The Cardiovascular System (CVS) ❤️ 🩸 - A Simple Introduction - Biology, Anatomy, Physiology

Summary

This educational video script delves into the intricacies of the cardiovascular system, focusing on the heart's function and circulation in both adults and fetuses. It explains the journey of blood from the left ventricle through systemic circulation, the role of various heart valves, and the unique characteristics of arteries and veins. The script also touches on fetal circulation, highlighting the differences in oxygen transport between fetuses and adults, and ends with a quiz to engage viewers.

Takeaways

• 🔬 The left ventricle pumps oxygenated blood to the aorta through the aortic valve, distributing it throughout the body.
• 🫁 The systemic circulation delivers oxygen to cells and returns carbon dioxide to the right atrium via the superior and inferior vena cava.
• ❤️ The right atrium sends deoxygenated blood to the right ventricle through the tricuspid valve, which then pumps it to the lungs via the pulmonary arteries.
• 🌬️ The lungs exchange carbon dioxide for oxygen, which is carried back to the left atrium through the pulmonary veins.
• 🩺 The left atrium pumps oxygenated blood to the left ventricle through the mitral valve, repeating the circulation process.
• 📖 The heart has four chambers (left and right atria, left and right ventricles) and four valves (mitral, tricuspid, aortic, and pulmonic).
• 🔄 Arteries carry blood away from the heart, while veins carry blood towards the heart; this applies to both oxygenated and deoxygenated blood.
• 👶 In fetal circulation, the placenta provides oxygenated blood through the umbilical vein, bypassing the liver and lungs via the ductus venosus and foramen ovale.
• 💡 Veins, but not arteries or capillaries, have valves to prevent backflow; the mitral valve has two cusps, while other heart valves have three.
• 🏃 Preload refers to the venous return to the heart before contraction, while afterload is the resistance faced by the heart after pumping.

Q & A

What is the main focus of the video script?

The main focus of the video script is an introduction to the cardiovascular system for biology students.

What is the pathway of blood starting from the left ventricle in the adult circulation?

In adult circulation, oxygenated blood leaves the left ventricle through the aortic valve into the aorta, travels all over the body in the systemic circulation, delivers oxygen to the cells, and collects carbon dioxide. Deoxygenated blood then returns to the right atrium via the inferior and superior vena cava.

What is the role of the mitral valve in the heart?

The mitral valve, which has two cusps, is located between the left atrium and the left ventricle. It allows oxygenated blood to flow from the left atrium to the left ventricle.

How does the fetal circulation differ from adult circulation?

In fetal circulation, the lungs are not functional. The fetus receives oxygenated blood from the mother's placenta through the umbilical vein. Blood bypasses the liver via the ductus venosus, moves from the right atrium to the left atrium through the foramen ovale, and from the pulmonary artery to the aorta via the ductus arteriosus, bypassing the non-functional lungs.

What are the four valves of the heart mentioned in the script?

The four valves of the heart are the mitral valve, tricuspid valve, aortic valve, and pulmonic valve.

Why is the mitral valve also known as the 'bishop's hat' valve?

The mitral valve is known as the 'bishop's hat' valve because it resembles the mitre, a hat worn by bishops, which has two cusps like the mitral valve.

What distinguishes veins from arteries in terms of their function and structure?

Veins carry blood towards the heart and have valves to prevent backflow, with thinner and weaker walls. Arteries carry blood away from the heart to other organs, have thicker walls to withstand higher pressure, and do not have valves (except the pulmonary arteries and veins, which carry deoxygenated and oxygenated blood, respectively).

How do preload and afterload relate to heart function?

Preload refers to the blood volume returning to the heart before it pumps (venous return), while afterload is the resistance the heart faces after pumping blood out to the arteries.

What is automaticity in cardiac muscles?

Automaticity is the ability of the cardiac muscles, specifically the sinoatrial node, to initiate their own electrical impulses without needing external stimuli.

What is the function of the ductus arteriosus in fetal circulation?

