[Music] hi and welcome back to three sighs lessons cold UK by the end of this video you should be able to describe the different parts of the blood and then state their functions you should then be able to describe the uses of blood products on state the risks of these this shows a picture of human blood under a microscope there are four important parts that you need to know first we've got blood plasma plasma is the liquid part of the blood in the plasma we find two different types of blood cells these are red blood cells and white blood cells we also find tiny fragments of cells and these are called platelets so we're going to look at the functions of the different parts of the blood and you need to learn these we're going to start with the blood plasma now as we said plasma is the liquid part of the blood and it's job is to transport dissolved substances around the body plasma transports soluble digestion product for example glucose from the small intestine to other organs plasma transports carbon dioxide from the body cells to the lungs to be breathed out and remember carbon dioxide produced by air roburt respiration lastly plasma transports the waste product urea from the liver to the kidneys to be excreted in Ulan okay let's look now at red blood cells red blood cells transport oxygen from the lungs to the body cells and to do this they've got three adaptations firstly red blood cells contain the oxygen calving molecule hemoglobin hemoglobin combines with oxygen in the lungs forming the molecule oxyhemoglobin like this the red blood cells then travel to the organs where the oxyhemoglobin releases the oxygen and i'm shown that here secondly red blood cells have got no nucleus which means they've got more room for hemoglobin and lastly red blood cells have got this shape in the center of the cell there are dimples scientists call this shape a biconcave disk this shape gives the red blood cells a greater surface area so oxygen diffuses in and out rapidly okay let's take a look at white blood cells white blood cells from part of the immune system for example making antibodies and we're going to take a closer look at that in a later video now the key feature of white blood cells is that they contain a nucleus this contains DNA which encodes the instructions so that the white blood cells need to do that job okay so the final part of blood are platelets and I'm showing those here platelets are tiny fragments of cells and their job is to help the blood to clot it's important that you learn that now lots of people are blood donors on donated blood has many uses in medicine for example it's used to replace blood loss during injury some people are given platelets extracted from blood to help in clotting and proteins extracted from blood can also be useful for example antibodies there were a couple of problems with using products from blood firstly in a blood transfusion we have to make sure that the donated blood is the same blood type as the patient's otherwise the body's immune system will reject the blood and the patient could die secondly there's the risk from infection lots of different diseases can be transmitted by our blood however I should point out that in the UK blood is screened for infection so the risk is extremely low remember you'll find plenty of questions on blood in my vision workbook and you can get that by clicking on the link above okay so hopefully now you should be able to describe the different parts of the blood and then state their functions you should then be able to describe the uses of blood products on state the risks of these [Music]