June 12, 2026 • 11 mins
Your heart needs blood as much as any other muscle in your body, and it receives it the same way -- just a little earlier than anyone else. Learn how the coronary arteries work (and what can go wrong when they don't) in this episode of BrainStuff, based on this article: https://health.howstuffworks.com/human-body/systems/circulatory/heart-pump-blood.htm
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Episode Transcript
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Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeartRadio. Hey brain Stuff,
Lauren Vogelbaum. Here. Your heart works NonStop to deliver nutrient
rich blood to every part of your body, but its
first priority is always to take care of number one, A,
meaning itself. You can think of it sort of like this.
(00:24):
When you deposit money into a checking account, you establish
a system where all of your money passes from you
to your bank and then follows one of two paths.
It may either earn interest while the bank loans it out,
or it may scatter to pay for your various expenses,
but the bank most likely ear marks some small portion
(00:45):
of those funds for itself. First. When you look at
your monthly statement, you'll see all of the deductions you
made from your account, and there at the top a
monthly checking fee from the bank. Your heart handles blood
in pretty much the same way. In the average adult human,
the heart pumps about two thousand gallons of blood a
(01:06):
day through its chambers. That's about seven five hundred liters.
Of course, the average adult human does not hold that
much blood. The heart is pumping the same blood over
and over. Your heart beats about one hundred thousand times
every day to supply the cells in your body with
freshly oxygenated blood. That's a seriously powerful muscle, and it
(01:28):
means that even though your heart's function is to provide
other muscles with blood, it needs its own supply too. Today,
let's talk about how your heart gets that blood and
what can go wrong when it doesn't. Your heart receives
oxygenated blood in the same way that your brain, your feet,
and the rest of your body does through an artery,
(01:51):
but the heart takes the very first cut of the
good stuff arriving in from the lungs, just as the
bank makes sure its fees are paid first. To mix
our metaphors, the heart basically has its own freeway exit
for fresh blood that it's just pumping out. The oxygenated
blood coming out of the heart is getting on the
freeway to the rest of your body, and a little
(02:12):
bit gets off at the first overpass and takes a
side road back into the heart. But okay, let's back
up a little. Your heart is divided into four chambers,
the left atrium and left ventricle, and then the right
atrium and right ventricle. The left side is receiving fresh,
oxygen rich blood from your lungs, then sending it through
(02:33):
the left atrium down into the left ventricle, where the
heart's contractions forces it throw valve into the aorta at
one of the heart's main outward bound pipelines. The right atrium,
on the other hand, handles oxygen poor blood coming in
from all over the body and ships it down into
the right ventricle. From there, the heart's contractions force this
(02:55):
less than fresh blood out into the pulmonary artery, which
forwards it to the lung for reoxygenation. The heart can't
just take its oxygens straight from the blood that's constantly
passing through its chambers, partially because if that were the
way it worked, the cells on the right side of
the heart that intakes used blood from the body would
(03:15):
be out of luck, so the rest of the body
doesn't want the heart's cast offs. If the heart replenished
its own oxygen supply directly from the river of blood
flowing through it, the blood leaving the heart would have
less oxygen to deliver to the body. Instead, the muscle
exercises some restraint and feeds itself through arteries that run
(03:36):
off of the aorda, just like every other part of
the body. These arteries are called appropriately the left and
right coronary arteries. Once the aorta leaves the heart, blood
can branch off almost immediately into the coronary arteries. The
left coronary artery feeds the left side of the heart
(03:57):
and usually splits into two large branches, the left anterior
descending which descends down the front of the heart, and
the left circumflex, which winds back around the heart. The
right cornary artery supplies the right side of the heart
and the nodes that provide electrical signals to the heart.
Plus it branches off into the posterior descending artery, which
(04:19):
descends down the back of the heart. Interestingly, we don't
all have the same network of arteries feeding our hearts.
Some people have a third main coronary artery that juts
off of the aorta, and others have only a single
main coronary artery. Sometimes it's the right one instead of
the left, that branches into two more arteries. Regardless of
(04:41):
these harmless differences, the result is the same. The arteries
branch off in two smaller arteries, and all the arteries
and their branches wrap around the heart sort of like
a crown, hence the term coronary. This way, all of
the heart's tissues receive a fresh blood supply, giving it
the fuel it needs to pump day in and day out.
(05:03):
But what happens if something goes wrong? Problems and blockages
in the coronary arteries are what cause heart attacks. These
arteries start out big, soft, and smooth inside. They're usually
around three to four millimeters in diameter, which is a
little bit over a tenth of an inch, or around
the size of a cocktail straw. But as we grow older,
(05:25):
we can damage those once supple arteries via wear and tear, stress,
fatty and salty foods, and not getting enough exercise. Over
the decades, they collect plaque, which are fatty deposits along
their inner walls, causing the arteries to harden and narrow.
