FETAL CIRCULATION
Summary
TLDRThis educational video script delves into fetal circulation, highlighting its distinct structures and processes compared to postnatal circulation. It emphasizes the role of the placenta and umbilical cord in oxygen and nutrient delivery, bypassing the lungs which are inactive in this stage. Key fetal circulation features include the foramen ovale, ductus arteriosus, and ductus venosus, facilitating blood flow. The script guides viewers through a flowchart for clearer understanding and concludes with postnatal changes where these fetal structures close, adjusting circulation for lung involvement in oxygenation.
Takeaways
- 🌟 Fetal circulation is also known as prenatal circulation and is distinct from postnatal circulation due to structural differences.
- 🩸 The placenta and umbilical cord are central to fetal circulation, carrying oxygenated blood from the mother to the fetus.
- 💙 The umbilical vein carries oxygenated blood, while the two umbilical arteries carry deoxygenated blood, which is contrary to the adult circulation.
- 🫀 The foramen ovale is an opening between the right and left atria in the fetal heart, allowing blood to bypass the lungs and enter the systemic circulation.
- 🔄 The ductus arteriosus is a shunt between the pulmonary artery and the aorta, directing blood away from the non-functioning lungs and into the systemic circulation.
- 🔄 The ductus venosus is a connection between the umbilical vein and the inferior vena cava, allowing oxygenated blood to bypass the liver.
- 🌀 Blood from the umbilical vein supplies the liver and the rest goes to the inferior vena cava, where it mixes with deoxygenated blood from the superior vena cava.
- 🚫 The lungs are not involved in fetal circulation as the fetus obtains oxygen and nutrients directly from the mother through the placenta.
- 🛑 Postnatal changes include the closure of the foramen ovale, which becomes the fossa ovalis, and the closure of the ductus arteriosus.
- 📚 Understanding the fetal circulation can be aided by creating a flowchart, which helps to visualize and remember the complex pathways of blood flow.
Q & A
What is fetal circulation?
-Fetal circulation, also known as fetal placental circulation or prenatal circulation, refers to the blood circulation that occurs during the prenatal period in a fetus. It is distinct from postnatal circulation due to several structural differences.
How does fetal circulation differ from postnatal circulation?
-In fetal circulation, the lungs are not involved as the fetus obtains oxygen and nutrients from the mother through the placenta. In postnatal circulation, the lungs play a crucial role in oxygenating the blood.
What are the key structures involved in fetal circulation?
-The key structures involved in fetal circulation include the placenta, umbilical cord, foramen ovale, ductus arteriosus, and ductus venosus.
What is the role of the placenta in fetal circulation?
-The placenta performs respiratory, nutritive, and supportive functions for the fetus, facilitating the exchange of oxygen, nutrients, and waste products between the fetus and the mother.
How does the umbilical cord contribute to fetal circulation?
-The umbilical cord contains one umbilical vein carrying oxygenated blood from the placenta to the fetus and two umbilical arteries carrying deoxygenated blood back to the placenta.
What is the foramen ovale and its function in fetal circulation?
-The foramen ovale is an opening between the right atrium and left atrium of the fetal heart, allowing blood to bypass the pulmonary circulation and directly enter the systemic circulation.
Describe the ductus arteriosus and its significance in fetal circulation.
-The ductus arteriosus is a connection between the pulmonary artery and the aorta, allowing blood to bypass the lungs and be circulated systemically. It is essential for fetal circulation as the lungs are not used for respiration.
What is the ductus venosus and its role in fetal circulation?
-The ductus venosus is a connection between the umbilical vein and the inferior vena cava, allowing a portion of the oxygenated blood from the placenta to bypass the liver and directly enter the heart.
How does blood flow through the fetal heart?
-In fetal circulation, blood from the umbilical vein flows into the liver and then divides, with some going to the inferior vena cava and some bypassing the lungs through the foramen ovale. Blood from the superior and inferior vena cava enters the right atrium, and most of it moves to the left atrium, while some goes to the right ventricle and then to the pulmonary artery, which is connected to the aorta via the ductus arteriosus.
What are the postnatal changes that occur in the fetal circulation structures?
-After birth, the foramen ovale closes and becomes the fossa ovalis, and the ductus arteriosus constricts and closes, eventually becoming a fibrous cord known as the ligamentum arteriosum. These changes are necessary for the transition to postnatal circulation.
Why is it important to understand fetal circulation for medical professionals?
-Understanding fetal circulation is crucial for medical professionals to diagnose and manage conditions related to fetal development, such as issues with the placenta or umbilical cord, and to understand the transition to postnatal circulation.
