What is the main function of blood?Ray Schilling:
Blood has many functions.
1. Most of all, blood transports oxygen from the lungs to all the tissues by way of hemoglobin that is embedded in the red blood cells. On the way back to the heart and lungs it transports CO2, which is exhaled by the lungs.
2. Nutrients are taken up in the capillaries of the gut, transported via the portal vein into the liver. Here many metabolic pathways are followed and the nutrients are further transported through the blood to all of the body cells.
3. Clotting factors in the plasma of the blood together with platelets contained in the blood see to it that any tiny tears or holes are immediately plugged. Blood has a certain blood pressure, so any defect cannot be tolerated or this could lead to a major bleed. It is interesting that coagulation from clotting factors/platelets and fibrinolysis are constantly balancing each other automatically.
4. Infection is being contained by white blood cells (lymphocytes for viruses, neutrophils for bacteria) on the one hand and antibodies from plasma cells on the other hand. This is quite an effective system to fight infection. Occasionally antibiotics are needed when our immune system is overwhelmed.
5. Hormones and other signaling molecules (e.g. nitric oxide) integrate the function of various organs. As long as all hormones are present and balanced we have energy and all our organs function perfectly. But when hormones are missing, we feel miserable. As we age, some hormones are not produced sufficiently. Having reviewed the literature, bioidentical hormone replacement will allow our system to get rebalanced.
6. Heat distribution and blood redistribution are other aspect of perfusion of our limbs with blood, our abdominal organs, the head and skin. After a meal the blood is rushing to the gut and the liver as we start to digest our meal. We may get tired, because some of the blood from the brain gets pulled away to the stomach, small intestine and the liver. On a hot day our skin veins open up wide, we sweat and lose some of our body heat through our skin. It’s the body’s way to keep us cool inside.
7. There is one aspect that seems to be out of our control. When we get excited or a person is extremely shy, the head, neck, and the ears will turn red. This is out of our control. Some people have this more than others and some don't have it at all. It comes from dilated skin blood vessels. When they dilate, blood rushes into that region giving your skin a reddened appearance.
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