Week 3

Question 1

What elements are required for erythropoiesis to occur?

Answer 1

Protein, iron, copper, folic acid and vitamin B12.

Question 2

Describe species differences of erythrocytes:

Answer 2

Dog- normal, central pallor.
Cat- smaller, anisocytosis( size variation) scarce central pallor.
Horse- clustering.
Camelid- ellipsoid.
Avian and reptile- nucleated, larger.

Question 3

Outline the source and effect of erythropoietin.

Answer 3

It controls rate of erythrocyte production. Early life, it’s expressed in yolk sac, liver and kidney. Adult, in kidney. If there’s low kidney O2, then EPO is transported by blood to bone marrow which accelerates reticulocyte release.

Question 4

Outline the removal and breakdown of erythrocytes:

Answer 4

As RBC’s age, they lose silica acid residues from their surface which exposes galactose moieties to induce phagocytosis. This occurs in the liver.

Question 5

Describe the metabolism of iron in the body:

Answer 5

Free iron is toxic as in induces free radical formation. Iron molecules released from haem are conveyed to bone marrow by transferrin or stored as insoluble iron in macrophages and hepatocytes.

Question 6

Compare PCV, haematochrit, total RBC count and haemoglobin concentration:

Answer 6

PCV: packed cell volume- fraction of whole blood volume that consists of RBC’s.
Haematochrit: % RBCs by total blood volume.
Total RBC count: blood cell population absolute no. per litre.
Haemoglobin concentration: MCHC, dividing haemoglobin by haematochrit.

Question 7

Explain MCV, MCH, MCHC:

Answer 7

MCV: mean corpuscular volume meaning the average volume of RBCs.
MCH: mean corpuscular haemoglobin: meaning average haemoglobin concentration.
MCHC: mean corpuscular haemoglobin concentration meaning average haemoglobin concentration in cells relative to size/volume.

Question 8

How can you interpret cell size( MCV), haemoglobin content( MCHC) and reticulocyte count?

Answer 8

MCV- microcytic, normochromic, microcytic.
MCHC- hypo chromic, normochromic.
Reticulocyte count- Regenerative or non-regenerative.

Question 9

Differentiate between the blood groups of dogs, cats and horses:

Answer 9

Dogs: either DEA1.1 negative or positive. Other blood types include DEA3 to 8 and dalmatians have their own blood type of DAL.
Cats: have A, B and AB. AB has no alloantibodies so is a UR. If the b cats receive type a blood- death.
Horses: 7 blood groups: A,C,D,K,P,Q and U. Aa,Qa and Ca are the most immunogenic.

Question 10

What are 3 ways blood group compatibility can be tested?

Answer 10

Blood typing: detects antigen pattern on erythrocyte surface using polyclonal/monoclonal antisera. for example, determines if dog is DEA1.1 pos or neg.
Blood typing cards: antibodies are embedded in paper that causes agglutination.
Blood cross-matching: assess blood group compatibility between donor and recipient.

Question 11

What is the transfusion rule of thumb and donor criteria?

Answer 11

• transfuse 2ml whole blood/kg body weight raises PCV by 1%*
• between 1-8 years old
• good temperament
• never travelled abroad
• good PCV
• vaccinated and wormed
• no previous pregnancies

Question 12

Describe the 3 steps of blood clotting:

Answer 12

1) Formation of prothrombinase:
Intrinsic- blood in contact with foreign surface.
Extrinsic- blood in contact with tissue.
2) Prothrombin converted into thrombin enzyme
3) Fibrinogen converted into insoluble fibrin.

Question 13

What occurs in primary, secondary and tertiary haemostats?

Answer 13

1”- blood vessel endothelium damage and platelets bind to von willebrand factor on endothelium. Platelet plug is formed.
2”- strengthening and reinforcement of pp and formation of fibrin clot.
3”- Fibrin clot removal- plasmin breaks down fibrin to fibrinogen.