3 PISMP PC/PJ/RBT PJM 3106 ISL (M14) 3. Maklumat dari http://science.howstuffworks.com/environmental/life/human- biology/heart3.htm. HEART IMAGE GALLERY Everyone knows that the heart is a vital organ. We cannot live without our heart. However, when you get right down to it, the heart is just a pump. A complex and important one, yes, but still just a pump. As with all other pumps it can become clogged , break down and need repair. This is why it is critic al that we know how the heart works. With a little knowledge about your heart and what is good or bad for it, you can significantly reduce your risk forheart disease. Heart disease is the leading cause of death in the United States. Almost 2,000 Americans die of heart disease each day. That is one death every 44 seconds. The good news is that the death rate from heart disease has been steadily decreasing. Unfortunately, heart disease still causes sudden death and many people die before even reaching the hospital.
3. Maklumat darihttp://science.howstuffworks.com/environmental/life/human-biology/heart3.htm.
HEART IMAGE GALLERY
Everyone knows that the heart is a vital organ. We cannot live without our heart.However, when you get right down to it, the heart is just a pump. A complex andimportant one, yes, but still just a pump. As with all other pumps it can becomeclogged, break down and need repair. This is why it is critical that we know howthe heart works. With a little knowledge about your heart and what is good or badfor it, you can significantly reduce your risk for heart disease.
Heart disease is the leading cause of death in the United States. Almost 2,000 Americans die of heart disease each day. That is one death every 44 seconds.The good news is that the death rate from heart disease has been steadily
decreasing. Unfortunately, heart disease still causes sudden death and manypeople die before even reaching the hospital.
The heart is divided into four chambers: (see Figure 2)
1. right atrium (RA)
2. right ventricle (RV)
3. left atrium (LA)
4. left ventricle (LV)
Figure 2
Each chamber has a sort of one-way valve at its exit that prevents blood from
flowing backwards. When each chamber contracts, the valve at its exit opens.When it is finished contracting, the valve closes so that blood does not flowbackwards.
When the heart muscle contracts or beats (called systole), it pumps blood out of the heart. The heart contracts in two stages. In the first stage, the right and leftatria contract at the same time, pumping blood to the right and left ventricles.Then the ventricles contract together to propel blood out of the heart. Then theheart muscle relaxes (called diastole) before the next heartbeat. This allowsblood to fill up the heart again.
The right and left sides of the heart have separate functions. The right side of theheart collects oxygen-poor blood from the body and pumps it to the lungs whereit picks up oxygen and releases carbon dioxide. The left side of the heart thencollects oxygen-rich blood from the lungs and pumps it to the body so that thecells throughout your body have the oxygen they need to function properly.
