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BELLWORK• Write these objectives in your notebook:
• SWBAT explain hemostasis
• SWBAT define antigen, antibody, and explain how this relates to blood types
BLOOD
HEMOSTASIS AND BLOOD TYPES
HEMOSTASIS• Stoppage of blood flow when a blood vessel breaks
• Three phases:
1. Platelet plug formation: platelets become sticky and pile up to form a “plug”
2. Vascular spasms: narrow blood vessel to decrease blood loss
3. Coagulation: basis of a clot
BLOOD CLOTTING• Usually clots within 3-6 minutes
• Clot stays until tissue regenerates
BAD CLOTTING• Can be deadly if it happens in heart or brain
• Thrombus• Clot inside blood vessel
• Embolus• A thrombus that breaks away and floats in blood stream
BLOOD LOSS• When you lose blood, your body usually compensates by
making more
• Losing 15-30% of total blood will make you pale and weak
• Losing 30%+ can cause shock and be fatal
TREATING BLOOD LOSS• May require a blood transfusion
• Blood collected from a donor, and mixed with anticoagulant (prevents clotting)
• If refrigerated, can be stored up to 35 days
ANTIGENS & ANTIBODIES• Antigen:
• protein within plasma membrane of RBC
• Your body thinks its foreign, and releases antibodies as a defense
• Antibody:
• Substances produced by body to provide immunity against antigen
ANTIGENS & ANTIBODIES• When antibodies bind to antigens, the cells clump
together – agglutination
• Clumps clog vessels, depriving tissues of oxygen
• Foreign RBCs rupture, freeing hemoglobin which may block tubules in kidney and cause kidney failure
BLOOD GROUPS• Over 30 common RBC antigens
• ABO and Rh groups cause the most severe transfusion reactions
• Blood groups are based on which antigens a person has
ABO BLOOD GROUPS
RH• Most Americans are Rh+ (carry Rh antigen on RBCs)
• If a Rh- person is given Rh+ blood, immune system will start producing antibodies
• Eventually RBCs will rupture
DONORS• Universal Donor: (who can donate to ANYBODY)
• Universal recipient: (who can receive from ANYBODY)
O-AB+
TESTING FOR BLOOD GROUP• In the lab:
• Mix a sample of the patient’s blood with 2 serums: antibody-A and antibody-B to determine blood type
• Crossmatch:• Sample of patients blood with
serum from donor• Sample of donor blood with patient
serum
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