BLOOD Human Biology 11
BLOOD • Carries the necessities of life to the cells and takes waste from the cells • What are the necessities of life? • Oxygen • Nutrients • Hormones • Antibodies • What are waste products? • Carbon Dioxide
WHAT IS BLOOD? Blood is composed of: • Plasma (55%) • Red Blood Cells (40%) • White Blood Cells (1%) • Platelets (4%) Bodies contain 5 L of blood
PLASMA • Liquid part of blood • Approx. 90% water • The other 10% consist of dissolved substances that are essential for life
RED BLOOD CELLS • Also known as erythrocytes • Main function is to “pick up” oxygen molecules and retrieve carbon dioxide molecules • Hemoglobin in the red blood cell carry the oxygen • Gets its red colour from the iron in hemoglobin when it carries oxygen • Iron acts as an oxygen magnet
WHITE BLOOD CELLS • Also known as leukocytes • Function to protect the body from infection and disease causing organisms • There are many different kinds
4 CHARACTERISTICS OF WHITE BLOOD CELLS • Capable of moving on their own and changing their shapes • Phagocytosis – surround or engulf bacteria and digest their harmful material • Capable of recognizing antigens, which are chemicals on the surface of cells. This allows the white blood cells to know if it belongs or is foreign • Produce antibodies which are special proteins which are used to destroy the pathogensn (Organsims that cause disease)
VIDEO OF A WHITE BLOOD CELL CHASING A BACTERIUM • http://www.youtube.com/watch?v=JnlULOjUhSQ
PLATELETS • Are responsible for the initial stages of blood clotting • Are not cells, but rather tiny fragments of white blood cells • Contain a special enzyme that initiates clotting
ANEMIA • occurs when there are not enough red blood cells to carry all the oxygen the body requires. • People who have this condition appear tired and lack energy to work efficiently. http://www.youtube.com/watch?v=_ZV5140OykE&feature=channel
TYPES OF ANEMIA The most common types of anemia: • Iron deficiency anemia – Not enough iron in diet which means that RBC can’t carry enough oxygen • Sickle cell anemia – RBC take on a sickle shape (half moon or crescent) which decreases the amount of oxygen it can carry
HEMOPHILIA • This blood disorder prevents normal blood clotting • Bleed for a longer time than others after an injury • Also may bleed internally, this bleeding can damage your organs or tissues and may be life threatening.
LEUKEMIA • Cancer of bone marrow • Most types increase the number of WBC and decrease the number of RBC • WBC reproduce rapidly but are ineffective • The body is unable to cope with infections • With decreased amounts of red blood cells, the body isn’t receiving enough oxygen
MONONUCLEOSISAKA “KISSING DISEASE” • Not really a disease of the blood but it does result in the production of large numbers of WBC • Most commonly transferred through saliva (hence why it is called the kissing disease) • Thought to be caused by a virus that is not easy to get rid off • Symptoms include: fatigue, swollen glands, fever, and sore throat.
HOW DO YOU SEEK TREATMENT? • Diagnosis – the process of identifying the disease or problem • Looking at blood samples can help diagnose the problem or disease • What do they look for? • Number of Red Blood cells • Number of White blood cells • Number of platelets
THE PROCESS OF BLOOD CLOTTING • Platelets break open at wound site and release thromboplastin. (reaction starts) • Thromboplastin causes calcium and prothrombin to unite and form thrombin. • Thrombin joins with fibrinogen to form fibrin • A network of fibrin threads traps red blood cells and forms a clot that plugs the wound.
BLOOD TYPES • Determined by the presence or absence of antigens on RBC • Antibodies recognize RBC as our own and will bind to RBC that they don’t recognize
BLOOD TYPES A, B, AB, O • There are 2 kinds of antigens A and B • If antigen A is present, the blood type is A • If antigen B is present, the blood type is B • Blood type AB, has both antigen A and B • Blood type O, has no antigens
ANTIBODIES AND BLOOD TYPES • Antibodies found in plasma are ALWAYS opposite the antigen on RBC • For example: • Blood type B has antigen B on the RBC so plasma would have antibodies for antigen A • Type AB blood have no antibodies • Type O blood have both A and B antibodies
THE RH FACTOR • The Rh factor is an antigen found on the RBC of most people • If you have the antigen, you are Rh+ • If you don’t have the antigen, you are Rh- • The disease associated with the Rh factor is known as Hemolytic Disease of the Newborn
TRANSFUSIONS • If antibodies and antigens of the same type come together, the RBC clump • Why is this important? • If blood type A is given blood type B, the antibodies bind to the antigens, clumping the blood which can be fatal