What is Heart: Definition and 159 Discussions

The heart is a muscular organ in most animals, which pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to the lungs. 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.In humans, other mammals, and birds, the heart is divided into four chambers: upper left and right atria and lower left and right ventricles. Commonly the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart. Fish, in contrast, have two chambers, an atrium and a ventricle, while reptiles have three chambers. In a healthy heart blood flows one way through the heart due to heart valves, which prevent backflow. 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.The heart pumps blood with a rhythm determined by a group of pacemaking cells in the sinoatrial node. These generate a current that causes contraction of the heart, traveling through the atrioventricular node and along the conduction system of the heart. The heart receives blood low in oxygen from the systemic circulation, which enters the right atrium from the superior and inferior venae cavae and passes to the right ventricle. From here it is pumped into the pulmonary circulation, through 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 to the systemic circulation−where the oxygen is used and metabolized to carbon dioxide. The heart beats at a resting rate close to 72 beats per minute. Exercise temporarily increases the rate, but lowers resting heart rate in the long term, and is good for heart health.Cardiovascular diseases (CVD) are the most common cause of death globally as of 2008, accounting for 30% of deaths. Of these more than three-quarters are a result of coronary artery disease and stroke. Risk factors include: smoking, being overweight, little exercise, high cholesterol, high blood pressure, and poorly controlled diabetes, among others. Cardiovascular diseases frequently do not have symptoms or 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, ECG, and ultrasound. Specialists who focus on diseases of the heart are called cardiologists, although many specialties of medicine may be involved in treatment.

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  1. A

    I Is Heart Rate Invariant in Different States of Motion?

    just something i think about, maybe it difficult to answer. i know, from study, that any observer moving along his world-line - in any state of motion - will not himself notice any difference to the rate which time passes for him. example: his heart-rate will feel normal (well, so long as he...
  2. M

    MHB What Are the Solutions to the System of Inequalities for Target Heart Rate?

    One formula for a person’s maximum heart rate is 220 − x, where x is the person’s age in years for 20 ≤ x ≤ 70. The American Heart Association recommends that when a person exercises, the person should strive for a heart rate that is at least 50% of the maximum and at most 85% of the maximum...
  3. Astronuc

    Mortality from heart disease, winter effect

    I came across one article, and I've been looking for similar articles for other nations or groups, e.g., EU. Mortality from heart disease apparently spikes around Winter Solstice and Christmas (end of the calendar year), as well as other causes, which may be related, e.g., obesity and diabetes...
  4. pairofstrings

    B Solving the Heart Curve Equation: 'y =

    Hello. I am trying to write the equation of this heart curve as 'y = '. So the following is my attempt to form that equation: 1 = 1/y (x6y + 3x4y3 - 3x4y + 3x2y5 - x2y4 - 6x2y3 + 3x2y + y7 - 3y5 + 3y3) Here, the graph of the above equation looks like this: Now, next I should write it as 'y =...
  5. jim mcnamara

    EPA and DHA Heart Disease study

    “Effect of Omega-3 Dosage on Cardiovascular Outcomes: An Updated Meta-Analysis and Meta-Regression of Interventional Trials” by Aldo A. Bernasconi, PhD; Michelle M. Wiest, PhD; Carl J. Lavie, MD; Richard V. Milani, MD; and Jari A. Laukkanen, MD, PhD, 17 September 2020, Mayo Clinic Proceedings...
  6. S

    Is the Timing of Heart Sounds Caused by the Opening and Closing of Valves?

    Greetings I am a high school science teacher and music teacher. I am finishing a unit for high school biology and 5th grade science about the human body systems. I have a question about the heart. It involves timing. I heard that the sound of the heart comes from the closing of the valves...
  7. AchillesWrathfulLove

    Philosophy or Math, what is at the heart of all science?