Outlines
🌀 Introduction to Fetal Circulation
The paragraph introduces the concept of fetal circulation, also known as prenatal circulation, which is distinct from postnatal circulation due to structural differences. It emphasizes that during prenatal circulation, the lungs are not involved, and the fetus obtains oxygen and nutrients from the mother via the placenta. The paragraph sets the stage for a detailed discussion of the structures involved in fetal circulation, such as the placenta, umbilical cord, and specific blood vessels. It also mentions the use of a flowchart to aid in understanding the complex circulation process.
🔍 Structures Involved in Fetal Circulation
This section delves into the structures that are unique to fetal circulation: the placenta, umbilical cord with its two arteries and one vein, foramen ovale, ductus arteriosus, and ductus venosus. It explains the roles of these structures, highlighting that the umbilical vein carries oxygenated blood, unlike typical veins, and the umbilical arteries carry deoxygenated blood, mirroring the pulmonary arteries in postnatal circulation. The foramen ovale is described as an opening between the atria of the heart that allows blood to bypass the lungs, a critical adaptation for fetal life.
🚀 Detailed Flow of Fetal Circulation
The paragraph provides a detailed explanation of the flow of blood in fetal circulation. It describes how blood from the placenta travels through the umbilical vein, partially to the liver and then through the ductus venosus to the inferior vena cava, and how most of it bypasses the pulmonary circulation through the foramen ovale. It also explains how blood from the right ventricle enters the pulmonary artery and, through the ductus arteriosus, is shunted into the aorta, avoiding the lungs. The paragraph concludes with a visual reference to a diagram that illustrates these pathways.
🔄 Continuation of Fetal Circulation Pathways
This paragraph continues the description of fetal circulation, focusing on the return path of blood to the placenta. It explains that blood from the aorta goes down the descending aorta, into the internal iliac arteries, and then forms the umbilical arteries that enter the umbilical cord, completing the circuit by delivering deoxygenated blood back to the placenta for reoxygenation. The paragraph reinforces the understanding of fetal circulation with a visual aid, making the complex process more accessible.
🛑 Postnatal Changes in Circulation
The final paragraph discusses the critical changes that occur after birth to transition from fetal to neonatal circulation. It explains that the foramen ovale, which allowed blood to bypass the lungs in fetal circulation, closes after birth, becoming the fossa ovalis. Similarly, the ductus arteriosus, which connected the pulmonary artery to the aorta, closes postnatally. These closures are essential for the newborn to establish normal pulmonary circulation as the lungs begin to function in gas exchange.
Mindmap
Keywords
💡Fetal Circulation
💡Placental Circulation
💡Umbilical Cord
💡Foramen Ovale
💡Ductus Arteriosus
💡Ductus Venosus
💡Postnatal Circulation
💡Oxygenation
💡Structural Differences
💡Circulatory System
💡Blood Vessels
Highlights
Fetal circulation is also known as prenatal circulation, occurring during the prenatal period.
Structural differences exist between prenatal and postnatal circulation.
Lungs are not involved in fetal circulation; fetus obtains oxygen and nutrients from the mother through the placenta.
Fetal circulation includes blood vessels within the placenta called umbilical arteries and vein.
Umbilical arteries carry deoxygenated blood, while the umbilical vein carries oxygenated blood.
Foramen ovale is an opening between the right and left atria in the fetal heart.
Ductus arteriosus is a connection between the pulmonary artery and the aorta in fetal circulation.
Ductus venosus is a connection between the umbilical vein and the inferior vena cava.
The placenta performs respiratory, nutritive, and supportive functions for the fetus.
The fetal heart's right side contains deoxygenated blood, while the left side contains oxygenated blood.
Blood from the umbilical vein bypasses the lungs and enters the systemic circulation through the foramen ovale.
Ductus arteriosus allows blood to be shunted away from the lungs and into the aorta.
Ductus venosus helps direct oxygenated blood from the umbilical vein to the inferior vena cava.
After birth, the foramen ovale closes and becomes the fossa ovalis.
The ductus arteriosus closes after birth, and failure to close results in patent ductus arteriosus.
Understanding the fetal circulation involves learning about the placenta, umbilical cord, foramen ovale, ductus arteriosus, and ductus venosus.
A flowchart is a helpful tool for remembering the steps of fetal circulation.
The video suggests creating a flowchart to better understand and remember fetal circulation.