The ductus arteriosus connects the left pulmonary artery to the aorta in fetal circulation, allowing blood to bypass the non-functional lungs and flow directly into the systemic circulation.

Outlines

00:00

💓 Introduction to the Cardiovascular System

This paragraph introduces the cardiovascular system to biology students, emphasizing the importance of watching the videos in order to understand the material thoroughly. The speaker, Mitochondria Perfectionist, explains the journey of blood from the left ventricle through the aorta and systemic circulation, highlighting the exchange of oxygen and carbon dioxide between blood and body cells. The return of deoxygenated blood to the right atrium via the vena cava is detailed, followed by its passage to the right ventricle and then to the lungs for reoxygenation. The description of the heart's four chambers and valves is provided, including the mitral valve's unique feature of having only two cusps, unlike the other valves which have three. The paragraph concludes with an encouragement for viewers to pause and recount the process themselves.

05:02

🔍 Detailed Exploration of Heart Valves and Fetal Circulation

The second paragraph delves deeper into the heart's valves, explaining the function of the mitral and tricuspid valves as atrioventricular valves and the aortic and pulmonic valves as semilunar valves. It clarifies common misconceptions about the types of blood carried by arteries and veins, using the pulmonary artery and pulmonary veins as exceptions to the general rules. The paragraph also touches on the differences between adult and fetal circulation, with a focus on the role of the placenta in providing oxygen to the fetus. The unique features of cardiac muscles, including their automaticity and structure, are briefly mentioned, and viewers are encouraged to explore the topic further through related videos. Lastly, the paragraph invites viewers to support the channel and provides a teaser for upcoming content on vasculature and muscle types.

10:04

👶 Fetal Circulation and its Transition to Adult Circulation

This paragraph provides an in-depth look at fetal circulation, detailing the path of oxygenated blood from the placenta to the fetus via the umbilical vein and its bypass of the liver through the ductus venosus. It explains how blood moves from the inferior vena cava to the right atrium, then through the foramen ovale to the left atrium, and subsequently to the systemic circulation. The role of the ductus arteriosus in bypassing the lungs by directing deoxygenated blood from the pulmonary artery to the aorta is highlighted. The paragraph also discusses the changes that occur at birth, as the lungs begin to function and the fetal circulatory pathways close. The summary ends with a prompt for viewers to engage with the content by answering a question about adult circulation and a reminder of available courses and discounts on the speaker's website.

Keywords

💡Left Ventricle

The left ventricle is one of the four chambers of the heart, responsible for pumping oxygenated blood into the aorta through the aortic valve. In the video, it's described as the starting point for systemic circulation, where oxygen-rich blood is distributed throughout the body.

💡Aorta

The aorta is the main artery that carries oxygenated blood from the left ventricle to the rest of the body. The video explains how blood travels from the left ventricle into the aorta, then throughout the systemic circulation to deliver oxygen to tissues.

💡Systemic Circulation

Systemic circulation is the part of the cardiovascular system that carries oxygenated blood from the heart to the body and returns deoxygenated blood back to the heart. The video describes this process in detail, emphasizing the role of the aorta and veins.

💡Right Atrium

The right atrium is one of the four chambers of the heart that receives deoxygenated blood from the body via the inferior and superior vena cava. The video highlights its role in passing deoxygenated blood to the right ventricle through the tricuspid valve.

💡Pulmonary Arteries

Pulmonary arteries carry deoxygenated blood from the right ventricle to the lungs for oxygenation. The video details how these arteries transport blood to the lungs, where carbon dioxide is exchanged for oxygen.

💡Pulmonary Veins

Pulmonary veins carry oxygenated blood from the lungs to the left atrium. In the video, these veins are highlighted as an exception to the rule that veins typically carry deoxygenated blood, bringing oxygen-rich blood back to the heart.

💡Mitral Valve

The mitral valve, located between the left atrium and left ventricle, has two cusps and allows oxygenated blood to flow from the atrium to the ventricle. The video explains its unique two-cusp structure and its critical role in the heart's function.