    I am wondering which you think is the foundation of all sciences, I have no real understanding of either but I have a general idea of it I think so please offer your opinion!
  8. gibberingmouther

    G-Force Tolerance and Heart Rate

    This is about my tabletop game again. Hypothetically speaking, if your heart rate was faster because of an "altered time rate" - anywhere from X2 to significantly more than that times the normal time rate - would that increase your g force tolerance? I'm speaking mainly about a g-force...
  9. D

    Understanding the Cardiac Cycle: Diastole & Systole

    I am unsure about the underlined parts of the cardiac cycle. I was taught that the cardiac cycle started when the blood flowed into the atrium, but wouldn't there be a period when both artia and ventricles are at diastole simultaneously? For the second underlined part I was taught and read that...
  10. Orangeator

    B Theoretical Question On The Twins Paradox and Heart Rate

    Okay, so if two identical twins put on a heart rate monitor that after let's say 400 million beats were detected (at 80bpm that's about 10 years) the monitor killed them. Now one gets in a spaceship and the other stays on earth. The one in the spaceship travels at say 95% of the speed of light...
  11. Asmaa Mohammad

    Rhythmicity of the heart and potassium ion

    Hello, I read that the rhythmicity of the heart increases due to decreasing in the permeability of SA node to K ions. I don't understand this mechanism, could anyone give me a simple explanation? Thanks!
  12. jim mcnamara

    Macro nutrients balance and heart disease

    From meeting of cardiologists in Spain: Study on +135000 people worldwide, researchers interpretation: Note that the study included many residents of third world countries where macronutrient (fats and carbohydrates) over consumption is not common. For biology types...
  13. Greg Bernhardt

    Apple Watch Can Detect An Abnormal Heart Rhythm

    As I get older I am very closely keeping track of smart watches for their medical purposes. As someone who has heart disease in their family I am very interested in smart watches tracking cardio properties. Seems at last there is now real progress. Does anyone think this is worth getting a...
  14. jim mcnamara

    Saturated dairy fat consumption and heart disease

    https://link.springer.com/article/10.1007/s10654-017-0243-1 Jung Huo et al, 2017 European Journal of Epidemiology, 'Milk and dairy consumption and risk of cardiovascular diseases and all-cause mortality: dose–response meta-analysis of prospective cohort studies' The takeaway is that saturated...
  15. C

    I What is the name for the "stuff" at heart of black hole?

    What is the name for the "stuff" (neither matter nor neutrons) at the heart of a black hole?
  16. caters

    Writing: Input Wanted How to Get Heart Specific EKG for My Kepler Bb Humanoids

    My Kepler Bb humanoids have 2 hearts and circulatory systems. If the 2 hearts are out of sync, there is definitely a problem. But I was thinking that a normal heart rate for them might be somewhere in the 40-80 BPM range. But how could they get heart specific EKGs is what I am really wondering...
  17. K-Feldspar

    Reading a plaque rupture flow chart correctly

    Homework Statement I am having a bit of trouble interpreting flow charts given in my biology question sets. Given the following stimulus: The question is : In which of the following options does each substance play two different roles in the series of events from plaque ruprture to MI? ADP...
  18. J

    Where can I find tech specs for prosthetic heart valves

    So I am doing a project for an advanced fluids class where I plan to do a CFD analysis of two different prosthetic heart valves, the bi-leaflet valve and the ball and cage (star-edwards). I cannot seem to find the technical specifications or drawings that I need in order to make a good cad...
  19. M

    Preparing for a Career in Heart Surgery: What Classes to Take in 9th Grade?

    i would like to be a heart surgeon but what classes should i take? I am in ninth grade and have a 96% average in all my classes but what would help me to get ahead in college?
  20. I

    Basic hydraulic pump work-energy relationship

    I have a very simple question that's been driving me nuts. It's biology context, but probably all the physics equates to normal positive displacement pumps. The pressure in and volume of the left ventricle of the heart can be measured experimentally. (For example...
  21. S

    Work out cardiac cycle and heart rate

    I would just like to know if i have worked out one cardiac cycle and heart rate correctly. I have attached the image of the ecg called 'after exercise' here are my workings out: 1. CARDIAC CYCLE: there are 4 cycles so: 9 (grids) x 0.05 = 0.45 9x 0.05 = 0.45 9x 0.05 = 0.45 9x 0.05 = 0.45...
  22. S

    Check my answers (questions on heart)

    Hi, I am having trouble filling these correctly! 1. After exercise the [a] pressure remains relatively unchanged while the (B) pressure increases. This is due to the increased cardiac [c] required during exercise. In some circumstances the [d] pressure may actually reduce slightly during...
  23. S

    Sharp Heart Pains, Am I Dying?