This condition is known as arthrosclerosis. Unchecked, it can develop
(05:47):
into coronary artery disease, also known as coronary heart disease.
As this condition advances, a number of things can happen.
For example, if a portion of your heart muscle is
receiving some but not enough oxygen due to partially blocked arteries,
your heart won't be happy about it. The muscle will
file a formal complaint with you in the form of
(06:10):
chest pain called angina. This can feel like pressure or
burning in your chest, like it's difficult to draw breath, or,
especially in women, like discomfort in the neck, jaw, or back,
maybe along with a stabbing chest or stomach pain. Angina
usually happens when you start exerting yourself, maybe if you're
(06:31):
climbing a flight of stairs or taking a brisk walk,
and will usually go away within a couple minutes once
you've had a chance to rest. You know, your heart
doesn't require much oxygen when you're sitting by the pool,
so it's usually fine, but the muscle will start feeling
the lack of oxygen when you start swimming laps. This
is called stable angina. It's something to pay attention to
(06:55):
and inform a healthcare provider about, but it's not an emergency.
Is an emergency is if you feel angina when you're
at rest, especially if it's severe and keeps going for
twenty minutes or longer. This is called unstable angina and
requires immediate medical attention because it means the heart isn't
(07:15):
getting enough blood to do its job period. Another thing
that can go wrong with the plaque build up inside
of your coronary arteries is sort of counterintuitive. You would
think that if one of these obstacles broke open, that
would be a good thing, but it can result in
a blood clot forming at the sight of the rupture
in the plaque. This little clot can totally block the artery.
(07:37):
Within minutes, heart tissue downstream of the artery will basically suffocate,
damaging the muscle. This is what's called a heart attack
or myocardial infarction. Similar symptoms apply a discomfort or pain
in the chest up through the jaw or down the
arm or back, shortness of breath, weakness or dizziness, and
(07:58):
sometimes a lot of nausea and sweating. And you probably
know this, but I'm going to say it anyway, this
is definitely a medical emergency, like to the point that
you should call medical professionals to send you help right away,
like dialing nine to one one instead of trying to
get yourself to a doctor. All of this can be
really scary, but there are lots of ways that healthcare
(08:21):
providers can help get a dangerously blocked coronary artery up
and running again. For example, Balloon angioplasty. This procedure uses
a tiny medical grade balloon to open a clogged artery
near the groin or in the arm. The provider accesses
a blood vessel that leads to an artery that leads
(08:41):
to the heart. They'll insert one or more wires and
catheters and thread them up through the artery using special
dye and an X ray machine. They'll find any blockages.
Once found, they lead the catheter to the blockage and
briefly inflate a tiny balloon on the tip to push
the plaque aside and allow blood to flow more freely.
(09:04):
This won't stop the arteries from blocking again, but it
will help prevent an emergency and ease any discomfort that
you're experiencing. Sometimes, in addition to or instead of an antioplasty,
a metal or plastic tube called a stent may be
inserted into a blocked artery to help prop it open.
Doctors may perform angioplasty and stenting on a patient before, after,
(09:28):
or during a heart attack. Some cardiologists prefer just stenting
without angioplasty. The drawback of this procedure is that stents
can clog just like your arteries. The upside to these
procedures is that they're relatively non invasive. The patient can
be awake, though mildly sedated. If things are a little
(09:49):
more serious, a provider may perform what's called a coronary
artery bypass graft. During this procedure, the provider temporarily stops
the heart and sets up artificial respiration. A vainer artery
that won't be missed too much is taken from somewhere
else in the body, possibly your arm or leg. Surgeons
attach one end of the graft to the a orda
(10:11):
and the other end to the artery on the far
side of the blockage. This detour enables blood to bypass
the blockage and flow unobstructed. When you hear the terms double, triple,
or even quadruple bypass surgery, it refers to the number
of arteries receiving bypass graphs. Of course, these procedures are
(10:32):
only part of a treatment plan for making sure that
your hard working heart gets the blood supply that it needs.
A health care provider may prescribe medications or recommend basically
cardiac physical therapy in the form of exercise or changes
to your diet or mental health care to help with
anxiety and stress. As always, if you're concerned about yourself
(10:53):
or a loved one, talking to a medical professional should
be the first step. There's a lot of information and
mis information out there about what's healthy, and they'll be
able to help you personally, cut through the noise and
keep that blood flowing. Today's episode is based on the
(11:13):
article how and why does the heart pump blood to
itself on how stuffworks dot com, written by Tom Sheeve.
