Blood
Plasma Red blood cells White blood cells Platelets Lymphocytes Leucocytes KEYWORDS Phagocytes Monocytes Erythocytes ABO groups Haemoglobin
Blood components: Components of blood: Plasma Red blood cells White blood cells Platelets
Plasma Pale, golden liquid Makes up 55% of blood Plasma is made of: 90% water 7% proteins 3% dissolved materials which are being transported
Plasma Types of plasma proteins: Antibodies: produced by white blood cells Clotting proteins: acted upon to form blood clots. Role of plasma: Transport dissolved materials (glucose, amino acids, vitamins, salts, carbon dioxide, urea and hormones) Plasma also carries heat
Red blood cells (erythrocytes) Produced in the bone marrow. Round and small Contain haemoglobin (a red protein) Cannot repair themselves so only live for 4 months. Dead red blood cells are broken down by the liver and spleen to produce bile.
Role of red blood cells: Transport oxygen Haemoglobin is based on molecules of iron NOTE: Anaemia: is a lack of haemoglobin or red blood cells (caused by a lack of iron in diet).
Detailed study of red blood cells Red blood cells are also known as erythrocytes. Lose nucleus as they mature Lack mitochondria Biconcave in shape (gives them larger surface area to allow them to exchange more oxygen) Haemoglobin Lungs Oxyhaemoglobin Haemoglobin Body cells Oxyhaemoglobin
White blood cells (leucocytes) Larger than red blood cells No definite shape Live for a few days Less numerous (700 red : 1 white) Made in the bone marrow Mature in the lymphatic system
Role of white blood cells Fight infections (attack bacteria) They engulf the harmful bacteria and digest them. White blood cells are known as phagocytes Other white blood cells (lymphocytes) produce antibodies NOTE: Leukaemia is a form of cancer in which white blood cells are produced to rapidly and are immature. They crowd out the other blood cells causing anaemia or increase the risk of infection.
Detailed study of white blood cells (leucocytes) Two types of white blood cells: 1) Lymphocytes 2) Monocytes Lymphocytes Made in bone marrow Stored in spleen and lymph nodes. Has a round nucleus Makes antibodies to fight infections.
Monocytes Large cells that digest other particles (phagocytes) Made in bone marrow Also known as macrophages Have a kidney shaped nucleus
Platelets Made in the bone marrow from large cells called megacytes. Role of platelets: Clot the blood Functions of blood clots: 1) Reduce blood loss 2) Prevent the entry of micro organisms.
Platelets NOTE: Haemophiliacs are unable to clot their blood and may suffer severe bleeding. Thrombosis is the clotting of blood from damaged blood vessel walls which can result in strokes or heart attacks.
RECAP: Functions of blood Transport: Transport of food, waste products and hormone by plasma. Transport heat (by plasma) to help maintain a constant body temperature. Transport oxygen by red blood cells
RECAP: Functions of blood Defence against disease: White blood cells (phagocytes) which engulf and digest bacteria. White blood cells (lymphocytes) which produce antibodies to destroy harmful bacteria and viruses. Platelets clotting the blood which prevent blood loss and the entry of disease causing organisms.
Videos The Components of Blood and Their Importance YouTube How White Blood Cells Work YouTube White Blood Cell Chases Bacteria YouTube How the Body Works : The Rh Factor - YouTube Blood Grouping YouTube Donating Blood for the First Time YouTube
Blood groups Karl Landsteiner (1930) discovered that humans have four major blood groups: Blood group % of the population A 55 B 31 AB 11 O 3
Blood groups In blood transfusions, it is important to match the incoming blood group to the blood group of the recipient. Failure to do this may result in blood clumping. Blood group O is called the universal donor as it can be safely given to all other four blood groups.
The rhesus factor Apart from the ABO blood group, there are about 400 blood groups. The best known is the rhesus factor. Rhesus factor 85% of Irish people have the chemical rhesus factor on their red blood cells. People who have this rhesus factor are rhesus positive (Rh +) People who do not have the rhesus factor are rhesus negative (Rh -) EXAMPLE: someone in blood group ) who has the rhesus factor is said to be O+
The rhesus factor Rhesus negative blood can be given safely to a rhesus positive person. So O- is blood that can always be used for blood transfusions.
Donating blood
Exam paper 2012, Question 15b: State two ways, other than colour, in which red blood cells differ from white blood cells: Name a group of white blood cells, other than lymphocytes:
Exam Paper 2006 Question 13a: State a precise location in the human body at which red blood cells are made: State two ways in which red blood cells differ from typical body cells, e.g from the cheek lining: