Unit VI (33-37) - Blood Cells, Immunity and Coagulation Flashcards by Emma Wright

What organ produces more of the red blood cells during the middle of gestation?

a. Bone marrow
b. Liver
c. Spleen
d. Lymph nodes

Answer: B (Guyton 33)

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What factors are required for appropriate red blood cell production?

a. Vitamin K and erythropoetin
b. Cyanocobalamin and erythropoetin
c. Iron and vitamin K
d. Cyanocobalamin and carotinids

Answer: B (Guyton 33)

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Hageman factor deficient cats may have a prolongation of their PTT with no clinical bleeding. What factor are they deficient in?

a. Fibrinogen
b. Factor V
c. Factor VII
d. Factor XII

Answer: D (Guyton 37)

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What does heparin combine with in order to act as an anticoagulant?

a. Antithrombin III
b. Fibrinogen
c. Prothrombin
d. Tissue factor

Answer: A (Guyton 37)

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Which of the following vitamins and minerals are required for appropriate red blood cell maturation?

a. Folate and Iron
b. B12 and Iron
c. B6, Cobalamin, and Iron
d. Folate, B12, and Iron

Answer d (Guyton 449)

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Which of the following is the initiating step in clot formation?

a. Cleavage of fibrinogen to form fibrin
b. Formation of prothrombin activator
c. Formation of fibrinogen activator
d. Conversion of prothrombin to thrombin

Answer b (Guyton 487)

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Which factor is primarily responsible for adherence of platelets to exposed subendothelium in areas of high shear stress?

a. von Willibrand
b. Hageman factor
c. Factor II (prothrombin)
d. Factor VII (proconvertin)

Answer: A

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Which factor is responsible for clot lysis by digesting fibrin fibers and other coagulation proteins?

a. Plasmin
b. Plasminogen
c. Fibrin
d. Fibrinogen

Answer: A

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Which part of the gastrointestinal system absorbs iron?

a. Stomach
b. Small intestine
c. Cecum
d. Large intestine

Answer: B; Guyton pg 450

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Which of the following initiates the extrinsic pathway for clotting?
A] Factor XII
B] Tissue factor 
C] Factor XI
D] Collagen

Answer: B Guyton and Hall Chapter 37

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The cause of pernicious anemia is deficiency of
A] Vitamin B12
B] Iron
C] Vitamin B6
D] Erythropoietin

Answer: A Guyton and Hall Chapter 33

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Lack of vitamin B12 and folic acid cause anemia by which mechanism?

a. Failure of division
b. Formational failure of hemoglobin
c. Maturation failure caused by diminished DNA synthesis
d. Production failure due to inhibition of CFU – S

Correct Answer: C; Ref: Guyton, pg. 449

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Heparin combines with which molecule to results in the removal of free thrombin from the bloodstream to act as an anticoagulant?

a. Antithrombin III
b. Factor V
c. Factor VII
d. Factor X

Correct Answer: A; Ref: Guyton, pg. 489

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In the first step of hemoglobin synthesis, which molecule combines with glycine to form a pyrrole?

a. citrate
b. oxaloacetate
c. succinyl-CoA
d. acetyl-CoA

Answer: C; Guyton 449

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Which of the following cytokines promotes growth and reproduction of virtually all the different types of committed stem cells in the bone marrow?

a. IL-3
b. IL-5
c. IL-8
d. IL-11

Answer: A. ; Reference: Guyton Ch. 33 Pg. 447

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Which of these ions is required for promotion or acceleration of the blood-clotting reactions in both the intrinsic and extrinsic pathways?

a. Potassium
b. Calcium
c. Sodium
d. Chloride

Answer: B; Reference: Guyton Ch. 37 Pg. 488

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Which mechanism is responsible for increased cardiac output in anemia patients? (Guyton Ch 33)

a. Decreased blood viscosity
b. Peripheral vasodilation
c. Tachycardia
d. All of the above

Answer: D Guyton 33

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What is the site of fibrinogen formation?

a. Vascular endothelium
b. Liver
c. Platelets
d. Skeletal muscle

Answer: B; (Guyton Ch 37)

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What is the effect of polycythemia on cardiac output?

a) Greatly decreased due to increased blood viscosity and decreased venous return
b) Greatly increased due to increased blood volume and increased venous return
c) Not far from normal because the changes in viscosity and volume neutralize each other
d) Venous return and cardiac output are not affected by polycythemia

Answer : c; Guyton (12th edition), p. 421

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Which of the following is the less likely cause of vitamin K deficiency?

a) Liver failure
b) Bile duct obstruction
c) Poor absorption of fats
d) Lack of vitamin K in the diet

Answer : d; Guyton (12th edition), p. 458

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The majority of the iron in the body is found in:

A. Myoglobin
B. Hemoglobin
C. Liver
D. Plasma

Answer: B

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Which of the following proteins is responsible for iron transport in plasma?

