Ch3 Erythrocyte

Structure of Erythrocytes

• membrane and associated proteins

• hemoglobin

• enzymatic pathways

• size and shapes

• species variations

• reticulocytes

Erythrocyte membrane

• lipid bi-layer

  • glycolipids (glycoproteins)

  • cholesterol (phospholipids)

  • cytoskeleton (inner)

Cytoskeleton helps to maintain

structure of the cell

Cholesterol helps the membrane to what?

be flexible

Lipid layer alterations are one cause of?

erythrocyte shape changes

• poikiloacytosis

Skeletal membrane proteins

• lattice on inner membrane

• important roles

  • membrane shape

  • deformability

  • durability

Most common erythrocyte shapes in mammals:

discocyte or bi-concave disc

Exception to mammal RBC shape?

camelid

• oval shaped

In-vitro artifacts: pigs

echinocytes (regularly spaced spiny projections

In-vitro artifacts: young ruminants and goat breeds

poikilocytes (variable shapes)

In-vitro artifacts: Deer

depanocytes (sickle shaped)

Non-mammalian RBC

nucleated

Drepanocytes

• fusiform or spindle-shaped (sickle cells)

• cervidae family

• some normal angora goats

How do drepanocytes form?

hemoglobin polymerization in vitro

• increase in oxygen tension

  • increase in pH

MCV

• measured by automated blood analyzers

  • highly variable across species

MCV is inverse with what value?

RBC count

Birds tend to have a larger MCV due to?

nucleated cells

RBC antigens

• molecule or substance that triggers antibody production

RBC membrane contains

• glycolipids

  • intergral membrane proteins

Animals receiving a blood transfusion may be at risk for a transfusion if?

they received or previously received blood from a donor with a different blood type

RBC Antigen: Horses

A and Q factors

RBC Antigen: Dogs

• DEA-1

• rarely DEA-4

• Dal

RBC Antigen: Cats

• AB group

• Mik group

Most species don’t form anti-erythrocyte antibodies until?

after the 1st transfusion or other exposure to foreign blood

What is the exception to the RBC antibody rule?

cats

• needs to be correct the 1st time

Blood group in cats?

AB

Type B cat

• antigen B on RBC/no antigen A

• high amounts of strong anti-A antibodies in plasma

Type A RBC to Type B cat

severe transfusion (can be fatal)

Type A cat

• antigen A on RBC, no antigen B

  • weak anti-B antibodies in plasma

Type B RBC to Type A cat

not useful, typically not fatal

RBC associations

individualized due to negative surface charge

• zeta potential

Rouleaux

• coin stack appearance of EBC

  • decreased or marked surface charge

What animals is Rouleaux normal in?

cats and horses

What does Rouleaux mean in other animals?

increase in plasma proteins

Agglutination

• meshwork

• grape like RBC clusters

  • stuck together antibodies

Agglutination is

pathologic

Agglutination is dangerous bc

• create meshwork and all the antigens are stuck together

  • ex: type A cat getting type B blood

Polychromatophils

• more purple on the stain means more immature RBC (just coming out of marrow)

  • romanowsky stain imparts blue/purple color due to an increase in RNA content

Dried blood film is fixed and stained using

Eosin stain anf Giemsa stain

Eosin stain

• pink orange

  • attracted to substance with basic pH

Giemsa stain

• attracted to substance with acidic

Reticulocytes

• immature eyrotrocytes

• still have rough ER

• can use automated or manual

Reticulocytes

• used New methylene blue (NMB) to stain

• aggregate of basophilic material inside RBC

Aggregate reticulocyte in cat

large RNA clumps

• only count these bc they’re only alive for 24 hours

Punctate reticulocyte in cat

scatted, individual, pin-point RNA

• don’t count these because their alive for over a week

What species does not release reticulocytes into peripheral blood, even in anemia?

Horses

What is the average life span of erythrocytes in mammals?

• related to body weight

• 2-5 months in domestic

How are erythrocytes cleared from circulation?

macrophage scavenger receptors

• recognize and bind to damaged erythrocytes

What waste product is produced from erythrocyte breakdown and how is it eliminated?

Pophyrin ring and it is converted into biliverdin → bilirubin → transported to lover for excertion in bile

• bilirubin circulates the blod bound to albumin

Hyperbilirubinemia

increases with liver disease or rapid/severe erythrocyte destruction