Brain Stuff is production of iHeartRadio in partnership with HowStuffWorks
dot Com, and it is produced by Tyler Klang. Four
more podcasts from my heart Radio. Visit the iHeartRadio app,
Apple Podcasts, or wherever you listen to your favorite shows.
Welcome to Brainstuff, a production of iHeartRadio. Hey brain Stuff,
Lauren Vogelbaum. Here. Your heart works NonStop to deliver nutrient
rich blood to every part of your body, but its
first priority is always to take care of number one, A,
meaning itself. You can think of it sort of like this.
(00:24):
When you deposit money into a checking account, you establish
a system where all of your money passes from you
to your bank and then follows one of two paths.
It may either earn interest while the bank loans it out,
or it may scatter to pay for your various expenses,
but the bank most likely ear marks some small portion
(00:45):
of those funds for itself. First. When you look at
your monthly statement, you'll see all of the deductions you
made from your account, and there at the top a
monthly checking fee from the bank. Your heart handles blood
in pretty much the same way. In the average adult human,
the heart pumps about two thousand gallons of blood a
(01:06):
day through its chambers. That's about seven five hundred liters.
Of course, the average adult human does not hold that
much blood. The heart is pumping the same blood over
and over. Your heart beats about one hundred thousand times
every day to supply the cells in your body with
freshly oxygenated blood. That's a seriously powerful muscle, and it
(01:28):
means that even though your heart's function is to provide
other muscles with blood, it needs its own supply too. Today,
let's talk about how your heart gets that blood and
what can go wrong when it doesn't. Your heart receives
oxygenated blood in the same way that your brain, your feet,
and the rest of your body does through an artery,
(01:51):
but the heart takes the very first cut of the
good stuff arriving in from the lungs, just as the
bank makes sure its fees are paid first. To mix
our metaphors, the heart basically has its own freeway exit
for fresh blood that it's just pumping out. The oxygenated
blood coming out of the heart is getting on the
freeway to the rest of your body, and a little
(02:12):
bit gets off at the first overpass and takes a
side road back into the heart. But okay, let's back
up a little. Your heart is divided into four chambers,
the left atrium and left ventricle, and then the right
atrium and right ventricle. The left side is receiving fresh,
oxygen rich blood from your lungs, then sending it through
(02:33):
the left atrium down into the left ventricle, where the
heart's contractions forces it throw valve into the aorta at
one of the heart's main outward bound pipelines. The right atrium,
on the other hand, handles oxygen poor blood coming in
from all over the body and ships it down into
the right ventricle. From there, the heart's contractions force this
(02:55):
less than fresh blood out into the pulmonary artery, which
forwards it to the lung for reoxygenation. The heart can't
just take its oxygens straight from the blood that's constantly
passing through its chambers, partially because if that were the
way it worked, the cells on the right side of
the heart that intakes used blood from the body would
(03:15):
be out of luck, so the rest of the body
doesn't want the heart's cast offs. If the heart replenished
its own oxygen supply directly from the river of blood
flowing through it, the blood leaving the heart would have
less oxygen to deliver to the body. Instead, the muscle
exercises some restraint and feeds itself through arteries that run
(03:36):
off of the aorda, just like every other part of
the body. These arteries are called appropriately the left and
right coronary arteries. Once the aorta leaves the heart, blood
can branch off almost immediately into the coronary arteries. The
left coronary artery feeds the left side of the heart
(03:57):
and usually splits into two large branches, the left anterior
descending which descends down the front of the heart, and
the left circumflex, which winds back around the heart. The
right cornary artery supplies the right side of the heart
and the nodes that provide electrical signals to the heart.
Plus it branches off into the posterior descending artery, which
(04:19):
descends down the back of the heart. Interestingly, we don't
all have the same network of arteries feeding our hearts.
Some people have a third main coronary artery that juts
off of the aorta, and others have only a single
main coronary artery. Sometimes it's the right one instead of
the left, that branches into two more arteries. Regardless of
(04:41):
these harmless differences, the result is the same. The arteries
branch off in two smaller arteries, and all the arteries
and their branches wrap around the heart sort of like
a crown, hence the term coronary. This way, all of
the heart's tissues receive a fresh blood supply, giving it
the fuel it needs to pump day in and day out.
(05:03):
But what happens if something goes wrong? Problems and blockages
in the coronary arteries are what cause heart attacks. These
arteries start out big, soft, and smooth inside. They're usually
around three to four millimeters in diameter, which is a
little bit over a tenth of an inch, or around
the size of a cocktail straw. But as we grow older,
(05:25):
we can damage those once supple arteries via wear and tear, stress,
fatty and salty foods, and not getting enough exercise. Over
the decades, they collect plaque, which are fatty deposits along
their inner walls, causing the arteries to harden and narrow.
This condition is known as arthrosclerosis. Unchecked, it can develop
(05:47):
into coronary artery disease, also known as coronary heart disease.
