Blood

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Histology (Anatomy 115) UCSF School of Pharmacy

2007

Gail Martin

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BLOOD

Fluid that circulates through the heart, arteries, capillaries, and veins;

chief means of transport within the body

Be able to describe:

• the cellular components of normal human peripheral blood (erythrocytes, leukocytes, and thrombocytes)

Size and shape of nucleus in leukocytes Types and function of cytoplasmic granules

• the function(s) of each of these cells as well as their site(s) of origin

• the principal nuclear and cytoplasmic changes that occur during erythropoiesis and granulocytopoiesis

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Blood

Centrifuge

hematocrit

• ~ 90% H20

• ~ 7% proteins

• (albumin, globulins, prothrombin, fibrinogen)

• ~ 1% inorganic salts

• ~ 2% organic compounds

• (amino acids, vitamins, hormones, lipoproteins) 3

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Erythrocytes (Red blood cells) Leukocytes (White blood cells)

Cells in Blood

Thrombocytes (Platelets)

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Erythrocytes

Carry O

₂

and CO

₂

• 7.5 micron diameter

• No nucleus or organelles;

lots of hemoglobin

• Biconcave disc

• large surface to volume ratio: efficient gas

exchange

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Sickle Cell Anemia

Normal RBC Normal RBC

Fig. 12-3 Fig. 12-3 Sickle RBC

Sickle RBC

Fig. 12-4 Fig. 12-4 6

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Leukocytes Leukocytes Leukocytes

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Neutrophilic

Neutrophilic granulocytegranulocyte Eosinophilic Eosinophilic granulocytegranulocyte

Basophilic granulocyte

Basophilic granulocyte LymphocyteLymphocyte

Monocyte

Monocyte MonocyteMonocyte ^{Fig. 12-5}^{Fig. 12-5}

Leukocytes

(White Blood Cells)

• • Granulocytes Granulocytes

• • Neutrophils Neutrophils

• • Eosinophils Eosinophils

• • Basophils Basophils

• • Agranulocytes Agranulocytes

• • Lymphocytes Lymphocytes

• • Monocytes Monocytes

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Granulocytes

(specific and azurophilic granules)

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Neutrophils

First line of defense against microorganisms

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Digestion

(lysozymal enzymes in azurophilic granules) Phagocytosis

Killing

(bactericial agents in specific granules)

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Neutrophils

•

60 - 70% of circulating leukocytes

Fig. 12-6 Fig. 12-6

•

Nucleus: 2-5 lobes ^{Fig. 12-7}^{Fig. 12-7}

Specific granules

Azurophilic granules

•

2 types cytoplasmic granules

specific: contain lactoferrin, lysozyme, bactericidal agents

azurophilic: contain lysosomal enzymes (myeloperoxidase, lysozyme, etc.)

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Fig. 12-8 Fig. 12-8

•

2-4% of circulating leukocytes

•

Bilobed nucleus

Eosinophils

defense against parasites; modulation of inflammatory processes

Fig. 12-10 Fig. 12-10

•

eosinophilic specific granules containing:

•

major basic protein (toxic to parasitic larvae),

•

lysosomal enzymes, peroxidase, histaminase

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Fig. 12-12 Fig. 12-12

basophilic granules:

contain heparin and histamine

Fig. 12-13 Fig. 12-13

•

< 1 % of circulating leukocytes

•

Nucleus irregular lobes

Basophils

release histamine and other inflammation mediators

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Agranulocytes

(azurophilic granules)

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Fig. 12-16 Fig. 12-16 Fig. 12-15

Fig. 12-15 Small lymphocytes

•

~30 % of circulating leukocytes

•

Round, densely stained nucleus; little cytoplasm

Lymphocytes

Immunological defense mechanisms

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Fig. 12-17 Fig. 12-17

Monocytes

Defense mechanisms (progenitors of macrophages)

•

5 % of circulating leukocytes

•

indented folded nucleus

Fig. 12-18 Fig. 12-18

Opaque, slightly basophilic cytoplasm;

fine azurophilic granules

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Thrombocytes (Platelets)

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Platelets

promote blood clotting, help repair gaps in blood vessel walls

Fragments of megakaryocytes;

no nucleus

Numerous cytoplasmic organelles

Fig. 12-19 Fig. 12-19 18

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Diapedesis

Neutrophils die in the process of combatting infections

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Hematopoiesis

generation of new blood cells

• Bone Marrow

• Erythropoiesis

• Granulopoiesis

• Monocytopoiesis

• Megakaryocytopoiesis

• Lymphoid organs

• Lymphocyte production

self-renewal 20

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Hematopoiesis

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Erythrocyte Maturation

hemoglobin synthesis:

numerous free ribosomes

increasing hemoglobin, decreasing ribosomes, decreasing nuclear activity

nucleus extruded

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Granulocyte Maturation

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