 Erythrocytes: Red Blood Cells  Non-nucleated  Outer portion thick  Inner portion thin  Haemoglobin  Carries Oxygen

 Leukocytes: White Blood Cells  Larger  Nucleated  Various shapes  Fights Infection  Pass through vessel

 Thrombocytes: Platelets  Parts of cells  Clotting

 All of these parts are made in the red bone marrow.  Blood stem cells are located in the ends of bones.  Stem cells become two different cells, one forms only one type of leukocyte, the other forms the other two leukocytes, platelets, and erythrocytes.

 Plasma  Maintains blood volume and blood pressure.  Transports dissolved materials  Originates from the fluid absorbed in large intestine.

 Proteins – from liver, affect pH, blood volume, osmotic pressure, clotting.  Salts – from small intestine, affect pH, metabolism, osmotic pressure.  Nutrients – from small intestine, used for metabolism.  Nitrogenous waste – from liver, ammonia.

 Blood Gases › Oxygen – from lungs, for cell respiration › CO 2 – from cells, waste  Other › Hormones – from various, for chemical communication. › Vitamins – from various, for metabolism

 Formed elements (cellular) › 45% of the blood volume  Serum (plasma and dissolved parts) › 55% of the blood volume

 Clotting: Damage occurs › Thrombocytes form (or attempt) plug › Damaged cells release Thromboplastin › Tp causes Prothrombin Activator to be released › PA acts on Prothrombin to form Thrombin › Thrombin acts on Fibrinogen to form fibres › fibres clog cut, reinforce platelet plug › Erythrocytes stop up remaining holes in plug  Leukocytes arrive to fight infection Present in blood Released into blood Made in blood

 Clotting: Damage Thromboplastin Prothrombin Activator ProthrombinThrombin Fibrinogen fibres Thrombocytes Erythrocytes Present in blood Released into blood Made in blood

 Antigens located on erythrocyte membranes.  Antigens give us the blood type.  Plasma has antibodies opposite to antigens.  When antigens contact antibodies of the same type agglutination occurs.  Haemolysis can also occur.

Type Antigen Antibody A B AB AB O

Type Give to Receive from A B AB AB O

 + or –  Have or not have on membrane  Antibodies are made only after exposure and only to positive.  mum is –, baby is +.  Antibodies to + are made in mum.  Haemolytic Disease of the newborn.