Erythrocytes

Question 1

What kind of erythrocyte is this

Answer 1

Dog:

Uniform size

Central pallor (concave)

Question 2

What kind of erythrocyte is this

Answer 2

Cat:

Smaller

Anisocytosis (variation in size)

Scarce central pallor (less concave)

Question 3

What kind of erythrocyte is this

Answer 3

Horse:

Rouleaux formation (clustering of RBCs in standing blood)

Not strong attachment but strong impact on sedimentation time (shorter)

Question 4

What kind of erythrocyte is this

Answer 4

Ruminant:

Crenation (silky appearance)

Variation in size

Question 5

What kind of erythrocyte is this

Answer 5

Camelid:

Ellipsoid

Question 6

How does haemoglobin binding work

Answer 6

In regions of high oxygen concentration (lung) globin releases CO2 & iron binds to O2 (oxyhaemoglobin)

In regions of low oxygen concentration, O2 is released & CO2 bound (carbaminohaemoglobin)

Question 7

What is erythropoiesis

Answer 7

Continuous process of replenishment

Occurs in red bone marrow & spleen

Formation of erythrocytes requires adequate amounts of:
Protein, iron, copper, folic acid & vitamins

Question 8

What is erythropoietin and where is it sourced from

Answer 8

Hormone that controls rate of erythrocyte production

Used for doping in horse racing

Source:
Embryonic life
Yolk sac, liver, kidney, spleen & bone marrow

Adult life
Kidney

Question 9

Label the erythrocyte production diagram

Answer 9

Question 10

Describe erythrocyte breakdown

Answer 10

As they age:
Lose sialic acid residues from their surface
Exposes galactose moieties that induce their phagocytosis
Become more fragile
May become swollen due to failure of normal membrane function

Normal lifespan in dogs = 120 days

Transfused lifespan much shorter (21 days)

Question 11

Describe iron metabolism

Answer 11

Free iron is toxic to cells as it acts as catalyst in formation of free radicals from reactive oxygen species

Question 12

What is PCV

Answer 12

Packed cell volume (PCV):

Measure of volume occupied by red blood cells in given volume of blood

Expressed as percentage

Question 13

What is hematocrit

Answer 13

Volume of red blood cells as percentage of total blood volume

Question 14

What is total RBC count

Answer 14

Absolute number of RBC in given volume of blood

Provides information about oxygen carrying capacity of blood

Question 15

What is haemoglobin concentration

Answer 15

Measures amount of haemoglobin in given volume of blood

Expressed as g/dl or g/L of blood

Reflects oxygen carrying capacity of blood

Important indicator of anemia

Question 16

Label parts of microhaematocrit

Answer 16

Question 17

What are the different microhaematocrits showing

Answer 17

Question 18

What is MCV

Answer 18

Mean cell volume (MCV)

Average volume or size of RBC

MCV = PCV/ total RBC count

Used to classify RBC into categories based on their size to diagnose anemias
Microcytic (small), normocytic (normal), macrocytic (large)

Question 19

What is MCH

Answer 19

Mean corpuscular hemoglobin (MCH)

Average amount of hemoglobin in single RBC

MCH = total hemoglobin/total RBC count

Helps evaluate type of anemia & classify RBC as hypochromic (low hemoglobin) or normochromic (normal hemoglobin)

Question 20

What is MCHC

Answer 20

Mean corpuscular hemoglobin concentration (MCHC)

Average concentration of hemoglobin in RBC

MCHC = (total hemoglobin/PCV) x 100

Question 21

What is anemia

Answer 21

Condition in which capacity of blood to transport oxygen is reduced

Reduced number of circulating erythrocytes

Reduced amount of hemoglobin per erythrocyte

Defined by 3 basic variables
Total hemoglobin
PCV/haematocrit
RBC count