Blood Tissue – White Blood Cells

Blood Tissue – White Blood Cells

Blood tissue is a special type of connective tissue that plays a vital role in the body. It consists of three main components: red blood cells, white blood cells, and plasma.

Red Blood Cells:

• They are spherical, biconcave, and approximately 7.5 ym in diameter.

• They stack on top of each other in blood vessels when observed under X250 magnification.

• Their biconcave shape can be clearly seen under X3000 magnification.

• They move passively with the blood flow.

• The blood viscosity of sickle cell red blood cells is higher than normal.

White Blood Cells:

• They are nucleated cells that move actively in the blood.

• They account for approximately 1% of the total blood cells.

• There are many types with different functions:

• Neutrophils (60-70%):

• Nucleus with 2-5 lobes, cytoplasm with small granules.

• Movement by pseudopodia.

• Phagocytize bacteria and cellular debris.

• Increase in acute inflammation.

• After death, they are phagocytized by macrophages.

• Monocytes (3-8%):

• Kidney-shaped, horseshoe-shaped, or U-shaped nucleus.

• Precursors of macrophages.

• Increase in chronic inflammation.

• Lymphocytes (20-25%):

• Large nucleus, occupying almost the entire cell.

• Size similar to red blood cells.

• Divided into two types: T lymphocytes (cell-mediated immunity) and B lymphocytes (humoral immunity).

• B lymphocytes not involved in humoral immunity need to differentiate into plasma cells.

• Increase in chronic inflammation.

• Basophils (0.5-1%):

• 2-lobed nucleus, dense cytoplasm, nucleus is difficult to see.

• Eosinophils (2-4%):

• 2-lobed nucleus, cytoplasm stains pink.

Platelets:

• They are fragments of megakaryocytes.

• They move by extending cytoplasmic processes through the blood vessels.

• They function in hemostasis and blood clotting.

Plasma:

• It is the liquid part of the blood.

• Serum is plasma without protein.

Macrophages:

• They are large phagocytic cells derived from monocytes.

• They phagocytize bacteria, cellular debris, and dead cells.

• There are different types depending on location:

• Lungs: Dust cells

• Liver: Kupffer cells

• Brain: Microglia

• Bone: Osteoclasts

Note:

• White blood cells have the ability to move actively through blood vessels.

• Immune cells play a crucial role in protecting the body from disease.

• Understanding the structure and function of the components in blood tissue helps us better understand our own health.