Idiopathic Thrombocytopenia Purpura

Question 0

What portion of the blood = Plasma?

Answer 0

55%

13

Question 1

What portion of the blood is the Hematocrit?

Answer 1

45%
(about 5 million mm3 + or - 1/2 million)
(14)

Question 2

What makes up the “Buffy Coat” in a centrifuged vile of blood?

Answer 2

Leukocytes and Platelets

13-14

Question 3

What is a decreased hematocrit indicative of?

Answer 3

Anemia
(below 4 million)
(14)

Question 4

What is an increased hematocrit indicative of?

Answer 4

Polycythemia
(above 6 million)
(14)

Question 5

About how many molecules of hemoglobin does 1 RBC carry?

Answer 5

250 million

14

Question 6

How many molecules of Oxygen does 1 RBC carry?

Answer 6

About 1 billion
(250 million hemoglobin)
(14)

Question 7

What hormone is in charge of RBC production?

Answer 7

Erythropoietin
*released from the kidneys then forms new RBCs through the process erythropoiesis in the bone marrow
(example of negative feedback)
(15)

Question 8

What are 2 examples of non-regulatory factors that affect RBC synthesis (their absence will alter production)?

Answer 8

Iron and Amino Acids for hemoglobin synthesis
Vitamin B12 and Folic Acid for DNA synthesis
(15)

Question 9

What is Pernicious Anemia caused by?

What is the result?

Answer 9

Caused by malabsorption of vitamin B12
Result = slowing of erythropoiesis produces large RBCs (macrocytes) that are fragile and easily destroyed
(15)

Question 10

When is the Erythrocyte Sedimentation Rate increased?

Answer 10

Elevated during infection, arthritis, and other inflammatory diseases
*During infections, tissues release “acute phase reactant proteins” which stick to RBCs and allow them to clump together = increase rate that they fall out of solution
(16)

Question 11

What are the 3 broad groups of plasma proteins?

Answer 11

Albumins (smallest and most common)
Globulins 
Fibrinogen (largest and least common)
*all made in liver except y-globulins (from lymphatic tissue)
(16)

Question 12

What does plasma colloidal osmotic pressure do?

Which plasma protein is the main contributor to plasma colloidal osmotic pressure?

Answer 12

Prevents excessive fluid filtration
Albumin = main contributor
(16)

Question 13

What will a lack of Albumin cause?

Answer 13

Hypoproteinemia
Decr. plasma protein = decr. plasma colloidal osmotic pressure = incr. loss of fluid from capillaries == Edema
(16)

Question 14

What is the general function of: a-globulin, b-globulin, y-globulin?

Answer 14

a-globulin = carrier proteins and clotting factors
b-globulin = carrier proteins i.e. transferrin, apo-protein B, b1, b2
y-globulin = antibodies
(17)

Question 15

What is the main precursor to a clot?

Answer 15

Fibrinogen
(fibrinogen = precursor for fibrin; fibrin forms insoluble mesh a.k.a coagulation/clotting)
(17)

Question 16

What is the term for the ability of blood to maintain its volume?
What are the 3 key mechanisms that make this possible?

Answer 16

Homeostasis 
1) vascular constriction 
2) platelet plugs
3) clot formation
(17)

Question 17

Describe the vascular constriction step of blood homeostasis

Answer 17

Trauma to vessel wall induces vasoconstriction
- nervous stimulation causes endothelin-1 (vasoconstrictive factor) to release from smaller vessels
- platelets release thromboxane A2 and serotonin = vasoconstriction
(17)

Question 18

During the platelet plug step of blood homeostasis, what 2 things promote platelet aggregation?

Answer 18

Thromboxane (from tissues) and Thrombin

17

Question 19

Define homeostasis

Answer 19

Dynamically balanced state of self-regulation
(always changing but always staying the same)
(8)

Question 20

What are the clinical features of idiopathic thrombocytopenia purpura?