💡Tricuspid Valve

The tricuspid valve is situated between the right atrium and right ventricle, allowing deoxygenated blood to flow from the atrium to the ventricle. The video notes its three-cusp structure and its importance in the cardiovascular system.

💡Preload and Afterload

Preload refers to the venous return or the blood entering the heart before contraction, while afterload is the resistance the heart faces after pumping. The video uses analogies to explain these concepts, emphasizing their significance in cardiac function.

💡Fetal Circulation

Fetal circulation refers to the blood flow in a fetus, which bypasses the lungs and relies on the placenta for oxygen exchange. The video contrasts fetal and adult circulation, explaining structures like the ductus arteriosus and foramen ovale.

Highlights

Introduction to the cardiovascular system for biology students, with a future series on cardiology for advanced learners.

Explanation of the flow of oxygenated blood from the left ventricle through the aorta to the systemic circulation.

Description of how cells use oxygen in metabolism, producing carbon dioxide, which is transported back to the heart via veins.

Overview of the heart's anatomy, including the four chambers: left atrium, left ventricle, right atrium, right ventricle.

Detailed description of the heart valves: mitral, aortic, tricuspid, and pulmonic, with their locations and functions.

Clarification of the difference between oxygenated and deoxygenated blood and how it flows through the heart and lungs.

Explanation of the unique characteristics of the mitral valve, including its two cusps and comparison to the bishop's hat (miter).

Discussion on the role of veins and arteries, including the exception of the pulmonary artery and veins in carrying blood.

Introduction to the concept of fetal circulation, highlighting differences from adult circulation, such as the placenta providing oxygen.

Explanation of the ductus venosus, foramen ovale, and ductus arteriosus in fetal circulation and their roles in bypassing the liver and lungs.

Clarification of the definitions of arteries and veins based on the direction of blood flow, not the oxygenation status.

Discussion of preload and afterload concepts in cardiac function, with an analogy to running and hitting a wall.

Comparison between skeletal, cardiac, and smooth muscles, emphasizing the unique features of cardiac muscles like automaticity.

Encouragement to review the fetal circulation before continuing with the adult circulatory system topics.

Promotion of additional learning resources, including animations on Picmonic and courses on the website Medicosis Perfectionalis.

