胎児循環グランプリ　～酸素を届ける壮絶なレースを実況してみました～

Summary

In a creative and educational analogy, the 'Fetal Circulation Grand Prix' vividly illustrates the journey of oxygen from the placenta through the fetal circulatory system. The script, narrated by Nekoo and Mr. Nekomori, explains the unique role of fetal hemoglobin and the strategic shortcuts—like the ductus venosus, foramen ovale, and ductus arteriosus—that ensure efficient oxygen delivery to vital organs, particularly the brain. The race metaphorically culminates at the placenta, symbolizing the continuous cycle of oxygen replenishment until birth.

Takeaways

• 🏁 The 'Fetal Circulation Grand Prix' is a creative metaphor for the process of fetal circulation, highlighting the efficient delivery of oxygen to the fetus.
• 👶 The starting point of the race is the placenta, where fetal blood picks up oxygen from the maternal blood supply.
• 🩸 Fetal hemoglobin has a higher oxygen-binding capacity than adult hemoglobin, allowing for more efficient oxygen exchange even in oxygen-poor conditions.
• 🚀 The primary goal of the 'race' is to deliver oxygen quickly and efficiently to vital fetal organs, especially the brain, which has a high oxygen demand.
• 🛤️ The script describes a 'shortcut' in the fetal circulatory system, the ductus venosus, which bypasses the liver to reach the heart more directly.
• 💓 The heart is a crucial checkpoint in the race, with blood taking a shortcut through the foramen ovale from the right atrium to the left atrium, bypassing the lungs.
• 🧠 The brain is a key destination for oxygen delivery, emphasizing the importance of rapid and effective circulation to this organ.
• 🔄 After oxygen delivery, the blood returns to the placenta to pick up more oxygen, completing the cycle and preparing for the next round of circulation.
• 🚫 The ductus arteriosus provides an alternative route for blood to bypass the lungs and enter the systemic circulation, further optimizing oxygen delivery.
• 🔁 The race continues until the baby is born, signifying the continuous nature of fetal circulation throughout pregnancy.
• 📚 The commentary by Mr. Nekomori provides educational insights into the unique aspects of fetal circulation, making the complex process more accessible and engaging.

Q & A

What is the 'Fetal Circulation Grand Prix' described in the script?

The 'Fetal Circulation Grand Prix' is a metaphorical race described in the script to explain the process of fetal circulation, where 'racers' represent blood cells carrying oxygen from the placenta to various parts of the fetus's body and back.

What is the role of the placenta in the 'Fetal Circulation Grand Prix'?

The placenta serves as the starting and ending point of the race, providing oxygen to the fetal blood through the umbilical artery and receiving deoxygenated blood back to be reoxygenated.

How does fetal hemoglobin differ from adult hemoglobin?

Fetal hemoglobin has a special subunit that gives it a higher oxygen-binding capacity, allowing for more efficient exchange of oxygen even in conditions where oxygen is less abundant.

Why is the heart the first checkpoint in the race?

The heart is the first checkpoint because it is the first major organ that the oxygen-rich blood from the placenta reaches, and it plays a crucial role in distributing this oxygen throughout the fetus's body.

What is the significance of the brain in the 'Fetal Circulation Grand Prix'?

The brain is significant because it consumes a lot of oxygen, making the quick and effective delivery of oxygen to the brain a key aspect of the race.

What is the 'ductus venosus' and its role in the race?

The 'ductus venosus' is a bypass that allows blood to avoid passing through the fetal liver, as the maternal liver is sufficient for the fetus's needs, thus optimizing the delivery of oxygen to other parts of the body.

Why do the racers make a shortcut through the 'foramen ovale'?

The 'foramen ovale' is a shortcut that allows blood to bypass the right ventricle and lungs, which are not used for breathing in the fetus, and instead go directly to the left atrium and then to the systemic circulation.

What is the 'ductus arteriosus' and its purpose in the race?

The 'ductus arteriosus' is a bypass that connects the pulmonary artery to the aortic arch, allowing blood to skip the lungs and directly enter the systemic circulation, thus delivering oxygen to the body more efficiently.

How do the racers return to the placenta after delivering oxygen?

After delivering oxygen, the blood returns to the placenta via the umbilical arteries, which are the last part of the racecourse and involve a long curve forming loops.

What is the importance of the 'Mother Oasis' mentioned at the end of the race?

The 'Mother Oasis' is a metaphorical term for the placenta, signifying its importance as the source of nourishment and oxygen for the fetus, and the final destination of the race.

What does the script imply about the end of the races?

The script implies that the races, or the process of fetal circulation, continue until the baby is born, emphasizing the continuous and vital nature of this process for the fetus's development.

