Do you understand the structure and function of your heart?

When the body is active, the tissues require more oxygen, so the blood must supply the oxygen required by the tissues. At this time, the number of healthy heart contractions increases, the amount of blood ejected each time increases, and the power increases by 10 times compared with calm times. When the heart is diseased, in order to send out a sufficient amount of blood, the heart needs to compensatoryly increase to ensure the blood is sent out. What exactly is going on is easy to understand through the following example. When we pull the rubber band apart, it contracts because of its elasticity. Within a certain limit, the longer it is stretched, the greater its contraction force. However, when the rubber band is damaged, no matter how hard it is pulled, its elasticity is not stronger than normal. If it is more serious, it will have no elasticity no matter how hard it is pulled, or even break.