06 - Blood, Hemostasis, Lympahtics

Question 1

What is an antigen

Answer 1

any substance that causes an antibody response to be generated (immune response)

Question 2

How does blood plasma interact with antigens

Answer 2

blood plasma contains antibodies that interact with antigens and can cause agglutination and hemolysis of incompatible donor blood types

Question 3

What are the ABO blood group antigens and antibodies

Answer 3

Type A - compatible A, O // incomp B, AB
Type B - compatible B, O // incomp A, AB
Type AB - compatible A, B, AB, O // incomp none
Type O - compatible O // incomp A, B, AB

Question 4

What are the methods of testing for blood type compatibiltiy

Answer 4

blood typing - mixing blood iwth different antisera

cross-match - donor RBC mixed with patient serum

screening - recipients serum tested against a panel of donor RBCs that carry antigens known to cause transfusion reactions

Question 5

Explain how hemolytic disease of the newborn (HDN) is developed

Answer 5

1. Rh- mother and first pregnancy Rh+ fetus
2. between pregnancies develop Rh antibody
3. second pregnancy Rh+ getus, mothers has Rh antibodies

mother and fetus’ blod doesn’t mix expcept when placenta is torn apart at delivery

Question 6

What is hemostasis

Answer 6

a sequence of responses that stops bleeding
prevents hemorrhage (loss of blood) from smaller blood vessels

Question 7

What are the three mechanisms that help hemostasis

Answer 7

vascular spasm
platelet plug formation
blood clotting (coagulation)

Question 8

What is vascular spasm

Answer 8

damage to arteries or arterioles results in immediate vascular spasm (intense vasoconstrcition)

reduces blood loss for minutes to hours

allows time for steps two and three to occur

Question 9

What is platelet plug formation

Answer 9

carried out by platelets released from the bone marrow
platelets are 2-4 um cell fragments with a lifespan of 5-9 days

derived from megakaryotes (production stimulated by thrombopoietin, secreted by hepatocytes)

1. platelet adhesion - damaged endothlium exposes collagen fibers to which platelets adhere
2. platelet release reaction - ADP activates platelets serotonin (vasoconstrictor) Thromboxane (vasoconstrictor and platelet activator)
   - release chemical mediator which activates more platelets of constricts smooth muscle
3. platelet aggregation - activated platelets adhere to one another creating a platelet plug

Question 10

What is blood clotting (coagulation)

Answer 10

blood can thicken to form a gel - coagulation
- series of chem rxn that result in the formation of insoluble firbin threads
- made by the liver (mant are inactive enzymes and require ca)

1. formation of prothrombinase
   - extreinsive pathway (tissue trauma) and intrinsic pathway (blood trauma)
2. thrombin acitvation (converts prothrombin to activate thrombin (requires calcium))
3. conversion of fibrinogen to fibrin (converts firbinogen to fibrin- require calcium)

Question 11

How are blood vessels repaired after clot formation

Answer 11

1. platelets pull on the fibrin threads, causing clot retraction
2. edges of the damaged vessel are pulled closer togehter
3. fibroblasts and endothelial cells help repair the blood vessel wall

Question 12

What is a thrombus

Answer 12

a clot that forms in a blood vessel

Question 13

What is a thromboembolism

Answer 13

a clot that travels to a distant site through the blood stream

Question 14

What is firbinolysis

Answer 14

active form of plasminogen (plasmin)
- breaks down fibrin threads in the clot

Question 15

What are ways to prevent/break up clots

Answer 15

antiplatelet agnts
anticoagluations that supress or prevent blood clotting
thrombolytics to break up clots

Question 16

What are the componenets of the lymphatic system

Answer 16

lymph (fluid)
lymphatic vessels
structures/organs containing lymphatic tissue (thymus, spleen, lymph nodes, lymph nodules)
red bone marrow

Question 17

What are the functions of the lymphatic system

Answer 17

1. drain excess interstitial fluid from tissue spaces and return it to the blood
2. transport dietary lipids and lipid-soluble vitamins from the GI tract
3. Carry out immune responses

Question 18

What do lympahtic vessels arise from
What do they do

Answer 18

begin as capillaries in the tissues and are held in palce by anchoring filaments

drain excess tissue fluid and returns it to the venous circulation (right or left subclavian vein)

right lympahtic duct drains the right half of head, neck and throax and left lymphatic duct (thoracic duct) drains the rest of the body

Question 19

What are the primary lymphoid tissues

Answer 19

reponsible for the production and education of immune cells
- red bone marrow
- thymus

Question 20

What are the secondary lymphoid tisseues

Answer 20

where most immune responses are initiated/occur
- lymph nodes
- lymph nodules
- spleen