Outlines

00:00

🏎️ 'Fetal Circulation Grand Prix' Begins

The script introduces a metaphorical race called the 'Fetal Circulation Grand Prix', where the objective is to efficiently deliver oxygen from the placenta to the fetus's organs, particularly the brain. The race commentary is led by Nekoo and Mr. Nekomori, who explain the unique properties of fetal hemoglobin and its higher oxygen-binding capacity. The race begins with the 'racers' (oxygenated blood) traveling through the umbilical vein, avoiding the liver via the ductus venosus, and taking a shortcut through the foramen ovale from the right atrium to the left atrium. The racers then enter the systemic circulation through the aorta, delivering oxygen to the brain and body. The commentary highlights the importance of quick and efficient oxygen delivery and the strategic bypassing of the lungs, which are not used for respiration in utero.

05:03

🏁 Completing the 'Fetal Circulation Grand Prix' Course

This paragraph summarizes the race's course and the strategies employed by the 'racers' to deliver oxygen effectively. The racers are described as taking two possible routes to enter the systemic circulation: one through the foramen ovale and the other via the right ventricle, pulmonary artery, and ductus arteriosus. After delivering oxygen to the body, the racers return to the placenta via the umbilical arteries, which are characterized by a long curve and loop. The commentary emphasizes the racers' use of extreme techniques to ensure the most efficient oxygen delivery. The race continues until the baby's birth, and the commentary concludes with a look forward to the next round of the 'Fetal Circulation Grand Prix'.

Keywords

💡Fetal Circulation

Fetal circulation refers to the unique blood flow pattern within a fetus that allows for the efficient exchange of nutrients and gases with the mother. In the video's theme, it is likened to a 'Grand Prix' race, emphasizing the efficiency and importance of oxygen delivery to the fetus. The script describes how oxygen-rich blood from the mother is delivered to the fetus's organs, highlighting the unique aspects of fetal hemoglobin and the bypass mechanisms that optimize this process.

💡Placenta

The placenta is an organ that connects the developing fetus to the uterine wall, allowing for nutrient uptake and waste elimination. In the video script, it is depicted as the starting point of the 'Fetal Circulation Grand Prix', where the 'racers' (blood cells) receive oxygen from the maternal blood. The placenta's role is crucial for the survival and development of the fetus, as it facilitates the exchange of essential substances.

💡Fetal Hemoglobin

Fetal hemoglobin is a type of hemoglobin found in fetuses that has a higher affinity for oxygen than adult hemoglobin. In the script, Mr. Nekomori explains that this special subunit allows for more efficient oxygen exchange, even in conditions where oxygen is less abundant, such as at the placenta. This is vital for the fetus's growth and development, as it ensures a steady supply of oxygen to vital organs.

💡Umbilical Artery

The umbilical artery is one of the two arteries that transport blood from the fetus to the placenta. In the video's narrative, the 'racers' travel through the umbilical artery to reach the placenta, where they pick up oxygen. This artery is part of the fetal circulatory system and plays a key role in the 'race' to deliver oxygen to the fetus.

💡Ductus Venosus

The ductus venosus is a blood vessel that bypasses the fetal liver, allowing oxygen-rich blood to be directed straight to the heart. In the script, it is mentioned as a crucial bypass that enables the 'racers' to avoid the liver, thus optimizing the delivery of oxygen to the fetus. This bypass is an example of the specialized adaptations within the fetal circulatory system.

💡Inferior Vena Cava (IVC)

The inferior vena cava is a large vein that carries blood from the lower part of the body back to the heart. In the video script, it is described as the 'major road' where the 'racers' converge after avoiding the liver, on their way to the heart. The IVC is a critical component of the circulatory system, ensuring that blood rich in oxygen and nutrients reaches the heart for distribution to the rest of the body.

💡Foramen Ovale

The foramen ovale is a fetal heart structure that allows blood to bypass the lungs by directing it from the right atrium to the left atrium. In the script, it is referred to as a 'shortcut' that the 'racers' use to avoid the lungs, which are not used for respiration in the fetus. This adaptation is essential for the efficient delivery of oxygenated blood to the fetus's body.

💡Ductus Arteriosus

The ductus arteriosus is a blood vessel that connects the pulmonary artery to the aorta, allowing blood to bypass the lungs and enter the systemic circulation. In the video, it is mentioned as another bypass mechanism that the 'racers' use to avoid the lungs, emphasizing the importance of delivering oxygen to the body's tissues efficiently.

💡Aorta

The aorta is the body's main artery, which carries oxygen-rich blood from the heart to the rest of the body. In the script, it is depicted as the pathway through which the 'racers' deliver oxygen to the brain and other organs. The aorta plays a central role in the 'Fetal Circulation Grand Prix', as it is the conduit for distributing vital oxygen throughout the fetus's body.