A. Ferritin
B. Hemosiderin
C. Transferrin
D. Apotransferrin

Answer: C

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Serum iron is increased with which condition?

a. Renal disease in cats
b. Hypothyroidism in dogs
c. Hyperadrenocorticism in dogs
d. Hypoalbuminemia in dogs

Answer: C (Latimer Chp 1)

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In a patient that is acutely anemic, when would you expect to see evidence of regeneration?

a. 24 hours
b. 5 days
c. 2 weeks
d. 1 month

Answer: B (Latimer Chp 1)

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Free hemoglobin in the plasma binds to which protein for transport to the liver? a. albumin b. hemopexin c. haptoglobin d. alpha-2 macroglobulin

Answer: C; Duncan and Prasse p. 12

``` Which of the following conditions may be associated with decreased serum iron? A. Hypothyroidism B. Hemolytic anemia C. Hyperadrenocorticism D. Hemochromatosis ```

ANSWER: A (Latimer)

``` Which of the following breeds has been described to have microcytic erythrocytes? A. Silken windhound B. Newfoundland C. Shiba Inu D. Kooiker ```

Answer: C; Latimer p 14

How does the site of erythropoiesis change through life?

Early weeks - yolk sac Middle trimester - mainly liver (some in spleen and LNs) Last month of gestation and after birth - bone marrow

How does IL-3 act on the bone marrow?

Promotes growth and reproduction of nearly all types of committed stem cells

What is the developmental journey of a RBC?

MHSC => CFU-S => CFU-B => CFU-E => pro erythroblast => basophil erythroblast => polychromatophil erythroblast => orthochromatic erythroblast => reticulocyte => erythrocyte

Which RBC precursor is the first to contain haemoglobin?

Polychromatophil erythroblast

After release from the marrow, how long does it take a reticulocyte to mature?

1-2 days

Where is EPO produced?

90% kidneys 10% liver

What are the steps for EPO production?

Renal hypoxia => increased tissue HIF-1 - transcription factor for hypoxia-inducible genes HIF-1 binds hypoxia response element in EPO gene, inducing transcription and EPO synthesis

How can non-renal hypoxia stimulate RBC production?

Norepinephrine, epinephrine and several prostaglandins stimulate EPO production

How does EPO increase RBC count?

Stimulates production of pro erythroblasts from stem cells, and increases rate of maturation

What is needed for final maturation of RBCs?

Vitamin B12 and folic acid

What molecules are needed for haemoglobin formation? Describe the steps

2 x succinyl-CoA (from Kreb's cycle) 2 x glycine Combine to form pyrrole 4 x pyrrole combine => protoporphyrin IX Combines with Fe => heme Heme combines with globin

How many oxygen molecules can one haemoglobin molecule bind?

Describe iron transport and metabolism

pg 444, F 33-7

How and where is iron absorbed?

All of small intestine Liver secretes apotransferrin in bile - combines => transferrin Complex absorbed by pinocytosis

How do the lysosomes of macrophages and neutrophils differ?

Macrophage lysosomes contain lipases - capable of digesting thick lipid membranes

What cytokines play dominant roles in the control of the macrophage response to inflammation?

TNF, IL-1, GM-CSF, C-CSF, M-CSF

What are the components of the innate immune system?

Phagocytosis Destruction of swallowed organisms by stomach acid/digestive secretions The skin Presence of lysozyme, basic polypeptides, complement and NK lymphocytes in the blood

What are the requirements for a substance to be antigenic?

Large molecular weight Must have regularly recurring molecular groups - epitopes

Where are lymphocytes processed?

T - thymus B - liver then bone marrow

Where is IL-1 produced and what is it's role?

