Blood

• Blood consists of four main components: red blood cells, white blood cells, platelets, and plasma.
• Red blood cells, which make up almost half of our blood by volume, carry oxygen from the lungs to our body's tissues.
• Red blood cells contain a red pigment called hemoglobin which combined oxygen to become oxyhemoglobin and then once those red blood cells have traveled around the body to the tissues the oxyhemoglobin can split back into hemoglobin and oxygen again so that the oxygen is free to diffuse into our tissues.
• Red blood cells have two adaptations that contribute to their role in transporting oxygen: they don't have a nucleus which means that there's more space for hemoglobin and oxygen, and they're shaped like a biconcave disc which gives them a large surface area for absorbing oxygen.
• White blood cells, which make up less than 1% of our blood by volume, are an essential part of our immune system which defends us against infection.
• White blood cells can do a whole range of useful things for us, including phagocytosis, juicing antibodies, and producing anti toxins.
• Unlike red blood cells, white blood cells actually do have a nucleus.
• Platelets are small fragments of cells in our blood waiting until we get a cut at which point they rush to the wound and act like a glue patching up the hole.
• The main reason we need platelets is to stop blood from pouring out of us whenever we get a cut.
• Another important reason for having platelets is to prevent microorganisms from getting in as they could cause an infection.
• Plasma, which makes up just over half of the blood's volume, is a liquid that carries just about everything including the red blood cells, white blood cells, and platelets.
• Plasma carries nutrients like glucose and amino acids, waste products like carbon dioxide and urea, as well as hormones, proteins, and the antibodies and toxins produced by the white blood cells.
• Doctors can give the patient new blood in the form of a blood substitute, which consists of salt water, to replace the lost volume.
• A better option is a blood transfusion in which a person is given a real blood that's been donated by blood donors.
• Red blood cells in a blood transfusion allow us to transport more oxygen, which is crucial for surviving blood loss.
• another name for Reb blood cells?

  Erythrocytes
• when do platelets clot?

  when a blood vessel has been damaged