💡Umbilical Arteries

Umbilical arteries are the blood vessels that carry deoxygenated blood from the fetus back to the placenta. In the video's narrative, they are the 'last curve and loop' that the 'racers' must navigate to return to the placenta, completing the 'race'. These arteries are essential for the return trip of blood to the placenta for reoxygenation.

💡Oxygen Delivery

Oxygen delivery is the process by which oxygen is transported from the placenta to the fetus's organs and tissues. In the video, it is the central focus of the 'Fetal Circulation Grand Prix', with the 'racers' representing the blood cells that carry out this vital function. The script highlights the efficiency and importance of this process in ensuring the health and development of the fetus.

Highlights

Introduction of the 'Fetal Circulation Grand Prix' with Nekoo and Mr. Nekomori as commentators.

The race begins at the 'placenta', the starting point on the fetal side where racers receive oxygen from maternal blood.

Explanation of fetal hemoglobin's higher oxygen-binding capacity, allowing for more efficient exchange in oxygen-insufficient conditions.

Importance of oxygen delivery speed and efficiency to fetal organs during the race.

Overview of the circuit's characteristics for delivering oxygen to the whole body, with a focus on the brain.

The racers' journey back to the placenta after oxygen delivery to receive more oxygen.

Description of the 'ductus venosus' bypass, allowing racers to avoid the liver.

The role of the 'Inferior vena cava (IVC)' as the major road connecting to the heart.

Shortcut through the atrial wall via 'foramen ovale' to bypass the right ventricle and pulmonary artery.

Explanation of why the lungs are bypassed during fetal circulation due to lack of breathing.

The 'ductus arteriosus' bypass, connecting the pulmonary artery to the aortic arch, skipping the lungs.

Delivery of oxygen to the brain and the whole body through the aorta after passing through the foramen ovale.

Some racers choose the right ventricle and pulmonary artery route instead of the foramen ovale.

The surprising discovery of the 'ductus arteriosus' as an alternative route to the systemic circulation.

Racers' journey through the aortic arch after oxygen delivery to various organs.

The final stretch of the race, with racers descending the aorta and heading towards the umbilical arteries.

The challenging last curve and loop formed by the umbilical arteries before reaching the placenta.

The racers' reactions after reaching the goal, the 'Mother Oasis', and the anticipation for the next round of races.

Conclusion of the race with Mr. Nekomori's appreciation for the racers' effective oxygen delivery efforts.

Transcripts

Nekoo: Now, with perfect condition at both fetal raceway and maternal supply system,

The ’Fetal Circulation Grand Prix’ is ​​about to begin.

Nekoo: The broadcast is me Nekoo.

And here's the commentary Mr. Nekomori.

Great to see you sir!

Mr. Nekomori: Thanks, nice to see you too!

Nekoo: Here you can see 'placenta' the starting point of the race located at fetal side.

They just came from umbilical artery and now waiting at the pit line.

At placenta, the racers are supposed to receive oxygen supplied by maternal blood.

By the way, I heard that 'fetal hemoglobin' has some difference from the adult one.

Could you explain what it is exactly, Mr. Nekomori?

Mr. Nekomori: I guess you mean the special subunit that only fetal hemoglobin has.

It has higher oxygen-binding capacity,

allowing fetal hemoglobin to exchange more efficiently even in an oxygen-insufficient situation.

Nekoo: I see.

Since oxygen is not abundant at placenta,

the fetal hemoglobin is designed for such a condition.

The 'speed' and 'efficiency' of oxygen delivery to the most important fetal organs

is the biggest concern during the 'Fetal Circulation Grand Prix'.

Now Mr. Nekomori, could you briefly explain the overall characteristics of the circuit?

Mr. Nekomori: In order to deliver the oxygen to the whole body,

the first point is to reach the heart by the shortest distance

Nekoo: Okay, the first is the heart.

Then what's the next?

Mr. Nekomori: Oxygen will be delivered all around the body,

especially the brain as it consumes lots of oxygen.

Thus, quick and effective oxygen delivery to the brain will be the key.

Nekoo: All right.

Then what will happen after oxygen delivery is done?

Mr. Nekomori: Well,

they will come back to the goal, the placenta,

in order to receive the oxygen again.

The way to the goal branches from this point,

so the racer will follow like this.

The racers who chose abdominal organs or lower limbs

will need to proceed to inferior vena cava first,

and then round through aortic arch, to reach the goal.

Nekoo: I see I see....

look! It seems oxygen supply has been done to all racers.

Nekoo: Finally, the race starts, here we go!

Nekoo: Every racer is running first on the 'umbilical vein' in order to reach the heart.

The first trap is the liver.

Let's see how they get through...

Oops what happened, there's a way to avoid the liver!