    OK, recently I've been having weird sharp sensations in my chest, it started in the left side but now it happens in the right too, the doctor said it was because of my weight training and that i had to stop, so i stopped but its been over a month now and it's still carrying on, also sometimes i...
  24. P

    Astronomers find galaxy cluster with bursting heart

    Astronomers find galaxy cluster with bursting heart An international team of astronomers has discovered a gargantuan galaxy cluster with a core bursting with new stars - an incredibly rare find. The discovery, made with the help of the NASA/ESA Hubble Space Telescope, is the first to show that...
  25. N

    How can I catch heart beat signals?

    Dear everyone, I am thinking about what know of machines in RF lab can catch heart beat signal, In the RF lab with spectrum and network analyzers, also have Function generator and more. They are just working on signal with high frequencies, but heart beats are very low frequencies about...
  26. A

    Max Accel for Pressure in Heart to Reach Brain

    A man is standing up in aircraft that has a constant accerelation upward. Find the maximum accerelation that heart can't pump blood to brain. Head is 50cm above the heart. Pheart=100mmHg ΣF=ma Fn-mg=ma Fn=m(g+a)=ρ(blood)V(g+a) Pfoot=ρ(blood)H(g+a) Pheart=Pfoot-ρ(blood)(H-0.5)(g+a) I don't know...
  27. G

    Power of human Heart and Brain

    If heart forces 4 litres of blood per minute and blood pressure is 125 mm of Hg column and we consider pulse rate as 60 beats per minute then by calculation power of heart comes as approx. 1.111 watts. If I consider the person is just lying down and obviously brain is also active . My question...
  28. Dr.ahmad adnan

    Hi , I want to know if the heart contains the nerve cell?

    Hi , I want to know if the heart contains the nerve cell?
  29. gracy

    The Largest heart among terrestrial animals

    Which of the following is correct 1-Elephant has the largest heart among all terrestrial animals. 2-Giraffe has the largest heart among all terrestrial animals. I have read somewhere that elephant has the largest heart among all terrestrial animals.But now I have seen a book where it is written...
  30. S.S

    Medical Sudden Increase in Heart Beat: Causes for Boys 17 Yrs

    What can be the possible causes for sudden increase in heart beat for a boy of 17 years?
  31. Cake

    Medical Heart Rate Jumps While Exercising

    Hey fellas and ladies. So I have an issue. I've been exercising regularly for about 3 months now by doing jogging and brisk walking. Just basic cardio to get my terrible heart into shape. The thing is, I can't jog for very long at all without my heart rate jumping up to 170-180+. I know this...
  32. E

    Weightlifitng strengthens your heart, bones, and lungs?

    Is it true that weightlifting strengthens your bones, your heart, and your lungs?
  33. Evil Bunny

    Exploring the Relationship Between Heart Rate and Calorie Burn During Exercise

    Is there a direct correlation between calorie burn and heart rate? If an athlete and a couch potato each weighed 175 lbs and ran a mile in 10 minutes, would they burn the same amount of calories? I would assume the couch potato would have a much higher heart rate during this event. Does that...
  34. R

    Can Someone Have Two Hearts and a Rare Heart Placement?

    can two +ve rhesus parents have a negative rh factor offspring? Can a person have heart on right and two hearts? I know it is rare.
  35. A

    Can an artificial human heart support 220v?

