Histology - Blood Formed Elements

what are the 2 components of blood?

• ECM (plasma) containing albumin, globulin, fibrinogen

• cell/cell gradments

  • red blood cells (erythrocytes)

  • white blood cells (leukocytes)

  • platelets (cell fragments)

b) a low level of hematocrit indicates anemia

c) arrow indicates where platelets are

what is the volume of packed erythrocytes in a sample of blood called?

hematocrit

t/f: males generally have higher levels of red blood cells compared to females

true (Male, 42-52%, female, 37-47%)

what is it called when red blood cell levels are too high? too low?

too high: polycythemia, too low: anemia

how to view blood cells? (why not just place a glass plate directly on top of a drop of blood?)

blood smear

• avoid breaking red blood cells

what type of staining can be done to differentiate different cells in a blood smear?

Romanowsky staining (mixture of acidic and basic dyes)

what components of blood demonstrate orthocrhomasia - red?

Erythrocytes, eosinophil granules

(stained only with acidic dye)

what components of blood demonstrate orthochromasia - gray blue or blue?

cytoplasm of monocyte

(stained only with basic dye)

what components of blood demonstrate metachromasia - violet purple?

Basophil granules

(color shift from certain basic dye from blue to violet purple)

what components of blood demonstrate polychromasia - purple?

• Azurophilic granules

• Neutrophil granules

• Chromatin (nucleus)

• Platelets

(layered with both basic and acidic dyes)

Metachromasia can happen with only certain basic dyes such as…?

toluidine blue, methylene blue

Metachromasia can happen any cell or tissues with abundant positive/negative charges: such as …?

negative

cartilage, mast cells

how does metachromasia happen in Romanowsky staining?

Polyion presence: when stained with a concentrated basic dye, the dye molecules are sufficiently close to form dimeric and polymeric aggregates---causing a shift in absorption properties

how does polychromasia happen in Romanowsky staining?

• basic dye binds to cellular structures first

• the acidic dye then binds to form a purple staining

______ is important in polychromasia in Romanowsky staining

timing

how many dyes are involved in ortho and meta-chromasia? polychromasia?

Ortho- and meta-chromasia involve only 1 dye; polychromasia involves 2 dyes

D

A

erythrocytes

what is the function of the biconcave disc shape of erythrocytes?

increasing surface area

what is the lifespan of erythrocytes?

120 days

diameter of RBC?

7.5 micrometers

what are the predecessors of red blood cells? (immature RBCs?)

reticulocytes (contains remaining cell organelles so will stain basophilic → polychromasia)

mature erythrocytes demonstrate what kind of staining?

orthochromasia

what is crenation?

RBC in hypertonic solution → spiky membrane

what is sickle cell anemia?

• mutation in hemoglobin (Glu → Val)

• distorts normal appearance to form sickle-like shape

• cannot get through blood vessels easily

sicle cell anemia is resistant to…?

malaria

(low oxygen → aggregate → premature rupture → parasite unable to reproduce)

Rouleaux formation (stacks of RBCs)

old and diseased RBCs are usually cleared in the _____?

spleen

what is the distribution of leukocytes?

• neutrophils (50-70%) → most abundant

• lymphocytes (20-40%)

• monocytes (3-8%)

• eosinophils (2-4%)

• basophils (0.5-1%) → least abundant

what are the 2 major types of white blood cells?

1. granulocytes (Neutrophils, Eosinophils, Basophils)

2. Agranulocytes (Lymphocytes, Monocytes)

neutrophils (granulocytes)

what is the function of neutrophils?

phagocytic and bactericidal (attracted to chemokines)

characteristics of neutrophil structure

• Nucleus: 2-5 lobes (polychromatic)

• Granules: 3 types (polychromatic)

• barr-body (condensed inactivated X-chromosome)

• 10-12 micrometers

what are the 3 types of granules in neutrophils?

1. Azurophilic (lysosomes)

2. Specific (Bactericidal enzymes)

3. Anti-Bacteria factors, including those the prevent bacteria migration

characteristics of eosinophils structure

• nucleus?

• granules?

• other characteristics?

• nucleus: 2 lobes

• granules; orthochromatic

• crystalline body (eosinophil-specific protein that gives red color)

function of eosinophils

anti-parasitic, allergy

eosinophils

characteristics of basophils;

nucleus?
granules?

Nucleus:

• often 2 lobes (polychromatic)

  • often masked by large and abundant granules

Granules:

1. Specific: contain histamine, and are very rich in glycosaminoglycan, which gives intense stainings (Metachromasia)

2. Azurophilic (lysosomes)

function of basophils?

Participate in allergic and parasitic reactions

basophils

basophils

characteristics of lymphocytes

nucleus?
cytoplasm?

Nucleus: Spherical or oval (often occupying majority of cell)

Cytoplasm: thin (orthochromatic)

what are the 2 types of lymphocytes?

1. Small: B-cells, T-cells

2. Large: granular cells (natural killer cells)

lymphocytes

function of lymphocytes

Acquired immunity (cell-mediated defense; antibody production)

what are the types of granulocytes?

neutrophils, eosinophils, basophils

what are the types of agranulocytes?

lymphocytes, monocytes

what is convalescent Covid 19 treatment?

using B lymphocyte derived plasma cells (antibodies from someone who already had covid) to help treat infected person

lymphocytes

characteristics of monocytes:

nucleus?
cytoplasm?

Nucleus: Folded, U-shaped (kidney-bean shape)

Cytoplasm: mostly orthochromatic, with fine azurophilic granules

• overall large in cell type

function of monocytes?

Precursors for mononuclear phagocyte system

monocytes

monocytes

B

A

what are the largest peripheral blood cells?

monocytes

C

D

A

platelets contain 2 regions. what are they?

1. Central region: granulomere (darker staining), contains mitochondria, vacuoles, a-granules and glycogen

2. Peripheral region: pale staining, sends out fine cytoplasmic processes

what are the small (2-4um) membrane-bound cellular fragments (polychromatic)?

platelets (cell fragments)

function of cell fragments (platelets)?

Aggregation and agglutination; clotting

platelets

platelets

what is the formation of blood cells called?

hematopoesis

Cancer of early forming blood cells (usually white blood cells) is called?

leukemia

leukemia

D

C (mast cells not present in peripheral blood)

f