Ch 16 Blood part 2

Question 1

3 stages of hemostasis

Answer 1

1. Vasoconstriction
2. Formation of platelet plug
3. Coagulation

Question 2

Hemostasis Stage 1

Answer 2

Vasoconstriction:smooth muscle contraction

• triggered by paracrine release from endothelium
• reduce outward flow of blood
• lasts 30 mins

Question 3

Hemostasis Stage 2

Answer 3

Formation of platelet plug

• platelets exposed to collagen develop spikes
• platelets stick together at site of damage

Question 4

What prevents activation of platelets

Answer 4

Blood vessel endothelial cells

• physical barrier to collagen and basement membrane molecules
• Endothelial cell surface (-) and platelets (-)
• Secrete prostacyclin and nitric oxide (inhibit platelet activation)
• Express CD39

Question 5

CD39

Answer 5

Enzyme that converts ADP (activator of platelets) to AMP by removing a phosphate
-Inhibits platelet activation

Question 6

Prep of basement membrane (blood vessel endothelial cells)

-Part of Stage 2

Answer 6

Secretion of Von Willebrand’s factor

-Binds to collagen and to platelets to form a very strong layer to resist force of flowing blood

Question 7

Platelet Release Action

-Part of Stage 2

Answer 7

Activation leads to Degranulation of vesicles containing ADP, serotonin(vasoconstrictor), thromboxane A (activates platelets and vasocontrictor)

• Platelets become stick and signal other platelets to do the same
• Creates layers of platelets in the plug

Question 8

What initiates coagulation?

-Part of Stage 2

Answer 8

Platelets bind to fibrinogen and fibrinin

Question 9

Hemostasis Stage 3

Answer 9

Coagulation: conversion of blood from liquid to gel

• Cascade that results in activation of fibrin
• Platelets contract to pull sides of vessel together
• Clots are dissolved by plasmin

Question 10

Fibrin

Answer 10

Polymerized into meshwork to traps other cells at the site

• activated during coagulation
• Clot stabilized by crosslinking proteins via factor 13
• Clot retraction

Question 11

Thrombus

Answer 11

blood clot

Question 12

Clot retraction

Answer 12

Contraction of entire mass, bringing edges together

Question 13

Healing process of blood clots

Answer 13

XII activates Kallikrein (plasminogin activator)
Converts plasminogin into active plasmin
Plasmin digests fibrin into small chains
Dissolution of the clot

Question 14

Anticoagulants

Answer 14

Thrombin bound to fibrin no longer activates fibrinogen 
Heparin
Chelators
Citric Acid
EDTA

Question 15

Heparin

Answer 15

A glycosaminoglycan prevents clotting by activation antithrombin III (inactivator of thrombin)

• Can be released by mast cells
• Clinical use as anticoagulant

Question 16

Chelators

Answer 16

Molecules that bind to metal ions (Ca, Mg) and prevent their binding elsewhere
-Citric acid

Question 17

Coumarin

Answer 17

Pharmacologic anticoagulant

• Precursor for many anticoagulants like Warfarin
• Found in leeches

Question 18

Warfarin (Coumadin)

Answer 18

Cause vit K deficiency

• Prevents formation of gamma carboxyglutamate-high Ca binding form of glutamate
• Must be administered and monitored over several days and then regularly afterward
• Rat poison

Question 19

Hemophilia

Answer 19

Lack of clotting factor
-VIII=type A
-IX=type B
-Prolonged Bleeding from injury and spontaneous internal bleeding
Treatment: injections of clotting factor

Question 20

Septicemia

Answer 20

Infection of the blood “blood poisoning”
Usually stem from prior injury or infection
Symptoms: fever, chills, elevated heart beat, shallow breathing, flushed skin
Treatment: IV antibiotics

Question 21

Anemia

Answer 21

Reduced O2 carrying capacity of the blood

• Iron deficiency
• Hemorrhagic, Pernicious, Hemolytic

Question 22

Pernicious Anemia

Answer 22

Reduced vit B12

Question 23

Hemolytic Anemia

Answer 23

Early destruction of RBCs (malaria, sickle cell)

Question 24

Blood Doping

Answer 24

Erythropoietin injections to increase O2 carrying capacity
-Used by athletes
Risks: heart must pump harder, increase risk of clots, stroke, heart attack, high bp

Question 25

Multiple Myeloma

Answer 25

Cancer of plasma cells 
-Lymphocyte that makes specific antibodies
-Increased risk of infection
-Bones and marrow are affected
Treatment: chemo and radiation

Question 26

Thrombocytopenia

Answer 26

Decreased number of circulating platelets
-Viral infection, anemia, leukemia, exposure to radiation, xrays, or drug reactions
Symptoms: excessive bleeding or bruising
Treatment: Underlying cause, spleen removal

Question 27

Leukemia

Answer 27

Proliferation of WBCs
-Fever, bruising, malaise, anemia, infections
Acute or chronic
Treatments: chemo, bone marrow transplants but must destroy recipients marrow and infection prone 1st 100 days