Mr. Nekomori: That is one of the most important bypass so-called 'ductus venosus (ductal vein)'.

Since maternal liver works well enough for the fetus,

the fetal liver is not the priority regarding the fetal circulation.

Nekoo: The racers might say 'there's no oxygen for you liver, goodbye!'

Now after avoiding the liver via ductus venosus, the course is joining to 'Inferior vena cava (IVC)'.

IVC is well known as the biggest vein connecting directly to the heart. Is that right Mr. Nekomori?

Mr. Nekomori: Exactly.

That's the major road where the racers run together.

Nekoo: I see.

From here the racers can go straight to the heart.

Now, the top runners have already reached the first checkpoint,the right atrium of the heart!

Each racer is supposed to turn right to the right ventr... nope!

And WOW! Most of them go straight and 'pierce' through the wall!

It seems they made a shortcut to LEFT atrium!

What's that?!

Isn't it supposed to be the right ventricle after the right atrium??

Mr. Nekomori: That's a shortcut so-called 'foramen ovale (oval foramen)'.

the blood on right atrium would go next to right ventricle --> pulmonary artery --> lungs --> pulmonary vein --> then left atrium.

But during fetal period, since they do not breath with lungs,

there's only little chance to supply oxygen there, so they know it's a waste of time.

Nekoo: What a smart decision!

They can even make a shortcut through the atrial wall in order not to waste oxygen!

After foramen ovale and left atrium, they reached left ventricle,

and there each racer speeds up to enter the aorta,

and delivers oxygen to brain and the whole body.

What an amazing speed...!

But Mr. Nekomori,

It seems that not all racers pass through the foramen ovale.

Mr. Nekomori: That's true.

There're some who actually chose right ventricle instead of foramen ovale.

Nekoo: Interesting. It seems that some racers still take care of lungs.

Let's take a look at those who did not choose foramen ovale!

Like the 'after-born', they turn right to the right ventricle and speed up to pulmonary artery.

And there they're supposed to enter the lun...

Oh my, what is that vessel?!

There's a bypass connecting from the pulmonary artery to the aortic arch!

Mr. Nekomori: That's so-called 'ductus arteriosus (ductal artery; ductus Botalli)'

Since they don't have so many chances to supply oxygen there,

there's a shortcut to the aorta in order to reach the whole body.

What a surprise,

they didn't really care about the lungs either,but just entered the systemic circulation through ductus arteriosus.

Here each racer travels to the tissues of several target organs waiting for the oxygen!

How do you feel about the racing so far, Mr. Nekomori?

Mr. Nekomori: Well,

I think they made an effort very well to deliver such a precious oxygen effectively :-)

Nekoo: Absolutely, it's awesome.

And what do you expect for the followings?

Mr. Nekomori: In order to receive the oxygen again,

they're supposed to go back to the placenta.

Nekoo: I see.

’The trip is not over until you get home' applies here like:

'The race is not over until you get back to placenta'

Now let's revise the overall course once again!

Mr. Nekmori: Sure.

The red line means the course we saw until now.

Departed placenta, avoided the liver through 'ductus venosus'...

and in the heart, they entered the aorta via 'foramen ovale' and then entered the systemic circulation.

Also, there's another route to enter the systemic circulation:

via right ventricle, pulmonary artery and then 'ductus arteriosus', instead of foramen ovale.

Now the blue line is the upcoming course.

The racers who chose brain to supply oxygen will follow like this (joining to superior vena cava (SVC)).

The ones who chose the other internal organs as well as lower limbs

will enter IVC first, and then,

they'll join altogether entering the aortic arch,

and finally will run toward the placenta like this.

Nekoo: That's great, thank you!

The race is already getting closer to the end!

Now let's return to the camera at the point of aorta.

Those being done with the oxygen delivery are 'descending' the aorta...

and now we can see the last branch directing to the goal placenta!

Mr. Nekomori: Those are 'umbilical arteries'.

It's a difficult point consisting of long curve forming loops.(Please note that umbilical arteries usually consists of two [right and left], unlike umbilical vein)

Exactly, that's the umbilical arteries,

the last curve and loop to reach the goal!

Now each racer thirsting for the oxygen bursts the last spurt

to reach the placenta, the 'Mother Oasis'!

And now the top reached the goal!!!

Look at the reactions of the racers after the goal.

Mr. Nekomori: It was an amazing race.

Nekoo: Definitely.

We saw several extreme techniques to deliver the precious oxygen in the most effective way.

However, time is coming again

to receive the new oxygen for the next round.

The races will last till the last moment that the baby has been born.

Stay tuned for the next one!

Mr. Nekomori!

Thank you for everything today.

Mr. Nekomori: Appreciate. Bye bye!