Heart Definition and 159 Threads

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. S

    Heart shaped observable universe?

    In another forum there was a discussion of the observable universe being heart shaped because of the expansion of space (unless I misinterpreted the drawing). Info that I have found says it to be spherical. Have you seen any drawings of anything heart shaped for anything cosmological?
  2. drizzle

    Brain vs. heart: Personality traits and organ transplants

    this may not be the right forum, but I guessed so, reading the thread posted by Rex S titled as “Can there be Artificial Consciousness and Emotion? ” reminds me of an article I read last year, it was about heart transplant, I was thinking of it a couple of weeks ago, and thought I would’ve post...
  3. C

    Solving N-dipole Problem in the Heart: How to Calculate Potential Fields

    I have been trying to solve this problem without any success. Not homework, just curious how to solve this, I'm trying to deduce physical models. Honestly I have no idea how to attack it, so I'd really appreciate if you could please provide some help. This is electrodynamics applied to...
  4. Ivan Seeking

    Medical An aspirin a day to help prevent heart attack and stroke

    http://health.usnews.com/articles/health/healthday/2009/03/16/experts-revise-guidelines-on-daily-aspirin-for.html According to one report, most experts think that a baby aspirin will do.
  5. lisab

    Exploring Octopus Intelligence: Are They Smart?

    I *heart* Octopi! You think cats are curious?!? http://www.sciam.com/article.cfm?id=are-octopuses-smart"found and turned a knob...just for fun. Just goofing around. Pulled a plug, and caused a flood. From the article :
  6. C

    What Is the Sequence of the Cardiac Cycle?

    Hey guys, can someone make things clear for me? Does the heart goes atrial systole followed by ventricle systole then followed by both the atrial and ventricle diastole (at once) or atrial systole, ventricle systole (at the same time atrial diastole) then only ventricle systole?
  7. H

    Women's heart disease awareness what about men?

    I learned today of http://www.nhlbi.nih.gov/health/hearttruth/index.htm , meant to show support for women's heart disease awareness. I cannot find a comparable "men's heart disease awareness" movement -- is there just cause for such gender discrimination?
  8. wolram

    Guinness can be beneficial to the heart

    Is guinness good for you? From Wiki, Studies claim that Guinness can be beneficial to the heart. Researchers found that antioxidant compounds in Guinness, similar to those found in certain fruits and vegetables, are responsible for health benefits because they slow down the deposit of...
  9. R

    Doppler Effect with heart motion

    Homework Statement Suppose a heart's ventricular wall moves in simple harmonic motion with amplitude 1.8mm and a frequency of 115 per minute. (a) Given a motion detector in contact with the chest produces sound at 2,000,000Hz which travels through tissue at 1.50 km/s. Find the maximum linear...
  10. C

    Advantages in the body in the change in breathing and heart rates.

    i'm stuck. i need to explain the advantage to the body in the change in breathing and heart rates. also what does the stimulus, the co-ordinator, and the effector mean.
  11. L

    Major Project on Physics of the Heart and Cardiovascular System

    1. As part of my Advanced Physics 11 course in high school, I have decided to do my major project on the physics of the human heart. I have found many resources and a lot of information, but I really need to go into more depth slash relate it better to physics (it's easy to find the biology side...
  12. wolram

    Help for KIA: Dealing with a Fiancé's Heart Attack

    KIAs bf has had a massive heart attack, they are due to be wed in 14 weeks time, i mean the guy does not smoke or drink, what the hey is going on, what can i do to help, i do not know how to help
  13. K

    Heart or brain - Split between 3 unrelated disciplines

    Good afternoon PF, I have been a lurker of this forum for over a year and it is now my time to seek academic advice. I am a university student who has recently finished first year. I have taken honors calculus, physics, chemistry, biology, and sociology and obtained very good standing in...
  14. Astronuc

    Medical Early warning signs of heart attack.

    I found this article, which is relavant to men and some women of 50 yrs or older. Not a Moment Too Soon, I Thought of Tim Russert Tim Russert, a well-known TV journalist died suddenly of a heart attack at the young age of 58. He was being treated for some heart/coronary disease, but...
  15. G

    Medical What is a Healthy Blood Pressure and Heart Rate for a 30-Year-Old Smoker?

