The heart is a muscular organ found in most animals. This organ pumps blood through the blood vessels of the circulatory system.[1] The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to the lungs.[2] In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the chest, called the mediastinum.[3] In humans, other mammals, and birds, the heart is divided into four chambers: upper left and right atria and lower left and right ventricles.[4][5] Commonly, the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart.[6] Fish, in contrast, have two chambers, an atrium and a ventricle, while most reptiles have three chambers.[5] In a healthy heart, blood flows one way through the heart due to heart valves, which prevent backflow.[3] The heart is enclosed in a protective sac, the pericardium, which also contains a small amount of fluid. The wall of the heart is made up of three layers: epicardium, myocardium, and endocardium.[7] In all vertebrates, the heart has an asymmetric orientation, almost always on the left side. According to one theory, this is caused by a developmental axial twist in the early embryo.[8] The heart pumps blood with a rhythm determined by a group of pacemaker cells in the sinoatrial node. These generate an electric current that causes the heart to contract, traveling through the atrioventricular node and along the conduction system of the heart. In humans, deoxygenated blood enters the heart through the right atrium from the superior and inferior venae cavae and passes to the right ventricle. From here, it is pumped into pulmonary circulation to the lungs, where it receives oxygen and gives off carbon dioxide. Oxygenated blood then returns to the left atrium, passes through the left ventricle and is pumped out through the aorta into systemic circulation, traveling through arteries, arterioles, and capillaries-where nutrients and other substances are exchanged between blood vessels and cells, losing oxygen and gaining carbon dioxide-before being returned to the heart through venules and veins.[10] The heart beats at a resting rate close to 72 beats per minute.[11] Exercise temporarily increases the rate, but lowers it in the long term, and is good for heart health.[12] Cardiovascular diseases are the most common cause of death globally as of 2008, accounting for 30% of all human deaths.[13][14] Of these more than three-quarters are a result of coronary artery disease and stroke.[13] Risk factors include: smoking, being overweight, little exercise, high cholesterol, high blood pressure, and poorly controlled diabetes, among others.[15] Cardiovascular diseases do not frequently have symptoms but may cause chest pain or shortness of breath. Diagnosis of heart disease is often done by the taking of a medical history, listening to the heart-sounds with a stethoscope, as well as with ECG, and echocardiogram which uses ultrasound.[3] Specialists who focus on diseases of the heart are called cardiologists, although many specialties of medicine may be involved in treatment.[14] A teenager's heartbeat Duration: 32 seconds.0:32 Sounds of a healthy 16-year-old child's heart beating normally, as heard with a stethoscope. Problems playing this file? See media help. heres a lesson about how he heart works
I'm just going to say this one thing tarantulas is going to add PVP mode Andrew is going to be new units in TTD watch a torrent video he is telling us this stuff what is going to be in the next update on all this stuff it's going to be awesome
Like if you want to go on Doodle Team that means you are a legend!
Comment if you wanna go in Arkey Team that means your super rare!
Ok
Like beggar 💀💀💀💀💀💀💀💀💀💀💀💀
@@tobyaxolotl320 ur you
@@jeanettethulin *you* and NO I AM NOT 🚫
For both do nothing
Who wants doodle too bring arkey mom
👇
Me
MEEEEE I WANNA SEE
Me bro that vid was insane
Me bich
What about doddles dad and arkeys mom and dad
11:48 😤 brainrot
14:11 🔥
14:12 AGHHH
14:15 💨
14:18 🎆
14:42 Doodle Hulk 🐟🟢
8:00 FEARSOME GODZIL…
DOODLE HAS EVOLVED
🔥🔥🗣️🔥🔥
Congrats on 800k🎉
9:54 BRO ARKEY WHAT
First time seeing doodle so mad to happy 😂😂😂
Coming back to toilet tower defence if 10 people like and want me to make content on it
Great videos doodle and arkey arkeys mom
W Doodle
Doodle team 👇
Same
Dude stop being rude idiots
Same
Yes
People like you should be banned from commenting permanently
Whoever gives a thumbs up. They are better than me.
