• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

How the Heart Works

Extracts from this document...

Introduction

How the Heart Works Although the heart is often referred to as a symbol of courage and love, it is no more than a muscular pump. From the moment it begins beating to the moment we die the heart works non-stop beating an average of 72 beats per minute, 37,843,200 beats per year and 2,838,240,000 beats per average lifetime1. Like most other pumps the human heart can break down, thus need repair. Heart disease is the leading cause of death in the United States, an amazing 2,000 Americans die of heart disease everyday that's an average of one every 44 seconds2. This is why it is important to know how your heart works, because with even the slightest bit of knowledge as to what is good and what is bad for it you can drastically reduce your risk for heart disease. The human heart weighs approximately 275 grams3 and is about the size of a clenched fist. Although many believe that the heart is located left of the chest, it is actually located perfectly center between the two lungs, protected by the sternum (breastbone), the rib cage, the vertebral column (spine), the scapular (shoulder blade) and the clavicle (collarbone). The human heart is enclosed in a two layered membrane called the pericardium, not only does it anchor the heart to its surrounding structures but prevents the heart from overfilling with blood. The outer wall of the heart is composed of three layers. The outer layer is called the visceral pericardium as the outer layer is in fact the inner layer of the pericardium. ...read more.

Middle

The artery splits up and eventually becomes capillaries which will resemble a filter (permeable layer) only allowing the good and useful substances (food and oxygen) to be obtained by the cells. This process is called diffusion and the fluids that exit the bloodstream have no distinct colour, proving that the membrane only allows certains substances to pass and obviously haemoglobin isn't one of them. Eventually the cells will send waste products such as CO2 into the bloodstream through veins which is how the blood becomes deoxygenated, any remaining fluid that isn't obtained by the cells, ergo seeped all the way through tissue, is obtained by lymph's and temporarily stored in a lymph node and eventually send back into the blood stream once again through veins. The blood travels up slowly and smoothly through the vein as there is very low pressure (some veins even have valves similar to the ones in our heart to prevent the blood from flowing back) and back to the heart through the superior and inferior vena cava. This process of blood flow is repeated countless times and does not stop till you die. How does the heart actually beat automatically? The answer lies in a group of specialized cells found in the natural pacemaker of the heart, the sinoatrial node located near the right atrium. These cells have the ability to generate electrical activity automatically, separating charged particles and spontaneously send them into the left and right atria causing them to contract simultaneously. As mentioned the middle layer of the heart myocardium consists of cardiac muscle, a special kind of fibre not found anywhere else in the body with the ability to conduct electricity. ...read more.

Conclusion

* Congenital heart defects - Heart defects presents from birth, possibly due to a fault during early embryo development * Valve disorders - There are several conditions that can affect the efficient functioning of any of the heart's four valves * Heart murmurs - Unusual heart sounds produced by turbulent blood flow which may be due to a heart valve defect Circulatory and heart-rate disorders - A constant and adequate blood supply is essential for healthy tissues. If a blockage occurs in a blood vessel the tissues will be starved of oxygen causing the tissue damage and in severe cases lead to tissue death. The heart may also be affected if the electrical system is disturbed. * Embolism - An embolus is a fragment of a material that breaks away from its original location which can cause partial or total blockage of a blood vessel * Thrombosis - The partial or total blockage of an artery, vein or even the heart can occur whena blood clot (thrombus) forms due to a circulatory problem * Aneurysm - Abnormal welling of a weakened arterial wall, which results in making the wall bulge out like a balloon * Hypertension - Internal organs can become damaged if not treated due to a high blood pressure * Arrhythmia - An abnormal heart rate of rhythm which is caused by a disturbance in the electrical system So if you wish to keep your heart healthy for the rest of your life do following: 1. Get plenty of exercise 2. Follow a good diet 3. Keep ypur heart clean and drug-free "Be heart smart and have a healthy heart. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our International Baccalaureate Biology section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related International Baccalaureate Biology essays

  1. To investigate how aerobic exercise affects the heart rate

    as the length of physical activity increases. Processed data Calculations Average = attempt 1 + attempt 2 + attempt 3 + attempt 4 + attempt 5 5 Standard deviation (done using a spreadsheet) Working Length of time to perform jumping jacks (min) �0.5s Pulse rate (bpm) � 1 bpm Calculations and working Average heart rate (bpm)

  2. biology extended essay - How different diets: vegetarian, vegan and a meat centered diet ...

    Many people become vegetarians and vegans for a combination of the reasons stated above.(5) 5 00511-062 08/09 1.2.5 What are the advantages of becoming a vegetarian or Vegan? [5] There are a number of advantages to becoming or being a vegetarian or vegan.

  1. Outline the control of the heart beat in terms of myogenic muscle contraction, the ...

    These cells contract without nevous stimulation. The sinoatrial node spontaneously sends out an electrical signal, which spreads out over the right atrium's wall into the wall of the left atrium by the Bachmanns bundle. That impulse spread through the atria, causing the atria to contract and to stimulate the atrioventricular node, that is located between the right atrium and the right ventricle.

  2. Should Animals have the same rights as Humans? Both animals and humans exhibit behaviours ...

    Penguin parents both feed their chicks regurgitated food, recognise and nurture only their own chick and are able to respond to the call of their own chick among hundreds of others. Animals have a range of behaviours based around what, when and how they eat their food and where they find it.

  1. Bilharzia. Schistosomiasis, commonly known as snail fever, bilharzia and bilharziasis, is a disease ...

    The worms fuels on red blood cells and nutrients, for example sugars and amino acids. This can cause anemia and reduced protection towards other diseases. Female worms will release thousands of eggs which pass out of the body depending on where they are located.

  2. Heart Recoil IA. Aim To compare the recoil and subsequent elastic limit of ...

    as this means I will have to dissect another heart to obtain an aorta and vena cava again. Conclusion The aim of this experiment was to compare the recoil and elastic limit of an aorta and vena cava. This was done by hanging weights onto the aorta/vena cava and measuring

  1. An investigation on the changes in tidal volume and vital capacity of lungs before ...

    was 1.7341, which is higher than t-value and thus, the null hypothesis was accepted ? the vital capacity of the lungs does not increase after short-term exercise. Hence, it can be concluded that the results obtained do, to some extent, support the theory as the tidal volume did increase but the vital capacity did not.

  2. Sleep is a normal part of human life. Investigate the neurobiological basis of normal ...

    The entrainment of the biological clock. Black bars, asleep; gray bars, awake. Hours by age Children need more sleep per day in order to develop and function properly: up to 18 hours for newborn babies, with a declining rate as a child ages.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work