Transcripts

what's going on everybody this is

mitochosis perfectionist where medicine

makes perfect sense let's carry on our

biology playlist in the last videos we

finished the respiratory system today

we'll talk about the cardiovascular

system in an introduction this is for

biology students for the pros stay tuned

for an upcoming series called cardiology

this is my biology playlist try to watch

these videos in order you have to be

able to repeat verbatim everything i'm

going to say in this slide let's start

here in your left ventricle left

ventricle is going to pump blood to the

aorta through the aortic valve blood is

in the aorta blood is going to go all

over your body in the systemic

circulation until you give each cell

oxygen the cell is going to use that

oxygen in metabolism as you know

metabolism produces carbon dioxide this

carbon dioxide will be dumped onto veins

in the systemic circulation until you

end up here in the inferior vena cava

and here the superior vena cava from the

lower half of the body and the upper

half of the body respectively regardless

you will end here in the right atrium

which contains deoxygenated blood which

means blood that has carbon dioxide and

less oxygen we are here in the right

atrium right atrium is gonna push blood

to the right ventricle through the

tricuspid valve deoxygenated blood is

here in the right ventricle right

ventricle is gonna pump this

deoxygenated blood into the pulmonary

trunk and then right pulmonary artery

left pulmonary artery will carry the

deoxygenated blood to the lungs the

lungs will take that carbon dioxide

breathe it out

and breathe oxygen in

this lovely oxygen is gonna go to the

blood and end up here in the pulmonary

veins two from the right lung two from

the left lung eventually the end up in

the left atrium now the left atrium

contains oxygenated blood left atrium is

gonna pump that oxygenated blood to the

left ventricle through the mitral valve

so we have four chambers in the heart

left atrium left ventricle right atrium

right ventricle we have four valves in

the heart mitral valve between left

atrium and left ventricle aortic valve

between left ventricle and aorta

tricuspid valve between right atrium and

right ventricle pulmonic valve between

right ventricle and pulmonary artery

please pause the video and try to tell

the story to yourself let's do it again

oxygenated blood leaves the left

ventricle through the aortic valve into

the aorta the aorta will take that

oxygenated blood all over your body give

oxygen to the cell take carbon dioxide

from the cell deoxygenated blood is

going to go to the inferior vena cava

and superior vena cava ending up in the

right atrium right atrium will give the

deoxygenated blood to the right

ventricle through the tricuspid valve a

valve with three cusps right ventricle

is gonna pump the deoxygenated blood to

the pulmonary trunk through the pulmonic

valve which also has three cusps

pulmonary trunk pulmonary arteries lungs

the lungs will get rid of the carbon

dioxide and provide you with oxygen

oxygenated blood is going to end up here

in the pulmonary veins into the left

atrium left atrium will give the

oxygenated blood to the left ventricle

via the mitral valve why do you call it

the mitral valve because this is lamitra

what's the meter this is the bishop's

hat which as you see here has like two

cusps mitral valve also has two cusps

that's why they called it mitral mitral

valve is the only valve with two cusps

everything else has three cusps or three

leaflets all of this was the adult

circulation but how above the fetal

circulation we talked about this in a

separate video in this biology playlist

it was epic the left side of the heart

contains oxygenated blood the right side

of the heart contains deoxygenated blood

and of course you remember that in

adults the lungs are functional but in a

fetus the lungs are not working but

where does the fetus get the oxygen from

from his mother's placenta doofus valves

the heart has valves vessels have valves

i'm talking about veins how about

arteries they don't have valves how

about capillaries they don't have valves

only veins do the heart has four valves

mitral valve tricuspid valve aortic

valve and pulmonic valve all of them

have three cusps except the mitral valve

which only has two cusps remember the

head of the bishop the miter la mitre my

french is on fleek the mitral valve is

between the left atrium and the left

ventricle here tricuspid valve is

between right atrium and right ventricle

here these are

atrioventricular valves between the

atrium and the ventricle between the

atrium and the ventricle love it their

anatomical location is here above them

is the aortic and pulmonic valve we call

these semilunar valves some people call

them ap valves if your aortic p is for

pulmonic mitral and tricuspid lie below

aortic and pulmonic four chambers four

valves and four pulmonic veins you know

that arteries are supposed to carry

oxygenated blood right the pulmonic

artery is an exception it's an artery

but it carries deoxygenated blood you

also know that veins are supposed to

carry deoxygenated blood except those

pulmonary veins they are veins but they

do carry oxygenated blood some people

are so naive to the point of believing

that an artery has to carry oxygenated

blood no that's not the definition of an

arch an artery is a vessel that takes

blood from the heart to another organ in

other words away from the heart and

towards the organ a vein is the exact

opposite it's a vessel that takes blood

from an organ to the heart towards the

heart away from the organ that's the

definition and this is true whether

you're talking about an adult or an