    I have a question. If an human have an artificial heart can the artifical heart support 220v? if the answer is yes. Can the human maipulate electricity? maybe is an stupid question but can you answer please
  36. L

    Does sugar truly cause heart disease? Evidence and explanations behind the link

    Recently I viewed a short video that recommended reducing sugar in our diets because new research suggests that sugar causes heart disease. What is the status of this research? How convincing is the evidence?
  37. Spinnor

    Medical Pain in heart radiates to jaw implies pain in jaw radiates to heart?

    Almost two weeks ago I had a lower rear molar numbed to oblivion, ground down, and caped with a temporary crown. Afterwards that tooth would from time to time get not painful but annoying. A pair of Advil would make things better. During this discomfort I noticed discomfort in my chest area as...
  38. B

    How accurate are heart rate monitors during walking/running

    I just started using this heart rate monitor, with the strap around the chest and the watch that you wear. I can't help suspecting that its just following my strides on the treadmill though, and also, if this is possible? How accurate are these monitors anyway, and how do they work? The...
  39. Astronuc

    What are the risk factors for heart disease in women?

    Apparently it has been thought that heart disease is mostly a men's disease. But - Since 1984, more women than men have died each year from heart disease. Heart disease is now the No. 1 killer of women, causing more deaths than all cancers combined! And yet only 56 percent of American women...
  40. A

    Mind says Engineering, heart says Physics Don't know what to do

    To keep it short, I am an Engineering undergrad. As the days go by, I keep coming closer to accepting the fact that I enjoy - and am passionate about - physics more than I am about Engineering. I know it would probably be easier to get a job with an Engineering degree(assumption?), and that...
  41. A

    What is the Average Power Output of a Human Heart Pump?

    Homework Statement during a human heart beat, 20g of blood are pushed into the main arteries. This blood is accelerated from a speed of 0.20ms-1 to 0.34ms-1. For a heart pulsing at 70 beats per minute, calculate the average power of the heart pump. Homework Equations KE=1/2mv2 The Attempt at a...
  42. W

    Why should people with congestive heart failure drink less fluid?

    People with congestive heart failure (CHF) are advised by doctors to restrict fluid intake. For example, while 8 cups of fluid per day is recommended for healthy individuals, people with CHF are recommended not to exceed 4 cups a day. The explanation, according to a medical student friend, is so...
  43. G

    Medical Can MRI Scans Affect Heart Rate?

    I was going to post in another thread with this title but it was closed? I had an MRI of the right shoulder today in an open MRI and went through about 6 cycles of scans (I think it was 6). During the 4th cycle I noticed that my heart rate was increasing. I went into this with a calm demeanor...
  44. D

    How Does Blood Flow and Pressure Work in the Human Heart?

    I have a school assignment about the physics of the human heart, primarily about the pressures in the ventricles and atriums, what causes the valves to open and what makes blood flow from the atrium to the ventricle, what is the pressure and where? I already know how what makes the heart beat...
  45. N

    MHB Probability of High BP & Heart Trouble in Hospital Patients

    I am not positive if this question has a formula behind it because that's how terrible my math is, 1. A hospital Survey indicates that 35% of patients admitted have high blood pressure, 53% have heart trouble, and 22% have both. Find the probability that a patient admitted to this hospital has...
  46. N

    Force problem (not for the faint of heart)

    Homework Statement Bob is pulling a sled up a 50 degree hill (meaning the incline is at an angle of fifty degrees above the horizontal). Sitting on the sled is Bob's niece (unknown mass). After pulling the sled 30.0 meters up the incline, Bob slips and falls releasing the rope...
  47. Greg Bernhardt

    Flu vaccine cuts heart attack risk

    New study out http://www.usatoday.com/story/news/nation/2013/10/22/flu-vaccine-heart-attack/3150819/
  48. T

    Programs Best Engineering degree for a physicist at heart?

    Hello PF community, I am currently a sophomore in college about to declare a major, and I wanted to know what engineering degree is most closely related to/has the most to do with physics. Physics is my passion, but I don't think I can commit to a physics degree. I am looking at a mountain of...