Transcripts
today we are going to discuss about the
fetal circulation fetal circulation or
fetal placental circulation fetal
circulation is also referred to as
prenatal circulation because this is the
circulation that is happening during the
prenatal period and is the circulation
same as that in the postnatal period no
there are many structural differences
during the prenatal circulation and the
postnatal circulation so in this topic
in this video we are going to mainly
discuss about the circulation during the
prenatal period or in the fetus and what
are the structures that are involved in
the circulation during the fetal life so
the fetal circulation or the feed of
placental circulation it includes the
efforts of um glycol called the blood
vessels within the placenta that carry
the fetal blood so here we can find the
involvement of unlike al called
blood vessels and the placenta that
carries the fetal blood and the lungs
are not involved in this type of
circulation this is the main difference
that we see in the prenatal circulation
and the postnatal circulation in the
postnatal circulation or in adult human
body or even after even after just the
birth of the baby when the normal the
normal circulation starts the lungs are
actively involved in the process of
circulation they have a very important
responsibility of carrying out the
oxygenation of the blood but here the
lungs are not involved the fetus obtains
its oxygen and nutrients from the mother
through the placenta and Liam like--all
called so this was just an introduction
about the feat of placental circulation
now we are going to understand about
this feat of placental circulation and
here we are going to take the help of a
flow chart because when we will be
understanding that flow chart it will be
easy to remember all these all these
steps of the circulation so this is the
fetal circulation this picture
many times we all see whenever we study
about the fetal circulation in any book
or from any source this is a very
commonly seen picture but but this is
very difficult to understand that what
kind of circulation is taking place
among these chambers these points we are
going to discuss here in a very simple
way so right now I am NOT explaining the
picture but first of all for
understanding the fetal circulation what
we need to understand is the structures
involved in the fetal circulation so the
first structure that is involved is
placenta and the unlike al called
then second is the blood vessels in the
M like--all cord
third is foramen ovale fourth ductus
arteriosus fifth ductus venosus these
are the these are the structures that
are different from the postnatal
circulation all these structures you
will never find in a postnatal or adult
human body circulation but these are
found in the fetal circulation so before
going to the fetal circulation first of
all we need to understand about these
structures so we will be dealing with
them one by one this is this is the
picture of the placenta and the
umbilical cord here you can see this is
the placenta placenta is is performing
many functions the respiratory function
the nutritive functions the support for
the fetus all these functions are
performed by the placenta then it is
covered by two layers amnion and chorion
and from the placenta comes out your
unlike al cord this is the unlike al
cord which is covered by the Wharton's
jelly and this is the whole structure of
the placenta and the unlike al cord then
when we take a cross section of the am
like alcott we can easily find the blood
vessels in the M like al ghad' see here
this this is the cross section of um
glycol code here that
two vessels are the imply chol arteries
and this one the red and color is the
unlike L win normally what we see is the
arteries carry oxygenated blood and the
veins carry deoxygenated blood but there
are two exceptions in the body one is
the unlike a lottery which carry the
deoxygenated blood and the other one is
the pulmonary artery which also carries
deoxygenated blood the pulmonary
arteries are seen in the postnatal
circulation and this unlikely arteries
play their role in the prenatal
circulation then similarly the vein
which usually carry deoxygenated blood
but here in the fetal circulation the
unlike L vein is the vein or the blood
vessel that carries the oxygenated blood
so this is the main thing that you need
to always keep in mind while studying
about the fetal circulation that there
is only one unlike L vein in the M
like--all called that carries oxygenated
blood and there are two unlike a
lotteries in the umbilical cord which
carry the deoxygenated blood
now the third structure that we are
going to look upon as the foramen ovale
foramen means an opening so this foramen
ovale is a opening between the right
atrium and the left atrium this is the
structure of the heart this the here you
can see the four chambers of the heart
this one is the right atrium this is the
right ventricle this is the left atrium
and this one is the left ventricle the
right side of the heart mainly contains
the deoxygenated blood whereas the left
side of the heart contains the
oxygenated blood during the fetal life
during the prenatal period there is a
opening between the right atrium and the
left atrium which allows the blood
coming through the inferior vena cava
and the superior vena cava to bypass the
pulmonary circulation and directly enter
into the systemic circulation through
the left atrium so the
opening that you are seeing here is
known as foramen ovale and this is
playing a very important role in the
fetal circulation you can see the arrows
pointing both face it means that the
blood can either shift from the right
atrium to the left atrium or can also
come from the left atrium to the right
atrium but the main thing to remember is
the pressure in the right side of the
heart is more than the left side of the
heart therefore the movement of the