As this condition advances, a number of things can happen.
For example, if a portion of your heart muscle is
receiving some but not enough oxygen due to partially blocked arteries,
your heart won't be happy about it. The muscle will
file a formal complaint with you in the form of
(06:10):
chest pain called angina. This can feel like pressure or
burning in your chest, like it's difficult to draw breath, or,
especially in women, like discomfort in the neck, jaw, or back,
maybe along with a stabbing chest or stomach pain. Angina
usually happens when you start exerting yourself, maybe if you're
(06:31):
climbing a flight of stairs or taking a brisk walk,
and will usually go away within a couple minutes once
you've had a chance to rest. You know, your heart
doesn't require much oxygen when you're sitting by the pool,
so it's usually fine, but the muscle will start feeling
the lack of oxygen when you start swimming laps. This
is called stable angina. It's something to pay attention to
(06:55):
and inform a healthcare provider about, but it's not an emergency.
Is an emergency is if you feel angina when you're
at rest, especially if it's severe and keeps going for
twenty minutes or longer. This is called unstable angina and
requires immediate medical attention because it means the heart isn't
(07:15):
getting enough blood to do its job period. Another thing
that can go wrong with the plaque build up inside
of your coronary arteries is sort of counterintuitive. You would
think that if one of these obstacles broke open, that
would be a good thing, but it can result in
a blood clot forming at the sight of the rupture
in the plaque. This little clot can totally block the artery.
(07:37):
Within minutes, heart tissue downstream of the artery will basically suffocate,
damaging the muscle. This is what's called a heart attack
or myocardial infarction. Similar symptoms apply a discomfort or pain
in the chest up through the jaw or down the
arm or back, shortness of breath, weakness or dizziness, and
(07:58):
sometimes a lot of nausea and sweating. And you probably
know this, but I'm going to say it anyway, this
is definitely a medical emergency, like to the point that
you should call medical professionals to send you help right away,
like dialing nine to one one instead of trying to
get yourself to a doctor. All of this can be
really scary, but there are lots of ways that healthcare
(08:21):
providers can help get a dangerously blocked coronary artery up
and running again. For example, Balloon angioplasty. This procedure uses
a tiny medical grade balloon to open a clogged artery
near the groin or in the arm. The provider accesses
a blood vessel that leads to an artery that leads
(08:41):
to the heart. They'll insert one or more wires and
catheters and thread them up through the artery using special
dye and an X ray machine. They'll find any blockages.
Once found, they lead the catheter to the blockage and
briefly inflate a tiny balloon on the tip to push
the plaque aside and allow blood to flow more freely.
(09:04):
This won't stop the arteries from blocking again, but it
will help prevent an emergency and ease any discomfort that
you're experiencing. Sometimes, in addition to or instead of an antioplasty,
a metal or plastic tube called a stent may be
inserted into a blocked artery to help prop it open.
Doctors may perform angioplasty and stenting on a patient before, after,
(09:28):
or during a heart attack. Some cardiologists prefer just stenting
without angioplasty. The drawback of this procedure is that stents
can clog just like your arteries. The upside to these
procedures is that they're relatively non invasive. The patient can
be awake, though mildly sedated. If things are a little
(09:49):
more serious, a provider may perform what's called a coronary
artery bypass graft. During this procedure, the provider temporarily stops
the heart and sets up artificial respiration. A vainer artery
that won't be missed too much is taken from somewhere
else in the body, possibly your arm or leg. Surgeons
attach one end of the graft to the a orda
(10:11):
and the other end to the artery on the far
side of the blockage. This detour enables blood to bypass
the blockage and flow unobstructed. When you hear the terms double, triple,
or even quadruple bypass surgery, it refers to the number
of arteries receiving bypass graphs. Of course, these procedures are
(10:32):
only part of a treatment plan for making sure that
your hard working heart gets the blood supply that it needs.
A health care provider may prescribe medications or recommend basically
cardiac physical therapy in the form of exercise or changes
to your diet or mental health care to help with
anxiety and stress. As always, if you're concerned about yourself
(10:53):
or a loved one, talking to a medical professional should
be the first step. There's a lot of information and
mis information out there about what's healthy, and they'll be
able to help you personally, cut through the noise and
keep that blood flowing. Today's episode is based on the
(11:13):
article how and why does the heart pump blood to
itself on how stuffworks dot com, written by Tom Sheeve.
Brain Stuff is production of iHeartRadio in partnership with HowStuffWorks
dot Com, and it is produced by Tyler Klang. Four
more podcasts from my heart Radio. Visit the iHeartRadio app,
Apple Podcasts, or wherever you listen to your favorite shows.
BrainStuff News
Host
Lauren Vogelbaum
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