Hemeostasis Hemeostasis- stopping blood loss Phases of hemeostasis –Vasoconstrictive phase- vascular spasm Blood vessels constrict- caused by damage to smooth muscle and reflex to pain receptors Decreases blood loss

Hemeostasis- cont. –Platelet aggregation phase Platelets swell- adhesion- sticks to damaged blood vessels Stick together and to tissues- relases reaction chemicals to make other platelets sticky Form a platelet plug- platelets stuck together –Coagulation phase Blood clotting Fibrinogen converted into fibrin Fibrin –Insoluble, stringy protein, entangles cells, creates clot

Coagulation Flow Chart Prothrominase Prothromin- needs vitamin K Thrombin Fibrinogen Fibrin

Anticoagulation Inhibition of clotting Anticoagulants –Smooth inner walls of blood vessels –Heparin produced by mast cells and basophils –Warfarin (Coumadin)- interferes with vitamin K to prevent coagulation

BLOOD TYPE Not everyone has the same blood type! Blood type refers to features of the person’s red blood cells. There are hundreds of these different features.

BLOOD TYPE The ABO blood groups are the features most people know about. In this group, there are 4 different types of red blood cells -- A, B, AB, and O.

BLOOD TYPE Over a third of us are blood group O The next most common is blood group A. Few people have type B, and even fewer have type AB.

Blood Grouping Determined by antigens (agglutinogens) on surface of RBCs Antigens –Proteins found on the surface of red blood cells –Two types of antigens Type A Type B

Blood Grouping Antibodies –Proteins dissolved in the plasma –Two types Anti-A Anti-B

Blood Type A Red blood cells have A antigens “A” individuals have anti- B antibodies Attacks blood types B or AB

Blood Type B Red blood cells have B antigens “B” individuals have anti- A antibodies Attacks blood types A or AB

Blood Type AB Red blood cells have A and B antigens “AB” individuals have neither A nor B antibodies Called the “universal acceptor” Can receive A, B, AB or O blood

Blood Type O No antigens (proteins on the red blood cells) Called the “universal donor” Types A, B, and AB individuals can accept type O blood Anti- A and anti-B antibodies are made Cannot accept any other blood type except O

ABO Blood Groups

Blood Typing Add antibodies to the blood and look for clumping Example: –Blood + Anti-A no clumping –Blood + Anti-B clumping –Result = Blood type B

Blood Typing Importance –Blood transfusions –Wrong type of blood produces clumping –Clumping could result in death of the individual

Agglutination Reaction

DO YOU KNOW ?

BLOOD TYPE Type O blood may be transfused into patients of any blood type. Rh negative blood may be transfused into patients of either Rh type. So O negative is a very special blood type in a blood donor.

DO YOU KNOW ?

BLOOD FACT About half of Americans can safely be blood donors. But only about 5 percent actually donate blood. The other 95% are relying on these donors if they ever need a transfusion.

BLOOD TYPE Th Rh blood groups are the next most familiar types. People whose red cells have a particular feature called the “ D antigen” are Rh positive. People who lack the factor are Rh negative. Most people are Rh positive.

Rh Blood Group First studied in rhesus monkeys Types –Rh positive: Have these antigens present on surface of RBCs –Rh negative: Do not have these antigens present Hemolytic disease of the newborn (HDN) –Mother produces anti-Rh antibodies that cross placenta and cause agglutination and hemolysis of fetal RBCs

Hemolytic disease of newborns Rh negative mother Rh positive father and baby Fetal blood crosses placenta and mixes with mother’s blood Mother produces antibodies against Rh+ blood

Second pregnancy of Hemolytic disease Rh negative mother Rh positive fetus Mothers anti-Rh- cross the placenta and enter fetal blood stream In the fetus –RBC’s clump –RBC’s destroyed –Bilirubin builds up –Jaundice of fetus –Fetus may die

Treatment of Hemolytic Disease Transfusion for the baby if the baby is born alive Drug treatment for the mother –Rhogram- drug given to the mother after the first pregnancy –Prevents maufacture of Rh antibodies

Erythroblastosis Fetalis

Diagnostic Blood Tests Type and crossmatch Complete blood count –Red blood count –Hemoglobin measurement –Hematocrit measurement White blood count Differential white blood count Clotting

Blood Disorders Erythrocytosis: RBC overabundance Anemia: Deficiency of hemoglobin –Iron-deficiency –Pernicious –Hemorrhagic –Hemolytic –Sickle-cell Hemophilia Thrombocytopenia Leukemia Septicemia Malaria Infectious mononucleosis Hepatitis Autoimmune Neutropenia