Blood circulation
The heart
The heart is a hollow muscle which encloses 4 cavities. It works like a pump. Each half works as an independent unit, working in synchrony with the other half; the heart is a double pump with two blood circulations.
Anatomy of the heart
- The right atrium
This is the place where all veins that transport the blood with a little oxygen to the heart arrives.
- The right cardiac chamber
If the right cardiac chamber contracts, it will push the blood trough the pulmonary artery to the lungs. A lid of the artery, that works in only one direction, prevent the blood from going back into the right cardiac chamber. In the lungs their is an exchange of oxygen and carbon dioxide.
- The left atrium
Here arrives the pulmonary vein, which contains blood that is now rich of oxygen from the lungs. If the left atrium contracts, the blood is sent to the left cardiac chamber.
- The left cardiac chamber
When the left cardiac chamber contracts the blood is sent with a huge power into the aorta, which sents it around in our whole body.
The double blood circulation
We, humans, have a double and closed blood circulation. We have 2 circulations: from the heart to the lungs and back to the heart. This is the little blood circulation. The second, from the heart through our whole body and back to the heart, is the big blood circulation.
The blood
The total amount of blood is 8% of our weight.
For the rest, the blood consists of:
- Blood plasma (55%)
The plasma contains for 90% from water and the rest are soluble materials like proteins, lipids, glucose and minerals.
- Erythrocytes or red blood cells (5 million/mm3)
Haemoglobin consist of 4 sub-units. Every sub-unit is a chain of proteins (= the globin part) and an ferriferous heem-group. It's this ferriferous material which easily react with oxygen. On this way, it becomes oxyhaemoglobin.
- Leucocyte or White blood cells (6000 to 8000/mm3)
- They defend our body against strange substances and micro-organisms that causes diseases (like bacteriums, mouls, virusses, parasites ...)
- They also clear dead cells.
- Blood platelets (300 000/mm3)
- They are the smallest blood cells.
- They have an important function with the congeal of blood.
This is the place where all veins that transport the blood with a little oxygen to the heart arrives.
If the right cardiac chamber contracts, it will push the blood trough the pulmonary artery to the lungs. A lid of the artery, that works in only one direction, prevent the blood from going back into the right cardiac chamber. In the lungs their is an exchange of oxygen and carbon dioxide.
Here arrives the pulmonary vein, which contains blood that is now rich of oxygen from the lungs. If the left atrium contracts, the blood is sent to the left cardiac chamber.
When the left cardiac chamber contracts the blood is sent with a huge power into the aorta, which sents it around in our whole body.
The plasma contains for 90% from water and the rest are soluble materials like proteins, lipids, glucose and minerals.
Haemoglobin consist of 4 sub-units. Every sub-unit is a chain of proteins (= the globin part) and an ferriferous heem-group. It's this ferriferous material which easily react with oxygen. On this way, it becomes oxyhaemoglobin.
- They defend our body against strange substances and micro-organisms that causes diseases (like bacteriums, mouls, virusses, parasites ...)
- They also clear dead cells.
- They are the smallest blood cells.
- They have an important function with the congeal of blood.