3 Composition of Blood4 main parts:PlasmaRed blood cellsWhite blood cellsPlatelets
4 Pale, golden liquid that makes up about 55% of blood PlasmaPale, golden liquid that makes up about 55% of bloodPlasma is made of:90% water7% proteins3% dissolved materials which are beingtransportedMain plasma proteins are:Antibodies – produced by white blood cells to kill foreign substances e.g. bacteriaClotting proteins – Which help to form blood clots.
5 b) Red blood cells (erythrocytes) Produced in the bone marrow of bones e.g. ribs and long bonesVery small and roundBiconcave shapeNo nucleus or mitochondriaAbout 5 million in 1 cubic millimetreContain a red protein called haemoglobinwhich carries oxygen around the body.Broken down in the liver and spleenMineral iron is needed to makeHaemoglobin
6 Haemoglobin + oxygen = oxyhaemoglobin Function of red blood cells: Carry oxygen gas from the lungs to all body cellsIron comes from foods e.g. meat and green veg.A lack of iron in the diet results in anaemia. Symptoms include being pale and feeling tired all the time. Treatment would usually involve increasing iron intake in your diet
7 c. White Blood Cells (Leucocytes) Larger than red blood cellsNo definite shapeOnly live for a few days700 red blood cells: 1 white blood cellsMade in the bone marrowSome mature in the lymphatic systemFunction of white blood cells:Defend the body against infection and fight infection
8 Many different types of white blood cell Most white blood cells (phagocytes) attack bacteria by surrounding them and then digesting them.Some white blood cells (lymphocytes) produce antibodies which react with invading bacteria and viruses.
9 Two main categories of white blood cell: LymphocytesMade in the bone marrowStored in lymphatic system e.g. spleen, tonsils etc.Make up 25% of all white blood cellsHave a large round nucleus and very little cytoplasmCan survive from 3 months to 10 yearsMain function is to make antibodies to resist infection
10 b) MonocytesLarge cells that scavenge throughout the body and digest bacteriaAlso called macrophagesFormed in the bone marrowMake up 5% of white blood cellsSurvive 6-9 daysHave kidney shaped nuclei
11 Leukaemia: Form of cancer in which white blood cells are produced too rapidly and are immature. They crowd out the other blood cells and may cause anaemia, increase the risk of infection and reduced ability to form blood clots. Treatment may include drugs, radiation and bone marrow transplants.
12 d. Platelets (Thrombocytes) Made in the bone marrow from large cells called megacytesSmaller than red blood cellsFunction of platelets:They reduce the loss of bloodThey prevent the entry of micro-organismsClots do not usually form in healthy undamaged blood vessels. If blood vessel walls are damaged a blood vessel may form (thrombosis). A blood clot in the brain causes a stroke and a blood vessel clot in the heart causes a heart attack.
14 Functions of BloodTransport of food, waste products, hormones and plasmaTransport of heat to help maintain body temperatureTransport of oxygen by red blood cellsDefence against disease using white blood cells and platelets
15 Blood GroupsIn 1900 Karl Landsteiner discovered that humans have 4 main blood groups (ABO Groups)He won the Nobel Prize for his workHe discovered that most red blood cells have a complex carbohydrate and protein chemical on their surface membraneFour main blood groups are A, B, AB and O
16 When blood transfusions are given it is important that to match the incoming blood group to the group of the recipient. Otherwise the blood may clump (stick together) in the recipient. Blood group O is called the universal donor because their blood can be given safely to any other group. Blood group AB is the universal recipient because they can receive blood from any other blood group.
17 Rhesus FactorThis is a factor present in some peoples blood.It was first discovered in Rhesus monkeys and is named after them.About 85% of Irish people have a chemical called the rhesus factor present on the surface of their red blood cells (called Rh+ or rhesus positive people)15% of the Irish population do not have the factor present (called Rh- or rhesus negative people)
18 People of blood group A may be A positive (also called A+ or A Rh+ blood) or A negative (also called A- or A Rh- blood) Similarly for B+, B-, O+, O-, AB+, AB- Rhesus negative blood can be given safely to a rhesus positive person. If rhesus positive blood is given to a rhesus negative person it may cause a serious reaction if the person received a transfusion of the rhesus positive blood before.
19 Rhesus factor may also lead to complications (problems) if a rhesus negative mother is pregnant with a rhesus positive baby. Her first rhesus positive baby will be safe but any further rhesus positive babies may have their red blood cells damaged. This may cause the baby to be anaemic or in severe cases brain damaged or stillborn.