embryo in adults arteries carry

oxygenated blood except pulmonary artery

but in an embryo the artery carries

deoxygenated blood as we have discussed

before example here is the umbilical

artery it's a branch of the internal

iliac artery of the embryo

takes that deoxygenated blood and gives

it to mommy's placenta in adults veins

carry deoxygenated blood except

pulmonary veins but in embryo veins are

vessels that carry the oxygenated blood

fresh from mommy's placenta towards the

baby's heart love it if my channel

helped you this year please consider

buying me a coffee go to buy me a coffee

dot com slash medicosis left ventricle

pumps oxygenate blood to the aorta here

is the ascending iota here is the aortic

arch and here is the descending aorta in

the chest or the thorax it's called the

descending thoracic aorta after it

descends below the diaphragm we call it

the abdominal aorta abdominal aorta

carries oxygenated blood from the heart

towards other organs but the inferior

vena cava which is next to the aorta

carries deoxygenated blood from organs

to the heart of course these organs are

in the lower half of the body notice the

difference between the thickness of the

wall of these vessels arteries have

stronger walls thicker walls they can

withstand higher blood pressure veins on

the other hand have weaker walls lower

pressure and therefore more easily

compressed we will talk about this point

in great detail in an upcoming video

titled the vasculature another concept

to understand is preload versus

afterload free means before after is

after

before the heart we're talking about the

venus return which is the blood coming

back to the heart after load is the

resistance that the heart is gonna face

after it pumps so after i pump oops i

have resistance here in the vessels

imagine that someone is running behind

you and then you hit a wall the person

who is behind you is the predate the

wall that is after you is the afterload

the heart has to live with both

skeletal muscles versus cardiac muscles

versus smooth muscles was a topic of a

separate video and you can search

youtube for skeletal muscles versus

cardiac muscles versus smooth muscles

and you will see my videos cardiac

muscles are striated branching

involuntary you need nucleated automatic

you cannot say to your heart hey pump

faster or slower you just can't the

heart can initiate its own nerve

impulses it does not need outside forces

the cyanoatrial node of the heart has

automaticity cardiac muscles have

troponin they have gap junction also

known as nexus now we will use the slide

to review the fetal circulation please

do not review this before you watch my

fetal circulation video first let's go

theta circulation here is the placenta

the placenta is providing the baby with

pure oxygenated blood oxygenated blood

is gonna go here we're talking about

umbilical vein which is going to the

heart what's the definition of a vein a

vessel that takes blood from an organ to

the heart thank you and this is carrying

oxygenated blood we're talking about the

fetus here here is a vein that is

carrying oxygenated blood this

oxygenated blood is gonna go up and

we're gonna bypass the liver how do you

bypass the liver through the ductus

venosus and then we are here in the

inferior vena cava we will go to the

right atrium

between the right atrium and the left

atrium there is a foramen known as the

foramen ovale here is the foramen blood

is gonna go from the right atrium to the

left atrium through the foramen ovale

which is open in the fetus but it's not

open in adults blood will go from left

atrium to the left ventricle from left

ventricle to the aorta from aorta

throughout your body this is the

systemic circulation back through

inferior and superior vena cava to the

right atrium blood is coming here from

the upper part of the body right this is

deoxygenated blood it's gonna go from

here to the right ventricle pulmonary

trunk pulmonary arteries and there is

ductus arteriosus which is a duct

between two arteries that's why it's

called arteriosus it's between the left

pulmonary artery and the aorta and this

is carrying

deoxygenated blood from the left

pulmonary artery to the iota why are we

doing this because we are bypassing the

lungs why are we bypassing the lungs

because this is a fetus the lungs are

not functioning yet deoxygenated blood

will leave the left pulmonary artery

goes to the iota and this deoxygenated

blood will end up in something called

umbilical artery which carries

deoxygenated blood towards mommy

placenta mommy's placenta is gonna get

rid of the carbon dioxide give us pure

lovely oxygenated blood back to the

umbilical vein and you repeat the cycle

for more lovely animations like these go

to pigmonic.com vip hookup slash

medicosis these are not just still

pictures these are animated videos as

well question of the day regarding the

adult circulation not fatal we're

talking adults here choose the correct

answer among these we're talking about

portal vein hepatic vein hepatic artery

pulmonary artery pulmonic vein which one

is oxygenated deoxygenated etc for

example if you chose a you agree that

the portal venous deoxygenated hepatic

is the oxygenated hepatic arteries

oxygenated pulmonary arteries

deoxygenated pulmonary venous

deoxygenated you know it goes this way

it also goes this way so let me know the

answer in the comment section you'll

find the correct answer in the next

biology video if you like this video

check out my cardiac pharmacology course

on my website

medicosisperfectionalist.com

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mitochosis perfixinatus where medicine

makes perfect sense