    While I was at work I had it tested. BP was 116 over 82. Heart rate was 63. I guess that's good considering I smoke and don't eat real healthy. .. and I'm 30 for the record. So is that good, bad, normal?
  16. M

    Acceleration of blood pumped by heart

    Hey, I"m having a few problems with some motion problems and was wondering if someone could help? The left ventricle of the heart accelerated blood from rest to a velocity of +23.9 cm s-1. If the displacement of the blood during the acceleration is +1.80 cm, determine its acceleration (in cm...
  17. ~christina~

    Heart-kun the puppy with the heart shaped fur pattern

    Heart-kun the puppy with the heart shaped fur pattern. :!) http://www.thatsweird.net/picture39.shtml :!) http://www.anicom-pafe.com/techo/archives/2007/10/post_42.html
  18. S

    Medical Incubator Electromagnetic Fields Alter Newborns' Heart Rates

    ScienceDaily (May 2, 2008) — The electromagnetic fields produced by incubators alter newborns' heart rates, reveals a small study published ahead of print in the Fetal and Neonatal Edition of Archives of Disease in Childhood. It is not clear what the long term effects might be, but this could...
  19. M

    Medical How to give CPR (in case of a heart attack) to an elderly person?

    Hello everyone I am asking this question because I haven't joined any CPR course yet. The normal procedure requires a lot of force to be applied on the chest. But isn't such a huge pressure harmful for extremely aged people, whose bones are fragile and who may develop other complications in...
  20. R

    Problem solving 2nd order ODE not for the faint of heart

    Problem solving 2nd order ODE...not for the faint of heart! Hey folks, I'm having problems solving the following set of ODE's: 3H_a^2+H_b^2+6H_aH_b=k_1\rho eq.1 \dot{H_a}+3H_a^2+2H_aH_b=k_2\rho eq.2 \dot{H_b}+2H_b^2+3H_aH_b=k_3\rho eq.3 These are cosmological equations. Note...
  21. C

    Medical Low Resting Heart Rate and the Possibility of Doubling with Age

    A long time ago I read somewhere that people with low heart rates (e.g. athletes) can experience a doubling of their heart rates when they get older (sort of bifurcation in which a single heart beat evolves into two heart beats). I tried to find out more about this phenomena but I didn't find...
  22. ShawnD

    Like a thousand needles stabbing your heart

    What is it called when you get a sudden chest pain that lasts for just a second or two? Homer Simpsons described it as a feeling of a thousand needles stabbing into his heart. I tried to google it but all I got was emo poetry. Your wordth are like a thouthand needleth thtabbing into my heart...
  23. A

    MATLAB Human Heart Radiation Using Matlab

    Human Heart Radiation Using Matlab ( Electric Bipole ) Homework Statement Hey There, i was given a project saying : Use Matlab to simulate the radiation from a human heart ( Electric Diode ). What am i supposed to do? How to begin ? Thank You. Homework Equations The Attempt at...
  24. A

    What is the fetal heart wall speed in m/s using the Doppler effect?

    Homework Statement A 1.50-MHz sound wave travels through a pregnant woman’s abdomen and is reflected from the fetal heart wall of her unborn baby. The heart wall is moving toward the sound receiver as the heart beats. The reflected sound is then mixed with the transmitted sound, and 85 beats...
  25. J

    Modeling the HEart with Calculus

    I'm receiving a lecture on Modeling the Heart for about three weeks. We were assigned a problem which required us to find the mean Psa value.. Where Psa(t) = Psa(0)*exp(-t/(Csa*Rs)) and Psa(0) is the initial value, and Csa and Rs are constants. Now What i did is intergrate this like...
  26. A

    What is the Heart Rate and Sound Frequency of a 5kg Carp?

    Hi, I'm trying to find out what would be the expected pulse rate and frequency of emitted sound by a carp's heart beat where the fish is of size around 5kg (10lb) plus. Does anyone know where I might find such information, or have a reasonable guess as to what it might be?
  27. R

    Compare Water Content of Muscle, Liver, Fat, Heart, Cartilage, Bone Marrow

    How would you rate the following in terms of water content: muscle, liver, fat, heart, cartilage, bone marrow and where could i find a table of comparison...?
  28. Ivan Seeking

    A funny thing happened while a guy was having a heart attack

    I walked right past him but didn't realize what was happening. I saw this truck driver parked in an odd place. Apparently he was talking on the cell phone which made me think he was lost, but I took note because he stared at me in a very odd manner as I walked by. I noticed that something was...
  29. Amith2006

    How Do You Calculate the Power of a Human Heart Pumping Blood?

    Sir, Please help me with this problem. # The heart of a man pumps 4 litres of blood per minute at a pressure of 130 mm of mercury. If the density of blood is 13.6 gm/cc, what is the power of the heart?
  30. chroot

    My Heart Issues: Stress Echocardiogram Referral & Worries

    I've been having some problems exercising recently. For the last six months or so, lifting weights (10-12 sets of 4 or 5 basic exercises with moderate weights) has often resulted in my heart rate staying at 160 bpm for half an hour, plus the added fun of cold, clammy hands, dizziness, and even...
  31. D

    Understanding the Heart's Electrical Charge: Origins and Function

    this may be outdated, but I was under the impression that it was an electrical charge that powered the heart to beat. If so, where does the initial charge come from that started this whole process? thanks dleacock
  32. S

