Heart
Heart is a muscular organ, which is made out of cardiac muscle (muscle that is working all the time), pump blood through the body. Heart is about the size of the fist. It is in behind the sternum (breastbone) and inside the rib cage.
When heart beats, blood are pushed to the blood vessel of the cardiovascular system.
Heart have left and right side with each an upper chamber and a lower chamber. The right side and left side is separated by septum, which is wall of tissue.
Atrium which is two upper chamber, receives blood that comes into the heart. In right atrium is a group of heart cell called peacemaker. They send signals, so the heart muscle contact.
Ventricle is lower chamber, which blood get pumped from there.
Lower chambers and upper chambers are separated by valves, which is flap of tissues that prevents blood from flowing backward. Still, valves is also located between the ventricles and the large blood vessels.
How the heart works
1. Fills blood inside chambers when heart muscle relaxes.
2. Blood get squeezed out of atria when atria contract which go to ventricle through valves.
3. Ventricle contract. Closing the valves between atria and blood vessels. Makes lub sound which squeezes the blood to blood vessels.
4. After, valves between the ventricles and blood vessels shuts, it makes dup sound.
When heart beats, blood are pushed to the blood vessel of the cardiovascular system.
Heart have left and right side with each an upper chamber and a lower chamber. The right side and left side is separated by septum, which is wall of tissue.
Atrium which is two upper chamber, receives blood that comes into the heart. In right atrium is a group of heart cell called peacemaker. They send signals, so the heart muscle contact.
Ventricle is lower chamber, which blood get pumped from there.
Lower chambers and upper chambers are separated by valves, which is flap of tissues that prevents blood from flowing backward. Still, valves is also located between the ventricles and the large blood vessels.
How the heart works
1. Fills blood inside chambers when heart muscle relaxes.
2. Blood get squeezed out of atria when atria contract which go to ventricle through valves.
3. Ventricle contract. Closing the valves between atria and blood vessels. Makes lub sound which squeezes the blood to blood vessels.
4. After, valves between the ventricles and blood vessels shuts, it makes dup sound.