by an average heart rate of 72 bpm gives a cardiac output of 5.4 liters per minute. This value increases during physical activity due to the need for higher blood flow.
🖥️ Learning More with Visible Body Courseware
This final paragraph encourages the use of visual and interactive resources, such as the Visible Body Courseware, for learning about the circulatory system. It highlights the value of these tools for both teaching and studying human anatomy and physiology, inviting learners to explore more through the provided platform.
Mindmap
Keywords
💡Heart
💡Heartbeat
💡Systole
💡Diastole
💡Ventricles
💡Blood pressure
💡Systolic pressure
💡Diastolic pressure
💡Cardiac output
💡Stroke volume
Highlights
The average adult human heart weighs around 300 grams and is approximately the size of a fist.
At rest, the average human heart beats around 72 times per minute.
The heartbeat is caused by the contracting and relaxing of the heart's lower chambers, the ventricles.
A heartbeat has two phases: systole, when the ventricles contract, and diastole, when the ventricles relax.
During systole, the mitral and tricuspid valves close, and the semilunar valves open to allow blood to leave the heart.
During diastole, the semilunar valves close, and the mitral and tricuspid valves open, allowing blood to flow into the ventricles.
Blood pressure is measured using two numbers: systolic and diastolic pressures.
Systolic pressure measures the highest pressure on the artery walls when the ventricles contract; the average systolic pressure is 120 mmHg.
Diastolic pressure measures the lowest pressure when the ventricles relax; the average diastolic pressure is 70 mmHg.
Blood pressure is measured using a sphygmomanometer in millimeters of mercury, which refers to the amount of pressure exerted by a one-millimeter column of mercury.
Cardiac output refers to how much blood the ventricles pump per minute.
Cardiac output is calculated by multiplying the stroke volume by the number of heartbeats per minute.
The average stroke volume is 70 milliliters, and multiplying this by 72 beats per minute results in a cardiac output of 5.4 liters per minute.
Cardiac output increases with physical activity as the heart rate rises.
Visible Body Courseware offers interactive 3D visuals and tools to learn and teach about the anatomy and physiology of the circulatory system.
Transcripts
[Music]
have you ever wondered why your heart
makes that Telltale sound or how much
blood it pumps out each time it beats
today you'll learn all this and more as
we explore the heartbeat blood pressure
and cardiac output using the 3D visuals
and interactive Beating Heart model
invisible body courseware
before we get fancy let's talk about the
heart's size and weight for its size the
heart is quite a little Powerhouse the
average adult human heart weighs around
300 grams that's less than a pound and
is around the size of a fist
typically the heart of an adult male is
a bit larger than the heart of an adult
female
your heartbeat is something you can both
feel and hear at rest the average human
heart beats around 72 times per minute
the heartbeat you feel and what really
gets your blood pumping is the
Contracting and relaxing of the muscular
tissue of the heart's lower Chambers the
ventricles
chart beat has two phases systole in
which the muscles of the ventricles
contract and squeeze the blood out of
the heart and diastole which is when
those muscles relax
the heartbeat you can hear is the sound
of the valves between the chambers of
the heart closing during systole the
mitral valve and tricuspid valve close
the semilunar valves are open allowing
blood to leave the Heart during diastole
the semilunar valves close and the
mitral valve and tricuspid valve open
allowing blood to flow from the Atria to
fill the ventricles
when the ventricles contract and push
blood out of the heart this puts
pressure on the walls of the blood
vessels throughout the body
blood pressure is measured using two
numbers
the first number systolic pressure
measures the highest pressure against
the artery walls when the heart's
ventricles are contracted the average
systolic pressure is around 120
millimeters of mercury the second number
diastolic pressure measures the lowest
pressure against artery walls when the
heart's ventricles are relaxed
the average diastolic pressure is around
70 millimeters of mercury
what are millimeters of mercury blood
pressure is measured using a
sphygnomanometer and millimeters of
mercury are a manometric unit of
measurement that is they measure applied
force on a Surface by a liquid
essentially one millimeter of mercury is
the amount of pressure exerted by a
column of mercury one millimeter high
cardiac output is a specific measurement
that refers to how much blood the
ventricles pump every minute in order to
calculate it you'll need to know the
average stroke volume how much blood the
heart pumps per heartbeat and the number
of times the heart beats in a minute
then you'll need to do some math
the average stroke volume is 70
milliliters and let's say your heart
also beats the average amount of 72
beats per minute multiply the stroke
volume by the number of beats per minute
and you'll get 5040 milliliters or 5.4
liters per minute as your cardiac output
cardiac output increases with the higher
heart rate required for increased
physical activity
use Visual and interactive resources
like these to learn and teach about the
anatomy and physiology of the
circulatory system with visible body
courseware learn more at visiblebody.com
courseware
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