    Women can see again after Heart attack

    http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/01/20/nblind20.xml&sSheet=/news/2006/01/20/ixhome.html How can having a heart attack make you see again:confused:
  33. Mk

    28th Stem Cell Therapy Patient to be Healed of Heart Failure in Thailand

    http://news.yahoo.com/s/nm/20060109/lf_nm/thailand_stemcells_dc
  34. G

    Vagus Nerve & Acetylcholine: Lowering Heart Rate

    By releasing acetylcholine, how does the vagus nerve lower heart rate?
  35. wolram

    Reliving Teenage Years: A Wish for the Young at Heart

    Please Evo will you scrub out the silly ones so i do not feel so ancient. i want to be teen age again.
  36. wolram

    Making Your Own "Have a Heart" Puzzles

    Has anyone made their own ? dad made the" have a heart" puzzle for us kids years ago, they can be fun and cheap to make. http://www.puzzles.ca/puzzles_2.html
  37. S

    Fetal Heart Wall Velocity from Ultrasound Reflection

    A sound wave travels at a frequency 2.25 MHz through a pregnant woman's abdomen and is reflected from the fetal heart wall of her unborn baby. The heart wall is moving toward the sound receiver as the heart beats. The reflected sound is then mixed with the transmitted sound, and 87.0 beats per...
  38. Ivan Seeking

    Telephone My Heart: Pacemakers & Spinal Cord Stimulators

    A customer was telling me today about his dad's pacemaker. Modifications are made by the doctor by telephone with the earpiece held over the heart. Apparently the doctor uses a device that emits audio tones for various programming functions. This way the pacemaker can be fine tuned to the...
  39. Mk

    Is lightning caused by ice particles?

    http://www.abc.net.au/science/news/stories/s1443052.htm One of many articles on the proof that lightning is caused by ice flying around in the atmosphere. Apparently meteorologists are pretty certain about this. What about on Venus? There's a lot of lightning there, but certainly no ice...
  40. N

    How does three chambers of heart help the amphibians?

    it seems that these kinds of animals can prevent blood going throught the lung (pulmonary vein,artey)Can anyone clarify it please?
  41. C

    Why Is Cold Solution Used for Open Heart Surgery?

    According to sources I've read, the heart can be stopped by flooding it with "a cold solution containing potassium ions" - why must it be cold? Thanks in advance. :smile:
  42. E

    Understanding Blood Pressure and Heart Rate Variations

    Can someone help me answer these questions?!? thanx!@ :confused: Explain why blood pressure and heart rate differ when measured in a reclining position and in a standing position. Explain why high blood pressure is a health concern. High blood pressure can lead to many other...
  43. J

    Heart Attacks: Connections to Photosynthesis & Respiration

    what do heart attacks have to do with cellular respiration and photosynthesis? If anyone can help me understand this, please reply to the thread thanks!
  44. D

    How Does Body Position and Fitness Level Affect Heart Rate and Blood Pressure?

    A few questions I need answered before a test. Why does a standing blood pressure and heart rate differ from a reclining blood pressure and heart rate? Why must an athlete exercise harder and longer to achieve a maximum heart rate and blood pressure as compared to an average person...
  45. Astronuc

    Changing Chemistry Helps Explain Estrogen Threat to the Heart

    by Toni Baker Feb. 16, 2005 http://www.mcg.edu/news/2005NewsRel/Estrogen.html (Press Release) Comments?
  46. S

    Emptiness is at the heart of Everything

    Someone here mentioned this idea, and I wish to present a possible explanation for review: Earlier, I proposed an hypothesis that mind existed independently of the particular neural substrate we see it implemented in with man (and others); in this view only the dynamics are essential for a...
  47. S

    Magnetic Force Question Really givin me a heart burn

    1)A beam of electrona travels along an evacuated tube towards a floriscent screen.A coil is placed around the tube producing magnetic field along the axis of the tube. a)describe and explain the motion of the beam if: 1)it is exactly parallel to the axis of the tube My working: I think...
  48. benzun_1999

    Can You Help Me Find a Heart Beat Detector Circuit with LED Display?

    can anyone sugest me a good heart beat detector circuit. note the circuit must detect the current from the heart and LED display in a column. -Benzun
  49. K

    How does chaos theory explain heart attacks?

    Hey everyone! This is not exactly a homework question, but i would like to know anyway.. can anyone tell me how the heart works from physics point of view? Or the nervous system? Any points would be great :) thanks! kateena
  50. K

    Physics of the Heart: Nerves & Pacemakers Explained

    Hey everyone! This is a plea for help! :) I was wondering if anyone could explain to me from a physics point of view how the heart/nerves work, and also if possible a pacemaker! Any points would be great, I am feeling a bit lost! :confused: Thanks! Kateena
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