Blood

BloodBlood

is a Connective Tissue

The Cells of Blood are Called “Formed Elements”

Agranulocytes

Monocytes Cells divide and differentiate Lymphocytes .

Granulocytes Neutrophils

Acidophils Terminally differentiated Basophils .

Erythrocytes No organelles .

Platelets Cell fragments .

The Hematocrit.

Left: Tubes with blood before centrifugation. Right: After centrifugation. The erythrocytes represent 43% of the blood volume in the centrifuged tube. Between the sedimented erythrocytes and the supernatant light-colored plasma is a thin layer of leukocytes called the buffy coat.

The Erythrocyte or Red Blood Cell

Erythrocytes

99.5% of the formed elements of blood.

Biconcave disks 7.5u in diameter.

Lack cell nucleus, other organelles, RNA .

Have a specialized cell membraneHave enzymes to produce ATP and NADPH

Circulate for 120 days.

The Leukocytes or white blood cells

Granulocytes Neutrophils Acidophils Basophils

Agranulocytes Monocytes Lymphocytes

Neutrophils

60% of leukocytes

Multilobed nucleus

Very small specific granules

Phagocyte for bacteria

3 Days

4 Days

4 Days

6-7 Hours

1-4 DaysCONNECTIVE TISSUE

“Band Cell”

Acidophil = Eosinophil

~5% of Leukocytes

Bi-lobed nucleus

Large granules (~1um)

Functions in allergies and worm infections

Basophils

< 1% of leukocytes

Elongated S-shaped nuclei

Large heterogeneous, basophilic granules

Secrete histamine and heparin

Monocytes

5% of leukocytes

Pale irregular nucleus

Largest of the leukocytes

Precursors to macrophages

Not phagocytic in blood

Main Functions of Macrophages

1. Ingest bacteria and cellular debris

2. Secrete various chemical messengers

3. Coordinate cell activities in inflammation and wound healing

4. Remove aged red blood cells

5. Roles in antibody formation

Diversity of

Macrophages

The Mononuclear Phagocyte SystemMPS

Includes monocytes and all cells that come from them.Examples: histiocytes of C.T. Kupffer cells of liver

microglia of brain alveolar macrophages

Excludes unrelated phagocytic cells that do not come from monocytes.Examples: neutrophils, Sertoli cells, mesangeal cells

Contrariwise if it was so it might be and if it were so it would be. But as it

isn’t it ain’t. That’s logic.

….and that’s the reticuloendothelial system.

Tweedledee told Alice in Alice in through the looking glass

Lymphocytes

constitute about 30% of leukocytes.

have a small dense round nucleus and a small rim of cytoplasm.

can divide and differentiate.

Small Medium Large

Platelets

Platelet

Cytological Structures in Platelets

Structural components microtubules, actin, myosinGranules alpha, delta, lambdaMembranes systems plasmalema, open canalicular system, dense tubular system

Functions of Platelets

Primary aggregationSecondary aggregationBlood coagulationClot retractionClot removal

All Done