blood is always is mainly in from the
right atrium to the left atrium so this
opening is known as foramen ovale this
was the third structure that was to be
discovered and that was to be discussed
for understanding the fetal circulation
now we are coming on to the fourth
structure that is ductus arteriosus the
meaning of ductus arteriosus is a
connection between the two arteries
arteriosus means arteries and ductus
arteriosus represents a connection or a
shunt between the two arteries so if you
see here this one is the pulmonary
artery this is coming out from the right
ventricle and this is the pulmonary
artery whereas this is the IATA
this is coming out from the left
ventricle and this is Iota and you can
see here the arrow pointing in this area
this area represents the ductus
arteriosus this is the area where both
the arteries the IATA and the pulmonary
artery are forming a connection and this
connection is known as ductus arteriosus
here patent ductus is written this is
written paetynn means open if this is
the heart of a adult human being then
this ductus arteriosus must be closed
normally the ductus arteriosus closes
after the birth but when this remains
open this condition is known as patent
ductus arteriosus by
when we have to study about the fetal
circulation then this condition will be
considered as normal so this is the
ductus arteriosus that is our opening
between two arteries the pulmonary
arteries and the IATA then the next
structure defect structure which we need
to discuss is the ductus venosus as the
ductus arteriosus meant the connection
between two arteries here the ductus
venosus means the connection between two
veins now we have to see that what which
are those two veins which are connected
so if you see here this light blue color
vein is the unlike Alvin the unlike
Alvin is coming this is the liver and
one part of the umbilical vein is
supplying the blood to the left portal
vein to the left portal vein whereas the
other part is forming a connection with
the inferior vena cava this one is the
inferior vena cava this is your arm like
a vein and here this is the connection
between the two veins unlike al vein and
the inferior vena cava and this
connection is known as ductus venosus
this is also a common or normal finding
in the fetal circulation but if found in
the in the adult circulation or after
birth then this is considered to be an
abnormality
so this opening sorry this connection is
the ductus venosus so till now we have
discussed the five main structures first
was placenta in the umbilical cord then
we saw the blood vessels there are two
unlike al arteries and one am like
alveen then we studied about the foramen
ovale then ductus arteriosus and at last
ductus venosus so again this is the
fetal circulation and to understand
about the fetal circulation you need to
understand those five terms because now
I'll be discussing this diagram this is
the placenta and the unlike al cord the
red color which you see here is the am
like a vein and the blue colored vessels
are the imply Col
arteries
since the umbilical vein is carrying the
oxygenated blood so it will be entering
the fetus and now come to this diagram
see the first point the blood arrives
via the amp like Alwyn
then this arrives into the liver and
gives a branch to the portal vein and
only about 1/3 of the blood reaches the
inferior vena cava rest 2/3 of the blood
goes to the liver so level is the is the
main organ or the first organ that that
gets and an extensive supply of
oxygenated blood so here this connection
is ductus venosus the connection between
the unlike al vein and the inferior vena
cava
now this inferior vena cava has reached
into the right atrium and from here the
superior vena cava is also bringing the
deoxygenated blood then you can see this
arrow this is pointing towards the
foramen of avail it means that most of
the blood is going directly into the
left atrium and only some amount of
blood is coming down into the right
ventricle then from this right ventricle
the blood the blood is going into the
pulmonary artery and from the right
atrium the blood is going down into the
left which ventricle and then to the
Iota and here between the IATA and the
pulmonary artery there is again a
connection and this connection is your
ductus arteriosus this connects the IATA
with the pulmonary artery further
shunting the blood away from the lungs
and into the iota since here the
involvement of lung is not there that is
why the blood cannot go to the lungs so
this is the connection that is there so
that if any blood is present inside the
pulmonary artery that directly goes into
the aorta and can carry out the systemic
circulation so this is your fetal
circulation now we are going to discuss
it in two parts we are going to make the
flowchart on the earth by dividing it in
two parts so this one is the first part
that we
be discussing then this box will be the
second part and this box will be the
third part now we are starting with the
first part the first part was our
placenta and DM like Alwyn so what will
happen here first of all the placenta
from the placenta arises the unlike a
cord from the umbilical cord one unlike
Alvin is there and to UM like--all
arteries are present so in the umbilical
cord one unlike Alvin is there and ii am
like--all arteries are present my Calvin
carries the oxygenated blood
whereas the unlike all arteries carry
the deoxygenated blood so this is about
the first part of our fetal circulation
that from the placenta the umbilical
cord arises and the unlike Olcott
contains two things one am like a vein
and to him like a arteries then we are
coming on to the next part the next box
then from the umbilical vein this unlike
Alwyn will get will give the supply to
the two parts here you can see the imply
Calvin is giving the supply of the blood
to the two parts one is the portal vein
that is present in the liver and the
next is inferior vena cava and this