Macrophages Promotes growth and reproduction of lymphocytes

Which antibody class is associated with the primary response to an antigen?

IgM

What component of the complement cascade activates phagocytosis?

C3b

What complement factors are responsible for lysis of invading organisms?

C5b6789

What complement factors are responsible for initiating chemotaxis of neutrophils and macrophages?

C5a

What complement components activate mast cells and basophils?

C3a, C$a abd C5a

What are the 7 effects of the compliment cascade?

1 - opsonisation and phagocytosis 2 - lysis 3 - agglutination 4 - neutralisation 5 - chemotaxis 6 - mast cell/basophil activation 7 - inflammation

What are the 3 major types of antigen presenting cells? Which cells respond to them?

Macrophages, B lymphocytes and dendritic cells T lymphocytes

How do APCs present antigen?

On MHCs

What are the two types of MHC and what id their purpose?

MHC I - present to cytotoxic T cells MHC II - present to T-helper cells

What are the most numerous T cells?

T helper cells

What T cell is CD4+?

T helper cell

What lymphokine stimulates growth and proliferation of cytotoxic and regulatory T cells?

IL-2

Which lymphokines stimulate the B-cell response?

IL-4, 5 and 6

What T cell is CD8+?

Cytotoxic T cell

How to cytotoxic T cells exert their effect?

Secrete hole-forming proteins - perforins Release cytotoxic substances into the attacked cell

What are the mechanisms causing vascular constriction after trauma to a blood vessel?

Local myogenic spasm Local autacoid factors (including thromboxane A2 from platelets Nervous reflexes

What is found in the platelet cytoplasm?

1 - actin, myosin and thrombosthenin 2 - ER and Golgi apparatus 3 - mitochondria 4 - enzyme systems for prostaglandin synthesis 5 - fibrin-stabilising factor 6 - growth factor

What components make up the platelet surface membrane? What are their function?

Glycoproteins - repulse adherence to normal endothelium but adhere to injured areas Phospholipids - role in activating clotting

What is the half life of a circulating platelet?

8-12 days

What happens to platelets following contact with a damaged vascular surface?

Swell and assume irregular form with multiple protruding pseudopods Contractile proteins contract and release granules Become 'sticky' - adhere to collagen and vWF Secrete ADP, PAF and thromboxane-A2

What are the possible sequelae following blood clot formation?

Invasion by fibroblasts and connective tissue formation Dissolution

What are the three essential steps to clotting?

Following vessel damage there is a cascade of chemical reactions, resulting in the formation of prothrombin activator This catalyses the conversion of prothrombin to thrombin This converts fibrinogen into fibrin

What is factor I?

Fibrinogen

What is factor II?

Prothrombin

What is factor III?

Tissue factor

What is factor IV?

Calcium

Where is prothrombin formed?

Liver

Where is fibrinogen formed?

Liver

What activates fibrin stabilising factor?

Thrombin

Briefly describe the extrinsic pathway

Tissue factor (FIII) released from traumatised tissue Complexes with FVII, in the presence of calcium activated FX Xa complexes with V to form prothrombin activator

Briefly describe the intrinsic pathway

Blood trauma causes activation of FXII and release of platelet phospholipids Activates FXI Activates FIX Activates FX (alongside FVIII, FIII and platelet phospholipids)

What is needed for the activation of FXI?

FXIIa High-molecular weight kininogen Accelerated by prekallikrein

Which steps of the coagulation cascade are dependent on calcium?

All except first 2 steps of intrinsic pathway

Which clotting pathway is fastest?

Extrinsic

What factors prevent blood clotting in the normal vascular system?

Endothelial factors 1 - smoothness of endothelial cell surface 2 - layer of glycocalyx on the endothelium 3 - thrombomodulin - binds thrombin 4 - production of prostacyclin and NO by norma intact endothelial cells Blood-based factors Fibrin fibres ATIII Heparin (not normally significant)

What is heparin's action?

Binds to ATIII and increases activity 100-1000x Removes thrombin and FIX-XIIa

What are the vitamin K-dependent factors?

II, VII, IX, X, protein C

Where is vita normally produced?

Intestine

How does liver disease cause vit K deficiency?

Lack of bile prevents adequate fat digestion and depresses vitK absorption