10:18 500 dollars away but it’s 50
2:19 GOT ME ROLLING 😂😂😂😂😂😂😂😂😂😂😂😂😂
Arkey mom
10:22 got me like😂
It sounded like he said “gay”
doodle was so happy 0:04
Anyone 2024 summer ? 😎
Me
The video was made one hour ago 💀
@@Shimmy_the_shrimpyour comment was 6 minutes ago😊
Me
Me
W doodle
only doodle and Arkey fans can like this comment
Stop the cap
Did bros account get hacked by a 5 year old?
Cap noob
Doodle: let's see how fast we can beat it. Arkey: 🤨🧐💀
hi doodle and arkey :)
Hi. Glad you liked the video
我快要达到 5 万订阅者的目标了。
15:13 WE FINALLY KNOW THAT ARKEY IS BALD😂😂😂
bro is so good at the tower defense .
me
5:56 got me rolling
Everytime i see doodle and arkey upload it makes my day better bc of how funny they are i wish they upload more often
only the person who thought i was gonna type doodle and arkey fans like the comment
👇
0:28 doodle why were you kidding 😞
Doodle smart and better then Arkey and Arkey never went to school lol😂
I tought tv woman was gonna be healer tv woman
Same
I thought it was gonna be titan tv man v2
@@marcinnnnn5322that titan cinema is a man not a woman you think is titan cinema woman☠️
The heart is a muscular organ found in most animals. This organ pumps blood through the blood vessels of the circulatory system.[1] The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to the lungs.[2] In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the chest, called the mediastinum.[3]
In humans, other mammals, and birds, the heart is divided into four chambers: upper left and right atria and lower left and right ventricles.[4][5] Commonly, the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart.[6] Fish, in contrast, have two chambers, an atrium and a ventricle, while most reptiles have three chambers.[5] In a healthy heart, blood flows one way through the heart due to heart valves, which prevent backflow.[3] The heart is enclosed in a protective sac, the pericardium, which also contains a small amount of fluid. The wall of the heart is made up of three layers: epicardium, myocardium, and endocardium.[7] In all vertebrates, the heart has an asymmetric orientation, almost always on the left side. According to one theory, this is caused by a developmental axial twist in the early embryo.[8]
The heart pumps blood with a rhythm determined by a group of pacemaker cells in the sinoatrial node. These generate an electric current that causes the heart to contract, traveling through the atrioventricular node and along the conduction system of the heart. In humans, deoxygenated blood enters the heart through the right atrium from the superior and inferior venae cavae and passes to the right ventricle. From here, it is pumped into pulmonary circulation to the lungs, where it receives oxygen and gives off carbon dioxide. Oxygenated blood then returns to the left atrium, passes through the left ventricle and is pumped out through the aorta into systemic circulation, traveling through arteries, arterioles, and capillaries-where nutrients and other substances are exchanged between blood vessels and cells, losing oxygen and gaining carbon dioxide-before being returned to the heart through venules and veins.[10] The heart beats at a resting rate close to 72 beats per minute.[11] Exercise temporarily increases the rate, but lowers it in the long term, and is good for heart health.[12]
Cardiovascular diseases are the most common cause of death globally as of 2008, accounting for 30% of all human deaths.[13][14] Of these more than three-quarters are a result of coronary artery disease and stroke.[13] Risk factors include: smoking, being overweight, little exercise, high cholesterol, high blood pressure, and poorly controlled diabetes, among others.[15] Cardiovascular diseases do not frequently have symptoms but may cause chest pain or shortness of breath. Diagnosis of heart disease is often done by the taking of a medical history, listening to the heart-sounds with a stethoscope, as well as with ECG, and echocardiogram which uses ultrasound.[3] Specialists who focus on diseases of the heart are called cardiologists, although many specialties of medicine may be involved in treatment.[14]
A teenager's heartbeat
Duration: 32 seconds.0:32
Sounds of a healthy 16-year-old child's heart beating normally, as heard with a stethoscope.
Problems playing this file? See media help.
heres a lesson about how he heart works
👇 arkey team
L arkey w doodoe
I feel like the large scientist should’ve evolved into healer tv
Hi
Hi virlance
Fake virlance!
Archie mom
You are first
Fake
Bruh you made me laugh 464 times 😂😂😂😂
Hi doodle
Doodle you mean
no no no.. pool noodle. and marchety!
