RBC - Morphology

Question 1

RBC

Answer 1

in most species have a round, bi-concave shape

Thinner in the middle than at the edge → central pallor

Question 2

Erythrocyte Color

Answer 2

Young RBCs

Released early

usually larger and more blue/purple from RNA

Presence/absence of polychromatophils is important in determining if anemai is regenerative or nonregenerative

Horses are unique, they do typically no relaese polychromatophilic cells in the face of anemia

Question 3

Rubricytosis

Answer 3

AKA, Nucleated red cells

Significance:

• regenerative anemia:
  
  • appropriate rubricytosis
  • Blood loss or hemolysis
• Nonregenerative anemia:
  
  • inappropriate rubricytosis
  • marrow damage - inflammation, necorsis, etc.
  • Lead poisoning in dogs
  • Extramedullary hematopoiesis, splenic contraction, splenectomy
    *

Question 4

Anisocytosis (variation in sizes)

Answer 4

significance depends on reason for vairiation of size

Macrocytes

Microcytes: decreased volume, hypochromic

Spherocytes: normal volume, decrease amount of membrane

Erythrocyte size is best determined by measuring the MCV

Question 5

Macrocyte

Answer 5

incomplete maturation or skipped cell division

• significance:
  
  • usually means increased erythropoiesis
    
    • release larger immature cells
  • Increased MCV with anisocytosis due to macrocytosis is the best evidence of increased erythropoiesis and bone marrow response to anemia in equine CBC

Increased diameter, and Volume

Question 6

Microcyte

Answer 6

increased cell divisions during development and decreased volume

• Potential causes:
  
  • iron deficiency
  • hepatic unsufficiency
  • Greed vairation

Question 7

Spherocyte

Answer 7

lack of central pallor together with the apparent hyperchromasia are characteristic

Question 8

Changes in Central Pallor

Answer 8

Question 9

Poikilocytosis

Answer 9

Variation in shape

significance depends on shape

Question 10

Echinocyte

Answer 10

often regularly spaces projections

Artifact - cell dehydration

envenomation

Other diseases but not consistently

Question 11

Acanthocytes

Answer 11

Irregularly spaced projections

altered lipid metabolism

Liver disease in cats

Hemangiosarcoma in dogs

Question 12

Shistocytes

Answer 12

RBC that is lysed by a fibrin strand in the artery/vein. The lysed fragment is the shistocyte

Question 13

Codocytes

Answer 13

Target Cells

Central focus of Hgb surrounded by ring of pallor

Formation: excess membrane relative to amount of Hgb

Question 14

Heinz bodies

Answer 14

indicative oxidative damage

Large, membrane bound affrefates of denatured hemoglobin

Question 15

Eccentrocytes

Answer 15

fused, unstained, cresent-shaped region of membrane, with a shift of hemoglobin to the opposite side

Hallmark of severe oxidative damage

Question 16

pyknocytes

Answer 16

Not sperocytes

different pathophysiology

Loss of fused membrane portion of eccentrocyte

Question 17

Basophilic Stippling

Answer 17

Formation: ribosomal RNA not degraded

Signifinance: Regenerative anemia

Lead poisoning

Question 18

Howell-Jolly bodies

Answer 18

Nuclear remnant

Significance: low numbers in health

Regenerative anemia

Most important thing is to not call these parasites

Question 19

Rouleaux

Answer 19

1 drop blood + 9 drops saline

Charge attraction - nonspecific sign on inflammation

Except in horses, where this is normal

Question 20

Agglutination

Answer 20

1 drop blood + 9 drops saline

Antibody-related cell bridging

Used to diagnose Immune Mediated hemolytic Anemia

Question 21

RBC Physiology:

Function

Answer 21

primary function of RBC is to carry O2 from the lungs to the tissue.

RBCs also transport CO2 from the tissue to the lungs and buffer H+

Question 22

RBC physiology:

Flexibility

Answer 22

in part due to the flexible membrane and shedding of the nucleus

Question 23

RBC physiology:

Strength

Answer 23

stong but flexible membrane able to withstand recurrent shear forces involved in blood circulation

Question 24

RBC physiology

Shape

Answer 24

biconcavity allows for increased surface are for gas exchange

Question 25

RBC physiology

Hemoglobin content

Answer 25

unique to the RBC, hemoglobin is pivotal to the development and oxygen transport ability due to its affinity for oxygen

Question 26

RBC physiology:

Lifespan

Answer 26

because the mature RBC has no nucleus, the cell cannot divide or repair itself. The lifespan is therefore relatively short and varies between species

Question 27

RBC deformability, structure, and Strength

Answer 27

Ability to change shape in response to stress and to recover once the stress is removed

• Deformity is dependent on:
  
  • structure of the membrane and cytoskeleton
  • High surface area to volume ratio
  • Low viscosity cytoplasm

Alterations in the lipid or protein composition of the membrane may result in abnormal red-cell shape

Deformability allows RBCs to move through the circulation without loss of structural integrity and is a major determinant of blood viscosity

Question 28

Erythropoeiesis

Answer 28

Is a complex process that occurs in the bone marrow. before a RBC arrives in the blood stream, it must develop from a stem cell and progress through a number of stages

Most effective in bone marrow

Tissue oxygenation is the main regulator

renal peritubular interstitial cells produce erythropoietin in response to renal hypoxia

anemia

poor oxyfenation of blood

poor renal perfusion

Question 29

High erythropoeitin

Answer 29

erythroid hyperplasia

shortened erythroid maturation time

increased hemoglobin synthesis in dividing cells

Decreased apoptosis of progenitor cells in the bone marrow

Accelerated release of reticulocytes from marrow

Question 30

Erythoproietin low

Answer 30

RBC production < RBC loss

Gradual onset of anemia

Causes: decreased function of renal tissue, and inflammation