connection between the imply Cal vein
and the inferior vena cava is the ductus
venosus you can see in this diagram
which we discussed earlier also this is
the umbilical vein and this is the
inferior vena cava and here the
connection that is present is the ductus
venosus so this is how the ductus
venosus will be formed and the blood
will move on further to the inferior
vena cava then from the inferior vena
cava the blood will go into the right
atrium you can see here in this diagram
from the inferior and the superior vena
cava the blood is coming into the right
atrium
then from the right atrium it has two
paths either to go into the right
ventricle or to go in the left atrium
and this will be because of the presence
of foramen ovale since the foramen ovale
is present here that is why the blood
from the right atrium will go into the
left atrium this was the structure that
I had already shown you this is the
presence of the foramen ovale which
allows the passage of blood from the
right atrium into the left atrium so
these are the two pathways which the
blood from the right atrium can follow
then the third structure here the right
atrium and the right sorry the right
ventricle and the right atrium we are
taking into consideration from the right
ventricle the blood can go into the
pulmonary artery and from the left
atrium the blood can go into the left
ventricle you can see here from this
right atrium the blood can come into the
right ventricle and then from right
ventricle it will go to the pulmonary
artery and from the left atrium it can
come into the left ventricle then from
the pulmonary artery and from the left
ventricle both of these will join into
the aorta here you can see this is the
pulmonary artery it also joins with the
IATA and this is the left ventricle from
here the elta originates so the
connection between the pulmonary artery
and the IATA is known as ductus
arteriosus so this is the connection
this is the connection between the
pulmonary artery and the IATA that is
known as ductus arteriosus so here we
have come across all the three terms
foramen ovale ductus arteriosus and
ductus venosus this was the structure of
the ductus arteriosus a connection
between the pulmonary artery and the
IATA now after the iota where will this
blood go and how will it come back
into the circulation in the placenta so
you can see here this is the whole fetal
circulation in another kind of picture
this is the iota then one branch of iota
that is the descending iota is coming
down now we will see how this blood will
come back into the placenta from the
iota the blood will come into the
descending iota
then from the descending iota it will
enter into the internal iliac artery
from the internal iliac artery it will
join it will form two arteries right
internal iliac artery and the left
internal iliac artery you can see here
this yellow portion this is the
descending aorta which is which is
bifurcating to form the internal iliac
arteries this one is the right internal
iliac artery and this is the left
internal iliac artery then the right
internal iliac artery and the left hand
internal iliac artery will form the
unlike L arteries you can see in this
diagram at the bottom the internal iliac
arteries are forming the unlike all
arteries so both the internal iliac
arteries right and left will form the
glycol artery and these two unlike L
arteries will enter into the umbilical
cord which we saw in the first in the
second picture that was the blood
vessels in the umbilical cord I told you
that there are two I'm like allot reefs
so where are these two umbilical
arteries coming from these two are
Michael arteries are coming from the
right internal iliac artery and the one
from the left internal iliac artery then
they will enter into the unlike al cord
and this son glycol cord will further
meet up with the placenta to give away
the day of deoxygenated blood for the
process of oxygenation and whereas this
oxygen received to the placenta from the
maternal circulation or from the mother
so so now when you are looking at this
picture
now after
understanding about the fetal
circulation now this picture will be
very easy to understand that how the
fetal blood circulation is occurring
from the placenta to the liver then to
the heart then again coming back to form
the umbilical arteries and ending up at
meeting with the placenta so this is
about the fetal circulation now one last
thing that we all must know that what
are the afterbirth changes after birth
changes are the postnatal changes in the
fetal circulation this is the fetal
heart this is the fetal heart and this
is the newborn heart I told you that all
these openings which are present there
are normal for the fetal heart but not
for the newborn heart they need to be
closed for the proper functioning during
the postnatal period
so this foramen ovale which was open
during the fetal heart circulation now
after the birth or in the newborn heart
this foramen ovale gets closed and this
is known as fossa ovalis this structure
turns out to be known as fossa ovalis
and this is the ductus arteriosus that
was opened during the fetal circulation
now this structure will be known as
ductus arteriosus and now this is closed
so this is about the afterbirth changes
or the postnatal changes in the fetal
heart circulation and in the newborn
heart circulation I hope that's that
this topic is clear to you and and one
suggestion I would like to give you that
the flowchart which I have discussed it
would be very nice if you try to make it
on your own study from this video and if
you want then copy the flowchart and
then try to understand the flowchart on
your own then this fetal circulation you
will be never never able to forget so
this was all about the fetal blood
circulation hope you liked the video and
do subscribe and like for the D coming
up videos thank you
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