@@Bigspike-d7fI misspelled it I meant to put doodle not coodle
@@sxnny9554bro
Congrats for 800k
1:37 lol
What
我快要达到 5 万订阅者的目标了。😂
I like when arkey do the mimic to doodle😂😂😂
If arkey comments doodles mom on this comment then im doing 10 jumping jacks
Skbidi rizz
Skibidi rizz
Why yall commenting skibidi rizz?
Reeee👹👹👹👹👹👹👹👹👹
People who hate doodles mom for that
W doodle gang
👇
12:43 doodle becomes a furry for 2 seconds
Doodle is better than arkey by far
Doodle fille and Arkey ahahahahahahhhahhha😂😂😂
Yay a new video
Doodle, Are date will be amazing!!
Arkeys mom??????
DOODLE IS THAT ARKEYS MOM!?😮😮😮😮😮😮
Under 1 hour 👇👇
Me
Yep
Idc
W doodle W Arkey doodle needs his revenge
First! I love your videos! (Doodle mom)
Nope
@@Rahh-fb3kh when I liked it there was 0 likes
we love your video doodle and arkey❤
Only true doodle and Arkey fans can like this comment 🫡
First
I'm do the longest Baba
Doodle and arkey im ur huge fan!! I watch ur video everday!
I thought tv woman would change into healer tv woman. I also thought titan speaker would change into hyper
ARKEY = BARBKEY DOODLE = POOPLE
Food
Video idea: dusty trip but with arkey's mom and / another video idea: TTD but with arkey's mom
Doodle snapped lol 5:18
5:57 and also this part
We need to see Doodle with arkeys mom
EARLY DOODLE AND ARKEY 31 MINS
W doodle and arkey team Yes I liked my comment + first /:
👇
Again with this? Pretty cool
so, so so so so cool
I wonder what doodles dad does when arkey takes her on a date
Do those trying to pump up a soccer ball when he accidentally pumped up himself😂😂😂😂😂😂😂😂😂😂😂
Hi doodle and arkey
Stepdad arkey got me😂😂😂😂😂😂😂😂😂
15:13 Arkey is confirmed bald LOL
I'm just going to say this one thing tarantulas is going to add PVP mode Andrew is going to be new units in TTD watch a torrent video he is telling us this stuff what is going to be in the next update on all this stuff it's going to be awesome
Like if doodle is best
Reply if u think arkey is best
(Not begging)
Poop
W DOODLE W ARKEY IM SUBBED AM I PART OF THE DOODLE AND ARKEY FAMILY???
W DOODLE AND W ARKEY W ARKEYS MOM W DOODLES MOM
Doodle and arkey is the goat
I love your videos. I watched them.
Hi doodle and arkey I'm such a big fan
Bro it doodle and arley😂😂😂😂😂😂😂😂😂
Doodle I asked my grandpa to print a picture of and that’s how much of a fan I am of you
Arkey:
Love your friend ❌
Love your mom friend ✅
Doodle:
###############
Nice video
You guys are so cool
I love doodle
Bro set him on fire 😂😂😂
*Thanks for 70k subscribers* 😢
Subed 🎉
YOU DON'T EVEN HAVE 70K SUBSCRIBERS
13:17 yooo arkey what did u say💀
KEEP SCREAMING AT ARKY DOODLE.
Arkey is feeling better
Doodle and arkey are the best
Archy and doodle. 😁How about you put more hyper’s 😮and you’ll be OP 😎like and subscribe 🎉🎉🎉
TV woman be the healer tv woman
people who love doodle like comment who love arkey
We need a Arkeyparkey mom date video
Doodle is the best
YES NEW VIDEO
Nicee
First comment first view and first like
Nope
Nope
Stopping kids from staying first
No your not
Doodle and Arkey mom are the best
11:47 DOODLE IS SO SIGMA
Who loves doodle and arkey
W arkeys MOM!!!!!!!!!!
W
Prank Archie to say that you are not his friend anymore and he's going on a day with his mom😂 lol
I love you guys ur so funny 😂
5:20 was funny lol
in 1:50 minute Arkey Laughs
9:36
Suggestion: If I win, My units (de)volved!