Answer 20

*Disorder of decreased platelet numbers*
Easy bleeding w/ increased bleeding time
Micro-bleeds at capillaries (purple spots on skin)
Easy bruising
Nosebleeds
(12)

Question 21

What is specific gravity and what is blood’s specific gravity?

Answer 21

Specific Gravity = measure of the density of a solution relative to water.
Blood’s specific gravity = 1.050 g/ml
(13)

Question 22

What is the pH of blood?
What is the temperature of blood?
Is blood more or less viscous than water?

Answer 22

pH = 7.4
temp = 98.6 F or 37 degrees C
blood = 3-5 times more viscous than water
(13)

Question 23

True or False: Erythropoiesis is a fast-acting form of negative feedback?

Answer 23

False;
Erythropoiesis (forming new RBC) is a slow-acting example of negative feedback
(15)

Question 24

What hormone is secreted to promote vasoconstriction of blood vessels?

Answer 24

Serotonin

18

Question 25

What conversion initiates the cascade of a clot formation?

Answer 25

Conversion of fibrinogen to fibrin (via prothrombin being converted to thrombin, thanks to prothrombin activator)
(18)

Question 26

Does the intrinsic pathway or extrinsic pathway of activating prothrombin require Factor IX (Christmas Factor)?

Answer 26

Intrinsic requires Christmas Factor (and needs Factor 8a as a co-factor for amplification)
(19)

Question 27

Which characteristics occur in the extrinsic pathway of activating prothrombin: Fast or slow, Strong or weak?

Answer 27

Extrinsic = Fast and Weaker than intrinsic
Intrinsic = Slow and Stronger than extrinsic pathway
(19)

Question 28

Which Factor(s) does the external pathway of activating prothrombin require?

Answer 28

Factor 7 and 3

19

Question 29

True or False: In the huge cascade of activating Prothrombin (intrinsic and extrinsic pathways), Thrombin acts as an agent of positive feedback?

Answer 29

True
Factors 5 and 8 function as-is, but are greatly improved after being activated by thrombin
(20)

Question 30

Removal of what molecule will result in stalled clotting reactions?

Answer 30

Calcium
-Calcium Chelation (removal of calcium via oxalates and citrates) used in test-tubes to keep blood from clotting
(20)

Question 31

What are 3 anti-clotting mechanisms?

Answer 31

1) Endothelial linings - smooth simple squamous cells w/ glycocalyx coating (repels clotting factors)
2) Consumption of clotting factors - thrombin activates antithrombin 3 (which is enhanced by Heparin)
3) Fibrinolysis - done by the protease Plasminogen
(22)

Question 32

What is the active form of Plasminogen? What activates it?

Answer 32

Plasmin
*activated by tPA (tissue plasminogen activator); released from injured tissue a day after injury
*Plasminogen to Plasmin conversion also done by Tissue Lysosomes
(22)

Question 33

Which lipid-soluble vitamin is taken to hepatocytes and required for the synthesis of several clotting factors?

Answer 33

Vitamin K

22

Question 34

What compound acts as a competitive inhibitor for vitamin K sites in hepatocytes, substantially reducing the amount of prothrombin, factors 7,9, and 10?

Answer 34

Coumarin (Dicoumarol)
*man-made version = warfarin
***Blood thinners
This minimizes dangerous clotting in some patients 
(22)

Question 35

What is an abnormal clot that forms in a vessel?

If it freely floats it is called … ?

Answer 35

Thrombus
Freely floating = embolism
(22)

Question 36

What is the chronic adult form of Idiopathic Thrombocytopenia Purpura due to?

Answer 36

Autoimmunity - antibodies to platelets found in patients
Childhood form is self-limiting; acute
(23)

Question 37

Why do some patients with idopathic thrombocytopenia purpura recieve a splenectomy?

Answer 37

Platelets are removed from the blood by the Spleen

23